| Since the development of plastics earlier this century, it has become a popular material used in a wide variety of ways. But now, plastics become a huge pollution problem in the world. Biodegradable plastics made with plant-based materials have been available for many years. Starch is a natural polymer. Because of its cheapness and regeneration, it has been recognized as a kind of potential raw material for producing biodegradable plastics.In this paper, based on amylose having better filming properties than native corn starch, the starch-based degradable film with higher amylose content was produced by chemical cross-linking. The optimal additives content and producing conditions are as following: polyvinyl alcohol (PVA), 40%; glycerol, 20%; glyoxal, 10%; urea, 2%; the reaction temperature, 90℃;cross–linking reaction pH, 2; stirring speed, 120r/min; and drying temperature, 70℃. The produced film's tensile strength, elongation at break, transmittance, water absorption and oil absorption were 32.8MPa, 135%, 42.1%, 41.7% and 0%, respectively. The films produced by native corn starch and corn starch of higher amylose content (82%) were characterized by FTIR and XRD. The spectrum proved that the chemical reaction took place between glyoxal and hydroxy. Thermodynamic properties of the films were analyzed by DSC, and the result showed corn starch of higher amylose content (82%) based film has better stability compared to native corn starch based film. The SEM photograph of film cross section displayed the structure of corn starch of higher amylose content (82%) based film was more compact than native corn starch based film. Starch based films were buried in soil in order to evaluate their degradability. The corn starch of higher amylose content (82%) based film has been decomposed 68.2% after 50 days. The SEM photograph of film revealed that amylose content affected the degradability of starch based film, and the preliminary explanation of this phenomenon was given.
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