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Synthesis and Characterization of Maize Starch Acetates and its Biodegradable Film

Starch acetates (SA) were synthesized by maize starch reacting with acetic acid/acetic anhydride, using sulfuric acid as catalyst. The biodegradable films were produced by thermal gelatinization of starch suspensions blending raw starch or SA with different degree of esterification (DS) and polyvinyl alcohol (PVA). Fourier transform infrared spectrogram (FT-IR) data showed acetate was introduced into the molecule chain of starch. Different structure of aggregation supported between the modified starch and the raw starch was determined by the scanning electron microscopy (SEM). Differential scanning calorimetry indicated SA glass transition temperature reduced with increasing of its DS. X-ray diffraction pattern of SA revealed the crystallinity of chain starch was destroyed, forming many completely even amorphous areas. SEM studies showed that amorphous was raised with DS of starch acetates. The mechanical and hydrophobic properties of the films were better than those of raw starch/PVA. In 50 days outdoor soil burial biodegradable experiment in summer, the weight loss of the films was almost 50%.