柠檬酸改性聚乙烯醇淀粉复合膜的结构及性能研究

为了改善聚乙烯醇淀粉膜的抗菌性能,采用流延法制备了不同质量分数的柠檬酸改性聚乙烯醇淀粉复合膜,通过XRD、FTIR、SEM等方法分析测试了复合膜的微观组织结构及性能。结果表明,添加柠檬酸并未改变复合膜的晶型结构,当柠檬酸含量在4%以上时膜层晶态衍射峰的强度显著增强。改性后的复合膜具有更加均匀平整的表面状态,同时膜层的断面结构也更加致密规则。随着柠檬酸含量的增加,复合膜含水率和水蒸汽透过率减小;复合膜拉伸强度减小而断裂伸长率增加。柠檬酸改性对复合膜透光率的影响较小,但复合膜雾度增加。改性后的复合膜对大肠杆菌具有良好的抑菌性能。添加量为6%柠檬酸改性复合膜具有最佳的综合性能。

Study on structure and properties of citric acid modified polyvinyl alcohol starch composite film

In order to improve the antibacterial properties of polyvinyl alcohol starch film,citric acid modified polyvinyl alcohol starch composite film with different mass fractions was prepared by tape casting method.The microstructure and properties of the composite film were analyzed by XRD,FTIR,SEM and other methods.The results show that adding citric acid did not change the crystal structure of the composite film,and the intensity of the crystalline diffraction peak of the film layer increased significantly when the content of citric acid was more than 4%.The modified composite film has a more uniform and flat surface state,and the section structure of the film layer is also more compact and regular.With the increase of citric acid content,the moisture content and water vapor transmittance of the composite film decrease.The tensile strength of the composite film decreases and the elongation at break increases.The citric acid modification has little effect on the transmittance of the composite film,but the haze of the composite film increased.The modified composite film has good bacteriostatic properties against e.coli.The addition amount of 6%citric acid modified composite film has the best comprehensive performance.