Effect of γ-Radiation on Thermal and Chemical Properties of Starch/Polystyrene Biopolymer Blend

Abstract

In this study, the starch/polystyrene (PS) biopolymer blend is prepared by utilizing an in solution polymerization process. Two different ratios (50/50 and 80/20) of starch/PS were dissolved in toluene associated with mechanical mixing to maintain the homogeneity of the blend. Thereafter, the blend was exposed to γ-radiation using Cobalt 60 (Co60) at different dosing rates. The thermal and chemical properties were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), enzymatic degradation, and disclosure of starch by iodine, respectively. The deviation of glass transition temperature (Tg ( and the IR peaks indicate that a good interaction between starch and polystyrene was achieved in the blend. Exposure of the starch/PS blend to the α-amylase enzyme and to iodine demonstrated that the γ-rays have affected the amylopectin part with no distinct effect on the amylose part of the starch. Moreover, the colour has completely disappeared at 100 kGray irradiation dose since the blend becomes more responsive to enzymatic degradation at higher irradiation dose, which in turn causes in breaking down of the amylose part in the starch.