Synthesis and Characterization of Polylactic Acid/ Polymethyl Methacrylate/silica Biodegradable Nanocomposite

Synthesis and Characterization of Polylactic Acid/ Polymethyl Methacrylate/silica Biodegradable Nanocomposite | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synthesis and Characterization of Polylactic Acid/ Polymethyl Methacrylate/silica Biodegradable Nanocomposite Berrak Cansu Cilek Kocak, Ayla Altınten This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7409193/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Nov, 2025 Read the published version in Journal of Polymer Research → Version 1 posted 5 You are reading this latest preprint version Abstract In this study, biodegradable nanocomposites were developed by blending polylactic acid (PLA) with polymethyl methacrylate (PMMA) and incorporating stearic acid-modified silica nanoparticles (SiO₂) to enhance thermal and mechanical properties. PMMA was synthesized via emulsion polymerization. PLA/PMMA/SiO₂ nanocomposites were then prepared using in-situ and solution blending methods with varying PLA:PMMA ratios (30:70, 50:50, 70:30 wt%) and SiO₂ contents (0, 2, 5, 10 wt%). The nanocomposite surface morphology was analyzed using scanning electron microscopy (SEM) and light microscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize the thermal behavior, and mechanical properties were evaluated via Shore-D hardness test and tensile test. Biodegradability was assessed through both biodegradation and enzymatic degradation tests. For the biodegradation study, samples were buried in cactus and humus soil, monitoring weight loss as an indicator of biodegradability. Microscopic imaging was used to analyze the structural changes that occurred before and after soil exposure. The results showed that, in both degradation methods, higher SiO₂ content led to an increased weight loss percentage. The incorporation of SiO₂ accelerated the biodegradation of PLA. polymeric nanocomposites biodegradable polymers SiO2 PMMA PLA Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1. Introduction Due to recent advancements in today's rapidly developing technologies, there is a growing need for a class of materials that meet all the desired properties. As a result, to address the demand for such materials, researchers are increasingly focusing on sustainable alternatives that perform better and are environmentally friendly compared to traditional materials. Green advanced materials, such as polymeric materials, green functional textiles, biomaterials, composites, and nanomaterials, are among the fastest-growing technologies due to their excellent chemical, electrical, optical, and biological properties. These characteristics make them suitable for various fields of science and technology, including biomedical, water treatment, packaging, cosmetics, and textile industries. Biodegradable nanocomposite polymers play a significant role in the search for environmentally sustainable materials. These materials combine desirable properties such as biodegradability with enhanced mechanical and barrier properties provided by nanotechnology. Biodegradable nanocomposites are designed to naturally degrade through microorganisms in the environment, promoting a circular economy in material usage while reducing pollution. Reducing environmental impact is paramount in various sectors such as packaging, agriculture, and biomedical devices. Due to the increased demand for eco-friendly packaging and technological advancements, it has become possible to process biopolymers like petroleum-based plastics. The environmental pollution caused by petrochemical-based and non-biodegradable plastic packaging materials has heightened the need for biodegradable packaging materials, which can be developed using renewable natural biopolymers. PLA is an aliphatic and thermoplastic polyester derived from renewable resources such as corn starch or sugarcane. It has gained significant attention due to its biodegradability, biocompatibility, and non-toxicity to the human body and the environment [ 1 ]. However, it sometimes lacks the required mechanical strength and barrier properties for specific applications. Poly(methyl methacrylate) (PMMA) is a glassy and transparent polymer that exhibits excellent properties for the packaging industry, as well as optical and biomedical applications, due to its high strength, optical clarity, desired dimensional stability, and weather resistance [ 2 ]. PMMA, due to its high hardness, exhibits significant brittleness, which limits its potential application areas [ 3 ]. On the other hand, PMMA is a non-biodegradable polymer. Considering the environmental friendliness, blending PMMA with biodegradable PLA could reduce PMMA consumption [ 4 ]. Blending PLA with PMMA presents a compelling strategy to combine the desirable properties of both polymers—namely, the biodegradability of PLA and the mechanical robustness and transparency of PMMA—thereby improving overall performance while reducing the environmental footprint of PMMA-based products. Furthermore, incorporating nanoparticles such as silica (SiO₂) into these polymer blends has significantly enhanced thermal stability, mechanical strength, and overall material integrity. Silica nanoparticles, owing to their high surface area and functionalizable surfaces, interact with the polymer matrix, improving interfacial bonding and dispersion. This makes biodegradable nanocomposites an excellent option for packaging applications that require strength and durability while prioritizing post-use environmental degradation. Previous studies have demonstrated the potential of PLA/PMMA/SiO₂ nanocomposites for various high-performance applications. Wu et al. (2015) developed PLA/PMMA/SiO₂ composites using a twin-screw extrusion process. They proposed that such blends could serve as environmentally friendly alternatives to polycarbonate polymers, particularly in LED light mask applications. To improve the inherent brittleness of PLA, nanosilica particles were incorporated into the blend, along with a chain extender aimed at reducing hydrolysis during processing. They observed that the chain extender increased the final tensile strength of the PLA/PMMA/SiO 2 composites by approximately 43%. Including of 0.5 wt% nanosilica particles increased the elongation at break and Izod impact resistance by 287% and 163%, respectively, compared to neat PLA. Considering mechanical performance, they suggested that the optimal blend ratio could be between PLA/PMMA/SiO 2 (90/10) and PLA/PMMA/SiO 2 (80/20) [ 4 ]. Hao et al. (2016) investigated the effect of nanosilica content on PLA/PMMA (50/50) melt blends by incorporating varying concentrations of SiO₂ (0%, 2%, 5%, and 10% by weight). Differential scanning calorimetry (DSC) analyses revealed that the inclusion of nanosilica not only raised the glass transition temperature of the blends but also broadened the transition range, indicating improved thermal behavior [ 5 ]. In another study, Wang et al. (2009) employed a sol-gel approach to synthesize a degradable PLA/PMMA/SiO₂ hybrid electrolyte. The formulation involved PLA, methyl methacrylate (MMA), and tetraethoxysilane (TEOS), with 3-methacryloxypropyl trimethoxysilane acting as a coupling agent. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirmed covalent bonding among PLA, PMMA, and silica units, forming a hybrid network. According to DSC results, increasing the SiO₂ content enhanced the material's thermal resistance [ 6 ]. Palma-Ramírez et al. (2021) examined the impact of silica nanoparticles on the processability and compatibility of PLA–polypropylene (PP) blends produced via melt blending. They evaluated PP 95 (PLA-SiO 2 ) 5 , PP 90 (PLA-SiO 2 ) 10 , and PP 80 (PLA-SiO 2 ) 20 nanocomposites in terms of their thermal, structural, morphological, mechanical, and degradation properties, with particular attention to packaging applications. Their findings showed that SiO₂ addition increased the crystallinity of PLA from 10% to 77% and improved thermal stability depending on the nanoparticle content. However, the inclusion of silica also limited the mobility of PLA chains, promoting more viscous behavior. Furthermore, inorganic nanostructures influenced microstructure and thermal stability (evidenced by lower degradation temperatures), likely due to altered dipole–dipole interactions between organic components. Notably, enhanced interfacial compatibility and mechanical properties were observed in PP90(PLA-SiO₂)10 composites, attributed to the uniform dispersion and favorable interaction of 1 wt% SiO₂ within the polymer matrix [ 7 ]. The study aims to mitigate the natural deficiencies of the thermoplastic polymer PMMA by blending it with the biodegradable polymer PLA to achieve biodegradability, while enhancing its thermal and mechanical strength with SiO 2 nanoparticles. In this study, it is expected that the interaction between the ester groups in PMMA and the carbonyl groups with the hydroxyl groups on the SiO 2 surface will enhance the material's thermal stability throughout its service life. Additionally, due to the moisture retention property of silica, it is anticipated that the biodegradation of the PLA component in the structure will accelerate at the end of the product's lifecycle. This innovative combination highlights the potential of biodegradable nanocomposites to meet performance and environmental sustainability requirements. Such advancements significantly push progress in biomaterials and sustainable materials science, demonstrating the importance of ongoing research and innovation. The use of these materials could reduce the amount of plastic waste. PMMA polymer was synthesized by the emulsion polymerization method using methyl methacrylate (MMA) monomer, sodium dodecyl sulfate (SDS) as emulsifier, and potassium persulfate (KPS) as initiator. Before using SiO 2 , it was modified with stearic acid (SA). Subsequently, PLA/PMMA/SiO 2 nanocomposites were synthesized using in-situ and solution blending methods, with SiO 2 nanoparticles incorporated at ratios of 0, 2, 5, and 10 wt%, and PLA/PMMA was used at ratios of 30:70, 50:50, and 70:30 wt. After emulsion polymerization, the percentage monomer conversion and viscosity average molecular weights of the polymers were determined. The surface properties of the prepared nanocomposite materials were examined using scanning electron microscopy (SEM). Thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, the mechanical properties of the synthesized nanocomposites were investigated using the Shore-D hardness test and tensile test. For biodegradability analysis, biological and enzymatic degradation studies were conducted. For biological degradation, samples buried in cactus and humus soil were monitored for weight loss, and their structural integrity was examined before and after burial using microscopic imaging. The biological degradation was monitored for 6 months, with microscopic images taken at specific intervals, and weight loss percentages were calculated. For enzymatic degradation, phosphate buffer solution (pH = 7.4) and lipase enzyme derived from pig pancreas were used. The samples were observed in the prepared solution for 15 days, and weight loss percentages were calculated. This work underscores the potential of biodegradable nanocomposites as sustainable alternatives in packaging and biomedical fields, offering a promising route toward high-performance, eco-friendly materials. Although studies reinforcing PLA/PMMA blends with inorganic fillers are present in the literature, this work introduces several novel aspects. In this study, silica nanoparticles were modified with stearic acid and employed to enhance interfacial interactions within PLA/PMMA blends. Nanocomposites were prepared through both in situ and solution blending methods, enabling a direct comparison of processing techniques and composition ratios across a wide range of PLA:PMMA ratios and filler loadings. Most importantly, this work provides a comprehensive evaluation of biodegradability under two different soil conditions as well as enzymatic degradation, revealing that the modified silica not only accelerates environmental degradation but also simultaneously improves mechanical and thermal performance. This dual functionality highlights the potential of the developed nanocomposites as sustainable, high-performance materials. 2. Materials and Methods The experimental study was conducted with the synthesis of PMMA via emulsion polymerization, modification of silica, and the synthesis of PLA/PMMA/SiO 2 using in-situ and solution blending methods. Subsequently, the study continued with various analytical and characterization techniques to investigate the thermal, mechanical, and biodegradability properties of the synthesized nanocomposites. The chemicals used in the experimental process were as follows: Methyl methacrylate (Merck, > 99%), Potassium persulfate (Merck, 99%), Sodium dodecyl sulfate (Merck, 99%), Methanol (Isolab, > 99.8%), Silica (Sigma-Aldrich, 5–15 nm, 99.5%), Stearic acid (Merck, 99.5%), Isopropyl alcohol (Isolab, > 99.5%), Ethanol (Merck, > 99.9%), PLA (Total-Corbion, Luminy LX175), Tetrahydrofuran (Merck, 99.5%), N, N Dimethylformamide (Merck, 99.8%), Chloroform (Merck, 99.4%), Toluene (Sigma-Aldrich, > 99.5%), Phosphate buffer solution (Pluriselect, pH = 7.4). 2.1. Modification of SiO 2 Due to the natural hydrophilicity of silica nanoparticles, surface modification is required to achieve homogeneous dispersion within the polymer matrix. The surface modification of SiO 2 is performed to impart hydrophobic characteristics to the silica particles' surface. Without surface modification, the van der Waals intermolecular forces between the nanoparticles are so strong that the particles tend to agglomerate, leading to a non-homogeneous distribution within the polymer and weakening the polymer's properties. Fluorinated hydrocarbons or silanes are expensive for surface modification and are also hazardous to human and environmental health. Stearic acid, a type of fatty acid, is a non-toxic, hydrophobic, non-reactive, inexpensive, and environmentally friendly surface modification agent. One end of the stearic acid molecule is hydrophilic, while the other is hydrophobic. The hydrophobic tail adsorbs to the polymer, and the hydrophilic head adsorbs to the silica, thereby ensuring bonding between the nanoparticle and polymer without needing a chemical reaction [ 8 ]. In the modification process, a mixture containing 3 g of SiO 2 , 3 g of stearic acid (CH₃(CH₂)₁₆COOH), and 100 mL of isopropyl alcohol was first homogenized in an ultrasonic homogenizer for 15 minutes, then stirred at 75°C for 6 hours at 350 rpm in a reflux system. At the end of the process, the solution was filtered, washed several times with ethanol, and dried in a vacuum oven at 75°C for 2 hours. 2.2. PMMA Synthesis The experimental study began with the synthesis of PMMA from MMA via emulsion polymerization. Potassium persulfate (KPS) was used as an initiator at a 1:200 molar ratio to MMA. Sodium dodecyl sulfate (SDS) was used as the emulsifying agent at a 3% by weight ratio to MMA. KPS and SDS were placed into a beaker. Then, 250 mL of distilled water was added, and the mixture was stirred at 500 rpm for 10 minutes using a magnetic stirrer. After this, 100 mL of MMA was added to the solution, followed by another 5 minutes of mixing. The prepared mixture was transferred to a four-neck round-bottom flask reactor placed on a reactor stirrer-equipped mantle heater. The reactor had a nitrogen gas inlet, a reflux condenser, and a thermometer. Nitrogen gas was passed through the system to remove oxygen during the experiment. Oxygen has a destructive effect on radicals, so this step ensured an inert environment. The mixture in the reactor was heated to 75°C and kept at this temperature for 5 hours to carry out the polymerization reaction. For molecular weight and monomer conversion calculations, 5 mL samples were regularly taken at 1-hour intervals during the synthesis stage and precipitated in 50 mL of methanol. At the end of the experiment, the remaining sample was transferred to a beaker and precipitated in methanol. The precipitated samples were left at room temperature for several days and filtered through a vacuum pump filtration system. After filtration, the obtained samples were first left in a desiccator for several days and then dried in a vacuum oven at 70°C for 4 hours. 2.3. Synthesis of PLA/PMMA/SiO 2 Nanocomposite by Solution Blending Method In the solution blending method, PMMA polymer produced by emulsion polymerization, modified SiO 2 , and commercial PLA were used. PLA/PMMA/SiO 2 nanocomposite plates were produced with weight ratios of 30:70, 50:50, and 70:30 for PLA:PMMA and modified SiO 2 content of 2%, 5%, and 10% by weight. For example, for a PLA:PMMA weight ratio of 50:50, 2 g of PLA, 14 mL of THF, and 6 mL of N,N-DMF were added to a flask and mixed at 60°C at 350 rpm using a magnetic stirrer until the PLA dissolved. At the same time, 2 g of PMMA and 15 mL of THF were placed in a beaker and mixed at room temperature using a magnetic stirrer until the PMMA completely dissolved. Then, SiO 2 was added in varying weight ratios (0%, 2%, 5%, and 10%) to prepare the PMMA/SiO 2 mixture. After both solutions were homogeneously dissolved, they were combined, and the resulting mixture was further stirred for 5 minutes on the magnetic stirrer. The obtained mixture was poured into petri dishes with a diameter of 50 mm. The samples in the petri dishes were left at room temperature for several days to form nanocomposite plates. 2.4. Synthesis of PLA/PMMA/SiO 2 Nanocomposite by In-situ Method SDS and modified SiO 2 with different weight percentages (2%, 5%, and 10%) were placed in a beaker, and 250 mL of distilled water was added. The resulting solution was stirred on a magnetic stirrer at 500 rpm for 10 minutes and mixed in an ultrasonic homogenizer for 10 minutes. KPS was then added to the solution and stirred for another 10 minutes on the magnetic stirrer. Afterward, 100 mL of MMA was added to the mixture and stirred for five more minutes on the magnetic stirrer. The steps involved in PMMA synthesis were then sequentially applied. PLA/PMMA/SiO 2 nanocomposite plates were produced by the in-situ polymerization method using PMMA/SiO 2 nanocomposites containing 2%, 5%, and 10% modified SiO 2 by weight, with weight ratios of 50:50, 70:30, and 30:70 for PLA:PMMA. As an example, for a 50:50 weight ratio of PLA:PMMA, 2 g of PLA, 14 mL of THF, and 6 mL of N,N-DMF were placed in a flask and stirred at 60°C at 350 rpm using a magnetic stirrer until the PLA dissolved. Meanwhile, 2 g of PMMA/SiO 2 containing 2%, 5%, and 10% SiO 2 and 15 mL of THF were placed in a beaker and stirred at room temperature on a magnetic stirrer until dissolved. After both solutions were homogeneously dissolved, the solutions were combined, and the resulting mixture was stirred for five more minutes on the magnetic stirrer. The obtained mixture was poured into four 50 mm diameter petri dishes. The samples in the petri dishes were left at room temperature for several days to form nanocomposite plates. The samples synthesized using the solution blending and in-situ methods are provided in Table 1 . Table 1 Synthesized PLA/PMMA/SiO 2 nanocomposites PLA:PMMA (wt %) SiO 2 (wt %) Sample name 30:70 2 30PLA/70PMMA/2SiO 2 5 30PLA/70PMMA/5SiO 2 10 30PLA/70PMMA/10SiO 2 50:50 2 50PLA/50PMMA/2SiO 2 5 50PLA/50PMMA/5SiO 2 10 50PLA/50PMMA/10SiO 2 70:30 2 70PLA/30PMMA/2SiO 2 5 70PLA/30PMMA/5SiO 2 10 70PLA/30PMMA/10SiO 2 2.5. Water Absorption Test of Nanocomposites After the synthesis process of the samples was completed using solution blending and in-situ methods, the water absorption percentages of the plates were determined. To determine the percentage of water absorption, 25 mL of distilled water was added to 60 mm diameter Petri dishes, and the samples were weighed before being placed into the Petri dishes filled with distilled water. The Petri dishes were then placed on a flat surface at room temperature. Afterward, the samples were removed from the Petri dishes every two days for 14 days and dried with a tissue. The dried samples were weighed, and the values were recorded. After each measurement, the distilled water in the Petri dishes was replaced, and the samples were placed back into the Petri dishes. The percentage of water absorption in the water absorption test was determined using Eq. 1 . $$\:\text{W}\text{a}\text{t}\text{e}\text{r}\:\text{A}\text{b}\text{s}\text{o}\text{r}\text{p}\text{t}\text{i}\text{o}\text{n}\:\left(\mathbf{\%}\right)=\frac{{\text{W}}_{wet}-\:{\text{W}}_{dry}}{{\text{W}}_{dry}}x100$$ 1 where, W dry is the initial weight of the sample (in grams) before exposure to water W wet is the weight of the sample (in grams) after exposure to water. 2.6. Biodegradability Analysis The study conducted biological and enzymatic degradation analyses to investigate the biodegradability properties of the synthesized nanocomposites. 2.6.1. Biodegradation process of nanocomposites The nanocomposite samples containing different weight percentages of silica (0%, 2%, 5%, and 10%) with 30:70, 50:50, and 70:30 PLA:PMMA ratios, synthesized using the solution blending and in-situ methods, were buried in two different soil types, humus soil and cactus soil, for biodegradability analysis. Before being buried in the soil, the nanocomposite samples were weighed for biodegradability analysis and imaged using a light microscope. After the necessary measurements for the analysis were completed, the samples were placed in protective mesh to prevent material loss during the burial process (Fig. S1 ). During the burial of the nanocomposite plates, care was taken to ensure that all samples were at the same depth and that the surface area in contact with the soil was maximized. After the burial process, both soil types were exposed to equal amounts of sunlight and irrigated three times a week to prevent the soil from losing moisture. The samples were observed for six months and removed from the soil at two-month intervals to measure weight loss. Before weight loss analysis, the samples were cleaned with a brush, washed with distilled water, and dried in a vacuum oven at 70°C until a constant weight was achieved. After drying, the samples were weighed, their microscopic images were taken, and the burial process was repeated. For humus soil, a high-yield soil type with a pH value of 6-7.5, containing coir, perlite, leonardite, peat, and earthworm compost, was selected, while for cactus soil, a high-yield soil type with a pH value of 5-7.5, containing earthworm compost, leonardite, perlite, and peat, was chosen. 2.6.2. Enzymatic degradation process of nanocomposites An enzymatic degradation solution was prepared and left for incubation for the biodegradability analysis of the synthesized nanocomposite samples. The enzymatic degradation solution was prepared using phosphate buffer solution with a pH value of 7.4 and lipase enzyme (L3126 code) produced from pig pancreas. Initially, the samples were weighed, and then a 1 mg mL − 1 lipase phosphate buffer solution was prepared. Each sample was placed in a petri dish containing 20 mL of the degradation solution and incubated at room temperature. Weight loss analysis was performed after the samples were left for 15 days under suitable conditions. Before the weight loss analysis, the samples were washed with distilled water and dried in a vacuum oven at 70°C until constant weight was achieved. In the biological and enzymatic degradation experiments, the percentage of weight loss determined the degradation amount. The percentage of weight loss was determined using Eq. 2 . $$\:\text{W}\text{e}\text{i}\text{g}\text{h}\text{t}\:\text{L}\text{o}\text{s}\text{s}\:\text{P}\text{e}\text{r}\text{c}\text{e}\text{n}\text{t}\text{a}\text{g}\text{e}\left(\text{\%}\right)=\frac{{W}_{0}-{W}_{t}}{{W}_{0}}x100$$ 2 Where: W 0 : Initial weight of the sample before degradation (in grams) W t : Weight of the sample after degradation (in grams) This equation gives the percentage of weight lost by the sample due to degradation (either biological or enzymatic) over the time period of the experiment. 2.7. Characterizations 2.7.1. Fourier transform infrared analysis (FTIR) Stearic acid (SA) modified and neat SiO 2 nanoparticles FTIR analysis was performed and the success of the modification was evaluated. Also a sample from two different nanocomposite production techniques was selected for FTIR analysis. This selection was made to evaluate the effects of the production techniques on the chemical structure and functional groups of the nanocomposite. Plates obtained by pouring into petri dishes were used in the analysis of nanocomposites. FTIR analyses were performed using the Jasco ATR-FT/IR-4700 device. 2.7.2. Thermal analysis Thermogravimetric analyses were performed using Perkin Elmer Pyris 1 TGA and SDT650 brand TGA-DSC devices in a nitrogen atmosphere, at a temperature range of 25°C – 600°C, at a heating rate of 10°C min − 1 . A nitrogen atmosphere was preferred to prevent oxidation and other reactions that could interfere with the thermal degradation process. 2.7.3. Hardness measurement (Shore-D) and tensile test Hardness measurements were performed using a Bareiss HPE II brand Shore-D hardness device to determine the mechanical properties of the synthesized nanocomposites. Hardness measurements were made using plates obtained by pouring into petri dishes. Each hardness measurement was repeated three times, and the average value was used. Tensile testing was performed to investigate the mechanical properties of the synthesized nanocomposites. The tensile test was carried out at a rate of 0.5 mm min − 1 using an INSTRON 4411 device. 2.7.4. Scanning electron microscopy (SEM) SEM analyses were carried out using a QUANTA 400F Field Emission Scanning Electron Microscope to examine the surface characteristics of nanocomposite samples synthesized via solution blending and in-situ methods. 2.7.5. Light microscopy Light microscope was employed to identify the phases before and during degradation and to determine the extent and nature of the degradation. Light microscopy images of the synthesized nanocomposite samples were captured using a Leica M205 C light microscope before and during the biodegradation period. 3. Experimental Results This section presents the results of all experimental studies, analyses, tests, and characterization methods conducted to investigate the thermal, mechanical, and biodegradability properties during the synthesis of PLA/PMMA/SiO 2 nanocomposites. 3.1. Results of Monomer Conversion and Viscosity Average Molecular Weight The monomer conversion values for PMMA polymer and PMMA/SiO2 nanocomposites containing different weight ratios of SiO 2 (2%, 5%, and 10%) synthesized using the in-situ method are presented in Table 2 . The viscosity average molecular weight (M v ) values were determined using a Ubbelohde viscometer and the Mark-Houwink-Sakurada equation with K = 3.4 x 10 − 3 and a = 0.83 [ 9 ]. Chloroform was used as the solvent, and the experiments were conducted at 25°C. The calculated viscosity average molecular weight values for PMMA and the samples containing different weight ratios of SiO 2 are presented in Table 2 . Table 2 Monomer Conversion and Viscosity Average Molecular Weight Values Sample Monomer conversion [%] Viscosity Average Molecular Weight [g mol − 1 ] PMMA 52.10 448,259.14 PMMA/2SiO 2 55.25 196,489.67 PMMA/5SiO 2 57.73 173,955.27 PMMA/10SiO 2 56.28 169,417.63 As seen in Table 2 , an increase in the amount of SiO 2 leads to a rise in the percent monomer conversion. Barari and Sharifi-Sanjani [ 10 ] in their study synthesized poly(methyl methacrylate)/silica nanocomposites via emulsion polymerization using dimethylaminoethyl methacrylate and mentioned that the polymerization also occurred on the silica surface. This finding supports the notion that the addition of SiO 2 generally enhances the monomer conversion rates during the polymerization process in this study as well. The reinforcing material can influence the molecular weight in polymer synthesis, either directly or indirectly. This effect depends on the chemical structure of the reinforcing material, its interaction with the polymer matrix, and the polymerization conditions. If the reinforcing material participates in chemical reactions, it can increase the molecular weight; however, physically, it may restrict the mobility of the polymer chains. This restriction could limit chain growth and result in shorter polymer chains. As seen in Table 2 , the viscosity average molecular weight of the synthesized PMMA is 448,259.14 g mol − 1 . It is observed that the molecular weights of PMMA/SiO 2 samples containing different weight ratios of SiO 2 are relatively lower than the synthesized PMMA. This situation is similar to the work of Bikiaris et al. [ 11 ], where they prepared nanocomposites with silica reinforcement and suggested that as the silica amount increased, the rate of intrinsic viscosity increase slowed down due to a higher degree of branching. A lower intrinsic viscosity rate leads to shorter chain structures. Moreover, the statement by Barari and Sharifi-Sanjani [ 10 ] that polymerization also occurs on the silica surface suggests the formation of relatively shorter chain structures in the material. 3.2. FTIR Analysis Results 3.2.1. ATR-FTIR results of SiO 2 surface modification The FTIR analysis results of stearic acid (SA) modified and neat SiO 2 nanoparticles are given in Fig. 1 . When FTIR spectra are examined, the typical peaks for neat SiO 2 and modified SiO 2 are: the peak at 454 cm − 1 shows Si-O-Si asymmetric bending, the peak at 797 cm − 1 shows Si-O-Si symmetric stretching, the peak at 952 cm − 1 shows Si-OH bond stretching, and the peak at 1067 cm − 1 shows Si-O-Si asymmetric stretching. The peak observed at 1407 cm − 1 in the modified SiO 2 spectrum shows COO- symmetric stretching originating from SA. Similarly, the peak at 2900 cm − 1 originating from SA shows C-H symmetric stretching of CH 2 , and the peak at 2978 cm − 1 shows C-H symmetric stretching of CH 3 [ 12 ]. When neat and modified SiO 2 spectra are compared, it is concluded that the modification process with SA is successful. 3.2.2. ATR-FTIR results of PLA/PMMA/SiO₂ nanocomposites The PLA/PMMA/SiO 2 nanocomposite with a PLA:PMMA ratio of 50:50 for both production techniques was selected for FTIR analysis to reflect the properties of both polymers equally and to observe the characteristic peaks of the reinforcement material more clearly. The FTIR spectrum of the 50PLA/50PMMA/10SiO₂ samples synthesized by solution blending and in-situ methods is given in Fig. 2 . The IR spectra and experimental data of the functional groups for PLA, PMMA, and SiO 2 in the literature are given in Table 3 [ 13 – 16 ]. In addition, the peaks between 2300 − 1800 cm − 1 wave numbers are the peaks belonging to the ATR crystal. Table 3 IR spectra of the functional groups and experimental data Component Functional group Wavenumber [cm − 1 ] Literature Experimental Solution blending In-Situ PLA PMMA C – H (belonging to CH 2 and CH 3 ) 3000–2800 [13, 14] 2943, 2994 2948, 2994 PLA PMMA C = O (stretching vibration) 1750–1720 [14, 15] 1726, 1756 1730, 1756 PLA PMMA – CH 3 (stretching vibration) 1480–1452 [13, 15] 1453 1454 PMMA O – CH 3 (deformation) 1387 [15] 1384 1385 PLA – CH – (asymmetric bending) 1363 [15] 1360 1360 PLA PMMA C – O (stretching vibration) 1270–1080 [14, 15] 1087, 1130, 1183 1084, 1129, 1181 SiO 2 Si – O – Si (symmetric stretching) 800 [16] 752 752 SiO 2 Si – O – Si (asymmetric bending) 450 [16] 456 457 The FTIR analysis results of both production methods show the characteristic peaks of PLA, PMMA, and SiO₂. The samples obtained by solution blending and in-situ methods confirm the chemical structure and the existence of functional groups stated in the literature. The amplitude of the Si – O – Si symmetric stretching peak expected around 800 cm -1 was interpreted as shifting towards lower frequency due to the interaction of silica with the polymer matrix and was observed at 752 cm -1 . These results reveal that the synthesis methods used create the nanocomposite's expected chemical structure, which can be clearly observed in the FTIR spectrum. 3.3. TGA Analysis Results Thermal properties of PLA/PMMA/SiO₂ nanocomposites containing different weight ratios of PLA:PMMA and different ratios of SiO 2 (0%, 2%, 5% and 10%) obtained by solution blending and in-situ methods were investigated using TGA. TGA thermogram of the nanocomposite samples obtained by the solution blending method is given in Fig. S2. Data obtained from TGA thermograms are given in Table 4 . According to literature data, degradation for neat PLA starts at approximately 320°C and continues up to 380°C, while for PMMA it starts at approximately 340°C and continues up to 420°C [ 17 , 18 ]. When the TGA thermograms of the samples are examined, it is seen that there is some weight loss in the range of 150–200°C. This weight loss is thought to occur due to the initial separation of volatile components that remain in the nanocomposite samples and cannot be completely removed from the structure. TGA thermograms analyses show that the initial degradation temperatures of some composites and nanocomposites occur in two stages. This situation is like the study conducted by Teoh et al. [ 17 ] on the thermal resistance of poly(lactic acid)/poly(methyl methacrylate) blends containing flame retardants, and they stated that there are two initial degradation temperatures for PLA and PMMA blends. It was observed that the initial degradation temperature in 30PLA/70PMMA composite, 50PLA/50PMMA/5SiO 2 , and 50PLA/50PMMA/10SiO 2 nanocomposites produced by the solution blending method occurred in two steps. For 30PLA/70PMMA, the first degradation temperature was observed at 325.9°C, while the second was at 380.5°C. For 50PLA/50PMMA/5SiO 2 nanocomposite, it was observed as 321.2°C and 380.0°C, respectively, and for 50PLA/50PMMA/10SiO 2 nanocomposite, it was observed as 323.6°C and 381.8°C, respectively. These values ​​are consistent with the degradation temperatures of PLA and PMMA reported in the study by Teoh et al. [ 17 ]. This situation shows that PLA and PMMA have separate degradation processes. The first degradation temperature belongs to PLA, and the second to PMMA. The highest initial and final degradation temperature is 30PLA/70PMMA/10SiO 2 nanocomposite. At the same time, it is the highest sample with 9.874% weight remaining without degradation. This situation can be explained by the high PMMA content by weight and the high SiO 2 content compared to other composites and nanocomposites. In addition, it was observed that the thermal stability of PLA/PMMA/SiO₂ nanocomposites containing the same PLA:PMMA ratio by weight increased in proportion to the increasing SiO 2 content. The addition of SiO₂ affects the thermal stability and the weight percentage remaining without degradation. The reason for this is that SiO 2 is resistant to high temperatures. Especially PLA/PMMA/SiO₂ nanocomposites containing 10% SiO₂ show resistance up to 450°C. The thermal properties of PLA/PMMA/SiO₂ nanocomposites prepared by the in-situ method were comprehensively evaluated by TGA, and the TGA thermograms are given in Fig. S3. Data obtained from TGA thermograms are given in Table 4 . It was observed that the initial degradation temperature of 30PLA/70PMMA/10SiO 2 and 50PLA/50PMMA/5SiO 2 nanocomposites produced by the in-situ method occurred in two steps. This shows the existence of separate degradation processes for PLA and PMMA. For 30PLA/70PMMA/10SiO 2 nanocomposite, the first degradation temperature was observed at 328.7°C and the second degradation temperature was observed at 377.2°C. For 50PLA/50PMMA/5SiO 2 nanocomposite, the first degradation temperature was observed at 325.1°C, and the second degradation temperature was observed at 382.5°C. The final degradation temperature for 30PLA/70PMMA/10SiO 2 nanocomposite was 454.8°C, and for 50PLA/50PMMA/5SiO 2 nanocomposite as 440.4°C. At the same time, the final degradation temperature of 454.8°C is the highest value in both production methods. This situation shows that the in-situ method has relatively higher thermal stability than the solution blending method despite the same amount of PLA:PMMA and SiO 2 by weight. This situation can be explained by the better dispersion of additives into the polymer matrix during in-situ polymerization and the formation of strong bonds by providing a more homogeneous structure. Table 4 Data obtained from TGA thermograms Method Sample Initial degradation Temperature [°C] Final degradation temperature [°C] Final residue [%] 1. 2. Solution blending 30PLA/70PMMA 325.9 380.5 434.5 0.853 30PLA/70PMMA/10SiO 2 332.4 - 449.0 9.874 50PLA/50PMMA/5SiO 2 321.2 380.0 438.6 3.761 50PLA/50PMMA/10SiO 2 323.6 381.8 447.1 1.863 70PLA/30PMMA 314.6 - 418.1 0.616 70PLA/30PMMA/10SiO 2 316.3 - 440.1 1.979 In-situ 30PLA/70PMMA/10SiO 2 328.7 377.2 454.8 2.481 50PLA/50PMMA/5SiO 2 325.1 382.5 438.1 3.320 50PLA/50PMMA/10SiO 2 328.8 - 450.0 3.841 70PLA/30PMMA/10SiO 2 322.5 - 435.3 2.420 PLA added to PMMA to provide biodegradability has a negative effect on thermal resistance. Thermal resistance decreased as the amount of PLA in the sample increased. The data obtained from the graphs show that SiO₂ addition improves thermal stability by increasing the thermal degradation temperature of the polymer matrix. These results reveal that the distribution and ratio of SiO₂ in the polymer matrix significantly affect thermal resistance. As a result, the thermal properties of PLA/PMMA/SiO₂ composites can be optimized depending on the percentage of the additive. These findings show that SiO₂ addition is an effective strategy to increase the performance of polymer composites in high-temperature applications. In addition, it was observed that SiO₂ addition increased the thermal stability of the composites with both methods, and this effect was more pronounced with the in-situ method. This superiority is due to the more homogeneous distribution of SiO₂ in the polymer matrix and the formation of a stronger matrix with the in-situ method. At the same time, thermal stability is thought to increase with the interaction between the carbonyl groups in PMMA and the hydroxyl groups of the SiO 2 surface. PLA and PMMA are both polar polymers containing ester groups, but their solubility parameters and thermal behaviours differ; therefore, most PLA/PMMA blends are immiscible and exhibit phase-separated morphologies with weak interfacial adhesion. Two-stage degradation was observed in some samples, indicating that separate degradation processes for PLA and PMMA still exist—i.e., partial phase separation. Especially in nanocomposite samples with a high PMMA ratio, there is a two-stage degradation. The addition of SiO₂ did not eliminate the pronounced degradation peaks of PLA and PMMA, meaning full miscibility was not achieved. However, it can be argued that, particularly in the in-situ synthesis method, SiO₂ particles settle at the interface and restrict chain movements, thus increasing miscibility between PLA and PMMA and making the phase boundary less pronounced. 3.4. DSC Analysis Results PLA/PMMA/SiO₂ samples, synthesized by the solution blending method in weight ratios of 30:70 and 50:50 of PLA:PMMA and containing 10% SiO₂, were analyzed by DSC to determine their glass transition temperature (T g ) and melting points (T m ). The results of the DSC analysis are presented in Table 5 . DSC curves are given in Fig. S4. For comparison purposes, the DSC results of PMMA produced by the emulsion polymerization method, as reported by Uzunoglu and Altinten [ 19 ], and commercially available PLA from the same brand, are also provided in the same table. In this literature study, since PMMA is amorphous, only the T g value is present. This value was determined as 110.10°C for PMMA and 59.53°C for neat PLA. The T m value for neat PLA was determined to be 174.71°C. Table 5 Data obtained from DSC curves along with PMMA and PLA values Method Sample T g [°C] T m [°C] Solution blending 30PLA/70PMMA/10SiO 2 n/a 170.61 50PLA/50PMMA/10SiO 2 n/a 165.37 In-situ 30PLA/70PMMA/10SiO 2 116.39 170.99 50PLA/50PMMA/10SiO 2 n/a 172.95 Emulsion Polymerization PMMA 110.10 [19] n/a Neat PLA 59.53 [19] 174.71 [19] According to literature data, the Tg value for neat PMMA ranges between 100–110°C, while this value for PLA is between 55–60°C. Due to PMMA's inherently higher viscosity compared to PLA, it restricts the movement of PLA chains [ 20 ]. The T g value for the 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the in-situ method was observed to be 116.39°C. This value being close to the T g of PMMA can be explained by the high mass content of PMMA and the restriction of PLA chain mobility. Additionally, the T g value being higher than that of neat PMMA is thought to be due to the effect of the SiO₂ reinforcement material, which has high thermal resistance, added to increase thermal durability. In the study by Teoh and Chow (2018), miscibility was observed in all blend ratios (i.e., 80/20, 60/40, 40/60, and 20/80) of PLA/PMMA blends prepared using the melt compounding technique. DMA results revealed the presence of a single T g for all PLA/PMMA blends, indicating miscibility, and showed that their thermal behavior was dependent on the composition [ 21 ]. Similarly, in our study, the presence of a single T g value for the mixture can be considered as an indicator of PLA/PMMA miscibility. In other samples, the T g value was observed, which is related to the intercalation state where the molecules are trapped in two-dimensional galleries. This trapping leads to decreased molecular mobility and hinders the segmental movements required during the glass transition, making the T g value more challenging to observe distinctly. There is a high degree of similarity between the T m values of the 30PLA/70PMMA/10SiO₂ nanocomposites synthesized by the solution blending and in-situ methods. This is attributed to the high content of PMMA. However, when the PMMA ratio is reduced, the T m value of the 50PLA/50PMMA/10SiO₂ sample synthesized by the in-situ method is higher than that of the sample produced by the solution blending method. This suggests that the in-situ method could be preferred for synthesizing PLA/PMMA and PLA/PMMA/SiO₂ composites with high thermal resistance. 3.5. Shore-D Hardness Analysis Results The Shore-D hardness measurement results for the solution blending and in-situ method samples are presented in Table 6 . Table 6 Shore-D hardness measurement values of nanocomposites produced by solution blending and in-situ methods Sample Shore-D hardness Solution blending In-situ 30PLA/70PMMA 32.2 - 30PLA/70PMMA/2SiO 2 25.5 31.4 30PLA/70PMMA/5SiO 2 23.2 27.3 30PLA/70PMMA/10SiO 2 21.0 29.9 50PLA/50PMMA 23.7 - 50PLA/50PMMA/2SiO 2 22.7 24.7 50PLA/50PMMA/5SiO 2 25.5 26.9 50PLA/50PMMA/10SiO 2 27.3 30.9 70PLA/30PMMA 17.2 - 70PLA/30PMMA/2SiO 2 15.7 16.0 70PLA/30PMMA/5SiO 2 14.6 15.9 70PLA/30PMMA/10SiO 2 12.3 14.9 PMMA/2SiO 2 32.3 32.7 PMMA/5SiO 2 31.8 32.1 PMMA/10SiO 2 31.5 32.1 The Shore-D hardness value of PLA was determined to be 22.2. On the other hand, the Shore-D hardness value of PMMA was 32.7, indicating that PMMA is a more rigid and durable material than PLA. According to the hardness measurement results, the hardness values of the samples vary depending on the PLA:PMMA ratio, the amount of added silica, and the production method. In mixtures with a high PMMA content, higher hardness values were observed. No significant change in hardness values was observed with the addition of SiO₂ at different weight ratios to PMMA, whether by solution blending or in-situ methods, and values similar to the hardness of neat PMMA were obtained. In PLA/PMMA/SiO₂ nanocomposites, however, a significant decrease in hardness values was observed as the PLA content increased. Adding SiO₂ to polymers containing different PLA:PMMA ratios generally reduced the hardness. In nanocomposites with a 50:50 weight ratio of PLA:PMMA, both methods observed an increase in Shore-D hardness values with the increasing SiO₂ content. In nanocomposites with weight ratios of 30:70 and 70:30 of PLA:PMMA, however, increased SiO₂ content decreased in Shore-D hardness values in both methods. When comparing nanocomposite production methods, the in-situ method generally resulted in higher hardness values than the solution blending method. It is suggested that the higher hardness values of the nanocomposites produced by the in-situ method are due to a more homogeneous distribution, providing better material integrity. 3.6. Tensile Test Results The tensile test results for the 50PLA/50PMMA/2SiO₂, 50PLA/50PMMA/10SiO₂ nanocomposites synthesized by the in-situ method, and the 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the solution blending method, are presented in Table 7 . Table 7 Tensile test results Method Sample Max. tensile strength [MPa] Breaking load [N] Ultimate tensile strength at break [%] Elongation at break [mm] Solution blending 30PLA/70PMMA/10SiO₂ 1.648 79.374 2.084 1.251 In-situ 50PLA/50PMMA/2SiO₂ 0.903 34.093 2.155 1.293 50PLA/50PMMA/10SiO₂ 1.055 43.702 3.460 2.076 According to the tensile test data, as the PMMA content increases, the material's maximum tensile strength and breaking load increase. The samples with a 50:50 PLA:PMMA ratio exhibit lower tensile strength compared to those with a 30:70 PLA:PMMA ratio, which is believed to be due to the stress-concentrating effect induced by the addition of nanosilica and the susceptibility of PLA to hydrolytic degradation. Since PMMA is generally more resistant to hydrolytic degradation, it is not affected by this. The blending of PLA with PMMA may reduce the elongation at break of the PLA/PMMA/SiO₂ composites due to the low elongation at break of pure PLA. However, the addition of SiO₂ compensates for this reduction. When the ultimate tensile strength and elongation at break values of the nanocomposites with a 50:50 PLA:PMMA ratio are compared, it was observed that the nanocomposite containing 10% SiO₂ has higher values than the one containing 2% SiO₂. This indicates that the incorporation of nanosilica particles into the PLA/PMMA polymer imparts ductile behavior to the nanocomposite. The tensile test results of the 50PLA/50PMMA/2SiO₂, 50PLA/50PMMA/10SiO₂ synthesized by the in-situ method, and the 30PLA/70PMMA/10SiO₂ synthesized by the solution blending method support the Shore-D analysis results. The 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the solution blending method has the highest tensile strength of 1.648 MPa and a breaking load of approximately 79 N. In the study, it was observed that as the PMMA content increased, both the maximum tensile strength and the breaking load of the material also increased. The lower tensile strength of the samples with a 50:50 PLA:PMMA ratio compared to those with a 30:70 PLA:PMMA ratio, both containing equal amounts of SiO₂, may be due to the stress-concentrating effect induced by the addition of nanosilica and the susceptibility of PLA to hydrolytic degradation, as noted by Wu et al. [ 4 ]. The blending of PLA with PMMA may reduce the elongation at break of PLA/PMMA/SiO₂ composites due to the low elongation at break of pure PLA. However, the addition of SiO₂ compensates for this reduction. In the work of Wu et al. [ 4 ], it was mentioned that the spherical shape and smooth, non-porous surfaces of SiO₂ can act as a lubricant in polymers, reducing the coefficient of friction. This lubricating effect of SiO₂, based on shear and ductile behavior, suggests that the inclusion of nanosilica particles in PLA/PMMA blends can increase the toughness of PLA/PMMA/SiO₂ composites and impart ductile behavior to the material. 3.7. Water Absorption Test Results Factors affecting the hydrolysis sensitivity of a particular polymer include water permeability and solubility, which are influenced by the polymer's chemical structure and physical state [ 24 ]. Water absorption testing frequently indicates a polymer's tendency to undergo hydrolytic degradation. Polymers can absorb water, swell, undergo hydrolysis, and then degrade in the environment. A high tendency for water absorption may indicate a high propensity for hydrolytic degradation [ 24 ]. Graphs showing the % water absorption values for PLA and PMMA are presented in Fig. 3 , graphs for the % water absorption values of samples produced by the solution blending method are shown in Fig. 4 , and graphs for the % water absorption values of samples synthesized by the in-situ method are presented in Fig. 5 . Resistance to water absorption is one of the important properties of biocomposite materials used in specific applications, such as packaging. Furthermore, water absorption plays a critical role in determining the biodegradability of PLA, as its degradation occurs through hydrolysis. As shown in Fig. 3 , the increasing % water absorption values of PLA over time indicate its biodegradability. In contrast, for PMMA, low % water absorption values over time indicate resistance to degradation. It has been observed that the PLA:PMMA ratios and SiO₂ additions significantly effect the water absorption percentages. In samples produced by solution blending and in-situ methods, it was observed that as the PLA content increased, the water absorption percentages also increased. Similarly, in samples containing different amounts of SiO₂, the water absorption percentage increased with the amount of SiO₂. When comparing the two nanocomposite production methods, the water absorption percentages of nanocomposites produced by the solution blending method are higher than those obtained by the in-situ method. Among the samples synthesized by the solution blending method, the 70PLA/30PMMA/10SiO₂ nanocomposite exhibited the highest water absorption rate of 23.90%. In the in-situ method, the 50PLA/50PMMA/10SiO₂ nanocomposite showed the highest water absorption at 18.48%. Water can increase the activity of microorganisms that accelerate biological degradation. However, excessive water absorption may negatively affect the mechanical properties of the composite. Therefore, a moderate level of water absorption is preferred. 3.8. Biological Degradation Results Nanocomposite samples containing 30:70, 50:50, and 70:30 PLA:PMMA ratios with different silica percentages (0%, 2%, 5%, and 10%) synthesized by the solution blending and in-situ methods were buried in two different soil types for biodegradability analysis. Since microorganisms in different soil types have varying biodegradation capabilities, the samples were buried in cactus soil and humus-rich soil. The biological degradation process of the buried samples was monitored for 6 months. The samples were regularly removed from the soil every two months, and weight loss analysis was conducted. Graphs showing the weight loss percentage values for PLA and PMMA are presented in Fig. 6 , for the samples buried in humus-rich soil and synthesized by the solution blending method in Fig. 7 , for the samples synthesized by the in-situ method in Fig. 8 , for the samples buried in cactus soil and synthesized by the solution blending method in Fig. 9 , and for the samples synthesized by the in-situ method in Fig. 10 . Analyses conducted on the biodegradation characteristics of PLA, PMMA, and PLA/PMMA/SiO₂ nanocomposite samples indicate that the biodegradation rate varies depending on the soil type and the sample's composition. The degradation of PLA occurs in two distinct stages. During the first stage, hydrolysis takes place, wherein high-molecular-weight PLA chains are hydrolyzed into lower-molecular-weight oligomers. This reaction is influenced by temperature and humidity, and can be accelerated in the presence of acids or bases. In the second stage, microorganisms present in the soil further break down these low-molecular-weight compounds into CO₂, water, and humus, thereby completing the degradation process. Throughout this process, factors such as the presence of microorganisms in the soil, weekly watering of the pots in which the PLA specimens are buried, and equal exposure to sunlight have been found to accelerate the degradation of PLA [ 24 ]. In general, samples buried in cactus soil exhibited higher biodegradation rates than those in humus-rich soil. This situation may be attributed to the cactus soil's higher moisture retention capacity. In a related study, Nikolić et al. [ 24 ] investigated the biodegradation of polystyrene-graft-starch copolymers in three different soil types. They reported that microorganisms responsible for biological degradation showed varying activity levels and degradation efficiency under identical conditions, with the highest weight loss observed in cactus soil. In cactus soil, the 70PLA/30PMMA/10SiO₂ nanocomposite synthesized via the in-situ method showed the highest biodegradation rate, with approximately 34.37% weight loss after 180 days. Similarly, in humus-rich soil, the highest biodegradation rate was also observed in the same sample, with a weight loss of 28.93%. The 70PLA/30PMMA sample without silica exhibited a weight loss of 26.09% in humus soil and 19.69% in cactus soil. These findings suggest that the presence of SiO₂ in the nanocomposite enhances the biodegradability of PLA, an effect that is particularly pronounced in samples with lower PLA content. It was further observed that increasing the silica content in the nanocomposites resulted in greater weight loss. Similarly, higher PLA content also correlated with increased weight loss. Samples synthesized via the in-situ method demonstrated greater weight loss than those produced by solution blending, likely due to their more homogeneous structure and improved material integrity. These findings highlight that PLA content, silica content, and the synthesis method employed significantly affect nanocomposites' biodegradability. 3.9. Enzymatic Degradation Results An enzymatic degradation solution was prepared for the biodegradability analysis of the synthesized nanocomposites, and samples were subjected to incubation. A phosphate buffer solution with a pH of 7.4 and lipase enzyme (catalog number L3126) derived from porcine pancreas was used for the enzymatic degradation medium. Weight loss analyses were performed after incubation under appropriate conditions for 15 days. The percentage weight loss results of PLA, PMMA, and samples synthesized by the solution blending method and in situ method are presented in Fig. 11 . In the presence of phosphate buffer, the polymer blends initially undergo hydrolysis, followed by enzymatic degradation. It was observed that the phosphate buffer solution, used alongside the lipase enzyme during the enzymatic degradation process, accelerates the biodegradation. Due to its sensitivity to hydrolytic degradation, PLA undergoes hydrolysis in the phosphate buffer solution. The enzymatic degradation results demonstrate the biodegradability of PLA samples. An increase in PLA content within the samples led to a corresponding increase in enzymatic degradation. Adding SiO₂ to PLA:PMMA samples with different ratios (30:70, 50:50, and 70:30) without silica enhanced enzymatic degradation. Furthermore, it was determined that increasing the SiO 2 content in nanocomposites resulted in higher weight loss. After 15 days, neat PLA exhibited a weight loss of 4.4%. In contrast, the 70PLA/30PMMA/10SiO 2 nanocomposite samples showed the highest degradation rates, with 4.83% weight loss in the solution blending method and 5.17% in the in-situ method. The incorporation of SiO 2 accelerated the biodegradability of PLA and compensated for the reduced degradation caused by PMMA. This effect may be attributed to forming a more porous structure within the polymer matrix, enabling easier enzyme access to polymer chains. Moreover, while neat PMMA exhibited a weight loss of only 0.55% after 15 days, an increase in the SiO 2 content led to a proportional increase in weight loss. When comparing the biodegradability of samples synthesized via solution blending and in-situ methods, it was observed that the in-situ synthesized samples exhibited higher weight loss. This is likely due to the homogeneous structure and well-dispersed silica phase in the in-situ samples, which enhances their interaction with enzymes in the solution and promotes a higher degradation rate. When comparing the biodegradation and enzymatic degradation of the 70PLA/30PMMA/10SiO 2 nanocomposite synthesized by the in-situ method— which exhibited the highest weight loss after 15 days— it can be concluded that enzymatic degradation proceeds approximately 15% faster than biodegradation under the tested conditions. 3.10. Light Microscopy Images Based on the results of the biological and enzymatic degradation analyses, light microscopy images of the 70PLA/30PMMA/10SiO₂ nanocomposite samples—which exhibited the highest weight loss and were produced via both solution blending and in-situ methods—are presented in Fig. 12 . Additionally, light microscopy images of the 30PLA/70PMMA/2SiO₂ nanocomposites—showing the lowest weight loss for both synthesis methods—are shown in the same figure. Light microscopy images taken prior to degradation revealed that the surfaces of the samples synthesized via the in-situ method were smoother, indicating a more homogeneous structure in these samples. This observation supports the conclusion that the in-situ synthesis method yields nanocomposites with a more uniform morphology. Light microscopy images captured at 60, 120, and 180 days after burial in soil showed increased surface deformation correlating with the progression of degradation. As degradation advanced, voids formed on the sample surfaces due to structural breakdown, and these voids became filled with soil particles—appearing as dark spots in the images. The increasing presence of soil particles on the sample surfaces visually supports the increasing percentage of weight loss recorded in the biodegradation analysis. When comparing the amount of soil accumulated on the surfaces of the samples with the highest weight loss (buried in cactus soil) to those with the lowest weight loss (buried in humus-rich soil), the difference is observable. This situation further confirms the influence of soil type on the extent of biodegradation. 3.11. SEM Analysis SEM analyses were carried out using a QUANTA 400F Field Emission Scanning Electron Microscope to examine the surface characteristics of nanocomposite samples synthesized via solution blending and in-situ methods. SEM images of the 70PLA/30PMMA/10SiO₂ and 30PLA/70PMMA/10SiO₂ nanocomposites synthesized by the in-situ method are presented in Fig. 13 , while SEM images of the 50PLA/50PMMA/5SiO₂ and 50PLA/50PMMA/10SiO₂ nanocomposites synthesized via the solution blending method are shown in Fig. 14 . SEM images reveal that the PLA/PMMA blend exhibits a typical single-phase morphology, indicating good miscibility between PLA and PMMA. It was observed that SiO₂ nanoparticles were more uniformly dispersed in the samples synthesized via the in-situ method, whereas a more heterogeneous distribution was evident in the samples produced using the solution blending method. As the amount of silica particles increased, the continuous phase became less pronounced, and a more nodular structure was observed. 4. Conclusion This study aimed to enhance the biodegradability of PMMA—a polymer known for its lack of environmental degradability—by blending it with PLA, a biodegradable polymer. Additionally, incorporating SiO₂ nanoparticles was intended to improve the resulting material's thermal stability and mechanical properties. Due to the moisture-absorbing nature of silica, it is also expected that the presence of SiO₂ would accelerate the biodegradation process at the end of the material's service life, facilitated by the PLA content. PLA/PMMA/SiO₂ nanocomposites were prepared using both solution blending and in-situ methods, with varying SiO₂ contents (0%, 2%, 5%, and 10% by weight) and PLA:PMMA ratios (30:70, 50:50, and 70:30). The addition of PLA, while imparting biodegradability to PMMA, had a negative impact on thermal stability. As the PLA content increased, a corresponding decrease in thermal resistance and hardness was observed. However, data obtained from TGA indicated that the inclusion of SiO₂ enhanced the thermal degradation temperature of the polymer matrix, thereby improving thermal stability. When comparing the nanocomposite fabrication methods, the in-situ method typically yielded higher thermal resistance and hardness than the solution blending method. This superiority is attributed to the more homogeneous dispersion of SiO₂ and the formation of a stronger polymer matrix during in-situ synthesis. According to tensile test data, as the amount of PMMA increases, the maximum tensile strength and breaking load of the material also increases. It was observed that SiO 2 increases the toughness of the material and gives it ductile behavior. The results of the soil burial test for PLA, PMMA, and PLA/PMMA/SiO₂ nanocomposite samples indicate that the biodegradation rates vary depending on the soil type and the sample composition. Generally, samples buried in cactus soil exhibited higher biodegradation rates than those buried in humus soil. This situation can be attributed to the cactus soil's higher moisture retention capacity. It was observed that the weight loss increased with the addition of PLA and silica content in the nanocomposites. The presence of SiO₂ in the nanocomposites was found to accelerate/increase the biodegradability of PLA, with this effect being more pronounced in samples with lower PLA content. Samples synthesized using the in-situ method, with their more homogeneous structure and material integrity, showed higher weight loss than the relatively heterogeneous solution-blended samples. The enzymatic degradation results were also in accordance with the biological degradation findings. The addition of SiO₂ accelerated the biodegradability of PLA and compensated for the slower degradation rate of PMMA. It is well known that the dispersion of nanofillers within the polymer matrix affects the physical properties of the polymer. The homogeneous distribution of nanofillers and the optimal interactions between the nanofillers and the polymer matrix can effectively enhance the thermal, mechanical, and rheological properties of the polymer matrix. Declarations Ethics approval and consent to participate Not applicable Consent for publication Not applicable Availability of data and material The data that support the findings of this study are available from the corresponding author upon request. Competing interests The authors declare no conflict of interest. Funding This work was supported by Gazi University Scientific Research Projects with project number FYL-2023-8607. Authors' contributions Conceptualization: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Methodology: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Formal analysis and investigation: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Writing–original draft preparation: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Writing – review and editing: [Ayla Altinten]; Funding acquisition: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Supervision: [Ayla Altinten]. Acknowledgments This study was supported by Gazi University Scientific Research Projects with project number FYL-2023-8607. TGA, DSC and SEM analyses were carried out at METU Central Laboratory. References Jonoobi M, Harun C, Mathew AP, Oksman K (2010) Mechanical properties of cellulose nanofiber (cnf) reinforced polylactic acid (PLA) prepared by twin screw extrusion. 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Environ Sci Pollut R 21:9877-9886. 10.1007/s11356-014-2946-0 Supplementary Files SupplementaryMaterials.pdf Cite Share Download PDF Status: Published Journal Publication published 21 Nov, 2025 Read the published version in Journal of Polymer Research → Version 1 posted Editor assigned by journal 08 Oct, 2025 Reviewers agreed at journal 02 Oct, 2025 Reviewers invited by journal 02 Oct, 2025 Editor invited by journal 01 Oct, 2025 First submitted to journal 30 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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2","display":"","copyAsset":false,"role":"figure","size":69585,"visible":true,"origin":"","legend":"\u003cp\u003eATR-FTIR spectrum of 50PLA/50PMMA/10SiO₂ samples synthesized by solution blending and in-situ methods\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/7834cdd2aa8fba486d822ac5.png"},{"id":93610793,"identity":"75ce91a1-ed13-4858-add0-867493b14d75","added_by":"auto","created_at":"2025-10-15 16:11:34","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":31388,"visible":true,"origin":"","legend":"\u003cp\u003eWater absorption results for PLA and PMMA\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/61f9bbfbd6243708e5a235c4.png"},{"id":93613408,"identity":"80d2cb41-1b70-4b34-8d13-0a359b6250a9","added_by":"auto","created_at":"2025-10-15 16:27:34","extension":"png","order_by":4,"title":"Figure 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produced by the solution blending method and buried in cactus soil\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/560bfbe15fb309d1022a6aa2.png"},{"id":93612445,"identity":"2bf75316-34eb-4af7-9d46-12afc9ff65a7","added_by":"auto","created_at":"2025-10-15 16:19:34","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":60894,"visible":true,"origin":"","legend":"\u003cp\u003eWeight loss percentage graph for samples produced by the in-situ method and buried in cactus soil\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/3c15d3da85cbd9d521e44a69.png"},{"id":93613410,"identity":"870e32be-f197-4171-9bd3-af4267459299","added_by":"auto","created_at":"2025-10-15 16:27:34","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":48473,"visible":true,"origin":"","legend":"\u003cp\u003ePercentage weight loss of PLA, PMMA and the samples produced by the solution blending method and the in-situ method during enzymatic degradation\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/2bd6fa262706cf3200172c3c.png"},{"id":93610804,"identity":"fdc81bd7-2241-4772-8d6c-bc14559c43b6","added_by":"auto","created_at":"2025-10-15 16:11:34","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":1635538,"visible":true,"origin":"","legend":"\u003cp\u003eLight microscopy images of \u003cstrong\u003e70PLA/30PMMA/10SiO₂ and \u003c/strong\u003e30PLA/70PMMA/2SiO₂ nanocomposite samples: (a) synthesized via the solution blending method, (b) synthesized via the in-situ method.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/23403e310b554376fac09341.png"},{"id":93610812,"identity":"a60a74c7-418c-4b29-b35e-98fc5d51188b","added_by":"auto","created_at":"2025-10-15 16:11:34","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":466081,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of nanocomposites synthesized via the in-situ method: (a) 70PLA/30PMMA/10SiO₂, and (b) 30PLA/70PMMA/10SiO₂\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/b26003c9a562d0f6f82d5ddb.png"},{"id":93610806,"identity":"9b90e624-8efb-4e96-bf69-174101abcdcd","added_by":"auto","created_at":"2025-10-15 16:11:34","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":463307,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of nanocomposites synthesized via the solution blending method: (a) 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e, and (b) 50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/a34774f674b5f875b7f784cc.png"},{"id":96651219,"identity":"fe171146-cd90-4028-ac10-d9fafae38ab2","added_by":"auto","created_at":"2025-11-24 16:14:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4708369,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/7c965633-dc3b-4ab9-a6cf-81d65ccb9d21.pdf"},{"id":93612448,"identity":"c6462f69-d5bb-4f89-834e-9769e493b06e","added_by":"auto","created_at":"2025-10-15 16:19:34","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":850192,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7409193/v1/49bb0307c94feffceb4f7f20.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eSynthesis and Characterization of Polylactic Acid/ Polymethyl Methacrylate/silica Biodegradable Nanocomposite\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003e\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eDue to recent advancements in today's rapidly developing technologies, there is a growing need for a class of materials that meet all the desired properties. As a result, to address the demand for such materials, researchers are increasingly focusing on sustainable alternatives that perform better and are environmentally friendly compared to traditional materials. Green advanced materials, such as polymeric materials, green functional textiles, biomaterials, composites, and nanomaterials, are among the fastest-growing technologies due to their excellent chemical, electrical, optical, and biological properties. These characteristics make them suitable for various fields of science and technology, including biomedical, water treatment, packaging, cosmetics, and textile industries.\u003c/p\u003e\u003cp\u003eBiodegradable nanocomposite polymers play a significant role in the search for environmentally sustainable materials. These materials combine desirable properties such as biodegradability with enhanced mechanical and barrier properties provided by nanotechnology. Biodegradable nanocomposites are designed to naturally degrade through microorganisms in the environment, promoting a circular economy in material usage while reducing pollution. Reducing environmental impact is paramount in various sectors such as packaging, agriculture, and biomedical devices. Due to the increased demand for eco-friendly packaging and technological advancements, it has become possible to process biopolymers like petroleum-based plastics. The environmental pollution caused by petrochemical-based and non-biodegradable plastic packaging materials has heightened the need for biodegradable packaging materials, which can be developed using renewable natural biopolymers.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePLA is an aliphatic and thermoplastic polyester derived from renewable resources such as corn starch or sugarcane. It has gained significant attention due to its biodegradability, biocompatibility, and non-toxicity to the human body and the environment [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. However, it sometimes lacks the required mechanical strength and barrier properties for specific applications. Poly(methyl methacrylate) (PMMA) is a glassy and transparent polymer that exhibits excellent properties for the packaging industry, as well as optical and biomedical applications, due to its high strength, optical clarity, desired dimensional stability, and weather resistance [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. PMMA, due to its high hardness, exhibits significant brittleness, which limits its potential application areas [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. On the other hand, PMMA is a non-biodegradable polymer. Considering the environmental friendliness, blending PMMA with biodegradable PLA could reduce PMMA consumption [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Blending PLA with PMMA presents a compelling strategy to combine the desirable properties of both polymers\u0026mdash;namely, the biodegradability of PLA and the mechanical robustness and transparency of PMMA\u0026mdash;thereby improving overall performance while reducing the environmental footprint of PMMA-based products. Furthermore, incorporating nanoparticles such as silica (SiO₂) into these polymer blends has significantly enhanced thermal stability, mechanical strength, and overall material integrity. Silica nanoparticles, owing to their high surface area and functionalizable surfaces, interact with the polymer matrix, improving interfacial bonding and dispersion. This makes biodegradable nanocomposites an excellent option for packaging applications that require strength and durability while prioritizing post-use environmental degradation.\u003c/p\u003e\u003cp\u003ePrevious studies have demonstrated the potential of PLA/PMMA/SiO₂ nanocomposites for various high-performance applications. Wu et al. (2015) developed PLA/PMMA/SiO₂ composites using a twin-screw extrusion process. They proposed that such blends could serve as environmentally friendly alternatives to polycarbonate polymers, particularly in LED light mask applications. To improve the inherent brittleness of PLA, nanosilica particles were incorporated into the blend, along with a chain extender aimed at reducing hydrolysis during processing. They observed that the chain extender increased the final tensile strength of the PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e composites by approximately 43%. Including of 0.5 wt% nanosilica particles increased the elongation at break and Izod impact resistance by 287% and 163%, respectively, compared to neat PLA. Considering mechanical performance, they suggested that the optimal blend ratio could be between PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e (90/10) and PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e (80/20) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Hao et al. (2016) investigated the effect of nanosilica content on PLA/PMMA (50/50) melt blends by incorporating varying concentrations of SiO₂ (0%, 2%, 5%, and 10% by weight). Differential scanning calorimetry (DSC) analyses revealed that the inclusion of nanosilica not only raised the glass transition temperature of the blends but also broadened the transition range, indicating improved thermal behavior [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In another study, Wang et al. (2009) employed a sol-gel approach to synthesize a degradable PLA/PMMA/SiO₂ hybrid electrolyte. The formulation involved PLA, methyl methacrylate (MMA), and tetraethoxysilane (TEOS), with 3-methacryloxypropyl trimethoxysilane acting as a coupling agent. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirmed covalent bonding among PLA, PMMA, and silica units, forming a hybrid network. According to DSC results, increasing the SiO₂ content enhanced the material's thermal resistance [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Palma-Ram\u0026iacute;rez et al. (2021) examined the impact of silica nanoparticles on the processability and compatibility of PLA\u0026ndash;polypropylene (PP) blends produced via melt blending. They evaluated PP\u003csub\u003e95\u003c/sub\u003e(PLA-SiO\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e5\u003c/sub\u003e, PP\u003csub\u003e90\u003c/sub\u003e(PLA-SiO\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e10\u003c/sub\u003e, and PP\u003csub\u003e80\u003c/sub\u003e(PLA-SiO\u003csub\u003e2\u003c/sub\u003e)\u003csub\u003e20\u003c/sub\u003e nanocomposites in terms of their thermal, structural, morphological, mechanical, and degradation properties, with particular attention to packaging applications. Their findings showed that SiO₂ addition increased the crystallinity of PLA from 10% to 77% and improved thermal stability depending on the nanoparticle content. However, the inclusion of silica also limited the mobility of PLA chains, promoting more viscous behavior. Furthermore, inorganic nanostructures influenced microstructure and thermal stability (evidenced by lower degradation temperatures), likely due to altered dipole\u0026ndash;dipole interactions between organic components. Notably, enhanced interfacial compatibility and mechanical properties were observed in PP90(PLA-SiO₂)10 composites, attributed to the uniform dispersion and favorable interaction of 1 wt% SiO₂ within the polymer matrix [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe study aims to mitigate the natural deficiencies of the thermoplastic polymer PMMA by blending it with the biodegradable polymer PLA to achieve biodegradability, while enhancing its thermal and mechanical strength with SiO\u003csub\u003e2\u003c/sub\u003e nanoparticles. In this study, it is expected that the interaction between the ester groups in PMMA and the carbonyl groups with the hydroxyl groups on the SiO\u003csub\u003e2\u003c/sub\u003e surface will enhance the material's thermal stability throughout its service life. Additionally, due to the moisture retention property of silica, it is anticipated that the biodegradation of the PLA component in the structure will accelerate at the end of the product's lifecycle. This innovative combination highlights the potential of biodegradable nanocomposites to meet performance and environmental sustainability requirements. Such advancements significantly push progress in biomaterials and sustainable materials science, demonstrating the importance of ongoing research and innovation. The use of these materials could reduce the amount of plastic waste.\u003c/p\u003e\u003cp\u003ePMMA polymer was synthesized by the emulsion polymerization method using methyl methacrylate (MMA) monomer, sodium dodecyl sulfate (SDS) as emulsifier, and potassium persulfate (KPS) as initiator. Before using SiO\u003csub\u003e2\u003c/sub\u003e, it was modified with stearic acid (SA). Subsequently, PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites were synthesized using in-situ and solution blending methods, with SiO\u003csub\u003e2\u003c/sub\u003e nanoparticles incorporated at ratios of 0, 2, 5, and 10 wt%, and PLA/PMMA was used at ratios of 30:70, 50:50, and 70:30 wt. After emulsion polymerization, the percentage monomer conversion and viscosity average molecular weights of the polymers were determined. The surface properties of the prepared nanocomposite materials were examined using scanning electron microscopy (SEM). Thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, the mechanical properties of the synthesized nanocomposites were investigated using the Shore-D hardness test and tensile test. For biodegradability analysis, biological and enzymatic degradation studies were conducted. For biological degradation, samples buried in cactus and humus soil were monitored for weight loss, and their structural integrity was examined before and after burial using microscopic imaging. The biological degradation was monitored for 6 months, with microscopic images taken at specific intervals, and weight loss percentages were calculated. For enzymatic degradation, phosphate buffer solution (pH\u0026thinsp;=\u0026thinsp;7.4) and lipase enzyme derived from pig pancreas were used. The samples were observed in the prepared solution for 15 days, and weight loss percentages were calculated. This work underscores the potential of biodegradable nanocomposites as sustainable alternatives in packaging and biomedical fields, offering a promising route toward high-performance, eco-friendly materials.\u003c/p\u003e\u003cp\u003eAlthough studies reinforcing PLA/PMMA blends with inorganic fillers are present in the literature, this work introduces several novel aspects. In this study, silica nanoparticles were modified with stearic acid and employed to enhance interfacial interactions within PLA/PMMA blends. Nanocomposites were prepared through both in situ and solution blending methods, enabling a direct comparison of processing techniques and composition ratios across a wide range of PLA:PMMA ratios and filler loadings. Most importantly, this work provides a comprehensive evaluation of biodegradability under two different soil conditions as well as enzymatic degradation, revealing that the modified silica not only accelerates environmental degradation but also simultaneously improves mechanical and thermal performance. This dual functionality highlights the potential of the developed nanocomposites as sustainable, high-performance materials.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003eThe experimental study was conducted with the synthesis of PMMA via emulsion polymerization, modification of silica, and the synthesis of PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e using in-situ and solution blending methods. Subsequently, the study continued with various analytical and characterization techniques to investigate the thermal, mechanical, and biodegradability properties of the synthesized nanocomposites. The chemicals used in the experimental process were as follows: Methyl methacrylate (Merck, \u0026gt;\u0026thinsp;99%), Potassium persulfate (Merck, 99%), Sodium dodecyl sulfate (Merck, 99%), Methanol (Isolab, \u0026gt;\u0026thinsp;99.8%), Silica (Sigma-Aldrich, 5\u0026ndash;15 nm, 99.5%), Stearic acid (Merck, 99.5%), Isopropyl alcohol (Isolab, \u0026gt;\u0026thinsp;99.5%), Ethanol (Merck, \u0026gt;\u0026thinsp;99.9%), PLA (Total-Corbion, Luminy LX175), Tetrahydrofuran (Merck, 99.5%), N, N Dimethylformamide (Merck, 99.8%), Chloroform (Merck, 99.4%), Toluene (Sigma-Aldrich, \u0026gt;\u0026thinsp;99.5%), Phosphate buffer solution (Pluriselect, pH\u0026thinsp;=\u0026thinsp;7.4).\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Modification of SiO\u003csub\u003e2\u003c/sub\u003e\u003c/h2\u003e\u003cp\u003eDue to the natural hydrophilicity of silica nanoparticles, surface modification is required to achieve homogeneous dispersion within the polymer matrix. The surface modification of SiO\u003csub\u003e2\u003c/sub\u003e is performed to impart hydrophobic characteristics to the silica particles' surface. Without surface modification, the van der Waals intermolecular forces between the nanoparticles are so strong that the particles tend to agglomerate, leading to a non-homogeneous distribution within the polymer and weakening the polymer's properties. Fluorinated hydrocarbons or silanes are expensive for surface modification and are also hazardous to human and environmental health. Stearic acid, a type of fatty acid, is a non-toxic, hydrophobic, non-reactive, inexpensive, and environmentally friendly surface modification agent. One end of the stearic acid molecule is hydrophilic, while the other is hydrophobic. The hydrophobic tail adsorbs to the polymer, and the hydrophilic head adsorbs to the silica, thereby ensuring bonding between the nanoparticle and polymer without needing a chemical reaction [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn the modification process, a mixture containing 3 g of SiO\u003csub\u003e2\u003c/sub\u003e, 3 g of stearic acid (CH₃(CH₂)₁₆COOH), and 100 mL of isopropyl alcohol was first homogenized in an ultrasonic homogenizer for 15 minutes, then stirred at 75\u0026deg;C for 6 hours at 350 rpm in a reflux system. At the end of the process, the solution was filtered, washed several times with ethanol, and dried in a vacuum oven at 75\u0026deg;C for 2 hours.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. PMMA Synthesis\u003c/h2\u003e\u003cp\u003eThe experimental study began with the synthesis of PMMA from MMA via emulsion polymerization. Potassium persulfate (KPS) was used as an initiator at a 1:200 molar ratio to MMA. Sodium dodecyl sulfate (SDS) was used as the emulsifying agent at a 3% by weight ratio to MMA. KPS and SDS were placed into a beaker. Then, 250 mL of distilled water was added, and the mixture was stirred at 500 rpm for 10 minutes using a magnetic stirrer. After this, 100 mL of MMA was added to the solution, followed by another 5 minutes of mixing. The prepared mixture was transferred to a four-neck round-bottom flask reactor placed on a reactor stirrer-equipped mantle heater. The reactor had a nitrogen gas inlet, a reflux condenser, and a thermometer. Nitrogen gas was passed through the system to remove oxygen during the experiment. Oxygen has a destructive effect on radicals, so this step ensured an inert environment. The mixture in the reactor was heated to 75\u0026deg;C and kept at this temperature for 5 hours to carry out the polymerization reaction. For molecular weight and monomer conversion calculations, 5 mL samples were regularly taken at 1-hour intervals during the synthesis stage and precipitated in 50 mL of methanol. At the end of the experiment, the remaining sample was transferred to a beaker and precipitated in methanol. The precipitated samples were left at room temperature for several days and filtered through a vacuum pump filtration system. After filtration, the obtained samples were first left in a desiccator for several days and then dried in a vacuum oven at 70\u0026deg;C for 4 hours.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Synthesis of PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e Nanocomposite by Solution Blending Method\u003c/h2\u003e\u003cp\u003eIn the solution blending method, PMMA polymer produced by emulsion polymerization, modified SiO\u003csub\u003e2\u003c/sub\u003e, and commercial PLA were used. PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite plates were produced with weight ratios of 30:70, 50:50, and 70:30 for PLA:PMMA and modified SiO\u003csub\u003e2\u003c/sub\u003e content of 2%, 5%, and 10% by weight. For example, for a PLA:PMMA weight ratio of 50:50, 2 g of PLA, 14 mL of THF, and 6 mL of N,N-DMF were added to a flask and mixed at 60\u0026deg;C at 350 rpm using a magnetic stirrer until the PLA dissolved. At the same time, 2 g of PMMA and 15 mL of THF were placed in a beaker and mixed at room temperature using a magnetic stirrer until the PMMA completely dissolved. Then, SiO\u003csub\u003e2\u003c/sub\u003e was added in varying weight ratios (0%, 2%, 5%, and 10%) to prepare the PMMA/SiO\u003csub\u003e2\u003c/sub\u003e mixture. After both solutions were homogeneously dissolved, they were combined, and the resulting mixture was further stirred for 5 minutes on the magnetic stirrer. The obtained mixture was poured into petri dishes with a diameter of 50 mm. The samples in the petri dishes were left at room temperature for several days to form nanocomposite plates.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Synthesis of PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e Nanocomposite by In-situ Method\u003c/h2\u003e\u003cp\u003eSDS and modified SiO\u003csub\u003e2\u003c/sub\u003e with different weight percentages (2%, 5%, and 10%) were placed in a beaker, and 250 mL of distilled water was added. The resulting solution was stirred on a magnetic stirrer at 500 rpm for 10 minutes and mixed in an ultrasonic homogenizer for 10 minutes. KPS was then added to the solution and stirred for another 10 minutes on the magnetic stirrer. Afterward, 100 mL of MMA was added to the mixture and stirred for five more minutes on the magnetic stirrer. The steps involved in PMMA synthesis were then sequentially applied.\u003c/p\u003e\u003cp\u003ePLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite plates were produced by the in-situ polymerization method using PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites containing 2%, 5%, and 10% modified SiO\u003csub\u003e2\u003c/sub\u003e by weight, with weight ratios of 50:50, 70:30, and 30:70 for PLA:PMMA. As an example, for a 50:50 weight ratio of PLA:PMMA, 2 g of PLA, 14 mL of THF, and 6 mL of N,N-DMF were placed in a flask and stirred at 60\u0026deg;C at 350 rpm using a magnetic stirrer until the PLA dissolved. Meanwhile, 2 g of PMMA/SiO\u003csub\u003e2\u003c/sub\u003e containing 2%, 5%, and 10% SiO\u003csub\u003e2\u003c/sub\u003e and 15 mL of THF were placed in a beaker and stirred at room temperature on a magnetic stirrer until dissolved. After both solutions were homogeneously dissolved, the solutions were combined, and the resulting mixture was stirred for five more minutes on the magnetic stirrer. The obtained mixture was poured into four 50 mm diameter petri dishes. The samples in the petri dishes were left at room temperature for several days to form nanocomposite plates. The samples synthesized using the solution blending and in-situ methods are provided in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSynthesized PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA:PMMA (wt %)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e (wt %)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSample name\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e30:70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30PLA/70PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30PLA/70PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e50:50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50PLA/50PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e70:30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70PLA/30PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70PLA/30PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5. Water Absorption Test of Nanocomposites\u003c/h2\u003e\u003cp\u003eAfter the synthesis process of the samples was completed using solution blending and in-situ methods, the water absorption percentages of the plates were determined. To determine the percentage of water absorption, 25 mL of distilled water was added to 60 mm diameter Petri dishes, and the samples were weighed before being placed into the Petri dishes filled with distilled water. The Petri dishes were then placed on a flat surface at room temperature. Afterward, the samples were removed from the Petri dishes every two days for 14 days and dried with a tissue. The dried samples were weighed, and the values were recorded. After each measurement, the distilled water in the Petri dishes was replaced, and the samples were placed back into the Petri dishes.\u003c/p\u003e\u003cp\u003eThe percentage of water absorption in the water absorption test was determined using Eq.\u0026nbsp;\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:\\text{W}\\text{a}\\text{t}\\text{e}\\text{r}\\:\\text{A}\\text{b}\\text{s}\\text{o}\\text{r}\\text{p}\\text{t}\\text{i}\\text{o}\\text{n}\\:\\left(\\mathbf{\\%}\\right)=\\frac{{\\text{W}}_{wet}-\\:{\\text{W}}_{dry}}{{\\text{W}}_{dry}}x100$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere,\u003c/p\u003e\u003cp\u003eW\u003csub\u003e\u003cem\u003edry\u003c/em\u003e\u003c/sub\u003e is the initial weight of the sample (in grams) before exposure to water\u003c/p\u003e\u003cp\u003eW\u003csub\u003e\u003cem\u003ewet\u003c/em\u003e\u003c/sub\u003e is the weight of the sample (in grams) after exposure to water.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6. Biodegradability Analysis\u003c/h2\u003e\u003cp\u003eThe study conducted biological and enzymatic degradation analyses to investigate the biodegradability properties of the synthesized nanocomposites.\u003c/p\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.6.1. Biodegradation process of nanocomposites\u003c/h2\u003e\u003cp\u003eThe nanocomposite samples containing different weight percentages of silica (0%, 2%, 5%, and 10%) with 30:70, 50:50, and 70:30 PLA:PMMA ratios, synthesized using the solution blending and in-situ methods, were buried in two different soil types, humus soil and cactus soil, for biodegradability analysis. Before being buried in the soil, the nanocomposite samples were weighed for biodegradability analysis and imaged using a light microscope. After the necessary measurements for the analysis were completed, the samples were placed in protective mesh to prevent material loss during the burial process (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e). During the burial of the nanocomposite plates, care was taken to ensure that all samples were at the same depth and that the surface area in contact with the soil was maximized. After the burial process, both soil types were exposed to equal amounts of sunlight and irrigated three times a week to prevent the soil from losing moisture. The samples were observed for six months and removed from the soil at two-month intervals to measure weight loss. Before weight loss analysis, the samples were cleaned with a brush, washed with distilled water, and dried in a vacuum oven at 70\u0026deg;C until a constant weight was achieved. After drying, the samples were weighed, their microscopic images were taken, and the burial process was repeated. For humus soil, a high-yield soil type with a pH value of 6-7.5, containing coir, perlite, leonardite, peat, and earthworm compost, was selected, while for cactus soil, a high-yield soil type with a pH value of 5-7.5, containing earthworm compost, leonardite, perlite, and peat, was chosen.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e2.6.2. Enzymatic degradation process of nanocomposites\u003c/h2\u003e\u003cp\u003eAn enzymatic degradation solution was prepared and left for incubation for the biodegradability analysis of the synthesized nanocomposite samples. The enzymatic degradation solution was prepared using phosphate buffer solution with a pH value of 7.4 and lipase enzyme (L3126 code) produced from pig pancreas. Initially, the samples were weighed, and then a 1 mg mL\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e lipase phosphate buffer solution was prepared. Each sample was placed in a petri dish containing 20 mL of the degradation solution and incubated at room temperature. Weight loss analysis was performed after the samples were left for 15 days under suitable conditions. Before the weight loss analysis, the samples were washed with distilled water and dried in a vacuum oven at 70\u0026deg;C until constant weight was achieved.\u003c/p\u003e\u003cp\u003eIn the biological and enzymatic degradation experiments, the percentage of weight loss determined the degradation amount. The percentage of weight loss was determined using Eq.\u0026nbsp;\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:\\text{W}\\text{e}\\text{i}\\text{g}\\text{h}\\text{t}\\:\\text{L}\\text{o}\\text{s}\\text{s}\\:\\text{P}\\text{e}\\text{r}\\text{c}\\text{e}\\text{n}\\text{t}\\text{a}\\text{g}\\text{e}\\left(\\text{\\%}\\right)=\\frac{{W}_{0}-{W}_{t}}{{W}_{0}}x100$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhere:\u003c/p\u003e\u003cp\u003eW\u003csub\u003e0\u003c/sub\u003e: Initial weight of the sample before degradation (in grams)\u003c/p\u003e\u003cp\u003eW\u003csub\u003e\u003cem\u003et\u003c/em\u003e\u003c/sub\u003e: Weight of the sample after degradation (in grams)\u003c/p\u003e\u003cp\u003eThis equation gives the percentage of weight lost by the sample due to degradation (either biological or enzymatic) over the time period of the experiment.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e2.7. Characterizations\u003c/h2\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e2.7.1. Fourier transform infrared analysis (FTIR)\u003c/h2\u003e\u003cp\u003eStearic acid (SA) modified and neat SiO\u003csub\u003e2\u003c/sub\u003e nanoparticles FTIR analysis was performed and the success of the modification was evaluated. Also a sample from two different nanocomposite production techniques was selected for FTIR analysis. This selection was made to evaluate the effects of the production techniques on the chemical structure and functional groups of the nanocomposite. Plates obtained by pouring into petri dishes were used in the analysis of nanocomposites. FTIR analyses were performed using the Jasco ATR-FT/IR-4700 device.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e2.7.2. Thermal analysis\u003c/h2\u003e\u003cp\u003eThermogravimetric analyses were performed using Perkin Elmer Pyris 1 TGA and SDT650 brand TGA-DSC devices in a nitrogen atmosphere, at a temperature range of 25\u0026deg;C \u0026ndash; 600\u0026deg;C, at a heating rate of 10\u0026deg;C min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. A nitrogen atmosphere was preferred to prevent oxidation and other reactions that could interfere with the thermal degradation process.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e2.7.3. Hardness measurement (Shore-D) and tensile test\u003c/h2\u003e\u003cp\u003eHardness measurements were performed using a Bareiss HPE II brand Shore-D hardness device to determine the mechanical properties of the synthesized nanocomposites. Hardness measurements were made using plates obtained by pouring into petri dishes. Each hardness measurement was repeated three times, and the average value was used. Tensile testing was performed to investigate the mechanical properties of the synthesized nanocomposites. The tensile test was carried out at a rate of 0.5 mm min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e using an INSTRON 4411 device.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\u003ch2\u003e2.7.4. Scanning electron microscopy (SEM)\u003c/h2\u003e\u003cp\u003eSEM analyses were carried out using a QUANTA 400F Field Emission Scanning Electron Microscope to examine the surface characteristics of nanocomposite samples synthesized via solution blending and in-situ methods.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section3\"\u003e\u003ch2\u003e2.7.5. Light microscopy\u003c/h2\u003e\u003cp\u003eLight microscope was employed to identify the phases before and during degradation and to determine the extent and nature of the degradation. Light microscopy images of the synthesized nanocomposite samples were captured using a Leica M205 C light microscope before and during the biodegradation period.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"3. Experimental Results","content":"\u003cp\u003eThis section presents the results of all experimental studies, analyses, tests, and characterization methods conducted to investigate the thermal, mechanical, and biodegradability properties during the synthesis of PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites.\u003c/p\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Results of Monomer Conversion and Viscosity Average Molecular Weight\u003c/h2\u003e\u003cp\u003eThe monomer conversion values for PMMA polymer and PMMA/SiO2 nanocomposites containing different weight ratios of SiO\u003csub\u003e2\u003c/sub\u003e (2%, 5%, and 10%) synthesized using the in-situ method are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eThe viscosity average molecular weight (M\u003csub\u003ev\u003c/sub\u003e) values were determined using a Ubbelohde viscometer and the Mark-Houwink-Sakurada equation with K\u0026thinsp;=\u0026thinsp;3.4 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e and a\u0026thinsp;=\u0026thinsp;0.83 [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Chloroform was used as the solvent, and the experiments were conducted at 25\u0026deg;C. The calculated viscosity average molecular weight values for PMMA and the samples containing different weight ratios of SiO\u003csub\u003e2\u003c/sub\u003e are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMonomer Conversion and Viscosity Average Molecular Weight Values\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMonomer conversion [%]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eViscosity Average Molecular Weight\u003c/p\u003e\u003cp\u003e[g mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e52.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e448,259.14\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e55.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e196,489.67\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e57.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e173,955.27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e56.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e169,417.63\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAs seen in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, an increase in the amount of SiO\u003csub\u003e2\u003c/sub\u003e leads to a rise in the percent monomer conversion. Barari and Sharifi-Sanjani [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e10\u003c/span\u003e] in their study synthesized poly(methyl methacrylate)/silica nanocomposites via emulsion polymerization using dimethylaminoethyl methacrylate and mentioned that the polymerization also occurred on the silica surface. This finding supports the notion that the addition of SiO\u003csub\u003e2\u003c/sub\u003e generally enhances the monomer conversion rates during the polymerization process in this study as well. The reinforcing material can influence the molecular weight in polymer synthesis, either directly or indirectly. This effect depends on the chemical structure of the reinforcing material, its interaction with the polymer matrix, and the polymerization conditions. If the reinforcing material participates in chemical reactions, it can increase the molecular weight; however, physically, it may restrict the mobility of the polymer chains. This restriction could limit chain growth and result in shorter polymer chains. As seen in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the viscosity average molecular weight of the synthesized PMMA is 448,259.14 g mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. It is observed that the molecular weights of PMMA/SiO\u003csub\u003e2\u003c/sub\u003e samples containing different weight ratios of SiO\u003csub\u003e2\u003c/sub\u003e are relatively lower than the synthesized PMMA. This situation is similar to the work of Bikiaris et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e11\u003c/span\u003e], where they prepared nanocomposites with silica reinforcement and suggested that as the silica amount increased, the rate of intrinsic viscosity increase slowed down due to a higher degree of branching. A lower intrinsic viscosity rate leads to shorter chain structures. Moreover, the statement by Barari and Sharifi-Sanjani [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e10\u003c/span\u003e] that polymerization also occurs on the silica surface suggests the formation of relatively shorter chain structures in the material.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e3.2. FTIR Analysis Results\u003c/h2\u003e\u003cdiv id=\"Sec20\" class=\"Section3\"\u003e\u003ch2\u003e3.2.1. ATR-FTIR results of SiO\u003csub\u003e2\u003c/sub\u003e surface modification\u003c/h2\u003e\u003cp\u003eThe FTIR analysis results of stearic acid (SA) modified and neat SiO\u003csub\u003e2\u003c/sub\u003e nanoparticles are given in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWhen FTIR spectra are examined, the typical peaks for neat SiO\u003csub\u003e2\u003c/sub\u003e and modified SiO\u003csub\u003e2\u003c/sub\u003e are: the peak at 454 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e shows Si-O-Si asymmetric bending, the peak at 797 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e shows Si-O-Si symmetric stretching, the peak at 952 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e shows Si-OH bond stretching, and the peak at 1067 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e shows Si-O-Si asymmetric stretching. The peak observed at 1407 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in the modified SiO\u003csub\u003e2\u003c/sub\u003e spectrum shows COO- symmetric stretching originating from SA. Similarly, the peak at 2900 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e originating from SA shows C-H symmetric stretching of CH\u003csub\u003e2\u003c/sub\u003e, and the peak at 2978 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e shows C-H symmetric stretching of CH\u003csub\u003e3\u003c/sub\u003e [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. When neat and modified SiO\u003csub\u003e2\u003c/sub\u003e spectra are compared, it is concluded that the modification process with SA is successful.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section3\"\u003e\u003ch2\u003e3.2.2. ATR-FTIR results of PLA/PMMA/SiO₂ nanocomposites\u003c/h2\u003e\u003cp\u003eThe PLA/PMMA/SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite with a PLA:PMMA ratio of 50:50 for both production techniques was selected for FTIR analysis to reflect the properties of both polymers equally and to observe the characteristic peaks of the reinforcement material more clearly. The FTIR spectrum of the 50PLA/50PMMA/10SiO₂ samples synthesized by solution blending and in-situ methods is given in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe IR spectra and experimental data of the functional groups for PLA, PMMA, and SiO\u003csub\u003e2\u003c/sub\u003e in the literature are given in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In addition, the peaks between 2300\u0026thinsp;\u0026minus;\u0026thinsp;1800 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e wave numbers are the peaks belonging to the ATR crystal.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eIR spectra of the functional groups and experimental data\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eComponent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eFunctional group\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e\u003cp\u003eWavenumber [cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLiterature\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eExperimental\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSolution blending\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eIn-Situ\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC \u0026ndash; H\u003c/p\u003e\u003cp\u003e(belonging to CH\u003csub\u003e2\u003c/sub\u003e and CH\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3000\u0026ndash;2800\u003csup\u003e[13, 14]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2943, 2994\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2948, 2994\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC\u0026thinsp;=\u0026thinsp;O\u003c/p\u003e\u003cp\u003e(stretching vibration)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1750\u0026ndash;1720\u003csup\u003e[14, 15]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1726, 1756\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1730, 1756\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026ndash; CH\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003cp\u003e(stretching vibration)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1480\u0026ndash;1452\u003csup\u003e[13, 15]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1453\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1454\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eO \u0026ndash; CH\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e\u003cp\u003e(deformation)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1387\u003csup\u003e[15]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1384\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1385\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026ndash; CH \u0026ndash;\u003c/p\u003e\u003cp\u003e(asymmetric bending)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1363\u003csup\u003e[15]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1360\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1360\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eC \u0026ndash; O\u003c/p\u003e\u003cp\u003e(stretching vibration)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1270\u0026ndash;1080\u003csup\u003e[14, 15]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1087, 1130, 1183\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1084, 1129, 1181\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSi \u0026ndash; O \u0026ndash; Si\u003c/p\u003e\u003cp\u003e(symmetric stretching)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e800\u003csup\u003e[16]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e752\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e752\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSi \u0026ndash; O \u0026ndash; Si\u003c/p\u003e\u003cp\u003e(asymmetric bending)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e450\u003csup\u003e[16]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e456\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e457\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe FTIR analysis results of both production methods show the characteristic peaks of PLA, PMMA, and SiO₂. The samples obtained by solution blending and in-situ methods confirm the chemical structure and the existence of functional groups stated in the literature. The amplitude of the Si \u0026ndash; O \u0026ndash; Si symmetric stretching peak expected around 800 cm\u003csup\u003e-1\u003c/sup\u003e was interpreted as shifting towards lower frequency due to the interaction of silica with the polymer matrix and was observed at 752 cm\u003csup\u003e-1\u003c/sup\u003e. These results reveal that the synthesis methods used create the nanocomposite's expected chemical structure, which can be clearly observed in the FTIR spectrum.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\u003ch2\u003e3.3. TGA Analysis Results\u003c/h2\u003e\u003cp\u003eThermal properties of PLA/PMMA/SiO₂ nanocomposites containing different weight ratios of PLA:PMMA and different ratios of SiO\u003csub\u003e2\u003c/sub\u003e (0%, 2%, 5% and 10%) obtained by solution blending and in-situ methods were investigated using TGA. TGA thermogram of the nanocomposite samples obtained by the solution blending method is given in Fig. S2. Data obtained from TGA thermograms are given in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eAccording to literature data, degradation for neat PLA starts at approximately 320\u0026deg;C and continues up to 380\u0026deg;C, while for PMMA it starts at approximately 340\u0026deg;C and continues up to 420\u0026deg;C [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eWhen the TGA thermograms of the samples are examined, it is seen that there is some weight loss in the range of 150\u0026ndash;200\u0026deg;C. This weight loss is thought to occur due to the initial separation of volatile components that remain in the nanocomposite samples and cannot be completely removed from the structure. TGA thermograms analyses show that the initial degradation temperatures of some composites and nanocomposites occur in two stages. This situation is like the study conducted by Teoh et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e17\u003c/span\u003e] on the thermal resistance of poly(lactic acid)/poly(methyl methacrylate) blends containing flame retardants, and they stated that there are two initial degradation temperatures for PLA and PMMA blends. It was observed that the initial degradation temperature in 30PLA/70PMMA composite, 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e, and 50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites produced by the solution blending method occurred in two steps. For 30PLA/70PMMA, the first degradation temperature was observed at 325.9\u0026deg;C, while the second was at 380.5\u0026deg;C. For 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite, it was observed as 321.2\u0026deg;C and 380.0\u0026deg;C, respectively, and for 50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite, it was observed as 323.6\u0026deg;C and 381.8\u0026deg;C, respectively. These values ​​are consistent with the degradation temperatures of PLA and PMMA reported in the study by Teoh et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This situation shows that PLA and PMMA have separate degradation processes. The first degradation temperature belongs to PLA, and the second to PMMA. The highest initial and final degradation temperature is 30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite. At the same time, it is the highest sample with 9.874% weight remaining without degradation. This situation can be explained by the high PMMA content by weight and the high SiO\u003csub\u003e2\u003c/sub\u003e content compared to other composites and nanocomposites. In addition, it was observed that the thermal stability of PLA/PMMA/SiO₂ nanocomposites containing the same PLA:PMMA ratio by weight increased in proportion to the increasing SiO\u003csub\u003e2\u003c/sub\u003e content. The addition of SiO₂ affects the thermal stability and the weight percentage remaining without degradation. The reason for this is that SiO\u003csub\u003e2\u003c/sub\u003e is resistant to high temperatures. Especially PLA/PMMA/SiO₂ nanocomposites containing 10% SiO₂ show resistance up to 450\u0026deg;C.\u003c/p\u003e\u003cp\u003eThe thermal properties of PLA/PMMA/SiO₂ nanocomposites prepared by the in-situ method were comprehensively evaluated by TGA, and the TGA thermograms are given in Fig. S3. Data obtained from TGA thermograms are given in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. It was observed that the initial degradation temperature of 30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e and 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e nanocomposites produced by the in-situ method occurred in two steps. This shows the existence of separate degradation processes for PLA and PMMA. For 30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite, the first degradation temperature was observed at 328.7\u0026deg;C and the second degradation temperature was observed at 377.2\u0026deg;C. For 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite, the first degradation temperature was observed at 325.1\u0026deg;C, and the second degradation temperature was observed at 382.5\u0026deg;C. The final degradation temperature for 30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite was 454.8\u0026deg;C, and for 50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite as 440.4\u0026deg;C. At the same time, the final degradation temperature of 454.8\u0026deg;C is the highest value in both production methods. This situation shows that the in-situ method has relatively higher thermal stability than the solution blending method despite the same amount of PLA:PMMA and SiO\u003csub\u003e2\u003c/sub\u003e by weight. This situation can be explained by the better dispersion of additives into the polymer matrix during in-situ polymerization and the formation of strong bonds by providing a more homogeneous structure.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eData obtained from TGA thermograms\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMethod\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eInitial degradation Temperature [\u0026deg;C]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eFinal degradation temperature [\u0026deg;C]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eFinal residue [%]\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003eSolution blending\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e325.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e380.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e434.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.853\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e332.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e449.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9.874\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e321.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e380.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e438.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.761\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e323.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e381.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e447.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.863\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e70PLA/30PMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e314.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e418.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.616\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e316.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e440.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.979\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eIn-situ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e328.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e377.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e454.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.481\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e325.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e382.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e438.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.320\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e328.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e450.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.841\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e322.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e435.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.420\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePLA added to PMMA to provide biodegradability has a negative effect on thermal resistance. Thermal resistance decreased as the amount of PLA in the sample increased. The data obtained from the graphs show that SiO₂ addition improves thermal stability by increasing the thermal degradation temperature of the polymer matrix. These results reveal that the distribution and ratio of SiO₂ in the polymer matrix significantly affect thermal resistance. As a result, the thermal properties of PLA/PMMA/SiO₂ composites can be optimized depending on the percentage of the additive. These findings show that SiO₂ addition is an effective strategy to increase the performance of polymer composites in high-temperature applications. In addition, it was observed that SiO₂ addition increased the thermal stability of the composites with both methods, and this effect was more pronounced with the in-situ method. This superiority is due to the more homogeneous distribution of SiO₂ in the polymer matrix and the formation of a stronger matrix with the in-situ method. At the same time, thermal stability is thought to increase with the interaction between the carbonyl groups in PMMA and the hydroxyl groups of the SiO\u003csub\u003e2\u003c/sub\u003e surface.\u003c/p\u003e\u003cp\u003ePLA and PMMA are both polar polymers containing ester groups, but their solubility parameters and thermal behaviours differ; therefore, most PLA/PMMA blends are immiscible and exhibit phase-separated morphologies with weak interfacial adhesion. Two-stage degradation was observed in some samples, indicating that separate degradation processes for PLA and PMMA still exist\u0026mdash;i.e., partial phase separation. Especially in nanocomposite samples with a high PMMA ratio, there is a two-stage degradation. The addition of SiO₂ did not eliminate the pronounced degradation peaks of PLA and PMMA, meaning full miscibility was not achieved. However, it can be argued that, particularly in the in-situ synthesis method, SiO₂ particles settle at the interface and restrict chain movements, thus increasing miscibility between PLA and PMMA and making the phase boundary less pronounced.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec23\" class=\"Section2\"\u003e\u003ch2\u003e3.4. DSC Analysis Results\u003c/h2\u003e\u003cp\u003ePLA/PMMA/SiO₂ samples, synthesized by the solution blending method in weight ratios of 30:70 and 50:50 of PLA:PMMA and containing 10% SiO₂, were analyzed by DSC to determine their glass transition temperature (T\u003csub\u003eg\u003c/sub\u003e) and melting points (T\u003csub\u003em\u003c/sub\u003e). The results of the DSC analysis are presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. DSC curves are given in Fig. S4. For comparison purposes, the DSC results of PMMA produced by the emulsion polymerization method, as reported by Uzunoglu and Altinten [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e19\u003c/span\u003e], and commercially available PLA from the same brand, are also provided in the same table. In this literature study, since PMMA is amorphous, only the T\u003csub\u003eg\u003c/sub\u003e value is present. This value was determined as 110.10\u0026deg;C for PMMA and 59.53\u0026deg;C for neat PLA. The T\u003csub\u003em\u003c/sub\u003e value for neat PLA was determined to be 174.71\u0026deg;C.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eData obtained from DSC curves along with PMMA and PLA values\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMethod\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eT\u003csub\u003eg\u003c/sub\u003e [\u0026deg;C]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eT\u003csub\u003em\u003c/sub\u003e [\u0026deg;C]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSolution blending\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003en/a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e170.61\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003en/a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e165.37\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eIn-situ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e116.39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e170.99\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003en/a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e172.95\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEmulsion Polymerization\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e110.10\u003csup\u003e[19]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003en/a\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNeat\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e59.53\u003csup\u003e[19]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e174.71\u003csup\u003e[19]\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAccording to literature data, the Tg value for neat PMMA ranges between 100\u0026ndash;110\u0026deg;C, while this value for PLA is between 55\u0026ndash;60\u0026deg;C. Due to PMMA's inherently higher viscosity compared to PLA, it restricts the movement of PLA chains [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The T\u003csub\u003eg\u003c/sub\u003e value for the 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the in-situ method was observed to be 116.39\u0026deg;C. This value being close to the T\u003csub\u003eg\u003c/sub\u003e of PMMA can be explained by the high mass content of PMMA and the restriction of PLA chain mobility. Additionally, the T\u003csub\u003eg\u003c/sub\u003e value being higher than that of neat PMMA is thought to be due to the effect of the SiO₂ reinforcement material, which has high thermal resistance, added to increase thermal durability. In the study by Teoh and Chow (2018), miscibility was observed in all blend ratios (i.e., 80/20, 60/40, 40/60, and 20/80) of PLA/PMMA blends prepared using the melt compounding technique. DMA results revealed the presence of a single T\u003csub\u003eg\u003c/sub\u003e for all PLA/PMMA blends, indicating miscibility, and showed that their thermal behavior was dependent on the composition [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Similarly, in our study, the presence of a single T\u003csub\u003eg\u003c/sub\u003e value for the mixture can be considered as an indicator of PLA/PMMA miscibility. In other samples, the T\u003csub\u003eg\u003c/sub\u003e value was observed, which is related to the intercalation state where the molecules are trapped in two-dimensional galleries. This trapping leads to decreased molecular mobility and hinders the segmental movements required during the glass transition, making the T\u003csub\u003eg\u003c/sub\u003e value more challenging to observe distinctly.\u003c/p\u003e\u003cp\u003eThere is a high degree of similarity between the T\u003csub\u003em\u003c/sub\u003e values of the 30PLA/70PMMA/10SiO₂ nanocomposites synthesized by the solution blending and in-situ methods. This is attributed to the high content of PMMA. However, when the PMMA ratio is reduced, the T\u003csub\u003em\u003c/sub\u003e value of the 50PLA/50PMMA/10SiO₂ sample synthesized by the in-situ method is higher than that of the sample produced by the solution blending method. This suggests that the in-situ method could be preferred for synthesizing PLA/PMMA and PLA/PMMA/SiO₂ composites with high thermal resistance.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\u003ch2\u003e3.5. Shore-D Hardness Analysis Results\u003c/h2\u003e\u003cp\u003eThe Shore-D hardness measurement results for the solution blending and in-situ method samples are presented in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eShore-D hardness measurement values of nanocomposites produced by solution blending and in-situ methods\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eShore-D hardness\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSolution blending\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eIn-situ\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e30PLA/70PMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e32.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e30PLA/70PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e25.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e30PLA/70PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e23.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e21.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e29.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50PLA/50PMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e23.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50PLA/50PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e22.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50PLA/50PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e25.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e27.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e70PLA/30PMMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e70PLA/30PMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e15.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e70PLA/30PMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e14.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e12.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/2SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e32.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/5SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePMMA/10SiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe Shore-D hardness value of PLA was determined to be 22.2. On the other hand, the Shore-D hardness value of PMMA was 32.7, indicating that PMMA is a more rigid and durable material than PLA. According to the hardness measurement results, the hardness values of the samples vary depending on the PLA:PMMA ratio, the amount of added silica, and the production method. In mixtures with a high PMMA content, higher hardness values were observed. No significant change in hardness values was observed with the addition of SiO₂ at different weight ratios to PMMA, whether by solution blending or in-situ methods, and values similar to the hardness of neat PMMA were obtained. In PLA/PMMA/SiO₂ nanocomposites, however, a significant decrease in hardness values was observed as the PLA content increased. Adding SiO₂ to polymers containing different PLA:PMMA ratios generally reduced the hardness. In nanocomposites with a 50:50 weight ratio of PLA:PMMA, both methods observed an increase in Shore-D hardness values with the increasing SiO₂ content. In nanocomposites with weight ratios of 30:70 and 70:30 of PLA:PMMA, however, increased SiO₂ content decreased in Shore-D hardness values in both methods. When comparing nanocomposite production methods, the in-situ method generally resulted in higher hardness values than the solution blending method. It is suggested that the higher hardness values of the nanocomposites produced by the in-situ method are due to a more homogeneous distribution, providing better material integrity.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec25\" class=\"Section2\"\u003e\u003ch2\u003e3.6. Tensile Test Results\u003c/h2\u003e\u003cp\u003eThe tensile test results for the 50PLA/50PMMA/2SiO₂, 50PLA/50PMMA/10SiO₂ nanocomposites synthesized by the in-situ method, and the 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the solution blending method, are presented in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eTensile test results\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMethod\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMax. tensile strength [MPa]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBreaking load [N]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eUltimate tensile strength at break [%]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eElongation at break [mm]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSolution blending\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30PLA/70PMMA/10SiO₂\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.648\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e79.374\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.084\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.251\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eIn-situ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/2SiO₂\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.903\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e34.093\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.155\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.293\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50PLA/50PMMA/10SiO₂\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.055\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e43.702\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.460\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e2.076\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAccording to the tensile test data, as the PMMA content increases, the material's maximum tensile strength and breaking load increase. The samples with a 50:50 PLA:PMMA ratio exhibit lower tensile strength compared to those with a 30:70 PLA:PMMA ratio, which is believed to be due to the stress-concentrating effect induced by the addition of nanosilica and the susceptibility of PLA to hydrolytic degradation. Since PMMA is generally more resistant to hydrolytic degradation, it is not affected by this. The blending of PLA with PMMA may reduce the elongation at break of the PLA/PMMA/SiO₂ composites due to the low elongation at break of pure PLA. However, the addition of SiO₂ compensates for this reduction. When the ultimate tensile strength and elongation at break values of the nanocomposites with a 50:50 PLA:PMMA ratio are compared, it was observed that the nanocomposite containing 10% SiO₂ has higher values than the one containing 2% SiO₂. This indicates that the incorporation of nanosilica particles into the PLA/PMMA polymer imparts ductile behavior to the nanocomposite.\u003c/p\u003e\u003cp\u003eThe tensile test results of the 50PLA/50PMMA/2SiO₂, 50PLA/50PMMA/10SiO₂ synthesized by the in-situ method, and the 30PLA/70PMMA/10SiO₂ synthesized by the solution blending method support the Shore-D analysis results. The 30PLA/70PMMA/10SiO₂ nanocomposite synthesized by the solution blending method has the highest tensile strength of 1.648 MPa and a breaking load of approximately 79 N. In the study, it was observed that as the PMMA content increased, both the maximum tensile strength and the breaking load of the material also increased. The lower tensile strength of the samples with a 50:50 PLA:PMMA ratio compared to those with a 30:70 PLA:PMMA ratio, both containing equal amounts of SiO₂, may be due to the stress-concentrating effect induced by the addition of nanosilica and the susceptibility of PLA to hydrolytic degradation, as noted by Wu et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The blending of PLA with PMMA may reduce the elongation at break of PLA/PMMA/SiO₂ composites due to the low elongation at break of pure PLA. However, the addition of SiO₂ compensates for this reduction. In the work of Wu et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], it was mentioned that the spherical shape and smooth, non-porous surfaces of SiO₂ can act as a lubricant in polymers, reducing the coefficient of friction. This lubricating effect of SiO₂, based on shear and ductile behavior, suggests that the inclusion of nanosilica particles in PLA/PMMA blends can increase the toughness of PLA/PMMA/SiO₂ composites and impart ductile behavior to the material.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec26\" class=\"Section2\"\u003e\u003ch2\u003e3.7. Water Absorption Test Results\u003c/h2\u003e\u003cp\u003eFactors affecting the hydrolysis sensitivity of a particular polymer include water permeability and solubility, which are influenced by the polymer's chemical structure and physical state [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Water absorption testing frequently indicates a polymer's tendency to undergo hydrolytic degradation. Polymers can absorb water, swell, undergo hydrolysis, and then degrade in the environment. A high tendency for water absorption may indicate a high propensity for hydrolytic degradation [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Graphs showing the % water absorption values for PLA and PMMA are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, graphs for the % water absorption values of samples produced by the solution blending method are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, and graphs for the % water absorption values of samples synthesized by the in-situ method are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eResistance to water absorption is one of the important properties of biocomposite materials used in specific applications, such as packaging. Furthermore, water absorption plays a critical role in determining the biodegradability of PLA, as its degradation occurs through hydrolysis. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the increasing % water absorption values of PLA over time indicate its biodegradability. In contrast, for PMMA, low % water absorption values over time indicate resistance to degradation. It has been observed that the PLA:PMMA ratios and SiO₂ additions significantly effect the water absorption percentages. In samples produced by solution blending and in-situ methods, it was observed that as the PLA content increased, the water absorption percentages also increased. Similarly, in samples containing different amounts of SiO₂, the water absorption percentage increased with the amount of SiO₂. When comparing the two nanocomposite production methods, the water absorption percentages of nanocomposites produced by the solution blending method are higher than those obtained by the in-situ method. Among the samples synthesized by the solution blending method, the 70PLA/30PMMA/10SiO₂ nanocomposite exhibited the highest water absorption rate of 23.90%. In the in-situ method, the 50PLA/50PMMA/10SiO₂ nanocomposite showed the highest water absorption at 18.48%. Water can increase the activity of microorganisms that accelerate biological degradation. However, excessive water absorption may negatively affect the mechanical properties of the composite. Therefore, a moderate level of water absorption is preferred.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec27\" class=\"Section2\"\u003e\u003ch2\u003e3.8. Biological Degradation Results\u003c/h2\u003e\u003cp\u003eNanocomposite samples containing 30:70, 50:50, and 70:30 PLA:PMMA ratios with different silica percentages (0%, 2%, 5%, and 10%) synthesized by the solution blending and in-situ methods were buried in two different soil types for biodegradability analysis. Since microorganisms in different soil types have varying biodegradation capabilities, the samples were buried in cactus soil and humus-rich soil. The biological degradation process of the buried samples was monitored for 6 months. The samples were regularly removed from the soil every two months, and weight loss analysis was conducted. Graphs showing the weight loss percentage values for PLA and PMMA are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, for the samples buried in humus-rich soil and synthesized by the solution blending method in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, for the samples synthesized by the in-situ method in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, for the samples buried in cactus soil and synthesized by the solution blending method in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, and for the samples synthesized by the in-situ method in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAnalyses conducted on the biodegradation characteristics of PLA, PMMA, and PLA/PMMA/SiO₂ nanocomposite samples indicate that the biodegradation rate varies depending on the soil type and the sample's composition. The degradation of PLA occurs in two distinct stages. During the first stage, hydrolysis takes place, wherein high-molecular-weight PLA chains are hydrolyzed into lower-molecular-weight oligomers. This reaction is influenced by temperature and humidity, and can be accelerated in the presence of acids or bases. In the second stage, microorganisms present in the soil further break down these low-molecular-weight compounds into CO₂, water, and humus, thereby completing the degradation process. Throughout this process, factors such as the presence of microorganisms in the soil, weekly watering of the pots in which the PLA specimens are buried, and equal exposure to sunlight have been found to accelerate the degradation of PLA [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn general, samples buried in cactus soil exhibited higher biodegradation rates than those in humus-rich soil. This situation may be attributed to the cactus soil's higher moisture retention capacity. In a related study, Nikolić et al. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e24\u003c/span\u003e] investigated the biodegradation of polystyrene-graft-starch copolymers in three different soil types. They reported that microorganisms responsible for biological degradation showed varying activity levels and degradation efficiency under identical conditions, with the highest weight loss observed in cactus soil. In cactus soil, the 70PLA/30PMMA/10SiO₂ nanocomposite synthesized via the in-situ method showed the highest biodegradation rate, with approximately 34.37% weight loss after 180 days. Similarly, in humus-rich soil, the highest biodegradation rate was also observed in the same sample, with a weight loss of 28.93%. The 70PLA/30PMMA sample without silica exhibited a weight loss of 26.09% in humus soil and 19.69% in cactus soil. These findings suggest that the presence of SiO₂ in the nanocomposite enhances the biodegradability of PLA, an effect that is particularly pronounced in samples with lower PLA content.\u003c/p\u003e\u003cp\u003eIt was further observed that increasing the silica content in the nanocomposites resulted in greater weight loss. Similarly, higher PLA content also correlated with increased weight loss. Samples synthesized via the in-situ method demonstrated greater weight loss than those produced by solution blending, likely due to their more homogeneous structure and improved material integrity. These findings highlight that PLA content, silica content, and the synthesis method employed significantly affect nanocomposites' biodegradability.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec28\" class=\"Section2\"\u003e\u003ch2\u003e3.9. Enzymatic Degradation Results\u003c/h2\u003e\u003cp\u003eAn enzymatic degradation solution was prepared for the biodegradability analysis of the synthesized nanocomposites, and samples were subjected to incubation. A phosphate buffer solution with a pH of 7.4 and lipase enzyme (catalog number L3126) derived from porcine pancreas was used for the enzymatic degradation medium. Weight loss analyses were performed after incubation under appropriate conditions for 15 days. The percentage weight loss results of PLA, PMMA, and samples synthesized by the solution blending method and in situ method are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn the presence of phosphate buffer, the polymer blends initially undergo hydrolysis, followed by enzymatic degradation. It was observed that the phosphate buffer solution, used alongside the lipase enzyme during the enzymatic degradation process, accelerates the biodegradation. Due to its sensitivity to hydrolytic degradation, PLA undergoes hydrolysis in the phosphate buffer solution. The enzymatic degradation results demonstrate the biodegradability of PLA samples. An increase in PLA content within the samples led to a corresponding increase in enzymatic degradation.\u003c/p\u003e\u003cp\u003eAdding SiO₂ to PLA:PMMA samples with different ratios (30:70, 50:50, and 70:30) without silica enhanced enzymatic degradation. Furthermore, it was determined that increasing the SiO\u003csub\u003e2\u003c/sub\u003e content in nanocomposites resulted in higher weight loss. After 15 days, neat PLA exhibited a weight loss of 4.4%. In contrast, the 70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite samples showed the highest degradation rates, with 4.83% weight loss in the solution blending method and 5.17% in the in-situ method. The incorporation of SiO\u003csub\u003e2\u003c/sub\u003e accelerated the biodegradability of PLA and compensated for the reduced degradation caused by PMMA. This effect may be attributed to forming a more porous structure within the polymer matrix, enabling easier enzyme access to polymer chains.\u003c/p\u003e\u003cp\u003eMoreover, while neat PMMA exhibited a weight loss of only 0.55% after 15 days, an increase in the SiO\u003csub\u003e2\u003c/sub\u003e content led to a proportional increase in weight loss. When comparing the biodegradability of samples synthesized via solution blending and in-situ methods, it was observed that the in-situ synthesized samples exhibited higher weight loss. This is likely due to the homogeneous structure and well-dispersed silica phase in the in-situ samples, which enhances their interaction with enzymes in the solution and promotes a higher degradation rate.\u003c/p\u003e\u003cp\u003eWhen comparing the biodegradation and enzymatic degradation of the 70PLA/30PMMA/10SiO\u003csub\u003e2\u003c/sub\u003e nanocomposite synthesized by the in-situ method\u0026mdash; which exhibited the highest weight loss after 15 days\u0026mdash; it can be concluded that enzymatic degradation proceeds approximately 15% faster than biodegradation under the tested conditions.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec29\" class=\"Section2\"\u003e\u003ch2\u003e3.10. Light Microscopy Images\u003c/h2\u003e\u003cp\u003eBased on the results of the biological and enzymatic degradation analyses, light microscopy images of the 70PLA/30PMMA/10SiO₂ nanocomposite samples\u0026mdash;which exhibited the highest weight loss and were produced via both solution blending and in-situ methods\u0026mdash;are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e. Additionally, light microscopy images of the 30PLA/70PMMA/2SiO₂ nanocomposites\u0026mdash;showing the lowest weight loss for both synthesis methods\u0026mdash;are shown in the same figure.\u003c/p\u003e\u003cp\u003eLight microscopy images taken prior to degradation revealed that the surfaces of the samples synthesized via the in-situ method were smoother, indicating a more homogeneous structure in these samples. This observation supports the conclusion that the in-situ synthesis method yields nanocomposites with a more uniform morphology. Light microscopy images captured at 60, 120, and 180 days after burial in soil showed increased surface deformation correlating with the progression of degradation. As degradation advanced, voids formed on the sample surfaces due to structural breakdown, and these voids became filled with soil particles\u0026mdash;appearing as dark spots in the images. The increasing presence of soil particles on the sample surfaces visually supports the increasing percentage of weight loss recorded in the biodegradation analysis. When comparing the amount of soil accumulated on the surfaces of the samples with the highest weight loss (buried in cactus soil) to those with the lowest weight loss (buried in humus-rich soil), the difference is observable. This situation further confirms the influence of soil type on the extent of biodegradation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec30\" class=\"Section2\"\u003e\u003ch2\u003e3.11. SEM Analysis\u003c/h2\u003e\u003cp\u003eSEM analyses were carried out using a QUANTA 400F Field Emission Scanning Electron Microscope to examine the surface characteristics of nanocomposite samples synthesized via solution blending and in-situ methods. SEM images of the 70PLA/30PMMA/10SiO₂ and 30PLA/70PMMA/10SiO₂ nanocomposites synthesized by the in-situ method are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e, while SEM images of the 50PLA/50PMMA/5SiO₂ and 50PLA/50PMMA/10SiO₂ nanocomposites synthesized via the solution blending method are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eSEM images reveal that the PLA/PMMA blend exhibits a typical single-phase morphology, indicating good miscibility between PLA and PMMA. It was observed that SiO₂ nanoparticles were more uniformly dispersed in the samples synthesized via the in-situ method, whereas a more heterogeneous distribution was evident in the samples produced using the solution blending method. As the amount of silica particles increased, the continuous phase became less pronounced, and a more nodular structure was observed.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study aimed to enhance the biodegradability of PMMA\u0026mdash;a polymer known for its lack of environmental degradability\u0026mdash;by blending it with PLA, a biodegradable polymer. Additionally, incorporating SiO₂ nanoparticles was intended to improve the resulting material's thermal stability and mechanical properties. Due to the moisture-absorbing nature of silica, it is also expected that the presence of SiO₂ would accelerate the biodegradation process at the end of the material's service life, facilitated by the PLA content. PLA/PMMA/SiO₂ nanocomposites were prepared using both solution blending and in-situ methods, with varying SiO₂ contents (0%, 2%, 5%, and 10% by weight) and PLA:PMMA ratios (30:70, 50:50, and 70:30). The addition of PLA, while imparting biodegradability to PMMA, had a negative impact on thermal stability. As the PLA content increased, a corresponding decrease in thermal resistance and hardness was observed. However, data obtained from TGA indicated that the inclusion of SiO₂ enhanced the thermal degradation temperature of the polymer matrix, thereby improving thermal stability. When comparing the nanocomposite fabrication methods, the in-situ method typically yielded higher thermal resistance and hardness than the solution blending method. This superiority is attributed to the more homogeneous dispersion of SiO₂ and the formation of a stronger polymer matrix during in-situ synthesis. According to tensile test data, as the amount of PMMA increases, the maximum tensile strength and breaking load of the material also increases. It was observed that SiO\u003csub\u003e2\u003c/sub\u003e increases the toughness of the material and gives it ductile behavior. The results of the soil burial test for PLA, PMMA, and PLA/PMMA/SiO₂ nanocomposite samples indicate that the biodegradation rates vary depending on the soil type and the sample composition. Generally, samples buried in cactus soil exhibited higher biodegradation rates than those buried in humus soil. This situation can be attributed to the cactus soil's higher moisture retention capacity. It was observed that the weight loss increased with the addition of PLA and silica content in the nanocomposites. The presence of SiO₂ in the nanocomposites was found to accelerate/increase the biodegradability of PLA, with this effect being more pronounced in samples with lower PLA content. Samples synthesized using the in-situ method, with their more homogeneous structure and material integrity, showed higher weight loss than the relatively heterogeneous solution-blended samples. The enzymatic degradation results were also in accordance with the biological degradation findings. The addition of SiO₂ accelerated the biodegradability of PLA and compensated for the slower degradation rate of PMMA. It is well known that the dispersion of nanofillers within the polymer matrix affects the physical properties of the polymer. The homogeneous distribution of nanofillers and the optimal interactions between the nanofillers and the polymer matrix can effectively enhance the thermal, mechanical, and rheological properties of the polymer matrix.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Gazi University Scientific Research Projects with project number FYL-2023-8607. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization:\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e[Berrak Cansu Cilek Kocak], [Ayla Altinten]; Methodology: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Formal analysis and investigation:\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e[Berrak Cansu Cilek Kocak], [Ayla Altinten]; Writing\u0026ndash;original draft preparation: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Writing \u0026ndash; review and editing: [Ayla Altinten]; Funding acquisition: [Berrak Cansu Cilek Kocak], [Ayla Altinten]; Supervision: [Ayla Altinten].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by Gazi University Scientific Research Projects with project number FYL-2023-8607. TGA, DSC and SEM analyses were carried out at METU Central Laboratory.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eJonoobi M, Harun C, Mathew AP, Oksman K (2010) Mechanical properties of cellulose nanofiber (cnf) reinforced polylactic acid (PLA) prepared by twin screw extrusion. Comp Sci Technol 70:1742-1747. \u003cstrong\u003ehttps://doi.org/10.1016/j.compscitech.2010.07.005\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003eVega-Gonzalez A, Subra-Paternault P, Lopez-Periago AM, Garcia-Gonzalez CA, Domingo C (2008) Supercritical CO\u003csub\u003e2\u003c/sub\u003e antisolvent precipitation of polymer networks of L-PLA, PMMA and PMMA/PCL blends for biomedical applications. 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Carbohyd Polym 213:50-58. \u003cstrong\u003ehttps://doi.org/10.1016/j.carbpol.2019.02.074\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003eBhat DK, Kumar MS (2006) Biodegradability of PMMA blends with some cellulose derivatives. J Polym Environ 14:385-392. \u003cstrong\u003ehttps://doi.org/10.1007/s10924-006-0032-5\u003c/strong\u003e\u003c/li\u003e\n \u003cli\u003eNikolic V, Velickovic S, Popovic A (2014) Biodegradation of polystyrene-graft-starch copolymers in three different types of soil. Environ Sci Pollut R 21:9877-9886. \u003cstrong\u003e10.1007/s11356-014-2946-0\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"polymeric nanocomposites, biodegradable polymers, SiO2, PMMA, PLA","lastPublishedDoi":"10.21203/rs.3.rs-7409193/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7409193/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, biodegradable nanocomposites were developed by blending polylactic acid (PLA) with polymethyl methacrylate (PMMA) and incorporating stearic acid-modified silica nanoparticles (SiO₂) to enhance thermal and mechanical properties. PMMA was synthesized via emulsion polymerization. PLA/PMMA/SiO₂ nanocomposites were then prepared using in-situ and solution blending methods with varying PLA:PMMA ratios (30:70, 50:50, 70:30 wt%) and SiO₂ contents (0, 2, 5, 10 wt%). The nanocomposite surface morphology was analyzed using scanning electron microscopy (SEM) and light microscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize the thermal behavior, and mechanical properties were evaluated via Shore-D hardness test and tensile test. Biodegradability was assessed through both biodegradation and enzymatic degradation tests. For the biodegradation study, samples were buried in cactus and humus soil, monitoring weight loss as an indicator of biodegradability. Microscopic imaging was used to analyze the structural changes that occurred before and after soil exposure. The results showed that, in both degradation methods, higher SiO₂ content led to an increased weight loss percentage. 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