The effect of composition on mechanical properties of biodegradable plastic based on chitosan/cassava starch/PVA/crude glycerol: Optimization of the composition using Box Behnken Design

Synthetic plastic waste is one of the most concerning problems on our earth today. For that reason, many researchers are currently developing biodegradable plastics as a substitute for synthetic plastics for food packaging purposes. However, biodegradable plastics have poor mechanical properties because of their characterteristics as biopolymers, such as brittle and fragile. Chitosan has often been used as an additive in starch or PVA mixtures because of its biodegradability. Meanwhile, PVA itself is widely used in polymer blends because it can increase the flexibility and tensile strength of biodegradable plastic. The aim of this study is to develop a biodegradable plastic based on chitosan, cassava starch, and PVA with the addition of crude glycerol as a plasticizer. Observation of the effect of chitosan, starch, and PVA content on the mechanical properties of chitosan/cassava starch/PVA biodegradable plastics were carried out using Design-Expert Version 10.0.1 with Response Surface Methodology-Box Behnken Design. The composition of chitosan, starch, and PVA was varied from the range of 1–3 g, 1–5 g, and 1–5 g respectively. The optimization results suggest that biodegradable plastic with the composition of 3 g chitosan, 1 g starch, and 5 g PVA has the highest tensile strength and elongation values. The optimum biodegradable plastic showed that it was degraded by 50.45% of its weight after being buried in the soil for 30 days. Furthermore, the optimum biodegradable plastic can be investigated for its characteristics in further research.