Chitosan-polyvinyl alcohol (PVA) based composite biofilm: The effect of solvent and nanofiller.

Environmental issues are the most critical and urgent factor for the increasing use of biopolymers in broader applications. Research on chitosan as a bioplastic material opens vast opportunities to improve its weak mechanical properties. These include blending with biopolymer/synthetic polymers as a matrix or incorporating with nanofillers. The use of organic solvents in dissolving chitosan is also interesting for further research. In this study, we synthesized a chitosan/PVA-based biofilm composite in five different ratios (100/0, 80/20, 60/40, 40/60, 0/100) in acetic acid and citric acid with the addition of 10% weight glycerol to get the optimum composition of mechanical properties. This optimum film would be conducted with SiO₂ nanoparticles (NPs) and Cellulose Nano Crystals (CNCs) to evaluate the reinforcement effects. Various properties, including surface morphology, functional, mechanical properties, and thermal behavior, were characterized. The experimental result showed that the tensile strength of the composite film in acetic acid was higher than in citric acid. With the addition of 2.5% w/w of SiO₂ NPs, the tensile strength of the composite film got its maximum value, 21.01 MPa, and the maximum of 25.77 MPa with 10% w/w of CNCs, which was 115,7% higher than with of the pure chitosan/PVA film in the ratio of 80/20 which was the optimum. The effect of adding CNC and SiO2 NPS has the opposite effect. The addition of filler CNCs will improve mechanical properties, while SiO2 NPs tend to decrease mechanical properties. All film characterizations demonstrated that the physicochemical interaction between CNCs and chitosan/PVA molecules improved their mechanical and thermal properties. [ABSTRACT FROM AUTHOR]