Evaluation of the thermomechanical properties and biodegradation of brown rice starch-based chitosan biodegradable composite films

Biodegradable films composed of starch and chitosan plasticized by palm oil were fabricated via a solvent casting technique. In this study, the influence of the ratio of brown rice starch and chitosan on the mechanical, thermal, antimicrobial, and morphological properties of the films was investigated. Antimicrobial films with a smooth surface and a compact structure of brown rice starch were obtained. The results showed that a higher proportion of chitosan in the polymer blends resulted in a substantial enhancement in the tensile strength (TS) and thermal stability of the film. The TS values for BRS100, BRS30CH70, BRS50CH50, BRS70CH30, and CH100 were 3.7, 15.2, 10.2, 9.3, and 8.8 MPa, respectively, and the elongation at break (EB) values of the BRS100, BRS30CH70, BRS50CH50, BRS70CH30, and CH100 samples were 39.5%, 34.7%, 7.3%, 11.5%, and 6.9%, respectively. The addition of chitosan to the brown rice starch samples resulted in a reduced water uptake of the film. The film with a balanced ratio of brown rice starch and chitosan exhibited excellent water resistance, with its water absorption being the lowest among all of the studied compositions.