可降解共混膜材料的制备与表征

Preparation and characterization of degradable polymer film

将一定取代度的醋酸酯淀粉(SA)与聚乙烯醇(PVA)共混,经流延成膜。以力学性能为目标函数,单因素分析和正交试验优化成膜条件得到:反应物的质量比(SA/PVA)为4∶6、温度为80℃、时间为2.0h时,膜的拉伸强度为39.2MPa,断裂伸长率为4.26%,表现出较好的力学性能与实用价值。土埋法考察膜的降解性,降解曲线表明:随着酯化淀粉取代度的提高,膜的降解性下降,但60d降解率仍可达70%。DSC分析表明随着酯化度的增加膜熔融温度降低,淀粉和PVA分子间的相容性得到改善。SEM观察可见SA/PVA共混膜的表面结构变得立体疏松,证明两相的相容性大大提高。

A certain degree of substitution of starch acetate （SA） blended with polyvinyl alcohol （PVA） to make the film by flow cast. Based on mechanical properties as objective function,film formation conditions were optimized by single factor experiment and orthogonal experiment. The results was as follows： when the quality ratio of reactant （SA/PVA） was 4：6, temperature was 80℃, reaction time was 2. 0h, the film got the optimized tensile strength was 39.2MPa, breaking elongation was 4. 26% ,and showed good mechanical properties and practical value. Soil burying method was used to examine the degradability of film. The degradation curve showed that with the increase of esterified starch substitution degree, the degradation rate decreased, But 60d degradation rate can reach 70 %. DSC analysis showed that melting temperature was reduced with the increase of esterification degree. The compatibility of starch and PVA molecules were improved. SEM observation showed that the surface structure of film became three-dimensional and loose. It was proved that the compatibility of two phase greatly increased.