介绍了聚乙烯醇(PVA)和淀粉多羟基、多氢键、高结晶等结构特点,以及根据此开发的可塑化方法和水溶性薄膜生产方法,包括最新的PVA薄膜一步熔融挤出法。PVA和淀粉水溶性薄膜熔融挤出法的难点在于均要破坏结晶结构,达到可塑化,前者主要是要获得增塑凝胶化可自由流动粒子,后者在于糊化处理。
The commercial water soluble PVA film was conventionally prepared via casting. The challenge of extrusion is that the melting temperature of PVA is higher than its decomposition temperature owing to its high concentration of hydroxy groups. Similar problems also exist in the processing of starch. In order to reduce the melting temperature various, plasticizers were used to destroy the degree of crystallinity. In particular, a technique called “gelatinization” has been developed in the extrusion of starch,which was considered as a material with great potential.