Hybrid Cornstarch and Eggshell Reinforcement for Enhanced Mechanical, Thermal, and Biodegradation Performance of Sustainable Polyvinyl Alcohol Bioplastic

Hybrid Cornstarch and Eggshell Reinforcement for Enhanced Mechanical, Thermal, and Biodegradation Performance of Sustainable Polyvinyl Alcohol Bioplastic | 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 Hybrid Cornstarch and Eggshell Reinforcement for Enhanced Mechanical, Thermal, and Biodegradation Performance of Sustainable Polyvinyl Alcohol Bioplastic FARASURAYA CHE ZAKARIA, SITI MAZNAH KABEB, FARAH HANANI ZULKIFLI This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7298605/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Jan, 2026 Read the published version in Waste and Biomass Valorization → Version 1 posted 5 You are reading this latest preprint version Abstract This study developed a novel hybrid polyvinyl alcohol (PVA)-based biofilm system incorporating eggshell (ES) and cornstarch (CS) as natural and waste-derived biofillers, crosslinked with citric acid, and systematically evaluated their synergistic effects on structural, morphological, and functional properties including mechanical strength, thermal, and biodegradability. The novelty lies in combining two distinct biofillers, CaCO 3 -rich ES and hydrophilic CS, within a PVA matrix to achieve a multifunctional biodegradable film. ES, predominantly composed of CaCO 3 , and CS, known for its hydrophilic nature, were blended with PVA at varying concentrations (1.0, 2.5, and 5.0 wt.%) using solution casting. Structural characterization confirmed ES as predominantly CaCO 3 , with essential hydroxyl (−OH) and carbonate (CO 3 2− ) groups for matrix interactions. CS showed comparable functional −OH and carbonyls (C = O) groups enhancing PVA matrix compatibility. The biofilm’s biodegradability significantly improved, with PVA films containing 5.0 wt.% CS and ES showing the highest weight losses at 23.13% and 22.40%, respectively. Although the PVACS2.5ES2.5 film exhibited reduced water absorption (247.49%) compared to neat PVA, its WVTR increased to 353.84 g/m 2 ·day. This suggests that while the film resists bulk water uptake, its microstructure modified by the hybrid filler network facilitates enhanced vapor permeability through interconnected pores or disrupted polymer chains. Films containing 5.0 wt.% CS and ES achieved tensile strengths of 19.58 MPa and 26.25 MPa, respectively. Thermal analysis showed balanced stability, with a 2.5% CS and 2.5% ES exhibiting T 10 at 59.11°C and T max at 353.65°C. These findings confirm the potential of the developed biofilm as a multifunctional, sustainable material, where the synergistic reinforcement using dual biofillers offers a novel and scalable pathway to improve PVA bioplastic performance for sustainable packaging. The approach promotes resource circularity through low-cost, bio-based fillers and aligns with global environmental goals. Polyvinyl alcohol Cornstarch Calcium Carbonate Bio-based plastic Tensile strength Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 1. INTRODUCTION Petroleum-based plastics dominate the market due to their superior mechanical strength and cost-effectiveness; however, their persistence in the environment leads to severe ecological challenges, particularly in landfills and oceans [ 1 ]. This growing concern necessitates urgent green engineering solutions to mitigate plastic waste accumulation. One promising approach is the development of biodegradable plastics derived from renewable sources, which offer a potential remedy to the environmental hazards posed by traditional plastics such as polyethylene and polyvinyl chloride [ 2 , 3 ]. Recent studies have highlighted the development and characterization of polyvinyl alcohol (PVA)-based biopolymers, demonstrating their potential across various applications, including packaging [ 4 – 6 ], biomedical devices [ 7 – 9 ], and agricultural films [ 10 , 11 ]. Despite being derived from petrochemical feedstocks via polyvinyl acetate, PVA is regarded as an environmentally friendly polymer owing to its water solubility, non-toxicity, and biodegradability. Its environmental profile can be further enhanced through the incorporation of renewable biofillers such as CS and ES powder. Biodegradable biopolymers, including cellulose [ 12 – 14 ], chitosan, and cassava starch [ 13 ], are increasingly explored for their potential to reduce environmental harm. Cornstarch (CS), a natural polymer abundant in renewable resources, is widely utilized in industries such as food, pharmaceuticals, textiles, and bioenergy [ 15 , 16 ]. CS’s favorable film-forming properties, attributed to its high amylose content, make it a suitable candidate for biodegradable packaging materials [ 17 ]. However, CS-based plastics often exhibit limitations such as poor mechanical strength and high-water sensitivity. To address these issues, researchers have explored the incorporation of biofillers and nanoparticles to improve both barrier and mechanical properties [ 18 , 19 ]. Eggshells (ES) are abundantly generated as a byproduct of poultry farming and kitchen waste disposal practices. In numerous regions, these valuable waste materials are often deposited in landfills without adequate treatment, contributing to waste management challenges. Although the primary component of ES, CaCO 3 , is not inherently harmful to the environment, the failure to repurpose or recycle this waste leads to its accumulation in landfills. Nevertheless, ES offers a promising avenue as it is primarily composed of CaCO 3 , constituting about 95% of its mass, complemented by approximately 5% organic materials such as collagen, sulfated polysaccharides, and other proteins [ 20 ]. Moreover, ES holds promise as an effective sorbent due to its elevated levels of carbon and calcium, as well as its substantial porosity and accessible functional groups [ 21 ]. These properties contribute to its effectiveness in absorbing moisture or other substances, which is crucial for packaging applications. To date, studies involving PVA bioplastics have primarily explored single biofillers, such as CS or ES powder, with limited attention has addressed the synergistic effects of hybrid biofillers on mechanical strength and biodegradability. This study fills this gap by investigating the combined impact of CS and ES fillers on the performance of PVA films. This approach builds upon earlier research on CS based composites, where the incorporation of ES powder as a waste-derived source rich in calcium carbonate aligns with sustainability goals by reducing the environmental impact associated with waste disposal [ 22 , 23 ]. To further enhance the material properties, citric acid crosslinking is introduced, leveraging its eco-friendly nature and ability to increase polymer network density, which in turn improves mechanical stability and durability of the bioplastic films. By examining various biofiller loadings and their effects on mechanical properties, biodegradability, and water absorption, this research contributes valuable understandings into the development of eco-friendly, high-performance packaging materials. The synergistic integration of CS and ES powder, two abundantly available agricultural and kitchen wastes, enables enhanced functionality compared to single-filler systems, thereby supporting the principles of waste-to-resource strategies and sustainable materials design. The incorporation of citric acid as a green crosslinker further enhances the environmental profile of the bioplastics. The novelty of this study lies in the hybrid incorporation of CS, a natural biopolymer, and ES, a waste-derived filler, into a PVA matrix, coupled with citric acid crosslinking an approach that has not been reported in existing literature. The integrated use of dual biofillers with a green crosslinker enables enhanced bioplastic performance, while supporting waste valorization and the principles of circular economy. 2. EXPERIMENTAL 2.1 Raw Materials The study utilized commercially purchased CS and ES from nearby Malaysian restaurant. PVA with a molecular weight range of 89,000−98,000 and purity of 99% was acquired from Sigma Aldrich/USA. Citric acid with a purity of 99%, 500 grams, was also sourced from Sigma Aldrich/USA. Glycerol was obtained from R&M, Malaysia. 2.2 Preparation of Eggshell Powder (ESP) The fresh ES were collected and underwent a thorough cleaning process with tap water and then repeatedly rinsed to get rid of any surface impurities. Subsequently, it was sun-dried for 24 hours (Fig. 1 ). The dried ES was then placed in a circulating oven at 100°C for approximately 5 hours to ensure complete moisture removal. The dried ES were initially crushed using a mechanical grinder, producing coarse particles approximately 7 mm in size. These coarse particles were subsequently subjected to ball milling at 200 rpm for 12 hours using alumina balls (20 mm and 10 mm diameters) to achieve finer particle size. The milled powder was then sieved using a 100 µm mesh to remove coarse particles, and the final particle size distribution. SEM images (Fig. 4 ) confirm the fine morphology and uniform dispersion of the ES powder, with particle size distribution ranging from 1.125 to 5.272 µm. Image analysis using ImageJ software indicates an average particle size of approximately 2.441 µm, demonstrating the suitability of the powder for composite formulation. 2.3 Preparation of PVA Bioplastic Films Initially, PVA was dissolved in 100 mL of distilled water at 90°C under continuous stirring at 580 rpm until a homogeneous solution was obtained. The dispersed biofillers (ES and CS) were then added to the PVA solution, followed by further stirring to ensure uniform distribution. Glycerol, serving as a plasticizer, and citric acid, acting as a crosslinker, were added according to the formulation detailed in Table 1 . Glycerol improves flexibility and processability, while citric acid facilitates crosslinking through esterification with hydroxyl groups on PVA and starch [ 24 ]. The pH of the mixture during the addition of citric acid was measured to be around 3–4, which is suitable for acid-catalyzed esterification [ 25 ]. The resulting mixture was cast into glass petri dishes and dried at room temperature for 48 hours. To initiate crosslinking, the partially dried films were cured in an oven at 120°C for 30 minutes. No catalyst was used in the crosslinking process. Finally, the films were further dried in an oven at 50°C for 48 hours, peeled off, and stored in a dry cabinet for subsequent characterization. Table 1 The Composition of PVA Bioplastic Films Sample PVA (wt.%) CS (wt.%) ES (wt.%) Glycerol (phr) Citric acid (phr) PVA0 100.0 - - 2.0 3.0 PVACS1.0 99.0 1.0 - 2.0 3.0 PVACS3.0 97.0 3.0 - 2.0 3.0 PVACS5.0 95.0 5.0 - 2.0 3.0 PVAES1.0 99.0 - 1.0 2.0 3.0 PVAES3.0 97.0 - 3.0 2.0 3.0 PVAES5.0 95.0 - 5.0 2.0 3.0 PVACS1.0ES5.0 94.0 1.0 5.0 2.0 3.0 PVACS2.5ES2.5 95.0 2.5 2.5 2.0 3.0 PVACS5.0ES1.0 94.0 5.0 1.0 2.0 3.0 2.4 Characterization and Property Measurements All relevant property characterizations, particularly those involving quantitative measurements, were conducted in triplicate to ensure data reliability and statistical significance. The data are presented as mean ± standard deviation and statistically analyzed using one-way ANOVA, with significance set at p < 0.05. 2.4.1 X-ray diffraction (XRD) Analysis The ES powder was subjected to XRD analysis to identify the phases of CaCO 3 . An angular range of 10° to 80° was used in the analysis, with a step size of 0.03. Each step was measured for 30 seconds to ensure optimal scanning and resolution. 2.3.2 Morphological Characterization The fracture surfaces of the bioplastic films were carefully cut into small pieces and mounted on aluminum stubs using double-sided carbon tape. The samples were then sputter-coated with a thin layer of gold (~ 10 nm) to enhance surface conductivity and image quality. Morphological observations were performed using a Scanning Electron Microscope (Hitachi TM3030 Plus) operating at an accelerating voltage of 15 kV. 2.3.3 Fourier Transform Infrared Analysis The spectra of the PVA bioplastic films were measured using a Perkin Elmer Spectrum 100 FTIR instrument, which ranged from 400 to 4000 cm − 1 . Data analysis was performed using FTIR Spectrum Software. 2.3.4 Biodegradability and Water Absorption Characteristics Biodegradability is a critical factor in assessing the environmental impact of bioplastics, reflecting their breakdown by microorganisms. The biodegradation test was carried out in triplicate using a modified soil-burial method, adapted from the principles of ASTM D5338. Bioplastic films with dimensions of 2 × 2 cm were buried approximately 4 cm deep in natural garden soil and incubated at ambient temperature (28 ± 2°C) for 28 days. The soil, with a pH of 6.8 ± 0.2, was maintained at about 40–50% moisture by periodic sprinkling with distilled water. After incubation, the films were washed with distilled water to remove soil and then dried in an oven until reaching a constant weight. This procedure ensures that the final weight accurately reflects the bioplastic material without moisture interference. The weight loss of the bioplastic films was calculated applying the subsequent formula: Where M i denotes the initial weight of the bioplastic and M f denotes the final weight of the bioplastic (g). This modified soil-burial method provides an indication of biodegradation behavior under natural environmental conditions, although it does not represent the fully controlled composting environment defined by ASTM D5338. Additionally, the water absorption test was performed following the general procedure of ASTM D570 to evaluate the hydrophilic characteristics of the bioplastic films. A specimen measuring 2 cm × 2 cm was submerged in 60 mL of water at ambient temperature (28 ± 2°C) for 24 hours. The water uptake percentage was determined using the subsequent equation: Where M i denotes the initial weight of the bioplastic and M f denotes the final weight of the bioplastic (g). 2.3.5 Water Vapor Transmission Rate (WVTR) The water vapor transmission rate (WVTR) test was conducted in triplicate, following the principles of ASTM E96/E96M-16 (Water Method) under controlled conditions of 50% relative humidity at 23°C. Circular bioplastic film specimens (diameter = 5.5 cm; exposed area ≈ 23.8 cm 2 ) were sealed over water-filled test cups using parafilm to prevent vapor leakage. Daily mass loss was recorded over 7 days. The test was continued until steady-state conditions were reached, as indicated by a consistent linear weight-loss trend for at least three consecutive days. WVTR was calculated using data from the steady-state (linear) portion of the mass-loss curve, according to the following equation: Where Δ m , t and A representing the mass change (g), time (day) and test surface area (m 2 ), respectively. 2.3.6 Mechanical Properties The evaluation of the mechanical properties of bioplastic films was carried out in compliance with ASTM D-882 (tensile testing of thin plastic film) standards utilizing a Shimadzu Autograph AGS-X Series Universal Tester Machine. Rectangular specimens of 10 mm width and 100 mm length, with a width-to-thickness ratio ≥ 8, were used. Tests were conducted at a crosshead speed of 10 mm/min with a predefined gauge length. All measurements were performed in triplicate to ensure reproducibility. 2.3.7 Thermogravimetric Analysis (TGA) Thermogravimetric analyser, Hitachi Model STA7000 was employed to assess the thermal stability of the bioplastic film. The sample was heated from ambient temperature up to 600°C in a nitrogen atmosphere at a rate of 10°C/min, with a gas flow rate of 60 mL/min. The weight of each sample utilized in the analysis ranged from 10 to 15 mg. 3. RESULT AND DISCUSSION 3.1 Structural Characterization of ES XRD patterns of ES particles exhibit characteristic diffraction peaks at 2θ angles of 23.26°, 29.43°, 31.68°, 36.20°, 39.63°, 43.39°, 47.75°, 48.71°, 56.77°, 57.58°, 60.92°, 64.84°, 65.93°, 70.72°, 73.19 and 77.54° (Fig. 2 ). These peaks correspond to the crystalline calcite phase of calcium carbonate, in good agreement with the standard reference pattern for calcite (JCPDS No. 05-0586) [ 26 ]. The most prominent peak at 2θ = 29.43° corresponds to the (104) crystallographic plane of calcite, confirming the presence of its semi-crystalline structure. This suggests that the film possesses a semi-crystalline structure of calcite as the major phase of ES [ 27 ]. The crystallinity of calcite plays a significant role in enhancing the mechanical stability and thermal resistance of the bioplastic films. This improved functionality reinforces the potential of eggshell-derived fillers in sustainable material engineering, supporting a circular bioeconomy and aligning with green material development to reduce reliance on virgin resources. It is known that ES is primarily composed of approximately 95.0% CaCO 3 , mainly as a calcite. The calcite phase is characterized by a rhombohedral crystal structure, where calcium (Ca 2+ ) and carbonate (CO 3 2− ) ions are strongly bonded. This structure imparts high rigidity and thermal stability to ES. The remaining 5.0% is made up of organic materials such type X-collagen, sulfated polysaccharides, and other proteins [ 28 ]. These organic materials contain functional groups such as carboxyl (-COOH), hydroxyl (-OH), and amine (-NH 2 ), which enhance the interfacial adhesion between the CaCO 3 particles and the film-forming matrix by forming hydrogen bonds and ionic interactions. The characteristics of the bioplastic films are improved by the presence of this organic matrix, which increases the interfacial adhesion between the CaCO 3 particles and the film-forming matrix. 3.2 Structural and Morphological Analysis of PVA Bioplastic Films Figure 3 shows a large peak in all FTIR spectra in the wavenumber range of 3200−3600 cm − 1 , corresponding to the stretching vibration of hydroxyl (O–H) groups in PVA, starch, and glycerol, including absorbed water molecules. Specifically, a peak at approximately 3296 cm − 1 indicates stretching of O−H groups [ 29 ]. A notable peak within the range of 2800−2950 cm − 1 corresponds to C−H functional groups [ 30 ]. Additionally, absorption related to water is evident with a peak around 1620−1650 cm − 1 [ 31 ]. This peak is primarily attributed to the bending vibrations of −OH groups, which indicates the presence of water molecules within the bioplastic films. Furthermore, bending vibrations of C–H groups and C–O bonds in aliphatic structures are shown by peaks at 1320−1380 cm − 1 . Additionally, vibrations related to the bending of C−O and O−H groups are detected in the region of 1010−1070 cm − 1 across all samples. The interactions between hydroxyl groups and absorbed water enhance the structural integrity and properties of the bioplastics, indicating that moisture content may play a significant role in their performance. The small band observed at 1730 cm − 1 indicated the presence of C = O bonds in ester groups, arising from the reaction between citric acid and hydroxyl groups of PVA and starch [ 32 ]. The absence of a pronounced O–H peak shift suggests that esterification occurred only to a limited extent, implying partial rather than extensive crosslinking (Fig. 11 ). The incorporation of ES and CS into PVA composites typically enhances hydrogen bonding, which would normally shift the −OH peak toward higher energy. However, the lack of a significant shift suggests that interactions between PVA, ES, and CS may not have altered the hydrogen bonding structure as anticipated. This indicates that the OH groups in CS, although abundant, are mainly retained within the starch molecular network rather than forming new hydrogen bonds with PVA, due to the partial restriction induced by citric acid crosslinking. Therefore, further investigation is needed to understand the implications of adding ES and CS on the structural integrity and properties of the PVA bioplastic films. Water adsorption in the amorphous regions of amylose influences the vibrational stretching of carbonyl groups (C = O), which is responsible for the peak bands found between 1636.78 and 1638.65 cm − 1 . Vonnie et. al (2023) reports that the films are composed of a variety of functional groups, such as carbonyls (C = O), hydroxyls (OH), alkanes (CH), carbonates (CO 3 2− ), and carboxylic acids (COOH), which served as active sites for pollutant adsorption. These functional groups enhance the films' potential as effective biosorption materials. Such functionality contributes to the environmental applicability of these bioplastic films, potentially offering pollutant adsorption capabilities in water or soil remediation contexts [34, 35]. In contrast, the present study employs a PVA matrix with controlled biofiller loadings and citric-acid-mediated crosslinking, producing films with distinct interfacial bonding characteristics and different structural organization compared to the purely biopolymer-based films.‬‬‬‬‬‬ The SEM images of PVA loaded with ES and CS show distinct morphological features, with average size of 2.44 µm and 5.25 µm, respectively (Fig. 4 ). The CS-filled regions exhibited sharper and irregular-edged particles, which can be attributed to the partial disruption and fragmentation of starch granules during mechanical stirring and localized heating (90°C) in PVA dissolution. Similar morphology was reported by Lacerda et. al (2024), where corn starch where corn starch granules became fractured and irregular upon exposure to heat or mechanical treatment. Conversely, the finely ground ES particles appear more uniform and compact with plate-like structures, consistent with the calcite-based morphology of CaCO 3 in eggshell powder [ 37 ]. In the hybrid film (PVACS2.5ES2.5), both smooth and irregular particles coexist, indicating the simultaneous presence of organic (CS) and inorganic (ES) fillers. This dual-phase morphology suggests a complementary interaction between the two, where ES enhances structural rigidity while CS contributes to flexibility and interfacial bonding. Such fine dispersion of ES within the hybrid matrix strengthens the overall structural integrity and mechanical performance of the bioplastic films, as discussed in Section 3.5 . Collectively, these observations confirm that the hybrid biofiller system provides synergistic reinforcement, improving uniformity, stability, and mechanical functionality of the developed bioplastics. 3.3 Biodegradation Studies of PVA Bioplastic Films Figure 5 presents the percentage of weight loss, reflecting the biodegradability of PVA bioplastic films at varying biofiller loadings measured over a period of 28 days. The values represent the mean of three independent replicates, highlighting consistent trends in microbial degradation. A greater weight loss indicates enhanced biodegradability, rendering the material more vulnerable to environmental decomposition, which is advantageous for mitigating plastic waste and environmental contamination. The results demonstrate the beneficial role of fillers in accelerating biodegradation, showing a clear correlation between higher biofiller loading and increased weight loss. Such behaviour supports the development of environmentally benign alternatives to conventional plastics, reinforcing their potential use in sustainable packaging or agricultural mulching applications. The bioplastic films containing 5.0 wt.% of CS and ES exhibited the highest weight loss, at 23.13% and 22.40%, respectively, indicating greater susceptibility to microbial attack. Although the weight loss increased compared to neat PVA, the overall biodegradation remained moderate. According to international compostability standards such as EN 13432 (≥ 90% mineralization within 180 days) and ASTM D6400 (≥ 60% carbon-to-CO 2 conversion within the same period) [ 38 ], the observed degradation level (≈ 23% after 28 days) indicates partial rather than complete compostability. Nonetheless, this moderate improvement is still meaningful, as it demonstrates that compositional tuning and crosslinking control can effectively influence degradation kinetics and material lifespan, particularly for short-term or controlled-life applications. The enhanced vulnerability can be attributed to the presence of biodegradable constituents in CS (mainly starch and hydroxyl-rich polysaccharides) that readily interact with microorganisms [ 39 , 40 ]. In contrast, ES, consisting predominantly of inorganic CaCO 3 , acts as a nucleating agent that facilitates microbial colonization and microcrack formation at the polymer–filler interface [ 41 ]. These interactions collectively facilitate enzymatic attack and structural disintegration of the film. Since both fillers possess micron-scale particle sizes, the improvement in biodegradability is more likely governed by their surface chemistry and interfacial reactivity. Since both fillers possess micron-scale particle sizes, the improvement in biodegradability is more likely governed by their surface chemistry and interfacial reactivity rather than surface area. Statistical analysis using one-way ANOVA confirmed that the differences in weight loss among formulations were significant (p < 0.05), validating the observed trend and reinforcing the reliability of the results. These findings align with previous research by Muthupandeeswari et. al (2022), which found that PVA bioplastic films containing 15.0 wt.% CaCO₃ experienced greater weight loss than those containing 5.0 wt.% CaCO₃, indicating that filler composition and distribution can influence biodegradation behavior. According to Table 2 , the hybrid PVACS1.0ES5.0 bioplastic films show a lower weight loss (7.36%) in the biodegradation test compared to the single biofillers PVACS1.0 (19.13%) and PVAES5.0 (22.40%). This indicates that the interaction between CS and ES results in a more complex structure. This indicates that the interaction between CS and ES results in a more complex structure. Specifically, citric acid can form ester linkages with hydroxyl groups in PVA and starch (CS), generating partial covalent crosslinking within the polymer matrix, as confirmed in previous studies where FTIR spectra showed esterification between citric acid and starch/PVA [ 43 ]. Concurrently, citric acid may react with CaCO 3 to form calcium citrate with CO₂ release, while limited ionic interactions (Ca 2+ –carboxylate bridging) can further occur within the network [ 44 ]. These ionic interactions contribute to the observed densification and stability rather than direct covalent crosslinking. Prapruddivongs et. al (2020) conducted a similar study that identified ES powder as a potential hydrolytic retardant for citric acid-filled thermoplastic starch. The research demonstrated that citric acid, serving as a crosslinking agent within the ES powder, facilitates the formation of ester bonds, which in turn leads to rapid sample biodegradation accompanied by accelerated hydrolysis. The denser hybrid structure may enhance barrier properties against microbial penetration, leading to increased stability and reduced microbial activity, thus decelerating the degradation process. The crosslinking induced by citric acid promotes stronger interfacial interactions between PVA and the incorporated ES–CS fillers, contributing to a more compact polymer network [ 22 ]. Such interactions may reduce the overall polarity and restrict the mobility of hydrophilic groups, resulting in lower water permeability and slower weight loss during degradation [ 33 ]. The compact structure also helps to limit water diffusion through the film, thereby improving water retention. Minimizing water absorption is crucial for maintaining the functionality and integrity of bioplastic products, ensuring their suitability for various packaging applications. Excessive water absorption can negatively impact on the performance and characteristics of a material, leading to dimensional instability, reduced mechanical strength, and material degradation over time [ 45 ]. Due of the higher concentration of hydrophilic groups in CS, such as OH groups, that attract and retain water, water absorption is typically higher in PVA filled with CS than in PVA filled with ES. In contrast, ES, which is primarily composed of CaCO 3 , is less likely to absorb water compared to hydrophilic materials like CS [ 23 ]. The data clearly show that PVA bioplastic films filled with CS and ES absorb less water than unfilled ones (Fig. 6 ). As the filler loading increases, the dispersion of filler particles within the bioplastic matrix densifies the structure, restricting polymer chain mobility and reducing water penetration. According to Vonnie et. al (2022), the strong crosslinked networks formed by the intramolecular interactions and arrangement of ES and CS granules inhibit water penetration into the ES/CS films, thereby reducing the film's water absorption capacity. These results highlight a potential tunable degradation mechanism through the dual biofiller system, offering flexibility for different end-use applications, a feature not typically observed in single-filler bioplastics. Table 2 Biodegradation Studies and Barrier Properties of Hybrid PVA Bioplastic Films Sample Weight Loss (%) Water Absorption (%) WVTR (g/m 2 ·day) PVACS1.0ES5.0 7.36 246.52 348.01 PVACS2.5ES2.5 13.38 247.49 353.84 PVACS5.0ES1.0 13.88 294.45 353.90 Error bars = ± SD (n = 3); p < 0.05 3.4 Barrier Properties PVA Bioplastic Films The water vapor transmission rate (WVTR) is a crucial parameter for packaging materials, as it evaluates their effectiveness in ensuring safety and extending product shelf life. In applications requiring breathable packaging, such as for fresh produce or moisture-sensitive goods, a higher WVTR can be advantageous, as it allows for controlled moisture exchange. Figure 7 shows a slight increase in WVTR with the incorporation of ES and CS fillers. The hybrid formulation PVACS2.5ES2.5 exhibited a modestly higher WVTR of 353.84 g/m 2 ·day compared to neat PVA (320.39 g/m²·day), likely due to enhanced porosity and microstructural disruption that facilitate vapor diffusion [ 46 , 47 ]. The relatively small increase in WVTR, combined with moderate water absorption (247.49%), indicates that the incorporation of CS and ES effectively tunes moisture permeability without substantially deteriorating barrier performance or compromising dimensional stability. This observation is consistent with studies on weight loss, suggesting that increased porosity may contribute to higher biodegradation rates. Additionally, filler particle aggregation may compromise the structural integrity of the film, leading to micro-defects and increasing WVTR [ 23 ]. In hybrid composites combining ES and CS, the overall WVTR was also elevated, potentially due to synergistic effects that increase heterogeneity and disrupt the polymer matrix continuity. The dual-filler interaction offers adjustable barrier properties, allowing for better control of moisture sensitivity, which is useful in specific packaging applications such as fresh produce or moisture-sensitive foods where tailored WVTR levels are required [ 38 , 48 ]. The presence of glycerol could also play a role in increasing film flexibility and reducing crystallinity, potentially forming channels or microvoids that improve moisture transport efficiency, leading to a slight increase in WVTR compared to single filler systems. An increased WVTR is desirable for compostable packaging, as it facilitates moisture transfer and accelerates material degradation in composting environments. This finding supports the objective of developing biodegradable materials with targeted moisture management properties for applications anticipating accelerated biodegradation. Error bars = ± SD (n = 3); p < 0.05 3.5 Mechanical Properties of PVA Bioplastic Films Figure 8 shows a notable improvement in the tensile strength of PVA bioplastic films with rising concentrations of ES and CS. At 5.0 wt.% CS and ES, the tensile strength reaches 19.58 MPa and 26.25 MPa, respectively. The reinforcing effect of CaCO 3 from ES facilitates stronger interactions with the PVA matrix compared to CS. The CaCO 3 particles restrict polymer chain movement and hinder crack propagation, leading to improved mechanical properties and increased tensile strength [ 42 ]. As the concentration of CaCO 3 increases, the density of reinforcement points rises, effectively distributing applied stress throughout the material, which reduces the burden on individual PVA chains, and leads to higher resistance to deformation and fracture under tensile stress [ 49 ]. Compared to CS, the smaller size of ES particles (Fig. 4 ) enhances interfacial interactions with the PVA matrix, possibly enhancing mechanical properties such as tensile strength and elongation at break. Figure 9 shows that at 5 wt.% CS, the elongation at break of PVA bioplastic films increases by about 20% to 376.8% compared to neat PVA. This upward trend signifies that a higher percentage of CS contributes to greater ductility, allowing for more extensive material deformation before reaching its breaking point [ 50 ]. Meanwhile, PVA films plasticized with glycerol and reinforced with 5 wt.% ES exhibited the highest elongation at break, reaching 471.52%, likely due to a combination of reinforcing effects and microstructural changes. While denser fillers like ES typically restrict elongation [ 51 ], their contribution to structural integrity and stress accommodation under certain strain conditions can still enhance ductility. Interestingly, the incorporation of 5 wt.% ES filler enhanced both tensile strength and elongation at break, a typically contradictory outcome, suggesting a synergistic effect. This is likely due to fine ES dispersion and strong interfacial bonding improving stress transfer, while glycerol and flexible matrix morphology preserved chain mobility. Statistical analysis confirmed that the improvements in elongation at break were significant (p < 0.05), validating the observed trends. Error bars in Figs. 8 and 9 represent standard deviations from triplicate measurements. The hybrid formulations, particularly those with higher ES content, provide a balance between tensile strength and elongation at break. For instance, PVACS1.0ES5.0 shows a tensile strength of 21.33 MPa and an elongation at break of 428.18%, which is higher than pure CS samples ( Table 3 ). This indicates that hybrid fillers offer a better combination of the flexibility from ES with the structural reinforcement from CS, resulting in a balanced set of mechanical properties through a synergistic reinforcement effect that enhances overall performance beyond what individual fillers can achieve. Statistical analysis also supports the performance of hybrid composites, with PVACS1.0ES5.0 showing a significant increase in both tensile strength and elongation compared to single-filler systems ( p < 0.05). Table 3 Mechanical Properties of Hybrid PVA Bioplastic Films Sample Tensile Strength (MPa) Elongation at Break (%) PVACS1.0ES5.0 21.33 428.18 PVACS2.5ES2.5 20.00 420.25 PVACS5.0ES1.0 24.67 399.73 3.6 Thermal Analysis The thermal stability of PVA bioplastic films with varying loadings of CS and ES fillers is presented in Table 4 . Pure PVA exhibited a T 5 of 56.97°C and T max of 323.64°C. When 1.0% CS was added, T 10 and T max slightly decreased to 56.27°C and 316.07°C, respectively, suggesting a minor decrease in thermal stability (Fig. 10 ). This decrement may result from the introduction of new thermal pathways for degradation, which can be associated with the processing conditions or the interactions between the components. However, the overall stability of the composite system improves at higher CS loadings (e.g., 5.0% CS), where both T 10 and T max increase to 58.60°C and 331.32°C, respectively, accompanied by an increased percent residue of 5.15%. The increase in thermal stability with CS loading can be attributed to the excellent CS-PVA compatibility, creates an effective barrier to heat transfer and thereby delays degradation [ 52 ]. The result reveal that the incorporating 1.0% ES resulted in a significant increase in T 10 to 66.38°C and T max to 361.96°C, reflecting a substantial improvement in thermal stability due to the inherent heat resistance properties of CaCO 3 from ES, which effectively inhibit the thermal degradation of PVA [ 23 ]. However, at 5.0% ES loading, T 10 decreased to 57.61°C and T max dropped significantly to 251.24°C, implying a detrimental effect on thermal stability at higher ES concentrations. This decrease, alongside an increased percent residue of 10.1%, can be attributed to particle agglomeration, which may create localized thermal stress points promoting earlier degradation [ 53 ], heterogeneous dispersion of ES particles, disrupting the continuity of the PVA matrix and reducing uniform thermal resistance and suboptimal PVA–ES interactions at elevated loadings, weakening interfacial bonding and further compromising thermal stability [ 54 , 55 ]. These findings underscore the complex interplay between filler loading, composite structure, and thermal stability in PVA bioplastic films. Table 4 Thermal Degradation Temperatures of PVA Bioplastic Films Sample T 5 (°C) a T 10 (°C) b T max (°C) c Residue (%) PVA0 56.97 83.64 323.64 3.81 PVACS1.0 56.27 87.92 316.07 3.83 PVACS5.0 58.60 92.69 331.32 5.15 PVAES1.0 66.38 110.85 361.96 5.11 PVAES5.0 57.61 81.43 251.24 10.1 PVACS2.5ES2.5 59.11 97.26 353.65 5.91 a, b T 5 and T 10 is defined as the temperature at 5% and 10% weight loss, respectively c T max defined as the temperature at a maximum mass loss A composite filler with 2.5% CS and 2.5% ES showed a balanced thermal stability, with T 10 at 59.11°C and T max at 353.65°C, indicating that combining both fillers can effectively enhance thermal properties. This combination effectively enhances the thermal properties due to a synergistic effect, with CS might offer improved dispersion and interaction with the PVA matrix, while ES contributes its inherent thermal stability. Adjustment of the CS–ES ratio enables precise tuning of the thermal properties, allowing the bioplastic to be optimised for targeted applications. The hybrid incorporation of CS and ES enhances the performance and environmental sustainability of PVA-based bioplastics. CS, which is rich in hydroxyl (–OH) groups, forms extensive hydrogen bonding interactions with PVA chains. These interactions improve interfacial compatibility and cohesion within the polymer matrix, reinforcing structural integrity and enhancing mechanical strength. In parallel, ES particles primarily composed of calcium carbonate (CaCO 3 ) function as rigid inorganic fillers that restrict polymer chain mobility and act as physical barriers, contributing to improved mechanical stiffness. Owing to their high thermal decomposition temperature, ES particles also enhance the thermal stability of the composite by serving as heat-resistant elements. Biodegradation occurs via microbial colonization and enzymatic degradation of the bioplastic matrix. CS serves as a biodegradable carbon source, facilitating microbial metabolism and accelerating the breakdown process. Although ES is not biodegradable, its porous structure and alkaline nature promote microbial attachment and help neutralize acidic byproducts generated during degradation. Overall, the synergistic interaction between CS and ES enhances the mechanical, thermal, and biodegradation performance of the PVA-based bioplastic, as summarized in Fig. 11 . 3.7 Optimization Outcome The optimization analysis revealed that the most balanced PVA bioplastic formulation was achieved through the hybrid incorporation of CS and ES biofillers. Each filler contributed distinct advantages: CS enhanced biodegradability and flexibility, while ES provided mechanical reinforcement and thermal stability (see Table 5 and Fig. 12 ). Among all tested compositions, the hybrid formulation PVACS2.5ES2.5 demonstrated the most favorable overall performance. This system achieved a tensile strength of 20.00 MPa with an elongation at break of approximately 420%, indicating strong yet flexible mechanical behavior. Thermal stability was significantly improved, with T 10 recorded at 59.11°C and T max at 353.65°C, outperforming the neat PVA and single-filler systems. In terms of environmental performance, the hybrid bioplastic exhibited controlled biodegradation, with a moderate weight loss of 13.38% after 28 days, making it suitable for regulated disposal. Although PVACS2.5ES2.5 showed the highest WVTR (353.84 g/m 2 ·day), its water absorption remained moderate (247.49%) compared to PVACS5.0ES1.0, indicating a possible balance in hydrophilic and hydrophobic interactions at the 2.5 wt.% filler ratio. These findings highlight the novelty of a dual biofiller approach in tailoring multifunctional properties such as mechanical robustness, thermal stability, and biodegradability, compared to single PVA-based film. Such synergy, rarely achieved in single filler or neat PVA systems, offers a promising platform for the development of eco-friendly packaging materials where both durability and environmental responsiveness are critical. Table 5 Comparative Performance of PVA Bioplastics Reinforced with ES and CS Samples Thermal Stability Mechanical Properties Barrier Properties Biodegradation Studies Overall performance T 5 (°C) T max (°C) Tensile Strength (MPa) Elongation at Break (%) WVTR (g/m 2 ·day) Water Absorption (%) Weight Loss (%) PVA0 56.97 323.64 12.57 302.76 320.39 398.20 18.50 Reference (limited performance) PVACS1.0 56.27 316.07 12.68 293.73 339.25 250.53 19.00 Limited enhancement PVACS3.0 16.94 360.71 293.38 290.00 20.00 Acceptable (balance) PVACS5.0 58.60 331.32 19.58 376.81 347.00 330.30 21.50 Limited enhancement PVAES1.0 66.38 361.96 17.73 441.86 327.13 287.20 18.70 Acceptable (balance) PVAES3.0 21.82 379.66 357.80 288.70 19.50 Acceptable PVAES5.0 57.61 251.24 26.26 471.52 389.31 299.60 22.50 Excess ES loading PVACS1.0ES5.0 21.33 428.18 348.01 246.52 7.36 Good if biodegradation prioritized) PVACS2.5ES2.5 59.11 353.65 20.00 420.25 353.84 247.49 13.38 Optimal balance PVACS5.0ES1.0 24.67 399.73 353.90 294.45 13.88 Very strong (if mechanical prioritized) 3.8 Environmental Perspective and Life Cycle Consideration (LCA) The developed PVA-based hybrid films demonstrate promising cost-effectiveness, scalability, and environmental potential. ES is a low-cost agro-waste material, while CS is a low-cost bio-derived material. Both require minimal processing, primarily cleaning, drying, grinding, and sieving which are compatible with standard polymer compounding techniques. Film fabrication via solution casting, ambient drying, and mild thermal curing contributes to a relatively low energy footprint and supports feasibility for industrial adoption using existing processing equipment. From a performance perspective, the PVACS2.5ES2.5 film offers a sustainable balance; tensile strength of 20.00 MPa, ~ 420% elongation at break, moderate biodegradation (13.38% mass loss in 30 days under ambient soil), and a WVTR of 353.84 g/m²·day at 23°C and 50% RH. Compared to commercial bioplastics such as PLA, PBAT, and crosslinked PVA (cPVA), it offers intermediate performance. PLA provides high tensile strength (50–70 MPa) but low flexibility (~ 5–10%), PBAT shows very high elongation (> 1000%) with moderate strength (10–20 MPa) [ 56 ], while cPVA achieves ~ 58.9 MPa strength but low elongation (~ 29.8%) due to its rigid crosslinked structure [ 57 ]. In contrast, PVACS2.5ES2.5 achieves a desirable mechanical–biodegradability compromise. While PLA degrades slowly and PBAT degrades rapidly in moist environments, the hybrid film presents a sustainable middle ground suitable for short-term packaging applications. Table 6 summarizes this comparison and positions PVACS2.5ES2.5 as a viable and eco-friendly packaging alternative. To complement the environmental assessment, the Life Cycle Inventory (LCI) was conducted in accordance with ISO 14040–14043 guidelines [ 58 ], focusing on a cradle-to-gate boundary encompassing raw material acquisition, filler processing, and film formation. Total estimated energy use per batch was ~ 12.1 kWh with a corresponding carbon footprint of ~ 5.45 kg CO 2 -eq, based on regional emission factors (0.45 kg CO 2 -eq/kWh). Key energy-consuming steps included oven drying (2.0 kWh), ball milling (4.0 kWh), and thermal curing (0.5 kWh). (See Table 7 for full LCI breakdown). Although a full cradle-to-grave LCA was not conducted, the use of low-energy processes and agro-waste inputs suggests a favorable environmental footprint relative to synthetic or biomass-derived polymers. This is notable, as energy consumption and raw material sourcing are major contributors to the global warming potential of plastic materials. Future studies should incorporate streamlined life cycle assessment (LCA) or carbon footprint analysis using standardized tools such as SimaPro or OpenLCA to quantitatively validate the environmental sustainability of the developed bioplastic system [ 59 ]. Table 6 Comparative Performance and Sustainability Attributes of PVACS2.5ES2.5 and Commercial Bioplastics (PLA, PBAT, cPVA Parameter PLA PBAT cPVA Hybrid PVACS2.5ES2.5 Tensile Strength 50–70 MPa [ 56 ] 10–20 MPa [ 56 ] ~ 58.9 MPa [ 57 ] 20.00 MPa Elongation at Break ~ 5–10% [ 56 ] 1237.8% [ 56 ] ~ 29.8% [ 57 ] ~ 420% Biodegradability ≈ 90% in 20 days at 58°C (industrial compost) [ 60 ] ≥ 64% in 45 days at 58°C; ~90% in 80 days industrial compost [ 56 ] Low 13.38% in 30 days (ambient soil) Main Source Fermented corn (industrial biomass Petrochemical-based Petrochemical or biomass-derived Bio-based (CS) + Agro-waste (ES) Energy Input Medium (fermentation + polymerization + extrusion) High (synthetic polymerization + extrusion) Medium (solution casting + crosslinking) Low (drying, grinding, and casting) Barrier (WVTR) 263 ± 14 (g/m²·day) (38°C, 90% RH) [ 61 ] Moderate to high (e.g. ~50–150 g/m²·day for PLA films) Moderate 353.84 g/m²·day ( 23°C, 50% RH) Processing Complexity Polymerization + extrusion Polymer synthesis Film casting or hydrogel prep Simple blending + casting Shelf-life Suitability Long-term rigid packaging Flexible short/medium-term packaging Variable (short to moderate; crosslinking enhances stability) Short-term packaging (designed for degradability) Cost of Raw Material Moderate High Moderate⁠ (depends on grade and processing) Low (agro-waste + bio-based) Potential applications of the developed PVACS2.5ES2.5 hybrid film include disposable food trays, compostable produce wraps, and agricultural mulching films, where controlled degradation, mechanical integrity during use, and post-use compostability are desired. Nonetheless, the use of natural fillers requires further evaluation of potential leaching and microbial safety, especially for food-contact applications. In addition, incorporation of compatibilizers or nano-fillers may enhance performance without compromising biodegradability. Long-term environmental performance under real-world composting or landfill conditions also warrants further study. Table 7 Estimated Life Cycle Inventory (LCI) for the Production of PVACS2.5ES2.5 Bioplastic Film Material / Process Estimated Energy Used (kWh) Carbon Footprint (kg CO 2 eq) Notes Polyvinyl Alcohol (PVA) 0.80 0.36 Based on industrial-scale production data CS 0.10 0.05 Bio-based material derived from corn. ES 1.50 0.68 Includes cleaning, oven drying, grinding, and ball milling Glycerol 0.05 0.02 Small-scale lab estimation Citric Acid 0.05 0.02 Based on basic chemical input data Tap Water for Cleaning 0.10 0.05 Estimated water use during initial ES cleaning Sun Drying (natural) 0.00 0.00 Passive drying, no energy input Oven Drying (100°C, 5 hours) 2.00 0.90 Oven-based dehydration step Ball Milling (12 hours) 4.00 1.80 Assumes standard benchtop milling setup Sieving (100 µm mesh) 0.50 0.23 Post-milling particle sizing Heating + Stirring (90°C, 580 rpm) 0.80 0.36 PVA dissolution and uniform filler dispersion Room Drying (48 hours, passive) 0.20 0.09 Passive evaporation step Oven Curing (120°C, 30 min) 0.50 0.23 Curing stage to facilitate crosslinking Oven Final Drying (50°C, 48 hours) 1.50 0.68 Final drying before film storage Total Energy: 12.1 kWh Total Emissions: ~5.45 kg CO 2 eq 4. CONCLUSION The incorporation of ES and CS as biofillers into PVA bioplastic films significantly enhanced their structural, mechanical, thermal, and environmental performance. Structural characterization confirmed that ES is mainly calcite-phase CaCO 3 , while CS provided functional groups (–OH, C = O) compatible with the PVA matrix. FTIR and XRD analyses supported effective filler–matrix interactions. Biodegradation results showed that while films with 5.0 wt.% single fillers (CS or ES) achieved higher weight loss (21.50% and 22.50%, respectively), the hybrid composition PVACS2.5ES2.5 offered a more balanced profile, with moderate biodegradation (13.38%) and superior barrier and mechanical performance. This hybrid film recorded a tensile strength of 20.00 MPa, elongation of ~ 420%, moderate water absorption (247.49%), and an increased WVTR (353.84 g/m 2 ·day) compared to neat PVA (320.39 g/m 2 ·day), indicating its suitability for compostable packaging requiring both breathability and structural integrity. Thermal analysis revealed enhanced stability, with T 10 at 59.11°C and T max at 353.65°C, further confirming the synergistic effect of dual fillers. Additionally, the use of agro-waste ES and bio-based CS, coupled with low-energy solution casting (~ 12.1 kWh per batch) and an estimated carbon footprint of ~ 5.45 kg CO 2 -eq, demonstrates both environmental and economic feasibility. In conclusion, the PVACS2.5ES2.5 formulation presents an optimally balanced, scalable, and eco-friendly alternative for short-term packaging applications, aligning with sustainable materials innovation and circular economy objectives. This dual biofiller approach also introduces a novel strategy to simultaneously enhance mechanical durability, thermal stability, moisture permeability, and biodegradability, features rarely achieved in conventional single filler systems. Declarations ACKNOWLEDGEMENT The authors would like to thank the Ministry of Higher Education for providing financial support under Fundamental Research Grant Scheme (FRGS) No. FRGS/1/2021/STG05/UMP/03/1 (University reference RDU210108) and Universiti Malaysia Pahang Al-Sultan Abdullah for laboratory facilities as well as additional financial support under Internal Research Grant RDU240317 and PGRS230374. Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The data that support the findings of this study are available from the corresponding author upon reasonable request. Author Contributions Chm. Ts. 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(2021) Cite Share Download PDF Status: Published Journal Publication published 12 Jan, 2026 Read the published version in Waste and Biomass Valorization → Version 1 posted Reviewers agreed at journal 31 Oct, 2025 Reviewers invited by journal 30 Oct, 2025 Editor invited by journal 30 Oct, 2025 Editor assigned by journal 29 Oct, 2025 First submitted to journal 28 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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1","display":"","copyAsset":false,"role":"figure","size":614354,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of the Preparation Process for PVA Bioplastic Films\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/f1b3f93f250fb3cc896b675a.png"},{"id":94950567,"identity":"cfac79f9-198d-4f0a-9238-57cc24a6c4b0","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":45977,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of the ES\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/8971b184b305353a249ce002.png"},{"id":94989142,"identity":"19096fe4-e19f-487d-87a6-1f3674d03a78","added_by":"auto","created_at":"2025-11-03 07:12:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":41052,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR Spectra of PVA Bioplastic Films\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/d57500356e50c1a184711b60.png"},{"id":94988862,"identity":"453b7d2a-1e9e-40f3-aa6d-7db786e0913b","added_by":"auto","created_at":"2025-11-03 07:11:10","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1175591,"visible":true,"origin":"","legend":"\u003cp\u003eThe SEM images of PVA bioplastic films (a) PVACS3.0 (\u003cem\u003e×\u003c/em\u003e1000) and (b,c) PVAES3.0 film with different magnifications (\u003cem\u003e×\u003c/em\u003e1000, \u003cem\u003e×\u003c/em\u003e5000) and \u0026nbsp;(d) PVACS2.5ES2.5 (\u003cem\u003e×\u003c/em\u003e5000)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/e6b5254d49df833a00bdcdf4.png"},{"id":94989179,"identity":"e651eafa-5a81-4851-826c-437afbaf47e2","added_by":"auto","created_at":"2025-11-03 07:12:21","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":39278,"visible":true,"origin":"","legend":"\u003cp\u003eWeight Loss (%) of PVA Bioplastic Films. Error bars = ± SD (n = 3); \u003cem\u003ep \u0026lt; 0.05\u003c/em\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/15bbbe8a663dc5317f6fb523.png"},{"id":94950565,"identity":"7ac96940-8ca4-4cf4-b314-547258d7140d","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":39279,"visible":true,"origin":"","legend":"\u003cp\u003eWater Absorption (%) of PVA Bioplastic Films.\u003c/p\u003e\n\u003cp\u003eError bars = ± SD (n = 3); \u003cem\u003ep \u0026lt; 0.05\u003c/em\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/80b11ff6281bc8aac32b6b4d.png"},{"id":94950585,"identity":"7104b1d5-0404-4b4f-a1af-fe981c200244","added_by":"auto","created_at":"2025-11-02 12:05:49","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":44289,"visible":true,"origin":"","legend":"\u003cp\u003eWater Vapor Transmission Rate of PVA Bioplastic Films.\u003c/p\u003e\n\u003cp\u003eError bars = ± SD (n = 3); \u003cem\u003ep \u0026lt; 0.05\u003c/em\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/b562cd3024185d0448fb9250.png"},{"id":94950576,"identity":"f5dd4a5a-78bf-4092-bbc1-a97a285d6be6","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":41297,"visible":true,"origin":"","legend":"\u003cp\u003eTensile Strength of PVA Bioplastic Films. Error bars = ± SD (n = 3); \u003cem\u003ep \u0026lt; 0.05\u003c/em\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/8437f68997a33cfec36857ff.png"},{"id":94988579,"identity":"2d542fc3-0103-4eed-92a1-564707d2d720","added_by":"auto","created_at":"2025-11-03 07:09:58","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":43647,"visible":true,"origin":"","legend":"\u003cp\u003eElongation at Break of PVA Bioplastic Films. Error bars = ± SD (n = 3); \u003cem\u003ep \u0026lt; 0.05\u003c/em\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/cf40276e7530fde3b35f6120.png"},{"id":94950573,"identity":"fe60bea5-0c08-4f44-a24a-28fb771d743f","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":35734,"visible":true,"origin":"","legend":"\u003cp\u003eTGA curves of PVA Bioplastic Films\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/a9ea52d14badd2c8fdf81d39.png"},{"id":94950579,"identity":"3e2911e0-eb28-439b-acd6-2a70d9cdd92a","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":366069,"visible":true,"origin":"","legend":"\u003cp\u003eProposed biodegradation mechanism of hybrid PVA bioplastic incorporating CS and ES. \u003cem\u003eThe figure illustrates the role of CS in hydrogen bonding and biodegradation, and the function of ES as a rigid, thermally stable filler that supports microbial attachment and neutralizes acidic byproducts.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/868dcb18aedb741c42f94c68.png"},{"id":94950575,"identity":"377c212c-9b98-4805-9a9b-fc964f841c98","added_by":"auto","created_at":"2025-11-02 12:05:48","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":108072,"visible":true,"origin":"","legend":"\u003cp\u003eOverall Performance Profile of Optimized PVA Bioplastic Formulation\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/5a764f4de0a57f66caca1bf2.png"},{"id":100616124,"identity":"369d5100-ea30-4cfc-8646-fe8a9d80a88e","added_by":"auto","created_at":"2026-01-19 17:40:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3498436,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7298605/v1/d3e47dcf-72c2-4b80-9170-c4c94b84a3e4.pdf"}],"financialInterests":"","formattedTitle":"Hybrid Cornstarch and Eggshell Reinforcement for Enhanced Mechanical, Thermal, and Biodegradation Performance of Sustainable Polyvinyl Alcohol Bioplastic","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003ePetroleum-based plastics dominate the market due to their superior mechanical strength and cost-effectiveness; however, their persistence in the environment leads to severe ecological challenges, particularly in landfills and oceans [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. This growing concern necessitates urgent green engineering solutions to mitigate plastic waste accumulation. One promising approach is the development of biodegradable plastics derived from renewable sources, which offer a potential remedy to the environmental hazards posed by traditional plastics such as polyethylene and polyvinyl chloride [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eRecent studies have highlighted the development and characterization of polyvinyl alcohol (PVA)-based biopolymers, demonstrating their potential across various applications, including packaging [\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], biomedical devices [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and agricultural films [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Despite being derived from petrochemical feedstocks via polyvinyl acetate, PVA is regarded as an environmentally friendly polymer owing to its water solubility, non-toxicity, and biodegradability. Its environmental profile can be further enhanced through the incorporation of renewable biofillers such as CS and ES powder. Biodegradable biopolymers, including cellulose [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], chitosan, and cassava starch [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], are increasingly explored for their potential to reduce environmental harm. Cornstarch (CS), a natural polymer abundant in renewable resources, is widely utilized in industries such as food, pharmaceuticals, textiles, and bioenergy [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. CS\u0026rsquo;s favorable film-forming properties, attributed to its high amylose content, make it a suitable candidate for biodegradable packaging materials [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. However, CS-based plastics often exhibit limitations such as poor mechanical strength and high-water sensitivity. To address these issues, researchers have explored the incorporation of biofillers and nanoparticles to improve both barrier and mechanical properties [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eEggshells (ES) are abundantly generated as a byproduct of poultry farming and kitchen waste disposal practices. In numerous regions, these valuable waste materials are often deposited in landfills without adequate treatment, contributing to waste management challenges. Although the primary component of ES, CaCO\u003csub\u003e3\u003c/sub\u003e, is not inherently harmful to the environment, the failure to repurpose or recycle this waste leads to its accumulation in landfills. Nevertheless, ES offers a promising avenue as it is primarily composed of CaCO\u003csub\u003e3\u003c/sub\u003e, constituting about 95% of its mass, complemented by approximately 5% organic materials such as collagen, sulfated polysaccharides, and other proteins [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Moreover, ES holds promise as an effective sorbent due to its elevated levels of carbon and calcium, as well as its substantial porosity and accessible functional groups [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. These properties contribute to its effectiveness in absorbing moisture or other substances, which is crucial for packaging applications.\u003c/p\u003e\u003cp\u003eTo date, studies involving PVA bioplastics have primarily explored single biofillers, such as CS or ES powder, with limited attention has addressed the synergistic effects of hybrid biofillers on mechanical strength and biodegradability. This study fills this gap by investigating the combined impact of CS and ES fillers on the performance of PVA films. This approach builds upon earlier research on CS based composites, where the incorporation of ES powder as a waste-derived source rich in calcium carbonate aligns with sustainability goals by reducing the environmental impact associated with waste disposal [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. To further enhance the material properties, citric acid crosslinking is introduced, leveraging its eco-friendly nature and ability to increase polymer network density, which in turn improves mechanical stability and durability of the bioplastic films.\u003c/p\u003e\u003cp\u003eBy examining various biofiller loadings and their effects on mechanical properties, biodegradability, and water absorption, this research contributes valuable understandings into the development of eco-friendly, high-performance packaging materials. The synergistic integration of CS and ES powder, two abundantly available agricultural and kitchen wastes, enables enhanced functionality compared to single-filler systems, thereby supporting the principles of waste-to-resource strategies and sustainable materials design. The incorporation of citric acid as a green crosslinker further enhances the environmental profile of the bioplastics. The novelty of this study lies in the hybrid incorporation of CS, a natural biopolymer, and ES, a waste-derived filler, into a PVA matrix, coupled with citric acid crosslinking an approach that has not been reported in existing literature. The integrated use of dual biofillers with a green crosslinker enables enhanced bioplastic performance, while supporting waste valorization and the principles of circular economy.\u003c/p\u003e"},{"header":"2. EXPERIMENTAL","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Raw Materials\u003c/h2\u003e\u003cp\u003eThe study utilized commercially purchased CS and ES from nearby Malaysian restaurant. PVA with a molecular weight range of 89,000\u0026minus;98,000 and purity of 99% was acquired from Sigma Aldrich/USA. Citric acid with a purity of 99%, 500 grams, was also sourced from Sigma Aldrich/USA. Glycerol was obtained from R\u0026amp;M, Malaysia.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Preparation of Eggshell Powder (ESP)\u003c/h2\u003e\u003cp\u003eThe fresh ES were collected and underwent a thorough cleaning process with tap water and then repeatedly rinsed to get rid of any surface impurities. Subsequently, it was sun-dried for 24 hours (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The dried ES was then placed in a circulating oven at 100\u0026deg;C for approximately 5 hours to ensure complete moisture removal. The dried ES were initially crushed using a mechanical grinder, producing coarse particles approximately 7 mm in size. These coarse particles were subsequently subjected to ball milling at 200 rpm for 12 hours using alumina balls (20 mm and 10 mm diameters) to achieve finer particle size. The milled powder was then sieved using a 100 \u0026micro;m mesh to remove coarse particles, and the final particle size distribution. SEM images (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) confirm the fine morphology and uniform dispersion of the ES powder, with particle size distribution ranging from 1.125 to 5.272 \u0026micro;m. Image analysis using ImageJ software indicates an average particle size of approximately 2.441 \u0026micro;m, demonstrating the suitability of the powder for composite formulation.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Preparation of PVA Bioplastic Films\u003c/h2\u003e\u003cp\u003eInitially, PVA was dissolved in 100 mL of distilled water at 90\u0026deg;C under continuous stirring at 580 rpm until a homogeneous solution was obtained. The dispersed biofillers (ES and CS) were then added to the PVA solution, followed by further stirring to ensure uniform distribution. Glycerol, serving as a plasticizer, and citric acid, acting as a crosslinker, were added according to the formulation detailed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Glycerol improves flexibility and processability, while citric acid facilitates crosslinking through esterification with hydroxyl groups on PVA and starch [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The pH of the mixture during the addition of citric acid was measured to be around 3\u0026ndash;4, which is suitable for acid-catalyzed esterification [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The resulting mixture was cast into glass petri dishes and dried at room temperature for 48 hours. To initiate crosslinking, the partially dried films were cured in an oven at 120\u0026deg;C for 30 minutes. No catalyst was used in the crosslinking process. Finally, the films were further dried in an oven at 50\u0026deg;C for 48 hours, peeled off, and stored in a dry cabinet for subsequent characterization.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eThe Composition of PVA Bioplastic Films\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePVA\u003c/p\u003e\u003cp\u003e(wt.%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCS\u003c/p\u003e\u003cp\u003e(wt.%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eES\u003c/p\u003e\u003cp\u003e(wt.%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eGlycerol\u003c/p\u003e\u003cp\u003e(phr)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCitric acid\u003c/p\u003e\u003cp\u003e(phr)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVA0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e100.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e99.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e97.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e95.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e99.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e97.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e95.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0ES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e94.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS2.5ES2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e95.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0ES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e94.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Characterization and Property Measurements\u003c/h2\u003e\u003cp\u003eAll relevant property characterizations, particularly those involving quantitative measurements, were conducted in triplicate to ensure data reliability and statistical significance. The data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation and statistically analyzed using one-way ANOVA, with significance set at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\u003ch2\u003e2.4.1 X-ray diffraction (XRD) Analysis\u003c/h2\u003e\u003cp\u003eThe ES powder was subjected to XRD analysis to identify the phases of CaCO\u003csub\u003e3\u003c/sub\u003e. An angular range of 10\u0026deg; to 80\u0026deg; was used in the analysis, with a step size of 0.03. Each step was measured for 30 seconds to ensure optimal scanning and resolution.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\u003ch2\u003e2.3.2 Morphological Characterization\u003c/h2\u003e\u003cp\u003eThe fracture surfaces of the bioplastic films were carefully cut into small pieces and mounted on aluminum stubs using double-sided carbon tape. The samples were then sputter-coated with a thin layer of gold (~\u0026thinsp;10 nm) to enhance surface conductivity and image quality. Morphological observations were performed using a Scanning Electron Microscope (Hitachi TM3030 Plus) operating at an accelerating voltage of 15 kV.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.3.3 Fourier Transform Infrared Analysis\u003c/h2\u003e\u003cp\u003eThe spectra of the PVA bioplastic films were measured using a Perkin Elmer Spectrum 100 FTIR instrument, which ranged from 400 to 4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Data analysis was performed using FTIR Spectrum Software.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e2.3.4 Biodegradability and Water Absorption Characteristics\u003c/h2\u003e\u003cp\u003eBiodegradability is a critical factor in assessing the environmental impact of bioplastics, reflecting their breakdown by microorganisms. The biodegradation test was carried out in triplicate using a modified soil-burial method, adapted from the principles of ASTM D5338. Bioplastic films with dimensions of 2 \u0026times; 2 cm were buried approximately 4 cm deep in natural garden soil and incubated at ambient temperature (28\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C) for 28 days. The soil, with a pH of 6.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2, was maintained at about 40\u0026ndash;50% moisture by periodic sprinkling with distilled water.\u003c/p\u003e\u003cp\u003eAfter incubation, the films were washed with distilled water to remove soil and then dried in an oven until reaching a constant weight. This procedure ensures that the final weight accurately reflects the bioplastic material without moisture interference. The weight loss of the bioplastic films was calculated applying the subsequent formula:\u003c/p\u003e\u003cp\u003e\u003cimg 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\" width=\"616\" height=\"88\"\u003e\u003c/p\u003e\u003cp\u003eWhere \u003cem\u003eM\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e denotes the initial weight of the bioplastic and \u003cem\u003eM\u003c/em\u003e\u003csub\u003e\u003cem\u003ef\u003c/em\u003e\u003c/sub\u003e denotes the final weight of the bioplastic (g). This modified soil-burial method provides an indication of biodegradation behavior under natural environmental conditions, although it does not represent the fully controlled composting environment defined by ASTM D5338.\u003c/p\u003e\u003cp\u003eAdditionally, the water absorption test was performed following the general procedure of ASTM D570 to evaluate the hydrophilic characteristics of the bioplastic films. A specimen measuring 2 cm \u0026times; 2 cm was submerged in 60 mL of water at ambient temperature (28\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C) for 24 hours. The water uptake percentage was determined using the subsequent equation:\u003c/p\u003e\u003cp\u003e\u003cimg 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\" width=\"622\" height=\"94\"\u003e\u003c/p\u003e\u003cp\u003eWhere \u003cem\u003eM\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e denotes the initial weight of the bioplastic and \u003cem\u003eM\u003c/em\u003e\u003csub\u003e\u003cem\u003ef\u003c/em\u003e\u003c/sub\u003e denotes the final weight of the bioplastic (g).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\u003ch2\u003e2.3.5 Water Vapor Transmission Rate (WVTR)\u003c/h2\u003e\u003cp\u003eThe water vapor transmission rate (WVTR) test was conducted in triplicate, following the principles of ASTM E96/E96M-16 (Water Method) under controlled conditions of 50% relative humidity at 23\u0026deg;C. Circular bioplastic film specimens (diameter\u0026thinsp;=\u0026thinsp;5.5 cm; exposed area\u0026thinsp;\u0026asymp;\u0026thinsp;23.8 cm\u003csup\u003e2\u003c/sup\u003e) were sealed over water-filled test cups using parafilm to prevent vapor leakage. Daily mass loss was recorded over 7 days. The test was continued until steady-state conditions were reached, as indicated by a consistent linear weight-loss trend for at least three consecutive days. WVTR was calculated using data from the steady-state (linear) portion of the mass-loss curve, according to the following equation:\u003c/p\u003e\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"628\" height=\"58\"\u003e\u003c/p\u003e\u003cp\u003eWhere Δ\u003cem\u003em\u003c/em\u003e, \u003cem\u003et\u003c/em\u003e and \u003cem\u003eA\u003c/em\u003e representing the mass change (g), time (day) and test surface area (m\u003csup\u003e2\u003c/sup\u003e), respectively.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\u003ch2\u003e2.3.6 Mechanical Properties\u003c/h2\u003e\u003cp\u003eThe evaluation of the mechanical properties of bioplastic films was carried out in compliance with ASTM D-882 (tensile testing of thin plastic film) standards utilizing a Shimadzu Autograph AGS-X Series Universal Tester Machine. Rectangular specimens of 10 mm width and 100 mm length, with a width-to-thickness ratio\u0026thinsp;\u0026ge;\u0026thinsp;8, were used. Tests were conducted at a crosshead speed of 10 mm/min with a predefined gauge length. All measurements were performed in triplicate to ensure reproducibility.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e2.3.7 Thermogravimetric Analysis (TGA)\u003c/h2\u003e\u003cp\u003eThermogravimetric analyser, Hitachi Model STA7000 was employed to assess the thermal stability of the bioplastic film. The sample was heated from ambient temperature up to 600\u0026deg;C in a nitrogen atmosphere at a rate of 10\u0026deg;C/min, with a gas flow rate of 60 mL/min. The weight of each sample utilized in the analysis ranged from 10 to 15 mg.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"3. RESULT AND DISCUSSION","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Structural Characterization of ES\u003c/h2\u003e\u003cp\u003eXRD patterns of ES particles exhibit characteristic diffraction peaks at 2θ angles of 23.26\u0026deg;, 29.43\u0026deg;, 31.68\u0026deg;, 36.20\u0026deg;, 39.63\u0026deg;, 43.39\u0026deg;, 47.75\u0026deg;, 48.71\u0026deg;, 56.77\u0026deg;, 57.58\u0026deg;, 60.92\u0026deg;, 64.84\u0026deg;, 65.93\u0026deg;, 70.72\u0026deg;, 73.19 and 77.54\u0026deg; (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). These peaks correspond to the crystalline calcite phase of calcium carbonate, in good agreement with the standard reference pattern for calcite (JCPDS No. 05-0586) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The most prominent peak at 2θ\u0026thinsp;=\u0026thinsp;29.43\u0026deg; corresponds to the (104) crystallographic plane of calcite, confirming the presence of its semi-crystalline structure. This suggests that the film possesses a semi-crystalline structure of calcite as the major phase of ES [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The crystallinity of calcite plays a significant role in enhancing the mechanical stability and thermal resistance of the bioplastic films. This improved functionality reinforces the potential of eggshell-derived fillers in sustainable material engineering, supporting a circular bioeconomy and aligning with green material development to reduce reliance on virgin resources.\u003c/p\u003e\u003cp\u003eIt is known that ES is primarily composed of approximately 95.0% CaCO\u003csub\u003e3\u003c/sub\u003e, mainly as a calcite. The calcite phase is characterized by a rhombohedral crystal structure, where calcium (Ca\u003csup\u003e2+\u003c/sup\u003e) and carbonate (CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e\u003csub\u003e)\u003c/sub\u003e ions are strongly bonded. This structure imparts high rigidity and thermal stability to ES. The remaining 5.0% is made up of organic materials such type X-collagen, sulfated polysaccharides, and other proteins [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. These organic materials contain functional groups such as carboxyl (-COOH), hydroxyl (-OH), and amine (-NH\u003csub\u003e2\u003c/sub\u003e), which enhance the interfacial adhesion between the CaCO\u003csub\u003e3\u003c/sub\u003e particles and the film-forming matrix by forming hydrogen bonds and ionic interactions. The characteristics of the bioplastic films are improved by the presence of this organic matrix, which increases the interfacial adhesion between the CaCO\u003csub\u003e3\u003c/sub\u003e particles and the film-forming matrix.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Structural and Morphological Analysis of PVA Bioplastic Films\u003c/h2\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows a large peak in all FTIR spectra in the wavenumber range of 3200\u0026minus;3600 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, corresponding to the stretching vibration of hydroxyl (O\u0026ndash;H) groups in PVA, starch, and glycerol, including absorbed water molecules. Specifically, a peak at approximately 3296 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e indicates stretching of O\u0026minus;H groups [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. A notable peak within the range of 2800\u0026minus;2950 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponds to C\u0026minus;H functional groups [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Additionally, absorption related to water is evident with a peak around 1620\u0026minus;1650 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. This peak is primarily attributed to the bending vibrations of \u0026minus;OH groups, which indicates the presence of water molecules within the bioplastic films. Furthermore, bending vibrations of C\u0026ndash;H groups and \u003cb\u003eC\u0026ndash;O bonds in aliphatic structures\u003c/b\u003e are shown by peaks at 1320\u0026minus;1380 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Additionally, vibrations related to the bending of C\u0026minus;O and O\u0026minus;H groups are detected in the region of 1010\u0026minus;1070 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e across all samples. The interactions between hydroxyl groups and absorbed water enhance the structural integrity and properties of the bioplastics, indicating that moisture content may play a significant role in their performance. The small band observed at 1730 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e indicated the presence of C\u0026thinsp;=\u0026thinsp;O bonds in ester groups, arising from the reaction between citric acid and hydroxyl groups of PVA and starch [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The absence of a pronounced O\u0026ndash;H peak shift suggests that esterification occurred only to a limited extent, implying partial rather than extensive crosslinking (Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe incorporation of ES and CS into PVA composites typically enhances hydrogen bonding, which would normally shift the \u0026minus;OH peak toward higher energy. However, the lack of a significant shift suggests that interactions between PVA, ES, and CS may not have altered the hydrogen bonding structure as anticipated. This indicates that the OH groups in CS, although abundant, are mainly retained within the starch molecular network rather than forming new hydrogen bonds with PVA, due to the partial restriction induced by citric acid crosslinking. Therefore, further investigation is needed to understand the implications of adding ES and CS on the structural integrity and properties of the PVA bioplastic films. Water adsorption in the amorphous regions of amylose influences the vibrational stretching of carbonyl groups (C\u0026thinsp;=\u0026thinsp;O), which is responsible for the peak bands found between 1636.78 and 1638.65 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Vonnie et. al (2023) reports that the films are composed of a variety of functional groups, such as carbonyls (C\u0026thinsp;=\u0026thinsp;O), hydroxyls (OH), alkanes (CH), carbonates (CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e), and carboxylic acids (COOH), which served as active sites for pollutant adsorption. These functional groups enhance the films' potential as effective biosorption materials. Such functionality contributes to the environmental applicability of these bioplastic films, potentially offering pollutant adsorption capabilities in water or soil remediation contexts [34, 35]. In contrast, the present study employs a PVA matrix with controlled biofiller loadings and citric-acid-mediated crosslinking, producing films with distinct interfacial bonding characteristics and different structural organization compared to the purely biopolymer-based films.‬‬‬‬‬‬\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe SEM images of PVA loaded with ES and CS show distinct morphological features, with average size of 2.44 \u0026micro;m and 5.25 \u0026micro;m, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The CS-filled regions exhibited sharper and irregular-edged particles, which can be attributed to the partial disruption and fragmentation of starch granules during mechanical stirring and localized heating (90\u0026deg;C) in PVA dissolution. Similar morphology was reported by Lacerda et. al (2024), where corn starch where corn starch granules became fractured and irregular upon exposure to heat or mechanical treatment. Conversely, the finely ground ES particles appear more uniform and compact with plate-like structures, consistent with the calcite-based morphology of CaCO\u003csub\u003e3\u003c/sub\u003e in eggshell powder [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. In the hybrid film (PVACS2.5ES2.5), both smooth and irregular particles coexist, indicating the simultaneous presence of organic (CS) and inorganic (ES) fillers. This dual-phase morphology suggests a complementary interaction between the two, where ES enhances structural rigidity while CS contributes to flexibility and interfacial bonding. Such fine dispersion of ES within the hybrid matrix strengthens the overall structural integrity and mechanical performance of the bioplastic films, as discussed in Section \u003cspan refid=\"Sec19\" class=\"InternalRef\"\u003e3.5\u003c/span\u003e. Collectively, these observations confirm that the hybrid biofiller system provides synergistic reinforcement, improving uniformity, stability, and mechanical functionality of the developed bioplastics.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Biodegradation Studies of PVA Bioplastic Films\u003c/h2\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e presents the percentage of weight loss, reflecting the biodegradability of PVA bioplastic films at varying biofiller loadings measured over a period of 28 days. The values represent the mean of three independent replicates, highlighting consistent trends in microbial degradation. A greater weight loss indicates enhanced biodegradability, rendering the material more vulnerable to environmental decomposition, which is advantageous for mitigating plastic waste and environmental contamination. The results demonstrate the beneficial role of fillers in accelerating biodegradation, showing a clear correlation between higher biofiller loading and increased weight loss. Such behaviour supports the development of environmentally benign alternatives to conventional plastics, reinforcing their potential use in sustainable packaging or agricultural mulching applications.\u003c/p\u003e\u003cp\u003eThe bioplastic films containing 5.0 wt.% of CS and ES exhibited the highest weight loss, at 23.13% and 22.40%, respectively, indicating greater susceptibility to microbial attack. Although the weight loss increased compared to neat PVA, the overall biodegradation remained moderate. According to international compostability standards such as EN 13432 (\u0026ge;\u0026thinsp;90% mineralization within 180 days) and ASTM D6400 (\u0026ge;\u0026thinsp;60% carbon-to-CO\u003csub\u003e2\u003c/sub\u003e conversion within the same period) [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], the observed degradation level (\u0026asymp;\u0026thinsp;23% after 28 days) indicates partial rather than complete compostability. Nonetheless, this moderate improvement is still meaningful, as it demonstrates that compositional tuning and crosslinking control can effectively influence degradation kinetics and material lifespan, particularly for short-term or controlled-life applications. The enhanced vulnerability can be attributed to the presence of biodegradable constituents in CS (mainly starch and hydroxyl-rich polysaccharides) that readily interact with microorganisms [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. In contrast, ES, consisting predominantly of inorganic CaCO\u003csub\u003e3\u003c/sub\u003e, acts as a nucleating agent that facilitates microbial colonization and microcrack formation at the polymer\u0026ndash;filler interface [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. These interactions collectively facilitate enzymatic attack and structural disintegration of the film. Since both fillers possess micron-scale particle sizes, the improvement in biodegradability is more likely governed by their surface chemistry and interfacial reactivity. Since both fillers possess micron-scale particle sizes, the improvement in biodegradability is more likely governed by their surface chemistry and interfacial reactivity rather than surface area. Statistical analysis using one-way ANOVA confirmed that the differences in weight loss among formulations were significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), validating the observed trend and reinforcing the reliability of the results. These findings align with previous research by Muthupandeeswari et. al (2022), which found that PVA bioplastic films containing 15.0 wt.% CaCO₃ experienced greater weight loss than those containing 5.0 wt.% CaCO₃, indicating that filler composition and distribution can influence biodegradation behavior.\u003c/p\u003e\u003cp\u003eAccording to Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the hybrid PVACS1.0ES5.0 bioplastic films show a lower weight loss (7.36%) in the biodegradation test compared to the single biofillers PVACS1.0 (19.13%) and PVAES5.0 (22.40%). This indicates that the interaction between CS and ES results in a more complex structure. This indicates that the interaction between CS and ES results in a more complex structure. Specifically, citric acid can form ester linkages with hydroxyl groups in PVA and starch (CS), generating partial covalent crosslinking within the polymer matrix, as confirmed in previous studies where FTIR spectra showed esterification between citric acid and starch/PVA [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Concurrently, citric acid may react with CaCO\u003csub\u003e3\u003c/sub\u003e to form calcium citrate with CO₂ release, while limited ionic interactions (Ca\u003csup\u003e2+\u003c/sup\u003e\u0026ndash;carboxylate bridging) can further occur within the network [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. These ionic interactions contribute to the observed densification and stability rather than direct covalent crosslinking. Prapruddivongs et. al (2020) conducted a similar study that identified ES powder as a potential hydrolytic retardant for citric acid-filled thermoplastic starch. The research demonstrated that citric acid, serving as a crosslinking agent within the ES powder, facilitates the formation of ester bonds, which in turn leads to rapid sample biodegradation accompanied by accelerated hydrolysis. The denser hybrid structure may enhance barrier properties against microbial penetration, leading to increased stability and reduced microbial activity, thus decelerating the degradation process.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe crosslinking induced by citric acid promotes stronger interfacial interactions between PVA and the incorporated ES\u0026ndash;CS fillers, contributing to a more compact polymer network [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Such interactions may reduce the overall polarity and restrict the mobility of hydrophilic groups, resulting in lower water permeability and slower weight loss during degradation [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The compact structure also helps to limit water diffusion through the film, thereby improving water retention.\u003c/p\u003e\u003cp\u003eMinimizing water absorption is crucial for maintaining the functionality and integrity of bioplastic products, ensuring their suitability for various packaging applications. Excessive water absorption can negatively impact on the performance and characteristics of a material, leading to dimensional instability, reduced mechanical strength, and material degradation over time [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Due of the higher concentration of hydrophilic groups in CS, such as OH groups, that attract and retain water, water absorption is typically higher in PVA filled with CS than in PVA filled with ES. In contrast, ES, which is primarily composed of CaCO\u003csub\u003e3\u003c/sub\u003e, is less likely to absorb water compared to hydrophilic materials like CS [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The data clearly show that PVA bioplastic films filled with CS and ES absorb less water than unfilled ones (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). As the filler loading increases, the dispersion of filler particles within the bioplastic matrix densifies the structure, restricting polymer chain mobility and reducing water penetration. According to Vonnie et. al (2022), the strong crosslinked networks formed by the intramolecular interactions and arrangement of ES and CS granules inhibit water penetration into the ES/CS films, thereby reducing the film's water absorption capacity. These results highlight a potential tunable degradation mechanism through the dual biofiller system, offering flexibility for different end-use applications, a feature not typically observed in single-filler bioplastics.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBiodegradation Studies and Barrier Properties of Hybrid PVA Bioplastic Films\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWeight Loss\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eWater Absorption\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eWVTR (g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0ES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e246.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e348.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS2.5ES2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e247.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e353.84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0ES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e13.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e294.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e353.90\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eError bars\u0026thinsp;=\u0026thinsp;\u0026plusmn;\u0026thinsp;SD (n\u0026thinsp;=\u0026thinsp;3); \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Barrier Properties PVA Bioplastic Films\u003c/h2\u003e\u003cp\u003eThe water vapor transmission rate (WVTR) is a crucial parameter for packaging materials, as it evaluates their effectiveness in ensuring safety and extending product shelf life. In applications requiring breathable packaging, such as for fresh produce or moisture-sensitive goods, a higher WVTR can be advantageous, as it allows for controlled moisture exchange. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows a slight increase in WVTR with the incorporation of ES and CS fillers. The hybrid formulation PVACS2.5ES2.5 exhibited a modestly higher WVTR of 353.84 g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day compared to neat PVA (320.39 g/m\u0026sup2;\u0026middot;day), likely due to enhanced porosity and microstructural disruption that facilitate vapor diffusion [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. The relatively small increase in WVTR, combined with moderate water absorption (247.49%), indicates that the incorporation of CS and ES effectively tunes moisture permeability without substantially deteriorating barrier performance or compromising dimensional stability. This observation is consistent with studies on weight loss, suggesting that increased porosity may contribute to higher biodegradation rates. Additionally, filler particle aggregation may compromise the structural integrity of the film, leading to micro-defects and increasing WVTR [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In hybrid composites combining ES and CS, the overall WVTR was also elevated, potentially due to synergistic effects that increase heterogeneity and disrupt the polymer matrix continuity. The dual-filler interaction offers adjustable barrier properties, allowing for better control of moisture sensitivity, which is useful in specific packaging applications such as fresh produce or moisture-sensitive foods where tailored WVTR levels are required [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe presence of glycerol could also play a role in increasing film flexibility and reducing crystallinity, potentially forming channels or microvoids that improve moisture transport efficiency, leading to a slight increase in WVTR compared to single filler systems. An increased WVTR is desirable for compostable packaging, as it facilitates moisture transfer and accelerates material degradation in composting environments. This finding supports the objective of developing biodegradable materials with targeted moisture management properties for applications anticipating accelerated biodegradation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eError bars\u0026thinsp;=\u0026thinsp;\u0026plusmn;\u0026thinsp;SD (n\u0026thinsp;=\u0026thinsp;3); \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e3.5 Mechanical Properties of PVA Bioplastic Films\u003c/h2\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows a notable improvement in the tensile strength of PVA bioplastic films with rising concentrations of ES and CS. At 5.0 wt.% CS and ES, the tensile strength reaches 19.58 MPa and 26.25 MPa, respectively. The reinforcing effect of CaCO\u003csub\u003e3\u003c/sub\u003e from ES facilitates stronger interactions with the PVA matrix compared to CS. The CaCO\u003csub\u003e3\u003c/sub\u003e particles restrict polymer chain movement and hinder crack propagation, leading to improved mechanical properties and increased tensile strength [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. As the concentration of CaCO\u003csub\u003e3\u003c/sub\u003e increases, the density of reinforcement points rises, effectively distributing applied stress throughout the material, which reduces the burden on individual PVA chains, and leads to higher resistance to deformation and fracture under tensile stress [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. Compared to CS, the smaller size of ES particles (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) enhances interfacial interactions with the PVA matrix, possibly enhancing mechanical properties such as tensile strength and elongation at break.\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows that at 5 wt.% CS, the elongation at break of PVA bioplastic films increases by about 20% to 376.8% compared to neat PVA. This upward trend signifies that a higher percentage of CS contributes to greater ductility, allowing for more extensive material deformation before reaching its breaking point [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. Meanwhile, PVA films plasticized with glycerol and reinforced with 5 wt.% ES exhibited the highest elongation at break, reaching 471.52%, likely due to a combination of reinforcing effects and microstructural changes. While denser fillers like ES typically restrict elongation [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e], their contribution to structural integrity and stress accommodation under certain strain conditions can still enhance ductility. Interestingly, the incorporation of 5 wt.% ES filler enhanced both tensile strength and elongation at break, a typically contradictory outcome, suggesting a synergistic effect. This is likely due to fine ES dispersion and strong interfacial bonding improving stress transfer, while glycerol and flexible matrix morphology preserved chain mobility. Statistical analysis confirmed that the improvements in elongation at break were significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), validating the observed trends. Error bars in Figs.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e and \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e represent standard deviations from triplicate measurements.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe hybrid formulations, particularly those with higher ES content, provide a balance between tensile strength and elongation at break. For instance, PVACS1.0ES5.0 shows a tensile strength of 21.33 MPa and an elongation at break of 428.18%, which is higher than pure CS samples \u003cb\u003e(\u003c/b\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e).\u003c/b\u003e This indicates that hybrid fillers offer a better combination of the flexibility from ES with the structural reinforcement from CS, resulting in a balanced set of mechanical properties through a synergistic reinforcement effect that enhances overall performance beyond what individual fillers can achieve. Statistical analysis also supports the performance of hybrid composites, with PVACS1.0ES5.0 showing a significant increase in both tensile strength and elongation compared to single-filler systems (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMechanical Properties of Hybrid PVA Bioplastic Films\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTensile Strength (MPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eElongation at Break (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0ES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e21.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e428.18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS2.5ES2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e20.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e420.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0ES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e24.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e399.73\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003e3.6 Thermal Analysis\u003c/h2\u003e\u003cp\u003eThe thermal stability of PVA bioplastic films with varying loadings of CS and ES fillers is presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Pure PVA exhibited a \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e5\u003c/em\u003e\u003c/sub\u003e of 56.97\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e of 323.64\u0026deg;C. When 1.0% CS was added, \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e slightly decreased to 56.27\u0026deg;C and 316.07\u0026deg;C, respectively, suggesting a minor decrease in thermal stability (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). This decrement may result from the introduction of new thermal pathways for degradation, which can be associated with the processing conditions or the interactions between the components. However, the overall stability of the composite system improves at higher CS loadings (e.g., 5.0% CS), where both \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e increase to 58.60\u0026deg;C and 331.32\u0026deg;C, respectively, accompanied by an increased percent residue of 5.15%. The increase in thermal stability with CS loading can be attributed to the excellent CS-PVA compatibility, creates an effective barrier to heat transfer and thereby delays degradation [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe result reveal that the incorporating 1.0% ES resulted in a significant increase in \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e to 66.38\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e to 361.96\u0026deg;C, reflecting a substantial improvement in thermal stability due to the inherent heat resistance properties of CaCO\u003csub\u003e3\u003c/sub\u003e from ES, which effectively inhibit the thermal degradation of PVA [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. However, at 5.0% ES loading, \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e decreased to 57.61\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e dropped significantly to 251.24\u0026deg;C, implying a detrimental effect on thermal stability at higher ES concentrations. This decrease, alongside an increased percent residue of 10.1%, can be attributed to particle agglomeration, which may create localized thermal stress points promoting earlier degradation [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e], heterogeneous dispersion of ES particles, disrupting the continuity of the PVA matrix and reducing uniform thermal resistance and suboptimal PVA\u0026ndash;ES interactions at elevated loadings, weakening interfacial bonding and further compromising thermal stability [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e, \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e]. These findings underscore the complex interplay between filler loading, composite structure, and thermal stability in PVA bioplastic films.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eThermal Degradation Temperatures of PVA Bioplastic Films\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e5\u003c/em\u003e\u003c/sub\u003e (\u0026deg;C)\u003csup\u003e\u003cem\u003ea\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e (\u0026deg;C)\u003csup\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eT\u003c/em\u003e \u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e (\u0026deg;C)\u003csup\u003e\u003cem\u003ec\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eResidue (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVA0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e56.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e83.64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e323.64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.81\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e56.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e87.92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e316.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e3.83\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e58.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e92.69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e331.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e66.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e110.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e361.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.11\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e57.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e81.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e251.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e10.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS2.5ES2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e59.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e97.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e353.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e5.91\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003e\u003cem\u003ea, b\u003c/em\u003e\u003c/sup\u003e \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e5\u003c/em\u003e and\u003c/sub\u003e \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e is defined as the temperature at 5% and 10% weight loss, respectively\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003e\u003cem\u003ec\u003c/em\u003e\u003c/sup\u003e \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e defined as the temperature at a maximum mass loss\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eA composite filler with 2.5% CS and 2.5% ES showed a balanced thermal stability, with \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e at 59.11\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e at 353.65\u0026deg;C, indicating that combining both fillers can effectively enhance thermal properties. This combination effectively enhances the thermal properties due to a synergistic effect, with CS might offer improved dispersion and interaction with the PVA matrix, while ES contributes its inherent thermal stability. Adjustment of the CS\u0026ndash;ES ratio enables precise tuning of the thermal properties, allowing the bioplastic to be optimised for targeted applications.\u003c/p\u003e\u003cp\u003eThe hybrid incorporation of CS and ES enhances the performance and environmental sustainability of PVA-based bioplastics. CS, which is rich in hydroxyl (\u0026ndash;OH) groups, forms extensive hydrogen bonding interactions with PVA chains. These interactions improve interfacial compatibility and cohesion within the polymer matrix, reinforcing structural integrity and enhancing mechanical strength.\u003c/p\u003e\u003cp\u003eIn parallel, ES particles primarily composed of calcium carbonate (CaCO\u003csub\u003e3\u003c/sub\u003e) function as rigid inorganic fillers that restrict polymer chain mobility and act as physical barriers, contributing to improved mechanical stiffness. Owing to their high thermal decomposition temperature, ES particles also enhance the thermal stability of the composite by serving as heat-resistant elements.\u003c/p\u003e\u003cp\u003eBiodegradation occurs via microbial colonization and enzymatic degradation of the bioplastic matrix. CS serves as a biodegradable carbon source, facilitating microbial metabolism and accelerating the breakdown process. Although ES is not biodegradable, its porous structure and alkaline nature promote microbial attachment and help neutralize acidic byproducts generated during degradation. Overall, the synergistic interaction between CS and ES enhances the mechanical, thermal, and biodegradation performance of the PVA-based bioplastic, as summarized in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\u003ch2\u003e3.7 Optimization Outcome\u003c/h2\u003e\u003cp\u003eThe optimization analysis revealed that the most balanced PVA bioplastic formulation was achieved through the hybrid incorporation of CS and ES biofillers. Each filler contributed distinct advantages: CS enhanced biodegradability and flexibility, while ES provided mechanical reinforcement and thermal stability (see Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e). Among all tested compositions, the hybrid formulation PVACS2.5ES2.5 demonstrated the most favorable overall performance. This system achieved a tensile strength of 20.00 MPa with an elongation at break of approximately 420%, indicating strong yet flexible mechanical behavior. Thermal stability was significantly improved, with \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e recorded at 59.11\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e at 353.65\u0026deg;C, outperforming the neat PVA and single-filler systems. In terms of environmental performance, the hybrid bioplastic exhibited controlled biodegradation, with a moderate weight loss of 13.38% after 28 days, making it suitable for regulated disposal. Although PVACS2.5ES2.5 showed the highest WVTR (353.84 g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day), its water absorption remained moderate (247.49%) compared to PVACS5.0ES1.0, indicating a possible balance in hydrophilic and hydrophobic interactions at the 2.5 wt.% filler ratio. These findings highlight the novelty of a dual biofiller approach in tailoring multifunctional properties such as mechanical robustness, thermal stability, and biodegradability, compared to single PVA-based film. Such synergy, rarely achieved in single filler or neat PVA systems, offers a promising platform for the development of eco-friendly packaging materials where both durability and environmental responsiveness are critical.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative Performance of PVA Bioplastics Reinforced with ES and CS\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSamples\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eThermal Stability\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eMechanical Properties\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBarrier Properties\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003eBiodegradation Studies\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eOverall performance\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e5\u003c/em\u003e\u003c/sub\u003e (\u0026deg;C)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e (\u0026deg;C)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTensile Strength (MPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eElongation at Break (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eWVTR (g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eWater Absorption\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eWeight Loss (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVA0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e56.97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e323.64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e302.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e320.39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e398.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e18.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eReference (limited performance)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e56.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e316.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e293.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e339.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e250.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e19.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eLimited enhancement\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e16.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e360.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e293.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e290.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e20.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eAcceptable\u003c/p\u003e\u003cp\u003e(balance)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e58.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e331.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e19.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e376.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e347.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e330.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e21.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eLimited enhancement\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e66.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e361.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e17.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e441.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e327.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e287.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e18.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eAcceptable\u003c/p\u003e\u003cp\u003e(balance)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e21.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e379.66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e357.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e288.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e19.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eAcceptable\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVAES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e57.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e251.24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e26.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e471.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e389.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e299.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e22.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eExcess ES loading\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS1.0ES5.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e21.33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e428.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e348.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e246.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e7.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eGood if biodegradation prioritized)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS2.5ES2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e59.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e353.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e20.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e420.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e353.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e247.49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e13.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eOptimal balance\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePVACS5.0ES1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e24.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e399.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e353.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e294.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e13.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eVery strong (if mechanical prioritized)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\u003ch2\u003e3.8 Environmental Perspective and Life Cycle Consideration (LCA)\u003c/h2\u003e\u003cp\u003eThe developed PVA-based hybrid films demonstrate promising cost-effectiveness, scalability, and environmental potential. ES is a low-cost agro-waste material, while CS is a low-cost bio-derived material. Both require minimal processing, primarily cleaning, drying, grinding, and sieving which are compatible with standard polymer compounding techniques. Film fabrication via solution casting, ambient drying, and mild thermal curing contributes to a relatively low energy footprint and supports feasibility for industrial adoption using existing processing equipment.\u003c/p\u003e\u003cp\u003eFrom a performance perspective, the PVACS2.5ES2.5 film offers a sustainable balance; tensile strength of 20.00 MPa, ~\u0026thinsp;420% elongation at break, moderate biodegradation (13.38% mass loss in 30 days under ambient soil), and a WVTR of 353.84 g/m\u0026sup2;\u0026middot;day at 23\u0026deg;C and 50% RH. Compared to commercial bioplastics such as PLA, PBAT, and crosslinked PVA (cPVA), it offers intermediate performance. PLA provides high tensile strength (50\u0026ndash;70 MPa) but low flexibility (~\u0026thinsp;5\u0026ndash;10%), PBAT shows very high elongation (\u0026gt;\u0026thinsp;1000%) with moderate strength (10\u0026ndash;20 MPa) [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e], while cPVA achieves\u0026thinsp;~\u0026thinsp;58.9 MPa strength but low elongation (~\u0026thinsp;29.8%) due to its rigid crosslinked structure [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. In contrast, PVACS2.5ES2.5 achieves a desirable mechanical\u0026ndash;biodegradability compromise. While PLA degrades slowly and PBAT degrades rapidly in moist environments, the hybrid film presents a sustainable middle ground suitable for short-term packaging applications. Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e summarizes this comparison and positions PVACS2.5ES2.5 as a viable and eco-friendly packaging alternative.\u003c/p\u003e\u003cp\u003eTo complement the environmental assessment, the Life Cycle Inventory (LCI) was conducted in accordance with ISO 14040\u0026ndash;14043 guidelines [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e], focusing on a cradle-to-gate boundary encompassing raw material acquisition, filler processing, and film formation. Total estimated energy use per batch was ~\u0026thinsp;12.1 kWh with a corresponding carbon footprint of ~\u0026thinsp;5.45 kg CO\u003csub\u003e2\u003c/sub\u003e-eq, based on regional emission factors (0.45 kg CO\u003csub\u003e2\u003c/sub\u003e-eq/kWh). Key energy-consuming steps included oven drying (2.0 kWh), ball milling (4.0 kWh), and thermal curing (0.5 kWh). (See Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e for full LCI breakdown). Although a full cradle-to-grave LCA was not conducted, the use of low-energy processes and agro-waste inputs suggests a favorable environmental footprint relative to synthetic or biomass-derived polymers. This is notable, as energy consumption and raw material sourcing are major contributors to the global warming potential of plastic materials. Future studies should incorporate streamlined life cycle assessment (LCA) or carbon footprint analysis using standardized tools such as SimaPro or OpenLCA to quantitatively validate the environmental sustainability of the developed bioplastic system [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative Performance and Sustainability Attributes of PVACS2.5ES2.5 and Commercial Bioplastics (PLA, PBAT, cPVA\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePLA\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePBAT\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ecPVA\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eHybrid PVACS2.5ES2.5\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTensile Strength\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50\u0026ndash;70 MPa [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u0026ndash;20 MPa [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e~\u0026thinsp;58.9 MPa [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e20.00 MPa\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eElongation at Break\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e~\u0026thinsp;5\u0026ndash;10% [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1237.8% [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e~\u0026thinsp;29.8% [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e~\u0026thinsp;420%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBiodegradability\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026asymp;\u0026thinsp;90% in 20 days at 58\u0026deg;C (industrial compost) [\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026ge;\u0026thinsp;64% in 45 days at 58\u0026deg;C; ~90% in 80 days industrial compost [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLow\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13.38% in 30 days (ambient soil)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMain Source\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFermented corn (industrial biomass\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePetrochemical-based\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePetrochemical or biomass-derived\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eBio-based (CS)\u0026thinsp;+\u0026thinsp;Agro-waste (ES)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEnergy Input\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMedium (fermentation\u0026thinsp;+\u0026thinsp;polymerization\u0026thinsp;+\u0026thinsp;extrusion)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eHigh (synthetic polymerization\u0026thinsp;+\u0026thinsp;extrusion)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMedium (solution casting\u0026thinsp;+\u0026thinsp;crosslinking)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eLow (drying, grinding, and casting)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBarrier (WVTR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e263\u0026thinsp;\u0026plusmn;\u0026thinsp;14 (g/m\u0026sup2;\u0026middot;day)\u003c/p\u003e\u003cp\u003e(38\u0026deg;C, 90% RH) [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eModerate to high (e.g. ~50\u0026ndash;150 g/m\u0026sup2;\u0026middot;day for PLA films)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e353.84 g/m\u0026sup2;\u0026middot;day\u003c/p\u003e\u003cp\u003e\u003cb\u003e(\u003c/b\u003e23\u0026deg;C, 50% RH)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eProcessing Complexity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePolymerization\u0026thinsp;+\u0026thinsp;extrusion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePolymer synthesis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFilm casting or hydrogel prep\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSimple blending\u0026thinsp;+\u0026thinsp;casting\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eShelf-life Suitability\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLong-term rigid packaging\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFlexible short/medium-term packaging\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eVariable (short to moderate; crosslinking enhances stability)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eShort-term packaging (designed for degradability)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCost of Raw Material\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eHigh\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eModerate⁠ (depends on grade and processing)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eLow (agro-waste\u0026thinsp;+\u0026thinsp;bio-based)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ePotential applications of the developed PVACS2.5ES2.5 hybrid film include disposable food trays, compostable produce wraps, and agricultural mulching films, where controlled degradation, mechanical integrity during use, and post-use compostability are desired. Nonetheless, the use of natural fillers requires further evaluation of potential leaching and microbial safety, especially for food-contact applications. In addition, incorporation of compatibilizers or nano-fillers may enhance performance without compromising biodegradability. Long-term environmental performance under real-world composting or landfill conditions also warrants further study.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEstimated Life Cycle Inventory (LCI) for the Production of PVACS2.5ES2.5 Bioplastic Film\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMaterial / Process\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEstimated Energy Used (kWh)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCarbon Footprint\u003c/p\u003e\u003cp\u003e(kg CO\u003csub\u003e2\u003c/sub\u003e eq)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNotes\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePolyvinyl Alcohol (PVA)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBased on industrial-scale production data\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBio-based material derived from corn.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eES\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eIncludes cleaning, oven drying, grinding, and ball milling\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGlycerol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSmall-scale lab estimation\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCitric Acid\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eBased on basic chemical input data\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTap Water for Cleaning\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eEstimated water use during initial ES cleaning\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSun Drying (natural)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePassive drying, no energy input\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOven Drying\u003c/p\u003e\u003cp\u003e(100\u0026deg;C, 5 hours)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.90\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOven-based dehydration step\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBall Milling (12 hours)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAssumes standard benchtop milling setup\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSieving (100 \u0026micro;m mesh)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePost-milling particle sizing\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHeating\u0026thinsp;+\u0026thinsp;Stirring (90\u0026deg;C, 580 rpm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePVA dissolution and uniform filler dispersion\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRoom Drying\u003c/p\u003e\u003cp\u003e(48 hours, passive)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePassive evaporation step\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOven Curing\u003c/p\u003e\u003cp\u003e(120\u0026deg;C, 30 min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eCuring stage to facilitate crosslinking\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOven Final Drying (50\u0026deg;C, 48 hours)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal drying before film storage\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eTotal Energy: 12.1 kWh\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eTotal Emissions: ~5.45 kg CO\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e \u003cb\u003eeq\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. CONCLUSION","content":"\u003cp\u003eThe incorporation of ES and CS as biofillers into PVA bioplastic films significantly enhanced their structural, mechanical, thermal, and environmental performance. Structural characterization confirmed that ES is mainly calcite-phase CaCO\u003csub\u003e3\u003c/sub\u003e, while CS provided functional groups (\u0026ndash;OH, C\u0026thinsp;=\u0026thinsp;O) compatible with the PVA matrix. FTIR and XRD analyses supported effective filler\u0026ndash;matrix interactions. Biodegradation results showed that while films with 5.0 wt.% single fillers (CS or ES) achieved higher weight loss (21.50% and 22.50%, respectively), the hybrid composition PVACS2.5ES2.5 offered a more balanced profile, with moderate biodegradation (13.38%) and superior barrier and mechanical performance. This hybrid film recorded a tensile strength of 20.00 MPa, elongation of ~\u0026thinsp;420%, moderate water absorption (247.49%), and an increased WVTR (353.84 g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day) compared to neat PVA (320.39 g/m\u003csup\u003e2\u003c/sup\u003e\u0026middot;day), indicating its suitability for compostable packaging requiring both breathability and structural integrity. Thermal analysis revealed enhanced stability, with \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e at 59.11\u0026deg;C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e at 353.65\u0026deg;C, further confirming the synergistic effect of dual fillers. Additionally, the use of agro-waste ES and bio-based CS, coupled with low-energy solution casting (~\u0026thinsp;12.1 kWh per batch) and an estimated carbon footprint of ~\u0026thinsp;5.45 kg CO\u003csub\u003e2\u003c/sub\u003e-eq, demonstrates both environmental and economic feasibility. In conclusion, the PVACS2.5ES2.5 formulation presents an optimally balanced, scalable, and eco-friendly alternative for short-term packaging applications, aligning with sustainable materials innovation and circular economy objectives. This dual biofiller approach also introduces a novel strategy to simultaneously enhance mechanical durability, thermal stability, moisture permeability, and biodegradability, features rarely achieved in conventional single filler systems.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eACKNOWLEDGEMENT\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank the Ministry of Higher Education for providing\u003cbr\u003efinancial support under Fundamental Research Grant Scheme (FRGS) No. FRGS/1/2021/STG05/UMP/03/1 (University reference RDU210108) and\u003cbr\u003eUniversiti Malaysia Pahang Al-Sultan Abdullah for laboratory facilities as well as additional financial support under Internal Research Grant RDU240317 and PGRS230374.\u003c/p\u003e\n\u003cp\u003eDeclaration of interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u0026nbsp;The data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eChm. Ts. Dr. Siti Maznah served as the corresponding author and contributed to the review and editing of the manuscript.\u003c/p\u003e\n\u003cp\u003eTs. Dr. Farah Hanani contributed to the conceptualization and data analysis.\u003c/p\u003e\n\u003cp\u003eFarasuraya Che Zakaria is the main author, responsible for the research design, data collection, and manuscript writing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eEl Menofy, N.G., Khattab, A.M.: \u003cem\u003ePlastics biodegradation and biofragmentation\u003c/em\u003e, in \u003cem\u003eHandbook of Biodegradable Materials\u003c/em\u003e, pp. 571\u0026ndash;600. Springer (2023)\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTanpichai, S., Oksman, K.: Crosslinked poly(vinyl alcohol) composite films with cellulose nanocrystals: Mechanical and thermal properties: ARTICLE. J. Appl. Polym. 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(2021)\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Polyvinyl alcohol, Cornstarch, Calcium Carbonate, Bio-based plastic, Tensile strength","lastPublishedDoi":"10.21203/rs.3.rs-7298605/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7298605/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study developed a novel hybrid polyvinyl alcohol (PVA)-based biofilm system incorporating eggshell (ES) and cornstarch (CS) as natural and waste-derived biofillers, crosslinked with citric acid, and systematically evaluated their synergistic effects on structural, morphological, and functional properties including mechanical strength, thermal, and biodegradability. The novelty lies in combining two distinct biofillers, CaCO\u003csub\u003e3\u003c/sub\u003e-rich ES and hydrophilic CS, within a PVA matrix to achieve a multifunctional biodegradable film. ES, predominantly composed of CaCO\u003csub\u003e3\u003c/sub\u003e, and CS, known for its hydrophilic nature, were blended with PVA at varying concentrations (1.0, 2.5, and 5.0 wt.%) using solution casting. Structural characterization confirmed ES as predominantly CaCO\u003csub\u003e3\u003c/sub\u003e, with essential hydroxyl (−OH) and carbonate (CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2−\u003c/sup\u003e) groups for matrix interactions. CS showed comparable functional −OH and carbonyls (C = O) groups enhancing PVA matrix compatibility. The biofilm’s biodegradability significantly improved, with PVA films containing 5.0 wt.% CS and ES showing the highest weight losses at 23.13% and 22.40%, respectively. Although the PVACS2.5ES2.5 film exhibited reduced water absorption (247.49%) compared to neat PVA, its WVTR increased to 353.84 g/m\u003csup\u003e2\u003c/sup\u003e·day. This suggests that while the film resists bulk water uptake, its microstructure modified by the hybrid filler network facilitates enhanced vapor permeability through interconnected pores or disrupted polymer chains. Films containing 5.0 wt.% CS and ES achieved tensile strengths of 19.58 MPa and 26.25 MPa, respectively. Thermal analysis showed balanced stability, with a 2.5% CS and 2.5% ES exhibiting \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e10\u003c/em\u003e\u003c/sub\u003e at 59.11°C and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003emax\u003c/em\u003e\u003c/sub\u003e at 353.65°C. These findings confirm the potential of the developed biofilm as a multifunctional, sustainable material, where the synergistic reinforcement using dual biofillers offers a novel and scalable pathway to improve PVA bioplastic performance for sustainable packaging. The approach promotes resource circularity through low-cost, bio-based fillers and aligns with global environmental goals.\u003c/p\u003e","manuscriptTitle":"Hybrid Cornstarch and Eggshell Reinforcement for Enhanced Mechanical, Thermal, and Biodegradation Performance of Sustainable Polyvinyl Alcohol Bioplastic","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-02 12:05:43","doi":"10.21203/rs.3.rs-7298605/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-10-31T14:51:57+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-31T01:47:28+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Waste and Biomass Valorization","date":"2025-10-31T00:54:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-29T06:18:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Waste and Biomass Valorization","date":"2025-10-29T01:21:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"waste-and-biomass-valorization","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"wave","sideBox":"Learn more about [Waste and Biomass Valorization](http://link.springer.com/journal/12649)","snPcode":"12649","submissionUrl":"https://submission.nature.com/new-submission/12649/3","title":"Waste and Biomass Valorization","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7499da5b-616a-46c4-89eb-dd99df8df4ef","owner":[],"postedDate":"November 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-19T17:05:29+00:00","versionOfRecord":{"articleIdentity":"rs-7298605","link":"https://doi.org/10.1007/s12649-025-03471-1","journal":{"identity":"waste-and-biomass-valorization","isVorOnly":false,"title":"Waste and Biomass Valorization"},"publishedOn":"2026-01-12 16:29:55","publishedOnDateReadable":"January 12th, 2026"},"versionCreatedAt":"2025-11-02 12:05:43","video":"","vorDoi":"10.1007/s12649-025-03471-1","vorDoiUrl":"https://doi.org/10.1007/s12649-025-03471-1","workflowStages":[]},"version":"v1","identity":"rs-7298605","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7298605","identity":"rs-7298605","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}