短梗霉多糖及其薄膜性能研究

微生物转化得到高分子短梗霉多糖，利用HAAKE RV12流变仪测量了多糖的粘性和流变性能，随着多糖分子量增大和浓度增加，其非牛顿指数相应减小，对多糖进行分析证明多糖无熔融和结晶特性，流延法制得0.02mm厚的薄膜，薄膜的SEM照片表明膜的二侧面不对称；薄膜的力学强度随多糖分子量增大而增大，多糖水分含量对多糖薄膜的热封性有重要影响，完全脱水的薄膜不具有热封性；多糖薄膜有很好的阻隔氧的性能。

STUDY ON THE PROPERTIES OF PULLULAN AND ITS FILM

Polysaccharide pullulan was synthesised from farm by products by microorganism Aureobasidiun pullulans. The viscosity and rheological properties of the polymer were tested with a HAAKE RV12 rheometer. The non newtonian index decreases with the increament of polysaccharide concentration and molecular weight. Thermal analysis proves the polysaccharide has no melting and crystalline characteristic. The polymer was manufactured into 0.02 mm thick film, SEM photograph of the film indicates the two sides of the film surface are asymmetrical. The film tensile strength and elongation percentage increase with the increament of the polymer molecular weight. The water content has importent effect on sealing ability of the film, water free polysaccharide films lose heat sealing ability. The film has notable oxygen impermeability.