Non-toxic and Carbon-neutral Green Composites Produced From Polylactic Acid (PLA) With Waste Sunflower Stem

Non-toxic and Carbon-neutral Green Composites Produced From Polylactic Acid (PLA) With Waste Sunflower Stem | 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 Non-toxic and Carbon-neutral Green Composites Produced From Polylactic Acid (PLA) With Waste Sunflower Stem Dilşad Öztürk, Özlem Mıhçıokur This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7582866/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Environmental concerns have significantly influenced the use of biopolymers. Polylactic acid (PLA), a key player in the biopolymer market, is utilised in food packaging, 3D printing, and textiles, and exhibits considerable potential for further development. This study investigates the feasibility of incorporating waste sunflower stalks (WSS) as a reinforcement material into PLA composites to improve material properties and promote sustainability. The composites were prepared with 20% and % 30% WSS concentrations and systematically evaluated for their mechanical, thermal, and morphological properties. The results indicate a significant increase in flexural strength with the addition of WSS, with the 30% WSS composite reaching a value of 96.4385 MPa compared to 93.6538 MPa for pure PLA. Thermogravimetric analysis revealed that WSS-modified composites exhibited an approximately 30–40°C increase in thermal decomposition temperature. Scanning electron microscopy revealed increased porosity in the 30% WSS composite, indicating potential applications as an adsorbent material. Furthermore, water swelling tests demonstrated that the composites maintained their resistance to water absorption. These findings suggest that WSS-reinforced PLA composites exhibit improved thermal properties and increased structural porosity compared to pure PLA, making them potentially suitable for applications such as sound and heat insulation. Additionally, they could serve as environmentally friendly adsorbents for removing pollution from environmental matrices. Biopolymer Polylactic acid (PLA) Sunflower stem waste Bio-composite Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Plastic production is estimated to be approximately 370 million tons (Mt) worldwide and is predicted to double within 20 years [ 1 ]. These fossil-derived plastics play a significant role in Turkey, with a total plastic production of 9.6 million tons, ranking first in packaging material production at 4 million tons and second in construction material production at approximately 2.5 million tons [ 2 ]. Plastic pollution poses serious environmental threats on a global scale due to its permanence in the environment and the release of toxic substances during its degradation [ 3 ]. Population growth and climate change highlight the need for biodegradable alternatives to fossil-based plastics. The emergence of bioplastics reflects essential research and innovation, with studies showing that creating high-value raw materials is a priority for developing countries like Türkiye. Biopolymers are polymers derived from biological sources, such as plants, animals, or microorganisms, and are biodegradable. Synthetic polymers made by humans from these sources are also considered biopolymers. Biodegradable polymers are divided into natural and synthetic based on their origin [ 3 ]. Natural biopolymers are produced using polysaccharides (such as chitin, cellulose, and starch), proteins (including collagen, gluten, and gelatine), and oils (such as fatty acids and wax). They are derived from renewable energy sources [ 4 ]. On the other hand, these synthetic biopolymers can be manufactured under specific conditions. Microorganisms in the soil can break down and transform them into harmless, environmentally friendly chemicals. Aliphatic polyesters are a type of polymer characterised by their unique structure, which includes ester functional groups and can take on either a linear or branched form. These materials are created by combining aliphatic (non-aromatic) diols with dicarboxylic acids. Aliphatic polyesters, such as polyhydroxyalkanoates (PHA), polyglycolide (PGA), polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB), and poly(lactic acid) (PLA), are biopolymers composed of repeating units bonded by ester linkages [ 5 ]. Their main features are biodegradability, thermoplastic behaviour, and machinable mechanical properties. This makes them suitable for various applications, including packaging materials, the bottle industry, textiles, and the agricultural and pharmaceutical sectors. Unlike other thermoplastics, PLA is relatively inexpensive, has a low carbon footprint, and exhibits several beneficial mechanical properties compared to other biodegradable polymers, making it a popular material [ 6 , 7 ]. Various sectors worldwide drive the global PLA market. While the demand for polylactic acid (PLA) reached 270,000 tons in 2019 due to the increase in disposable product demand worldwide during the COVID-19 pandemic, it increased by approximately 20% in 2020 [ 6 ]. Today, the production of PLA is projected to surpass 2.4 million metric tons by 2027 [ 7 ]. PLA and other bioplastic polymer production capacities by global market segment are shown in Fig. 1. PLA is a thermoplastic polyester derived from cornstarch, 100% biodegradable, approximately eight times recyclable, and compostable at the end of its expected useful life. Pure PLA has an approximately tensile strength (40-52.5 MPa), flexural strength (52.5–66 MPa), compressive strength (48–62 MPa), impact strength (2–6 KJ/m 2 ), an electrical conductivity (5.6x10 − 9 S/m) with low density (1.2 g/cm 3 ), less water absorption (1.2%) and contact angle (59.57 o ) as physical properties [ 8 ], [ 9 ], [ 10 ], [ 11 ]. However, PLA is very brittle, has poor heat resistance (heat deflection temperature: 55–65°C), and exhibits a slow crystallisation rate [ 12 ]. Improving PLA's weak properties (low thermal resistance, lightness, brittleness, and low decomposition reaction rate) using methods such as physical mixing, chemical mixing, and copolymerisation is crucial for expanding its usage areas in the industry [ 13 ]. Recent studies indicate that to improve the mechanical properties of PLA, some additives must be added to the pure PLA form. Figure 1. Usage percentages of biodegradable plastics the globally [ 14 ] Sunflowers contain large amounts of fibre and hydrophobic patches of high-quality protein, including 11S globulin and 2S albumin, which are known to form stable emulsions, making them an underutilised plant protein [ 15 ]. The sunflower stem (SS) is part of the flowering plant. Moreover, this plant has a hairy structure and is quite robust. Although cellulose-containing sunflowers, whose crystal plane is estimated to be approximately 3.3 nm, are not trees, their mechanical strength is comparable to that of tree species [ 16 ]. However, its negative features are its internal pore volume and thermal conductivity, which prevent shrinkage [ 17 ]. The approximate percentage composition of sunflower stem constituents in dry matter is as follows: cellulose ranges from 35% to 50%, lignin from 15% to 25%, hemicellulose from 15% to 35%, and water constitutes about 10% to 15%. Additionally, the protein content is approximately 2% to 3%, and the oil content is around 1% to 2% [ 18 ]. Other organic compounds and substances make up a small portion of the total. These proportions may vary depending on the plant's growth stage and cultivation conditions. The molecular structures of PLA and SS (representative cellulose chemical structure), along with the preparation steps for the composite, are shown in Fig. 2. Turkey is among the world's leading sunflower producers (Helianthus annuus L.), with an annual production of approximately 30–35 million metric tons. The total yearly sunflower production in Türkiye contributes approximately 6% to global sunflower production, amounting to over 1.6 million tons [ 18 , 19 , 20 ]. Additionally, approximately 20% of the products are derived from SS. The volume of sunflower residues produced worldwide has a substantial environmental impact, averaging 5 tons of dry matter per hectare per year [ 16 ]. Therefore, post-harvest waste from sunflowers remains a global problem, although it is primarily utilised in bioethanol production [ 19 ]. Although some producer villagers use these wastes for heating, Turkey faces a significant storage problem, with an average of 600,000 tons stored annually [ 20 ]. Figure 2. Synthesis Steps and Chemical Form of the PLA/SS Composite Material SS composites are a crucial research area for environmental sustainability and the development of new materials. Such composites are primarily used in packaging, construction, automotive, and biomedical fields and are valuable as recycled materials. Polylactic acid (PLA) is a widely used bioplastic that can be combined with various materials to create a range of composite products. In today’s studies, the PLA matrix is developed by blending carbon fibres, glucose additives, bio-ceramics, mineral fillers, and natural plant fibres, such as kenaf fibres, which are a popular type. These biodegradable, bio-based polymer composites are eco-friendly and highly sustainable. Moreover, PLA is the only biopolymer that requires less energy and emits fewer greenhouse gases [ 21 ]. The studies on the mechanical properties of PLA composites with different reinforcement fibres are summarised in Table 1 . This study focused on the large-scale production of PLA/SS composite materials and the development of eco-friendly PLA composite materials to meet the need for high-strength, sustainable materials across various industries. It has discussed the mechanical property gains of the PLA/SS composite and presented the rationale for using SSs as reinforcement material to improve the properties of PLA. Additionally, the abundance of sunflower waste in Turkey, particularly the substantial amount of sap waste, is a key motivation for this research. Table 1 Comparison of the mechanical properties of PLA composites with different reinforcement fibres Ref. Composites PLA % (w/w) Deg. Temp. ( o C) Impact Strength (kJ/m 2 ) Tensile Strength (MPa) Flexural Strength (MPa) Young’s modulus (MPa) [ 22 ] Pure PLA 100 173.8 1.6 62.1 93.65 1175 [ 23 ] Recycled PLA 30 168 16.96 33.82 - - [ 24 ] PLA/Bamboo 70 258 5.7 58.7 106.2 - [ 22 ] PLA/sisal/coir 70 - 2.1 49 96 - [ 25 ] PLA/SF 70 233 0.032 34.72 47.43 - [ 26 ] PLA/Al 90 205 - 68.10 - 5260 [ 27 ] PLA/GF 80 385 2.75 62.60 115.20 - [ 28 ] PLA/wood 80 260 - 21.64 335 - [ 29 ] PLA/CF 20 - 4.67 35.54 - - [ 30 ] PLA/Jute-Nettle 70 - 16.20 2.426 157.33 69.68 [ 31 ] PLA/CF5.5/PBO 70 360 17.2 63.65 116.07 - [ 32 ] PLA/CF-Graphen 98 - 6.52 45.56 64.87 1040–1260 [ 33 ] PLA/Si 3 N 4 95 - 2.625 54.82 78.37 2676 Present Work PLA/SS 70 325 - 43.57 96.43 429 CF: Carbon Fiber, KF: Kenaf Fiber, SF: Sisal Fiber, FDT: Fused Deposition Technique 2. Materials and methods SS waste is obtained from sunflowers harvested from the Bünyan district of Kayseri. The PLA biopolymer granule (3-mm nominal size) (CAS No: 26100-51-6) was purchased from Sigma-Aldrich, a Merck company. Experimental processes (SS extrusion, injection moulding, fused filament fabrication techniques) were conducted at the Erciyes University Textile Engineering Research Laboratories. 2.1. Preparation for Composite Material Waste of SS collected from the Bünyan district was broken into small pieces, which were ground in a mill grinder and converted to powder form. Similarly, granular PLA also turned into powder form using the same grinder. Powdered PLA and sunflower stalk were weighed on analytical precision scales. After that, they were kept in the oven at 80 0 C for approximately 12 hours to remove the moisture. Two different concentrations were prepared by mixing 20% (w/w) and 30% (w/w) blended SS with PLA. The obtained mixtures were prepared for use in the extrusion machine (Fig. 2(a), (b), (c), (d)). 2.1.1. Plasticization of SS/ PLA mixture The mixture of SS/PLA, after removing the moisture removed by the heating process, was then placed into a twin-screw extruder, melted, and extruded. According to the extrusion conditions, the inlet temperature at which the mixture enters the extruder is 40°C. The remarkable temperatures are divided into five regions: Region A (160°C), Region B (165°C), Region C (170°C), Region D (175°C), and Region E (180°C), along with their corresponding transition temperatures. The sample exiting the hot melt extruder was then cooled using a fan with airflow assistance and subsequently turned into small pieces by the granulator device (Fig. 2). 2.1.2. Injection Molding of Granular PLA/SS mixture The SS/PLA granules, reduced to small pieces in the granulator device, were placed in the injection machine, and each sample was held there for 4 minutes at 185°C. At the end of the period, the mould in the machine was opened, and the composite material was removed. The same processes were applied to pure polylactic acid (PLA). As a result of the experiment, the composite materials were obtained for pure PLA and PLA with 20% and 30% SS additives, respectively. 2.1.3. Mechanical Properties The tensile test applied to the produced composites is by the ASTM D638 standard. 10 mm/min test rules will be provided in 3 parallel ways in the tensile testing device. The bending test was conducted on the composites produced according to the ASTM D-790 standard using a bending test machine at a test speed of 10 mm/min, with three parallel tests. The experiments were performed in triplicate. The tensile strength, Young’s modulus, and elongation at break were calculated using the following equations (1), (2), (3), and (4). The test data obtained using the MATLAB R2015a code was replaced, and the graph was drawn within the MATLAB program (Fig. 3). Tensile strength (MPa) σt = F/A (1) Flexural strength (MPa) σf = 3PL/2bd 2 (2) Young’ s modulus (MPa) = σ/ε 96 (3) Elongation at break (%) = L f – L o / L o × 100 (4) Where F = Force, A = Area, P = max load, L = span, P = width, d = depth σ = Tensile Stress, ε = Strain, Lf = Final length, Lo = Initial length 2.1.4. Thermal Properties Thermal properties were assessed via Thermogravimetric Analysis (TGA), with TGA curves illustrating the relationship between weight loss and temperature for various samples (pure PLA, 20% SS + PLA, and 30% SS + PLA), thereby providing insights into their thermal stability. Figure 3. Elongation at break (%) calculation MATLAB code 2.1.5. Morphological Properties The morphological properties of the composite materials were investigated through Scanning Electron Microscopy (SEM). This technique facilitated the examination of the surface topography of PLA-based composites containing different concentrations of sunflower stem (SS), allowing for an assessment of how microstructural variations might influence mechanical behaviour (Magnification: 100X and 150X). 2.1.6. Swelling Properties The dry weights of composite materials containing 20% and 30% sunflower stalk additives were determined using a precision scale. Their dimensions were subsequently measured with a calliper. The specimens were then immersed in distilled water at room temperature. After a 10-minute immersion period, the samples were removed, surface water was carefully blotted, and their weight and dimensions were re-measured. The water temperature was maintained at a constant level throughout the experiment. This process was repeated iteratively until the composite materials exhibited dimensional stability. 3. Results and discussion 3.1. Tensile and flexural properties Figure 4 illustrates the mechanical properties, including tensile strength, elongation at break and Young's modulus, of pure PLA and the fabricated composites in different concentrations of SS additives, in both granular and filament forms. The results indicate that as the SS content increases, the tensile modulus of PLA/SS composites improves. Figure 4. Elongation at Break-Young Modulus-Tensile Strength of Pure PLA and PLA/SS composites with 20% and 30% concentrations. As the SS content increases, a trend is observed in the flexural strength. On the other hand, the tensile strength shows a continuous decreasing trend. The lowest tensile strength (43.57 MPa) and the highest flexural strength (96.43 MPa) are observed in the composite with the highest SS content. Pure PLA shows the lowest flexural strength (93.6538 MPa). However, this increase in strength is accompanied by a significant decrease in the modulus of elasticity, indicating a loss of hardness and increased material flexibility. In addition, the elongation at break decreases with higher SS content (from 5.47% to 3.34%), which can be interpreted as indicating that the porous structure in the material hurts its rupture strength. These findings demonstrate that the incorporation of SS into PLA results in a softer yet more brittle composite, with the substantial decline in the modulus of elasticity highlighting the reduction in material hardness. 3.2. Thermogravimetric Analyses Figure 5 illustrates the thermogravimetric analysis (TGA) curves for three different samples: pure PLA, 20% SS + PLA, and 30% SS + PLA. These curves illustrate how the percentage of weight loss varies with increasing temperature, offering insights into the thermal stability of each material. The data clearly show that pure PLA experiences a rapid and significant decrease in weight within a narrow temperature range, as evidenced by the marked points A1 and B1. (A1: ~340 0 C, A2: ~277 0 C, A3: ~273 0 C; B1: ~380 0 C, B2: ~335 0 C, B3: ~325 0 C) Figure 5. TGA Properties of Pure PLA and PLA/SS Composite Materials This rapid degradation indicates that pure PLA begins to thermally decompose at relatively low temperatures, reflecting its limited heat resistance. In contrast, the curves for the samples containing SS, both at 20% and 30%, shift toward higher temperatures, as indicated by markers A2 and B2. This shift suggests that the addition of SS particles to the PLA matrix effectively enhances the material’s thermal stability. Not only does this imply that these composites can withstand higher temperatures before decomposing, but it also indicates potential for broader industrial applications where higher heat resistance is required. Furthermore, the curve corresponding to the 30% SS-loaded sample shows a similar shift towards higher temperatures, even surpassing the stability observed in the 20% SS composite. This trend suggests a dose-dependent improvement in thermal performance, indicating that increasing SS content could further enhance the material’s resistance to thermal degradation. In summary, the analysis reveals that pure PLA undergoes rapid degradation within a specific and narrow temperature range, underscoring its susceptibility to heat. Conversely, the incorporation of SS additive markedly improves the thermal stability of the biodegradable polymer. These findings provide valuable insights into how the inclusion of SS particles can modify the thermal properties of PLA, making it more suitable for applications where higher temperature endurance is essential. Overall, the results reinforce the potential of SS-reinforced PLA composites as advanced, thermally stable bioplastics with promising industrial applications. Considering the increase in thermal resistance of the material and the significant impact of the SS additive on the porous structure, it has become clear that further research is needed to investigate the usability of this material as a thermal barrier and sound insulator in the production of composite materials. In terms of environmental engineering, the addition of the 10% SS additive to the composite material creates a porous structure, increasing the material's surface area. It shows that it can be an effective adsorbent in pollutant removal. 3.3. Morphological Analyses of the tested specimens In this part of the study, the surface morphology of PLA-based composites with varying SS contents was examined using Scanning Electron Microscope (SEM) images, and the effects of microstructural differences on potential mechanical performance were evaluated. According to Fig. 6, the composite with 20% SS exhibits a smoother surface and contains longer, fibre-like structures, indicating lower surface roughness. In the composite with 30% SS, the surface appears much rougher and more irregular, with pores and fragments. As the SS content increases from 20% to 30%, the surface area increases significantly. This increase can strengthen the structural bonds or fibre-matrix interactions of the composite, demonstrating the bio-composite material's ability to serve as an eco-friendly adsorbent. However, this feature is utilised in the production of certain industrial materials, which increases surface brittleness and susceptibility to cracking. Figure 6. SEM images of PLA/SS composites Surface morphology is known to have a direct impact on mechanical performance in composites [ 22 ]. This is because materials with more porous and irregular surfaces may gain strength due to the internal structure but may be more susceptible to surface cracks and breakage. Additive manufacturing offers applications related to filament material failure and poor surface quality due to suboptimal process parameters. Accordingly, it is considered a 20% more suitable option to produce 3D PLA parts in load-bearing structural applications that require high strength. 3.4. Swelling Characterisation The results obtained after waiting for the composite material, prepared by performing weight percentage swelling tests in pure water, to swell for 24 hours (until it reaches equilibrium), are given in Fig. 7. Figure 7. The swelling results of PLA/SS composites PLA/SS composites, whose dry weights were measured on a precision scale and whose dimensions were measured separately with a calliper, were subjected to a swelling test in pure water. Swelling increases over time for both compositions. The 30% SS + PLA (blue line) exhibits a higher swelling percentage at all time points compared to the 20% SS + PLA (black line). Peak swelling for the 30% SS + PLA occurs at approximately 16% at around 20 minutes, and then slightly decreases or plateaus. The 20% SS + PLA exhibits a lower maximum swelling, reaching approximately 6% at the same time. 4. Conclusion In conclusion, this study demonstrates that waste sunflower stems (SS) can be effectively utilised to develop sustainable and eco-friendly PLA-based composites. The incorporation of SS improved the tensile strength and thermal stability of PLA, making it more suitable for applications requiring higher temperature resistance. However, increasing SS content significantly reduced the ductility of the material, with elongation at break decreasing by 14.26% and 38.94% for 20% and 30% SS incorporation, respectively. SEM analysis revealed that higher SS content increased the porosity of the composites, indicating potential applicability as eco-friendly adsorbents in future environmental remediation efforts. Moreover, swelling tests showed that 30% SS + PLA composites exhibited higher swelling percentages at all time points compared to 20% SS + PLA, with a maximum swelling of approximately 16% occurring at 20 minutes. These findings suggest that while SS reinforcement enhances the mechanical and thermal properties of PLA, optimisation of the filler ratio is crucial to balance strength, ductility, and functional performance. Overall, SS-reinforced PLA composites present a promising route towards the development of advanced, thermally stable, and sustainable bioplastics with broad industrial applications, while also offering potential benefits as environmentally friendly adsorbent materials. Declarations Author Contribution D.O. wrote the main manuscript D.O. prepared figures 1-7.O.M. did the experiments. Acknowledgements We want to thank Prof. Dr. Mehmet Doğan, a faculty member of the Department of Textile Engineering at Erciyes University, for providing us with the laboratory infrastructure necessary for conducting experimental measurements. We also appreciate the support of his team members, Ayşegül Erdem and Alperen Kaplan. Asst. Refik Alp Çağdaş, faculty member of the Department of Metallurgical and Materials Engineering at Erciyes University, for his valuable recommendations, discussions and unique experience in materials science. References Walker TR, Fequet L (2023) Current trends of unsustainable plastic production and micro(nano)plastic pollution. TrAC Trends Anal Chem 160:116984 PAGEV, Turkish Plastics Industrialists Research Türkiye Plastics Industry Monitoring Report, 2017. [Online]. Available: Doppalapudi S, Jain A, Khan W, Domb AJ (2014) Biodegradable polymers-an overview. Polym Adv Technol 25(5):427–435 Pooja N, Chakraborty I, Rahman MH, Mazumder N (2023) An insight on sources and biodegradation of bioplastics: a review, 3 Biotech. 13(7):1–22 Bikiaris DN (2013) Nanocomposites of aliphatic polyesters: An overview of the effect of different nanofillers on enzymatic hydrolysis and biodegradation of polyesters. Polym Degrad Stab 98(9):1908–1928 Swetha TA, Ananthi V, Bora A, Sengottuvelan N, Ponnuchamy K, Muthusamy G, Arun A (2023) A review on biodegradable polylactic acid (PLA) production from fermentative food waste - Its applications and degradation. Int J Biol Macromol 234:123703 Tadi SP, Mamilla RS (2024) Fabrication of SS 316L particle-infilled PLA composite filaments from cast-off bi-material extrudates for 3D printing applications. Waste Manag 193:386–397 Pappu A, Pickering KL, Thakur VK (2019) Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding. Ind Crops Prod 137:260–269 Mtibe A, Motloung MP, Bandyopadhyay J, Ray SS (2021) Synthetic Biopolymers and Their Composites: Advantages and Limitations—An Overview. Macromol Rapid Commun 42(15):1–28 Satsum A, Busayaporn W, Rungswang W, Soontaranon S, Thumanu K, Wanapu C (2022) Structural and mechanical properties of biodegradable poly(lactic acid) and pectin composites: using bionucleating agent to improve crystallization behavior. Polym J 54(7):921–930 Vengadesan E, Muralidharan TAS, Hrishikesh KD (2025) Hybrid Bio-composites Reinforced with Natural Wood Saw Dust and Eco-friendly Graphite: Evaluation of Physical, Mechanical, and Thermal Properties. Fibers Polym 26(3):833–854 Cisar J, Drohsler P, Pummerova M, Sedlarik V, Skoda D (2023) Composite based on PLA with improved shape stability under high-temperature conditions. Polym J 276:125943 Shou T, Wu Y, Yin D, Hu S, Wu S, Zhao X, Zhang L (2024) In-situ self-crosslinking strategy for super-tough polylactic acid/ bio-based polyurethane blends. Int J Biol Macromol 261:129757 da Silva Pens CJ, Klug TV, Stoll L, Izidoro F, de Flores SH (2024) Oliveira Rios, Poly (lactic acid) and its improved properties by some modifications for food packaging applications: A review. Food Packag Shelf Life 41:101230 Sneharani AH (2019) Curcumin–sunflower protein nanoparticles—A potential antiinflammatory agent. J Food Biochem 43(8):1–8 Thomas LH, Forsyth VT, Martel A, Grillo I, Altaner CM, Jarvis MC (2014) Structure and spacing of cellulose microfibrils in woody cell walls of dicots, Cellulose, 21 (6) 3887–3895 Chabannes M, Nozahic V, Amziane S (2015) Design and multi-physical properties of a new insulating concrete using sunflower stem aggregates and eco-friendly binders. Mater Struct Constr 48(6):1815–1829 Eom IY, Yu JH (2015) Structural characterization of the solid residue produced by hydrothermal treatment of sunflower stalks and subsequent enzymatic hydrolysis. J Ind Eng Chem 23:72–78 Jung CD, Yu JH, Eom IY, Hong KS (2013) Sugar yields from sunflower stalks treated by hydrothermolysis and subsequent enzymatic hydrolysis. Bioresour Technol 138:1–7 Hanifi B, Sevinç AH, Eken M (2012) Ayçiçek Sapı Ve Tekstil Atıkları İle Yalıtım Malzemesi Üretimi, KSU Mühendislik Bilim. Derg 15(1):1–5 Phiri R, Mavinkere Rangappa S, Siengchin S, Oladijo OP, Dhakal HN (2023) Development of sustainable biopolymer-based composites for lightweight applications from agricultural waste biomass: A review. Adv Ind Eng Polym Res 6(4):436–450 Duan J, Wu H, Fu W, Hao M (2018) Mechanical properties of hybrid sisal/coir fibers reinforced polylactide biocomposites. Polym Compos 39(1):E188–E199 Atakok G, Kam M, Koc HB (2022) Tensile, three-point bending and impact strength of 3D printed parts using PLA and recycled PLA filaments: A statistical investigation. J Mater Res Technol 18:1542–1554 Young WB, Tsao YC (2015) The mechanical and fire safety properties of bamboo fiber reinforced polylactide biocomposites fabricated by injection molding. J Compos Mater 49(22):2803–2813 Chaitanya S, Singh I, Song JI (2019) Recyclability analysis of PLA/Sisal fiber biocomposites, Compos. Part B Eng 173:106895 Zhang X, Chen L, Mulholland T, Osswald TA (2019) Effects of raster angle on the mechanical properties of PLA and Al/PLA composite part produced by fused deposition modeling. Polym Adv Technol 30(8):2122–2135 Wang G, Zhang D, Wan G, Li B, Zhao G (2019) Glass fiber reinforced PLA composite with enhanced mechanical properties, thermal behavior, and foaming ability. Polymer 181:121803 Vigneshwaran K, Venkateshwaran N (2019) Statistical analysis of mechanical properties of wood-PLA composites prepared via additive manufacturing. Int J Polym Anal Charact 24(7):584–596 Kamaal M, Anas M, Rastogi H, Bhardwaj N, Rahaman A (2021) Effect of FDM process parameters on mechanical properties of 3D-printed carbon fibre–PLA composite. Prog Addit Manuf 6(1):63–69 Chaudhary V, Radhakrishnan S, Das PP, Dwivedi SP, Mishra S, Gupta P (2023) Development and mechanical characterization of PLA composites reinforced with jute and nettle bio fibers. Biomass Convers Biorefinery 15(3):3443–3455 Wan H, Sun C, Xu C, Wang B, Chen Y, Yang Y, Tan H, Zhang Y (2024) Synergistic reinforcement of polylactic acid/wood fiber composites by cellulase and reactive extrusion. J Clean Prod 434:140207 Abas M, Habib T, Khan I, Noor S (2024) Definitive screening design for mechanical properties enhancement in extrusion-based additive manufacturing of carbon fiber-reinforced PLA composite. Prog Addit Manuf 10(1):139–157 John LK, Ramu M, Singamneni S, Binudas N (2024) Strength evaluation of polymer ceramic composites: a comparative study between injection molding and fused filament fabrication techniques. Prog Addit Manuf 10(1):339–347 Rajiev R, Saravanan S, Rajkumar R (2025) Assessing surface quality with SEM analysis and evaluating the parameters and mechanical properties of PLA parts produced by 3D printing. Interact 246:1–19 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7582866","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":535743979,"identity":"2bb0120a-8927-40a2-ac33-33b9ff698400","order_by":0,"name":"Dilşad Öztürk","email":"data:image/png;base64,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","orcid":"","institution":"Erciyes University","correspondingAuthor":true,"prefix":"","firstName":"Dilşad","middleName":"","lastName":"Öztürk","suffix":""},{"id":535743980,"identity":"7f8cab7b-48af-4ef9-bb4f-995d793a0261","order_by":1,"name":"Özlem Mıhçıokur","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Özlem","middleName":"","lastName":"Mıhçıokur","suffix":""}],"badges":[],"createdAt":"2025-09-10 12:23:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7582866/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7582866/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":94825380,"identity":"a1cf6b1b-9392-486b-9ca6-6d6f8fae5769","added_by":"auto","created_at":"2025-10-31 06:50:10","extension":"png","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":735038,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/b365573566ac16c7ec683983.png"},{"id":94825184,"identity":"8447f243-5ef5-45d1-9106-3d9adc15f547","added_by":"auto","created_at":"2025-10-31 06:49:57","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":94953,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/6b848ab514e7a373975eb103.docx"},{"id":94775726,"identity":"37703d35-32e2-45f4-95fa-7975a0e00d39","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":559332,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/de8ae04396f259e0d5fdb378.png"},{"id":94824175,"identity":"3905ee2b-61bf-4b61-b52f-43dc11319e54","added_by":"auto","created_at":"2025-10-31 06:48:36","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":27893,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/0af180b576d36bd03d0d844e.docx"},{"id":94775720,"identity":"d021c266-22be-4778-8c31-a965c47acd87","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":154560,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/9af76542b7604964dc4cd4af.png"},{"id":94824424,"identity":"0cde9341-f75a-408a-b860-d8f55bf35697","added_by":"auto","created_at":"2025-10-31 06:48:59","extension":"png","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":739456,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/fe562e4460d608ab35a5ada8.png"},{"id":94825408,"identity":"cc0381ab-d861-45dc-af13-c6aabeac7ead","added_by":"auto","created_at":"2025-10-31 06:50:14","extension":"png","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":460284,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/2ec98927a1aef09465f660fa.png"},{"id":94825453,"identity":"04e48152-d944-40ca-8882-94ee1a39852f","added_by":"auto","created_at":"2025-10-31 06:50:20","extension":"png","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1216868,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/48a257a0eca1d06cde3bee25.png"},{"id":94825395,"identity":"e291666d-881e-464e-8929-265c569a1395","added_by":"auto","created_at":"2025-10-31 06:50:13","extension":"png","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":506749,"visible":true,"origin":"","legend":"","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/3ef65ee4f4eae47a046a9755.png"},{"id":94825336,"identity":"38ccf88a-c73c-4d6f-9a93-47270b6d08b5","added_by":"auto","created_at":"2025-10-31 06:50:08","extension":"json","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":4123,"visible":true,"origin":"","legend":"","description":"","filename":"b78d37a3531e443a8b89e2ec33cef19e.json","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/19b294a32c0a46ad684a6ad2.json"},{"id":94775730,"identity":"31dd948f-b1fb-49b7-9d9d-67e05acf6971","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"xml","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":98924,"visible":true,"origin":"","legend":"","description":"","filename":"b78d37a3531e443a8b89e2ec33cef19e1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/8215752df817e8f79f29137e.xml"},{"id":94775741,"identity":"082c59d1-1720-4173-b55a-78ab3d5b7cb6","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":735038,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/784f5278fe2cb0fcdd7bcf18.png"},{"id":94775736,"identity":"872b369c-d658-4776-8faa-4718b591a379","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":559332,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/e2fd9de0e433f53ce420fd2f.png"},{"id":94775732,"identity":"1ac5a640-3007-414a-bf0b-9cd66d56bfc6","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":154560,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/a922ccf4038e7faee2bc2cb1.png"},{"id":94824361,"identity":"95f11f5e-86c5-4be3-8dd0-158b83db1355","added_by":"auto","created_at":"2025-10-31 06:48:56","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":739456,"visible":true,"origin":"","legend":"","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/84d1f6948568dc3f4006df3e.png"},{"id":94775739,"identity":"b32d2947-d0ad-40fb-adab-e42eee1a31a0","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":460284,"visible":true,"origin":"","legend":"","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/de11264cb3860ede6dfe35e4.png"},{"id":94824234,"identity":"4378822a-33ce-42dd-94fa-764d8f578d15","added_by":"auto","created_at":"2025-10-31 06:48:41","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":1216868,"visible":true,"origin":"","legend":"","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/e8f55a9e875a70cbaa850fed.png"},{"id":94825191,"identity":"0510785b-1f84-4a28-a5f4-8a96552cafe7","added_by":"auto","created_at":"2025-10-31 06:49:57","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":506749,"visible":true,"origin":"","legend":"","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/2072b9d2c770b99707f5d540.png"},{"id":94825071,"identity":"2871196b-e388-41c6-b9da-119ad5323ace","added_by":"auto","created_at":"2025-10-31 06:49:47","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":92600,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/6f56f901482d794ca8e3e08a.png"},{"id":94775748,"identity":"19f3ebf4-f08e-4b97-9850-55ea5d94fc19","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":78504,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/b4c6f9192320687345144be6.png"},{"id":94824050,"identity":"8c5e143f-8fdf-407d-a5f3-c6f97c8a49b8","added_by":"auto","created_at":"2025-10-31 06:48:24","extension":"png","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":27813,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/12f032d69da873701ee43ba7.png"},{"id":94825473,"identity":"c5d9edba-2705-431a-86b7-9b487271d7f4","added_by":"auto","created_at":"2025-10-31 06:50:20","extension":"png","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":75844,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/0eb68ddaf3154c118c85f4a4.png"},{"id":94823944,"identity":"3a4843e2-6288-45f1-8b19-0d1273596a83","added_by":"auto","created_at":"2025-10-31 06:48:18","extension":"png","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":44321,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/f282e12dbeb642160d7010ee.png"},{"id":94825371,"identity":"5e231d68-8530-4967-a563-a097d6b6eaa9","added_by":"auto","created_at":"2025-10-31 06:50:10","extension":"png","order_by":23,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":231584,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure6.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/d7ad603058f3cc611712a51f.png"},{"id":94775740,"identity":"84b0949c-fbc5-4959-80ef-366477c9035b","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"png","order_by":24,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":53214,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineFigure7.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/8c2d43d9112d6bd59fa00290.png"},{"id":94775746,"identity":"00b0e70e-c9bf-4613-a230-2a145bbf9c01","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"xml","order_by":25,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":97144,"visible":true,"origin":"","legend":"","description":"","filename":"b78d37a3531e443a8b89e2ec33cef19e1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/8f52b347b12e128289582d14.xml"},{"id":94775747,"identity":"fbf48a25-4e98-4716-8a50-3e002592297e","added_by":"auto","created_at":"2025-10-30 14:44:25","extension":"html","order_by":26,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":103191,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/e65d781b5ddcbf78e549c468.html"},{"id":94775715,"identity":"f2ef4cbd-0ad7-43db-a3ea-5a37d0557d72","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":735038,"visible":true,"origin":"","legend":"\u003cp\u003eUsage percentages of biodegradable plastics the globally [14]\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/614b645905d649bd949c5465.png"},{"id":94775714,"identity":"f986493c-dcc9-41c6-92f3-1043ab345f7c","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":559332,"visible":true,"origin":"","legend":"\u003cp\u003eSynthesis Steps and Chemical Form of the PLA/SS Composite Material\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/7974b0571abe3dde63678110.png"},{"id":94775716,"identity":"b574a34d-4c4e-41ed-b41b-b1f93b67b1c2","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":154560,"visible":true,"origin":"","legend":"\u003cp\u003eElongation at break (%) calculation MATLAB code\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/d10590bf2f528ef993c9cd07.png"},{"id":94775717,"identity":"6a571400-f410-4519-a206-572fe8a37d9e","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":739456,"visible":true,"origin":"","legend":"\u003cp\u003eElongation at Break-Young Modulus-Tensile Strength of Pure PLA and PLA/SS composites with 20% and 30% concentrations.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/18a099df741777347b526979.png"},{"id":94775718,"identity":"cadcf3a0-5940-40e4-a360-bc93b2b289a7","added_by":"auto","created_at":"2025-10-30 14:44:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":460284,"visible":true,"origin":"","legend":"\u003cp\u003eTGA Properties of Pure PLA and PLA/SS Composite Materials\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/c22f9507c6dd28f8d3d030fa.png"},{"id":94824292,"identity":"b2a7c31f-08a7-4571-a93f-e513b5e4eb79","added_by":"auto","created_at":"2025-10-31 06:48:46","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1216868,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of PLA/SS composites\u003c/p\u003e","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/d6d73c8ced86b1b1260830db.png"},{"id":94825079,"identity":"78475add-29c5-4296-9893-9b892459f63b","added_by":"auto","created_at":"2025-10-31 06:49:47","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":506749,"visible":true,"origin":"","legend":"\u003cp\u003eThe swelling results of PLA/SS composites\u003c/p\u003e","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/1f4fcafef7e73d8684fe4b91.png"},{"id":102297499,"identity":"0237327f-25d4-44c9-88c2-467c8cb968f5","added_by":"auto","created_at":"2026-02-10 10:27:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5255152,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7582866/v1/3a09f962-5682-4b19-929e-686e924479f0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eNon-toxic and Carbon-neutral Green Composites Produced From Polylactic Acid (PLA) With Waste Sunflower Stem\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePlastic production is estimated to be approximately 370\u0026nbsp;million tons (Mt) worldwide and is predicted to double within 20 years [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. These fossil-derived plastics play a significant role in Turkey, with a total plastic production of 9.6\u0026nbsp;million tons, ranking first in packaging material production at 4\u0026nbsp;million tons and second in construction material production at approximately 2.5\u0026nbsp;million tons [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003ePlastic pollution poses serious environmental threats on a global scale due to its permanence in the environment and the release of toxic substances during its degradation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Population growth and climate change highlight the need for biodegradable alternatives to fossil-based plastics. The emergence of bioplastics reflects essential research and innovation, with studies showing that creating high-value raw materials is a priority for developing countries like T\u0026uuml;rkiye.\u003c/p\u003e\u003cp\u003eBiopolymers are polymers derived from biological sources, such as plants, animals, or microorganisms, and are biodegradable. Synthetic polymers made by humans from these sources are also considered biopolymers. Biodegradable polymers are divided into natural and synthetic based on their origin [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Natural biopolymers are produced using polysaccharides (such as chitin, cellulose, and starch), proteins (including collagen, gluten, and gelatine), and oils (such as fatty acids and wax). They are derived from renewable energy sources [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. On the other hand, these synthetic biopolymers can be manufactured under specific conditions. Microorganisms in the soil can break down and transform them into harmless, environmentally friendly chemicals. Aliphatic polyesters are a type of polymer characterised by their unique structure, which includes ester functional groups and can take on either a linear or branched form. These materials are created by combining aliphatic (non-aromatic) diols with dicarboxylic acids. Aliphatic polyesters, such as polyhydroxyalkanoates (PHA), polyglycolide (PGA), polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB), and poly(lactic acid) (PLA), are biopolymers composed of repeating units bonded by ester linkages [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Their main features are biodegradability, thermoplastic behaviour, and machinable mechanical properties. This makes them suitable for various applications, including packaging materials, the bottle industry, textiles, and the agricultural and pharmaceutical sectors. Unlike other thermoplastics, PLA is relatively inexpensive, has a low carbon footprint, and exhibits several beneficial mechanical properties compared to other biodegradable polymers, making it a popular material [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eVarious sectors worldwide drive the global PLA market. While the demand for polylactic acid (PLA) reached 270,000 tons in 2019 due to the increase in disposable product demand worldwide during the COVID-19 pandemic, it increased by approximately 20% in 2020 [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Today, the production of PLA is projected to surpass 2.4\u0026nbsp;million metric tons by 2027 [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. PLA and other bioplastic polymer production capacities by global market segment are shown in Fig.\u0026nbsp;1.\u003c/p\u003e\u003cp\u003ePLA is a thermoplastic polyester derived from cornstarch, 100% biodegradable, approximately eight times recyclable, and compostable at the end of its expected useful life. Pure PLA has an approximately tensile strength (40-52.5 MPa), flexural strength (52.5\u0026ndash;66 MPa), compressive strength (48\u0026ndash;62 MPa), impact strength (2\u0026ndash;6 KJ/m\u003csup\u003e2\u003c/sup\u003e), an electrical conductivity (5.6x10\u003csup\u003e\u0026minus;\u0026thinsp;9\u003c/sup\u003e S/m) with low density (1.2 g/cm\u003csup\u003e3\u003c/sup\u003e), less water absorption (1.2%) and contact angle (59.57\u003csup\u003eo\u003c/sup\u003e) as physical properties [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, PLA is very brittle, has poor heat resistance (heat deflection temperature: 55\u0026ndash;65\u0026deg;C), and exhibits a slow crystallisation rate [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Improving PLA's weak properties (low thermal resistance, lightness, brittleness, and low decomposition reaction rate) using methods such as physical mixing, chemical mixing, and copolymerisation is crucial for expanding its usage areas in the industry [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Recent studies indicate that to improve the mechanical properties of PLA, some additives must be added to the pure PLA form.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 1.\u003c/b\u003e Usage percentages of biodegradable plastics the globally [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eSunflowers contain large amounts of fibre and hydrophobic patches of high-quality protein, including 11S globulin and 2S albumin, which are known to form stable emulsions, making them an underutilised plant protein [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The sunflower stem (SS) is part of the flowering plant. Moreover, this plant has a hairy structure and is quite robust. Although cellulose-containing sunflowers, whose crystal plane is estimated to be approximately 3.3 nm, are not trees, their mechanical strength is comparable to that of tree species [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, its negative features are its internal pore volume and thermal conductivity, which prevent shrinkage [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The approximate percentage composition of sunflower stem constituents in dry matter is as follows: cellulose ranges from 35% to 50%, lignin from 15% to 25%, hemicellulose from 15% to 35%, and water constitutes about 10% to 15%. Additionally, the protein content is approximately 2% to 3%, and the oil content is around 1% to 2% [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Other organic compounds and substances make up a small portion of the total. These proportions may vary depending on the plant's growth stage and cultivation conditions. The molecular structures of PLA and SS (representative cellulose chemical structure), along with the preparation steps for the composite, are shown in Fig.\u0026nbsp;2. Turkey is among the world's leading sunflower producers (Helianthus annuus L.), with an annual production of approximately 30\u0026ndash;35\u0026nbsp;million metric tons. The total yearly sunflower production in T\u0026uuml;rkiye contributes approximately 6% to global sunflower production, amounting to over 1.6\u0026nbsp;million tons [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Additionally, approximately 20% of the products are derived from SS. The volume of sunflower residues produced worldwide has a substantial environmental impact, averaging 5 tons of dry matter per hectare per year [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Therefore, post-harvest waste from sunflowers remains a global problem, although it is primarily utilised in bioethanol production [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Although some producer villagers use these wastes for heating, Turkey faces a significant storage problem, with an average of 600,000 tons stored annually [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 2.\u003c/b\u003e Synthesis Steps and Chemical Form of the PLA/SS Composite Material\u003c/p\u003e\u003cp\u003eSS composites are a crucial research area for environmental sustainability and the development of new materials. Such composites are primarily used in packaging, construction, automotive, and biomedical fields and are valuable as recycled materials. Polylactic acid (PLA) is a widely used bioplastic that can be combined with various materials to create a range of composite products. In today\u0026rsquo;s studies, the PLA matrix is developed by blending carbon fibres, glucose additives, bio-ceramics, mineral fillers, and natural plant fibres, such as kenaf fibres, which are a popular type. These biodegradable, bio-based polymer composites are eco-friendly and highly sustainable. Moreover, PLA is the only biopolymer that requires less energy and emits fewer greenhouse gases [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The studies on the mechanical properties of PLA composites with different reinforcement fibres are summarised in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eThis study focused on the large-scale production of PLA/SS composite materials and the development of eco-friendly PLA composite materials to meet the need for high-strength, sustainable materials across various industries. It has discussed the mechanical property gains of the PLA/SS composite and presented the rationale for using SSs as reinforcement material to improve the properties of PLA. Additionally, the abundance of sunflower waste in Turkey, particularly the substantial amount of sap waste, is a key motivation for this research.\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\u003eComparison of the mechanical properties of PLA composites with different reinforcement fibres\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\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=\"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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRef.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eComposites\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003cp\u003e% (w/w)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDeg. Temp.\u003c/p\u003e\u003cp\u003e(\u003csup\u003eo\u003c/sup\u003eC)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eImpact Strength\u003c/p\u003e\u003cp\u003e(kJ/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eTensile Strength\u003c/p\u003e\u003cp\u003e(MPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eFlexural Strength\u003c/p\u003e\u003cp\u003e(MPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eYoung\u0026rsquo;s modulus\u003c/p\u003e\u003cp\u003e(MPa)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePure PLA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e173.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e62.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e93.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1175\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRecycled PLA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e168\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e16.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e33.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/Bamboo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e258\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e58.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e106.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/sisal/coir\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\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\u003e2.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/SF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e233\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.032\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e34.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e47.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/Al\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e205\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e68.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5260\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/GF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e385\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e62.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e115.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/wood\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e260\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e21.64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e335\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/CF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e20\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\u003e4.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e35.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/Jute-Nettle\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\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\u003e16.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.426\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e157.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e69.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/CF5.5/PBO\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e360\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e17.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e63.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e116.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/CF-Graphen\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e98\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\u003e6.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e45.56\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e64.87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1040\u0026ndash;1260\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e95\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\u003e2.625\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e54.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e78.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2676\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePresent Work\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA/SS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e325\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e43.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e96.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e429\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eCF: Carbon Fiber, KF: Kenaf Fiber, SF: Sisal Fiber, FDT: Fused Deposition Technique\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cp\u003eSS waste is obtained from sunflowers harvested from the B\u0026uuml;nyan district of Kayseri. The PLA biopolymer granule (3-mm nominal size) (CAS No: 26100-51-6) was purchased from Sigma-Aldrich, a Merck company. Experimental processes (SS extrusion, injection moulding, fused filament fabrication techniques) were conducted at the Erciyes University Textile Engineering Research Laboratories.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Preparation for Composite Material\u003c/h2\u003e\u003cp\u003eWaste of SS collected from the B\u0026uuml;nyan district was broken into small pieces, which were ground in a mill grinder and converted to powder form. Similarly, granular PLA also turned into powder form using the same grinder.\u003c/p\u003e\u003cp\u003ePowdered PLA and sunflower stalk were weighed on analytical precision scales. After that, they were kept in the oven at 80 \u003csup\u003e0\u003c/sup\u003eC for approximately 12 hours to remove the moisture. Two different concentrations were prepared by mixing 20% (w/w) and 30% (w/w) blended SS with PLA. The obtained mixtures were prepared for use in the extrusion machine (Fig.\u0026nbsp;2(a), (b), (c), (d)).\u003c/p\u003e\u003cdiv id=\"Sec4\" class=\"Section3\"\u003e\u003ch2\u003e2.1.1. Plasticization of SS/ PLA mixture\u003c/h2\u003e\u003cp\u003eThe mixture of SS/PLA, after removing the moisture removed by the heating process, was then placed into a twin-screw extruder, melted, and extruded. According to the extrusion conditions, the inlet temperature at which the mixture enters the extruder is 40\u0026deg;C. The remarkable temperatures are divided into five regions: Region A (160\u0026deg;C), Region B (165\u0026deg;C), Region C (170\u0026deg;C), Region D (175\u0026deg;C), and Region E (180\u0026deg;C), along with their corresponding transition temperatures. The sample exiting the hot melt extruder was then cooled using a fan with airflow assistance and subsequently turned into small pieces by the granulator device (Fig.\u0026nbsp;2).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section3\"\u003e\u003ch2\u003e2.1.2. Injection Molding of Granular PLA/SS mixture\u003c/h2\u003e\u003cp\u003eThe SS/PLA granules, reduced to small pieces in the granulator device, were placed in the injection machine, and each sample was held there for 4 minutes at 185\u0026deg;C. At the end of the period, the mould in the machine was opened, and the composite material was removed. The same processes were applied to pure polylactic acid (PLA). As a result of the experiment, the composite materials were obtained for pure PLA and PLA with 20% and 30% SS additives, respectively.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\u003ch2\u003e2.1.3. Mechanical Properties\u003c/h2\u003e\u003cp\u003eThe tensile test applied to the produced composites is by the ASTM D638 standard. 10 mm/min test rules will be provided in 3 parallel ways in the tensile testing device. The bending test was conducted on the composites produced according to the ASTM D-790 standard using a bending test machine at a test speed of 10 mm/min, with three parallel tests. The experiments were performed in triplicate. The tensile strength, Young\u0026rsquo;s modulus, and elongation at break were calculated using the following equations (1), (2), (3), and (4). The test data obtained using the MATLAB R2015a code was replaced, and the graph was drawn within the MATLAB program (Fig.\u0026nbsp;3).\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eTensile strength (MPa) σt\u0026thinsp;=\u0026thinsp;F/A (1)\u003c/p\u003e\u003cp\u003eFlexural strength (MPa) σf\u0026thinsp;=\u0026thinsp;3PL/2bd\u003csup\u003e2\u003c/sup\u003e (2)\u003c/p\u003e\u003cp\u003eYoung\u0026rsquo; s modulus (MPa) = σ/ε 96 (3)\u003c/p\u003e\u003cp\u003eElongation at break (%)\u0026thinsp;=\u0026thinsp;L\u003csub\u003ef\u003c/sub\u003e \u0026ndash; L\u003csub\u003eo\u003c/sub\u003e / L\u003csub\u003eo\u003c/sub\u003e \u0026times; 100 (4)\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhere F\u0026thinsp;=\u0026thinsp;Force, A\u0026thinsp;=\u0026thinsp;Area, P\u0026thinsp;=\u0026thinsp;max load, L\u0026thinsp;=\u0026thinsp;span, P\u0026thinsp;=\u0026thinsp;width, d\u0026thinsp;=\u0026thinsp;depth σ\u0026thinsp;=\u0026thinsp;Tensile Stress, ε\u0026thinsp;=\u0026thinsp;Strain, Lf\u0026thinsp;=\u0026thinsp;Final length, Lo\u0026thinsp;=\u0026thinsp;Initial length\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\u003ch2\u003e2.1.4. Thermal Properties\u003c/h2\u003e\u003cp\u003eThermal properties were assessed via Thermogravimetric Analysis (TGA), with TGA curves illustrating the relationship between weight loss and temperature for various samples (pure PLA, 20% SS\u0026thinsp;+\u0026thinsp;PLA, and 30% SS\u0026thinsp;+\u0026thinsp;PLA), thereby providing insights into their thermal stability.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 3.\u003c/b\u003e Elongation at break (%) calculation MATLAB code\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\u003ch2\u003e2.1.5. Morphological Properties\u003c/h2\u003e\u003cp\u003eThe morphological properties of the composite materials were investigated through Scanning Electron Microscopy (SEM). This technique facilitated the examination of the surface topography of PLA-based composites containing different concentrations of sunflower stem (SS), allowing for an assessment of how microstructural variations might influence mechanical behaviour (Magnification: 100X and 150X).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.1.6. Swelling Properties\u003c/h2\u003e\u003cp\u003eThe dry weights of composite materials containing 20% and 30% sunflower stalk additives were determined using a precision scale. Their dimensions were subsequently measured with a calliper. The specimens were then immersed in distilled water at room temperature. After a 10-minute immersion period, the samples were removed, surface water was carefully blotted, and their weight and dimensions were re-measured. The water temperature was maintained at a constant level throughout the experiment. This process was repeated iteratively until the composite materials exhibited dimensional stability.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Tensile and flexural properties\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;4 illustrates the mechanical properties, including tensile strength, elongation at break and Young's modulus, of pure PLA and the fabricated composites in different concentrations of SS additives, in both granular and filament forms. The results indicate that as the SS content increases, the tensile modulus of PLA/SS composites improves.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 4.\u003c/b\u003e Elongation at Break-Young Modulus-Tensile Strength of Pure PLA and PLA/SS composites with 20% and 30% concentrations.\u003c/p\u003e\u003cp\u003eAs the SS content increases, a trend is observed in the flexural strength. On the other hand, the tensile strength shows a continuous decreasing trend. The lowest tensile strength (43.57 MPa) and the highest flexural strength (96.43 MPa) are observed in the composite with the highest SS content. Pure PLA shows the lowest flexural strength (93.6538 MPa). However, this increase in strength is accompanied by a significant decrease in the modulus of elasticity, indicating a loss of hardness and increased material flexibility. In addition, the elongation at break decreases with higher SS content (from 5.47% to 3.34%), which can be interpreted as indicating that the porous structure in the material hurts its rupture strength.\u003c/p\u003e\u003cp\u003eThese findings demonstrate that the incorporation of SS into PLA results in a softer yet more brittle composite, with the substantial decline in the modulus of elasticity highlighting the reduction in material hardness.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Thermogravimetric Analyses\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;5 illustrates the thermogravimetric analysis (TGA) curves for three different samples: pure PLA, 20% SS\u0026thinsp;+\u0026thinsp;PLA, and 30% SS\u0026thinsp;+\u0026thinsp;PLA. These curves illustrate how the percentage of weight loss varies with increasing temperature, offering insights into the thermal stability of each material. The data clearly show that pure PLA experiences a rapid and significant decrease in weight within a narrow temperature range, as evidenced by the marked points A1 and B1.\u003c/p\u003e\u003cp\u003e(A1: ~340 \u003csup\u003e0\u003c/sup\u003eC, A2: ~277 \u003csup\u003e0\u003c/sup\u003eC, A3: ~273 \u003csup\u003e0\u003c/sup\u003eC; B1: ~380 \u003csup\u003e0\u003c/sup\u003eC, B2: ~335 \u003csup\u003e0\u003c/sup\u003eC, B3: ~325 \u003csup\u003e0\u003c/sup\u003eC)\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 5.\u003c/b\u003e TGA Properties of Pure PLA and PLA/SS Composite Materials\u003c/p\u003e\u003cp\u003eThis rapid degradation indicates that pure PLA begins to thermally decompose at relatively low temperatures, reflecting its limited heat resistance. In contrast, the curves for the samples containing SS, both at 20% and 30%, shift toward higher temperatures, as indicated by markers A2 and B2. This shift suggests that the addition of SS particles to the PLA matrix effectively enhances the material\u0026rsquo;s thermal stability. Not only does this imply that these composites can withstand higher temperatures before decomposing, but it also indicates potential for broader industrial applications where higher heat resistance is required.\u003c/p\u003e\u003cp\u003eFurthermore, the curve corresponding to the 30% SS-loaded sample shows a similar shift towards higher temperatures, even surpassing the stability observed in the 20% SS composite. This trend suggests a dose-dependent improvement in thermal performance, indicating that increasing SS content could further enhance the material\u0026rsquo;s resistance to thermal degradation. In summary, the analysis reveals that pure PLA undergoes rapid degradation within a specific and narrow temperature range, underscoring its susceptibility to heat. Conversely, the incorporation of SS additive markedly improves the thermal stability of the biodegradable polymer. These findings provide valuable insights into how the inclusion of SS particles can modify the thermal properties of PLA, making it more suitable for applications where higher temperature endurance is essential. Overall, the results reinforce the potential of SS-reinforced PLA composites as advanced, thermally stable bioplastics with promising industrial applications. Considering the increase in thermal resistance of the material and the significant impact of the SS additive on the porous structure, it has become clear that further research is needed to investigate the usability of this material as a thermal barrier and sound insulator in the production of composite materials. In terms of environmental engineering, the addition of the 10% SS additive to the composite material creates a porous structure, increasing the material's surface area. It shows that it can be an effective adsorbent in pollutant removal.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.3. Morphological Analyses of the tested specimens\u003c/h2\u003e\u003cp\u003eIn this part of the study, the surface morphology of PLA-based composites with varying SS contents was examined using Scanning Electron Microscope (SEM) images, and the effects of microstructural differences on potential mechanical performance were evaluated. According to Fig.\u0026nbsp;6, the composite with 20% SS exhibits a smoother surface and contains longer, fibre-like structures, indicating lower surface roughness. In the composite with 30% SS, the surface appears much rougher and more irregular, with pores and fragments. As the SS content increases from 20% to 30%, the surface area increases significantly. This increase can strengthen the structural bonds or fibre-matrix interactions of the composite, demonstrating the bio-composite material's ability to serve as an eco-friendly adsorbent. However, this feature is utilised in the production of certain industrial materials, which increases surface brittleness and susceptibility to cracking.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 6.\u003c/b\u003e SEM images of PLA/SS composites\u003c/p\u003e\u003cp\u003eSurface morphology is known to have a direct impact on mechanical performance in composites [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. This is because materials with more porous and irregular surfaces may gain strength due to the internal structure but may be more susceptible to surface cracks and breakage. Additive manufacturing offers applications related to filament material failure and poor surface quality due to suboptimal process parameters. Accordingly, it is considered a 20% more suitable option to produce 3D PLA parts in load-bearing structural applications that require high strength.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.4. Swelling Characterisation\u003c/h2\u003e\u003cp\u003eThe results obtained after waiting for the composite material, prepared by performing weight percentage swelling tests in pure water, to swell for 24 hours (until it reaches equilibrium), are given in Fig.\u0026nbsp;7.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFigure 7.\u003c/b\u003e The swelling results of PLA/SS composites\u003c/p\u003e\u003cp\u003ePLA/SS composites, whose dry weights were measured on a precision scale and whose dimensions were measured separately with a calliper, were subjected to a swelling test in pure water. Swelling increases over time for both compositions. The 30% SS\u0026thinsp;+\u0026thinsp;PLA (blue line) exhibits a higher swelling percentage at all time points compared to the 20% SS\u0026thinsp;+\u0026thinsp;PLA (black line). Peak swelling for the 30% SS\u0026thinsp;+\u0026thinsp;PLA occurs at approximately 16% at around 20 minutes, and then slightly decreases or plateaus. The 20% SS\u0026thinsp;+\u0026thinsp;PLA exhibits a lower maximum swelling, reaching approximately 6% at the same time.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn conclusion, this study demonstrates that waste sunflower stems (SS) can be effectively utilised to develop sustainable and eco-friendly PLA-based composites. The incorporation of SS improved the tensile strength and thermal stability of PLA, making it more suitable for applications requiring higher temperature resistance. However, increasing SS content significantly reduced the ductility of the material, with elongation at break decreasing by 14.26% and 38.94% for 20% and 30% SS incorporation, respectively. SEM analysis revealed that higher SS content increased the porosity of the composites, indicating potential applicability as eco-friendly adsorbents in future environmental remediation efforts. Moreover, swelling tests showed that 30% SS\u0026thinsp;+\u0026thinsp;PLA composites exhibited higher swelling percentages at all time points compared to 20% SS\u0026thinsp;+\u0026thinsp;PLA, with a maximum swelling of approximately 16% occurring at 20 minutes. These findings suggest that while SS reinforcement enhances the mechanical and thermal properties of PLA, optimisation of the filler ratio is crucial to balance strength, ductility, and functional performance. Overall, SS-reinforced PLA composites present a promising route towards the development of advanced, thermally stable, and sustainable bioplastics with broad industrial applications, while also offering potential benefits as environmentally friendly adsorbent materials.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eD.O. wrote the main manuscript D.O. prepared figures 1-7.O.M. did the experiments.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eWe want to thank Prof. Dr. Mehmet Doğan, a faculty member of the Department of Textile Engineering at Erciyes University, for providing us with the laboratory infrastructure necessary for conducting experimental measurements. We also appreciate the support of his team members, Ayşeg\u0026uuml;l Erdem and Alperen Kaplan. Asst. Refik Alp \u0026Ccedil;ağdaş, faculty member of the Department of Metallurgical and Materials Engineering at Erciyes University, for his valuable recommendations, discussions and unique experience in materials science.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWalker TR, Fequet L (2023) Current trends of unsustainable plastic production and micro(nano)plastic pollution. TrAC Trends Anal Chem 160:116984\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePAGEV, Turkish Plastics Industrialists Research T\u0026uuml;rkiye Plastics Industry Monitoring Report, 2017. [Online]. Available: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e\u003c/span\u003e\u003cspan address=\"http://www.pagev.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDoppalapudi S, Jain A, Khan W, Domb AJ (2014) Biodegradable polymers-an overview. Polym Adv Technol 25(5):427\u0026ndash;435\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePooja N, Chakraborty I, Rahman MH, Mazumder N (2023) An insight on sources and biodegradation of bioplastics: a review, 3 Biotech. 13(7):1\u0026ndash;22\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBikiaris DN (2013) Nanocomposites of aliphatic polyesters: An overview of the effect of different nanofillers on enzymatic hydrolysis and biodegradation of polyesters. Polym Degrad Stab 98(9):1908\u0026ndash;1928\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSwetha TA, Ananthi V, Bora A, Sengottuvelan N, Ponnuchamy K, Muthusamy G, Arun A (2023) A review on biodegradable polylactic acid (PLA) production from fermentative food waste - Its applications and degradation. Int J Biol Macromol 234:123703\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTadi SP, Mamilla RS (2024) Fabrication of SS 316L particle-infilled PLA composite filaments from cast-off bi-material extrudates for 3D printing applications. Waste Manag 193:386\u0026ndash;397\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePappu A, Pickering KL, Thakur VK (2019) Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding. Ind Crops Prod 137:260\u0026ndash;269\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMtibe A, Motloung MP, Bandyopadhyay J, Ray SS (2021) Synthetic Biopolymers and Their Composites: Advantages and Limitations\u0026mdash;An Overview. Macromol Rapid Commun 42(15):1\u0026ndash;28\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSatsum A, Busayaporn W, Rungswang W, Soontaranon S, Thumanu K, Wanapu C (2022) Structural and mechanical properties of biodegradable poly(lactic acid) and pectin composites: using bionucleating agent to improve crystallization behavior. Polym J 54(7):921\u0026ndash;930\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVengadesan E, Muralidharan TAS, Hrishikesh KD (2025) Hybrid Bio-composites Reinforced with Natural Wood Saw Dust and Eco-friendly Graphite: Evaluation of Physical, Mechanical, and Thermal Properties. Fibers Polym 26(3):833\u0026ndash;854\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCisar J, Drohsler P, Pummerova M, Sedlarik V, Skoda D (2023) Composite based on PLA with improved shape stability under high-temperature conditions. Polym J 276:125943\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShou T, Wu Y, Yin D, Hu S, Wu S, Zhao X, Zhang L (2024) In-situ self-crosslinking strategy for super-tough polylactic acid/ bio-based polyurethane blends. Int J Biol Macromol 261:129757\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eda Silva Pens CJ, Klug TV, Stoll L, Izidoro F, de Flores SH (2024) Oliveira Rios, Poly (lactic acid) and its improved properties by some modifications for food packaging applications: A review. Food Packag Shelf Life 41:101230\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSneharani AH (2019) Curcumin\u0026ndash;sunflower protein nanoparticles\u0026mdash;A potential antiinflammatory agent. J Food Biochem 43(8):1\u0026ndash;8\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eThomas LH, Forsyth VT, Martel A, Grillo I, Altaner CM, Jarvis MC (2014) Structure and spacing of cellulose microfibrils in woody cell walls of dicots, Cellulose, 21 (6) 3887\u0026ndash;3895\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChabannes M, Nozahic V, Amziane S (2015) Design and multi-physical properties of a new insulating concrete using sunflower stem aggregates and eco-friendly binders. Mater Struct Constr 48(6):1815\u0026ndash;1829\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEom IY, Yu JH (2015) Structural characterization of the solid residue produced by hydrothermal treatment of sunflower stalks and subsequent enzymatic hydrolysis. J Ind Eng Chem 23:72\u0026ndash;78\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJung CD, Yu JH, Eom IY, Hong KS (2013) Sugar yields from sunflower stalks treated by hydrothermolysis and subsequent enzymatic hydrolysis. Bioresour Technol 138:1\u0026ndash;7\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHanifi B, Sevin\u0026ccedil; AH, Eken M (2012) Ay\u0026ccedil;i\u0026ccedil;ek Sapı Ve Tekstil Atıkları İle Yalıtım Malzemesi \u0026Uuml;retimi, KSU M\u0026uuml;hendislik Bilim. Derg 15(1):1\u0026ndash;5\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePhiri R, Mavinkere Rangappa S, Siengchin S, Oladijo OP, Dhakal HN (2023) Development of sustainable biopolymer-based composites for lightweight applications from agricultural waste biomass: A review. Adv Ind Eng Polym Res 6(4):436\u0026ndash;450\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDuan J, Wu H, Fu W, Hao M (2018) Mechanical properties of hybrid sisal/coir fibers reinforced polylactide biocomposites. Polym Compos 39(1):E188\u0026ndash;E199\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAtakok G, Kam M, Koc HB (2022) Tensile, three-point bending and impact strength of 3D printed parts using PLA and recycled PLA filaments: A statistical investigation. J Mater Res Technol 18:1542\u0026ndash;1554\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYoung WB, Tsao YC (2015) The mechanical and fire safety properties of bamboo fiber reinforced polylactide biocomposites fabricated by injection molding. J Compos Mater 49(22):2803\u0026ndash;2813\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChaitanya S, Singh I, Song JI (2019) Recyclability analysis of PLA/Sisal fiber biocomposites, Compos. Part B Eng 173:106895\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang X, Chen L, Mulholland T, Osswald TA (2019) Effects of raster angle on the mechanical properties of PLA and Al/PLA composite part produced by fused deposition modeling. Polym Adv Technol 30(8):2122\u0026ndash;2135\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang G, Zhang D, Wan G, Li B, Zhao G (2019) Glass fiber reinforced PLA composite with enhanced mechanical properties, thermal behavior, and foaming ability. Polymer 181:121803\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVigneshwaran K, Venkateshwaran N (2019) Statistical analysis of mechanical properties of wood-PLA composites prepared via additive manufacturing. Int J Polym Anal Charact 24(7):584\u0026ndash;596\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKamaal M, Anas M, Rastogi H, Bhardwaj N, Rahaman A (2021) Effect of FDM process parameters on mechanical properties of 3D-printed carbon fibre\u0026ndash;PLA composite. Prog Addit Manuf 6(1):63\u0026ndash;69\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChaudhary V, Radhakrishnan S, Das PP, Dwivedi SP, Mishra S, Gupta P (2023) Development and mechanical characterization of PLA composites reinforced with jute and nettle bio fibers. Biomass Convers Biorefinery 15(3):3443\u0026ndash;3455\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWan H, Sun C, Xu C, Wang B, Chen Y, Yang Y, Tan H, Zhang Y (2024) Synergistic reinforcement of polylactic acid/wood fiber composites by cellulase and reactive extrusion. J Clean Prod 434:140207\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAbas M, Habib T, Khan I, Noor S (2024) Definitive screening design for mechanical properties enhancement in extrusion-based additive manufacturing of carbon fiber-reinforced PLA composite. Prog Addit Manuf 10(1):139\u0026ndash;157\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJohn LK, Ramu M, Singamneni S, Binudas N (2024) Strength evaluation of polymer ceramic composites: a comparative study between injection molding and fused filament fabrication techniques. Prog Addit Manuf 10(1):339\u0026ndash;347\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRajiev R, Saravanan S, Rajkumar R (2025) Assessing surface quality with SEM analysis and evaluating the parameters and mechanical properties of PLA parts produced by 3D printing. Interact 246:1\u0026ndash;19\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Biopolymer, Polylactic acid (PLA), Sunflower stem waste, Bio-composite","lastPublishedDoi":"10.21203/rs.3.rs-7582866/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7582866/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eEnvironmental concerns have significantly influenced the use of biopolymers. Polylactic acid (PLA), a key player in the biopolymer market, is utilised in food packaging, 3D printing, and textiles, and exhibits considerable potential for further development. This study investigates the feasibility of incorporating waste sunflower stalks (WSS) as a reinforcement material into PLA composites to improve material properties and promote sustainability. The composites were prepared with 20% and % 30% WSS concentrations and systematically evaluated for their mechanical, thermal, and morphological properties. The results indicate a significant increase in flexural strength with the addition of WSS, with the 30% WSS composite reaching a value of 96.4385 MPa compared to 93.6538 MPa for pure PLA. Thermogravimetric analysis revealed that WSS-modified composites exhibited an approximately 30\u0026ndash;40\u0026deg;C increase in thermal decomposition temperature. Scanning electron microscopy revealed increased porosity in the 30% WSS composite, indicating potential applications as an adsorbent material. Furthermore, water swelling tests demonstrated that the composites maintained their resistance to water absorption. These findings suggest that WSS-reinforced PLA composites exhibit improved thermal properties and increased structural porosity compared to pure PLA, making them potentially suitable for applications such as sound and heat insulation. Additionally, they could serve as environmentally friendly adsorbents for removing pollution from environmental matrices.\u003c/p\u003e","manuscriptTitle":"Non-toxic and Carbon-neutral Green Composites Produced From Polylactic Acid (PLA) With Waste Sunflower Stem","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-30 14:44:20","doi":"10.21203/rs.3.rs-7582866/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8240c1b4-596b-435b-92b6-8eb342f3f471","owner":[],"postedDate":"October 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-09T21:54:21+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-30 14:44:20","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7582866","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7582866","identity":"rs-7582866","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}