PVA/CSP/AgNPs hybrid biocomposite films: Optimization of process constraints using Taguchi-based grey relational analysis and functional property evaluation

Abstract

Polyvinyl alcohol (PVA)-based hybrid biocomposite films were developed using coconut shell powder (CSP, 5–25 wt.%) as an organic filler and silver nanoparticles (AgNPs, 1–5 mM) as an inorganic filler. The films were fabricated by molding a homogeneous PVA/CSP/AgNPs solution in Petri dishes, and their mechanical and thermal properties were evaluated according to ASTM standards. The synthesis process and the contributions of CSP and AgNPs for enhanced mechanical and thermal stability were analyzed using the Taguchi-based Grey Relational Analysis (GRA) technique. Tensile strength, Young’s modulus, elongation at break, and maximum degradation temperature were assessed using an L25 orthogonal array. Grey regression analysis identified the optimal film composition as 10% CSP and 1 mM AgNPs, which achieved a tensile strength of 38.1 MPa, Young’s modulus of 92.3 MPa, an elongation at break of 18.1%, and a maximum degradation temperature of 315°C. ANOVA indicated that AgNPs and CSP contributed 50.46% and 41.58%, respectively, to overall performance. FTIR, XRD, TGA, and SEM analyses revealed enhanced matrix-filler compatibility, increased crystallinity (23.4%), uniform dispersion of fillers, and improved thermal stability in the optimal film. UV transmittance and water absorption were reduced by 45% and 56.7%, respectively, compared to pure PVA films. Soil burial tests indicated slower degradation of the optimal film due to reduced moisture absorption. The results highlight the suitability of PVA/10%CSP/1 mM AgNPs films for packaging applications, owing to their superior mechanical, thermal, water barrier, UV barrier, and biodegradability properties. The Taguchi-based GRA technique effectively optimized filler combinations for improved performance.