Thermomechanical, barrier, and morphological properties of chitosan-reinforced starch-based biodegradable composite films

Abstract

Chitosan-reinforced starch-based biodegradable composite films were prepared by solution casting. The chitosan content in the films was varied from 20% to 80% (w/w). Tensile strength (TS) and tensile modulus (TM) of the starch-based composites were improved significantly with the addition of chitosan. Water vapor permeability (WVP) and oxygen transmission rate (OTR) of chitosan-reinforced starch-based films showed a significant reduction compared to native chitosan film and indicated better barrier properties to water vapor and oxygen. The water uptake of the films pointed out better hydrophobic character due to the incorporation of chitosan in starch-based films. Thermal stability was also found to increase with the addition of chitosan in starch-based films and was confirmed by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Fourier transform infrared (FT-IR) spectroscopy supported the molecular interactions due to the reinforcement of chitosan in starch-based films. Surface and interface morphologies of chitosan film and starch/chitosan composite film were examined by scanning electron microscope (SEM) and suggested sufficient homogenization of starch and chitosan in the biodegradable composite films.