大豆分离蛋白／聚乙烯醇塑料的制备及性能研究

摘要

Polymer blends were prepared via thermo-pressing mixtures of soy protein isolate（SPI） and poly （vinyl alcohol） （PVA） using glycerol as a plasticizer. The structure, morphology, and properties of the blends were investigated using X-ray diffraction, dynamic mechanical analyzer, differential scanning calorimetry analyzer, universal electronic tensile testing machine, and scanning electron microscopy. Phase separation was observed between glycerol and SPI forming glycerol-rich and protein-rich domains. The addition of PVA significantly damaged the crystalline structure of SPI in glycerol-rich domain, and increased its glass transition temperature. When the content of PVA was 1 phr, the tensile strength of SPI/PVA increased by 41.5 %, and the 24 h water absorption of SPI/PVA decreased from 134.86 % to 77.38 %, based on neat SP1.%将聚乙烯醇（PVA）按不同比例与大豆分离蛋白（SPI）混合，采用丙三醇作为增塑剂，经模压成型制备SPI／PVA塑料，采用X射线衍射仪、动态热机械分析仪、差示扫描量热仪、万能电子拉力试验机、扫描电子显微镜等研究了SPI／PVA塑料的结构、形态和性能。结果表明，丙三醇增塑的SPI会出现微相分离，即出现富丙三醇微区和富蛋白微区，而PVA的加入主要破坏了SPI在富丙三醇微区的晶体结构，并使富丙三醇微区的玻璃化转变温度向高温方向偏移。PVA的加入还明显提高了SPI／PVA塑料的拉伸强度，当PVA含量为1份时，其拉伸