关键词: 木薯淀粉, 动力学, 接枝共聚, 反相乳液, 聚合速率

Abstract: The kinetics of graft copolymerization in a five-component system of inverse emulsion, starch/monomer/emulsifier/water/oil, was investigated with cassava starch and acrylamide (AM) as the raw material, ammonium persulfate as the initiator and a mixture of two kinds of surfactants (Span-80 and OP-4) as the emulsifier.The rate orders of graft copolymerization with respect to the concentration of initiator, monomer, starch and emulsifier were determined.In the polymerization process,termination of fast chain and termination of slow chain existed at the same time.The effect of the concentration of the individual components in the polymerization system on conversion were investigated.The results showed that the dependence of the polymerization rate Rp on the concentration of components in the polymerization system could be expressed for all four components by the following equation: R_p∝［I］^0.93［M］^1.28［St］^1.47［E］^0.61.The overall activation energy for the polymerization process was 82.01 kJ•mol^-1 at 35—55℃.Based on the experimental results, some aspects of the polymerization mechanism were discussed.

Key words: 木薯淀粉, 动力学, 接枝共聚, 反相乳液, 聚合速率