反相乳液法淀粉丙烯酰胺接枝共聚反应的研究

Graft Co-polymerization of Acrylamide onto Starch in Inverse Emulsion

以木薯淀粉为主要原料,研究了淀粉/丙烯酰胺单体/乳化剂/油/水反相乳液体系的接枝共聚反应规律,考察了反应温度、引发剂和乳化剂浓度、淀粉单体比、油水比等因素对淀粉接枝丙烯酰胺共聚反应过程的影响,并对反应机理进行了探讨。结果显示:在本实验考察范围内引发剂浓度、单体淀粉比、反应温度影响显著;乳化剂用量和油水比对反相乳液体系的形成及稳定有重要的影响;淀粉与亲水性单体丙烯酰胺的接枝共聚反应为淀粉团粒表面控制。

Graft co-polymerization of acrylamide onto cassava starch in a five-component inverse emulsion system, starch/monomer/emulsifier/water/oil, was conducted with （NH4）2S2O8 as initiator. The effects of reaction temperature, ratio of starch to acrylamide monomer, concentrations of initiator and emulsifier, and the ratio of oil to water on the conversion of acrylamide, graft percent and graft efficiency were investigated. Meanwhile, the graft co-polymerization mechanism in inverse emulsion was described primarily. The results show that the influences of reaction temperature, ratio of starch to acrylamide monomer and initiator concentration on graft co-polymerization are predominant among the five factors mentioned above. The emulsifier content and the ratio of oil to water are two main factors for forming inverse emulsion and maintaining its stability. It is believed that in the five-component inverse emulsion system, graft co-polymerization of acrylamide monomer onto cassava starch occurs at the surface of the starch granules.