Synthesis and Characterization of Transparent Biodegradable Chitosan: Exopolysaccharide Composite Films Plasticized by Bio-Derived 1,3-Propanediol

Abstract

In this study, chitosan-based composite films blended with a dextran like exopolysaccharide derived from lactic acid bacteria were prepared using the solvent casting method. Later, these composite films were plasticized with 1,3-propanediol (1,3-PDO) produced biologically using biodiesel derived crude glycerol. Further, their physical properties, such as tensile strength, water vapor barrier, thermal behavior, and antioxidant properties, were tested. In comparison to the control chitosan-exopolysaccharide films, 1,3-PDO plasticized films increased tensile strengths (20.08 vs. 43.33 MPa) with an elongation percentage (%E) of 20.73, which was two times more than the control films. As a polymer composite, the Fourier transform infrared (FTIR) spectrum displayed the characteristic peaks at 1000 cm−1, 1500 cm−1, and 3000–3500 cm−1 to describe the functional groups related to chitosan, exopolysaccharide, and 1,3-PDOThe thermogravimetric analysis displayed a significant three-step degradation at 100–105 °C, 250–400 °C, and 600 °C, where 100% of the films were degraded. The plasticized films were observed to have enhanced water solubility (51%) and rate of moisture absorption (193%). The plasticized films displayed enhanced physico-chemical properties, anti-oxidant properties, and were100% biodegradable.