大豆分离蛋白-海藻酸丙二醇酯-天然乳胶共混膜的制备及性能研究

采用杂凝聚法分别将大豆蛋白和海藻酸丙二醇酯与天然乳胶共混制备共混膜，红外光谱测试结果表明海藻酸丙二醇酯与大豆蛋白可形成共价复合物。通过对改性前后乳胶膜进行透射电镜、扫描电镜、原子力显微镜以及粒径分布测试，考察了大豆蛋白和海藻酸丙二醇酯对乳胶粒子形态及乳液固化成膜的影响。结果表明：适量添加大豆蛋白可增强膜的拉伸强度，当其固含量为0.83%时，共混改性膜的力学性能最优；进一步添加海藻酸丙二醇酯可较明显地提升断裂伸长率和拉伸强度，在其固含量为0.25%时，力学性能达到最大值；大豆蛋白和海藻酸丙二醇酯共混改性乳胶膜表面光滑度、致密性及力学性能均有所改善

Preparation and performance of soybean protein isolate-propylene glycol alginate-natural rubber latex

Blend films have been prepared by heterocoagulation blending of a mixture of soybean protein isolate (SPI) and propylene glycol alginate (PGA) in natural rubber latex (NRL). The particle morphology of NRL and the film formation process were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and particle size distribution measurements. The SPI and PGA can form conjugates via the covalent attachment as indicated by the infrared spectra. The tensile strength was improved by addition of an appropriate amount of SPI. The elongation at break was optimized when the loading of SPI was 0.83%. However, the elongation at break of the films increased significantly after PGA loading, and the tensile strength also showed a small rise. When the loading of PGA was 0.25%, the mechanical properties were optimized. The results show that the smoothness, compactness and mechanical properties of the membrane were all improved by addition of SPI PGA conjugates.