Abstract
Plasticized maize starch/Schiff base modified chitosan (PLST/MCS) blend films were prepared by solution casting and then irradiating to various doses using an electron beam. The effect of electron beam irradiation on the structure-property behavior of each blend was characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical measurements, and scanning electron microscopy (SEM). PLST/MCS blends loaded with Cu(II) were also investigated using electron spin resonance (ESR) and infrared spectroscopy (FTIR). The results of thermogravimetric analysis (TGA), in terms of weight loss and rate of decomposition, indicated that the thermal stabilities of the PLST/CS blends were higher than that of pure PLST, particularly at >350 degrees C, which was thought to be due to a cyclization process upon ammonia removal. Electron beam irradiation slightly affected the thermal stability of the blends up to 50 kGy. The IR spectra indicated that there was a shift in the carbonyl bands upon the chelation of copper ion with the polymer. The IR spectra also exhibited a narrowing in the bands at 3600-3200 cm(-1) due to the coordination of the NH2 and OH groups with copper ions. The ESR results revealed that Cu(II) uptake occurred through coordination with lone pairs of electrons on NH2 and OH in PLST/CS blends.