摘要
采用反相乳液法进行淀粉与丙烯酰胺接枝共聚反应的机理研究，考察以过硫酸铵引发机械活化淀粉（mSt）与丙烯酰胺（AM）接枝共聚反应速率Rg与引发剂浓度[I]、乳化剂浓度[E]、单体浓度[M]和淀粉浓度[mSt]的关系，推导并验证该反应体系的动力学模型及反应机理。结果表明，本实验得出的动力学关系式为：Rg∞[mSt]1.24[I]0.76[M]1.54[E]0.33，与理论推导出的动力学关系式：Rp∞[mSt]0.5~1[I]0.5~1[M]1~1.5[E]0.6基本一致，机械活化淀粉与丙烯酰胺在反相乳液中进行接枝共聚反应符合自由基聚合机理；在聚合过程中，引发剂分解副反应、诱导分解及“笼壁效应”导致引发效率降低，单基终止和双基终止反应同时存在；推导出共聚物消耗单体量与参加反应单体总量的比值（X）：1/X=1＋K1[M]0.5/[Mst]0.5＋K2[Mst]0.5[I]0.5/[M]＋K3[I]0.5/[Mst]0.5单体浓度、淀粉乳浓度和引发剂浓度对其有重要影响。
The graft co-polymerization reaction mechanism of acrylamide and mechanically-activated starch in an inverse emulsion system was investigated. The effects of concentrations of initiator （with ammonium persulfate as the initiator）, monomer, starch, and emulsifier on the reaction rate of graft co-polymerization （Rg） were determined. The kinetic model was studied and modified to fit the experimental results. The results show that the relationship between R g and the concentration of components in the polymerization system can be expressed for all of the four components by the following equation：Rg∞[mSt]1.24 [I]0.76 [M]1.54 [E]0.33 , which is consistent with the kinetic equation from theoretical studies：Rp∞[mSt]0.5~1 [I]0.5~1 [M]1~1.5 [E]0.6 . It can be concluded that the graft co-polymerization reaction of hydrophilic monomer onto starch in inverse emulsion follows the mechanism of free radical polymerization. Unimolecular and bimolecular termination of free radicals are both presented in the reaction process. The relation between the grafted monomer and the reacted monomer is：1/X=1＋K1[M]0.5/[Mst]0.5＋K2[Mst]0.5[I]0.5/[M]＋K3[I]0.5/[Mst]0.5 .
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2014年第3期567-573,共7页
Journal of Chemical Engineering of Chinese Universities
基金
广西自然科学基金重点项目(2011GXNSFD018013)
广西教育厅科研基金(201103YB012)
广西石化资源加工及过程强化技术重点实验室主任课题基金资助(2012Z09)
广西大学科研基金(XBZ100104)
关键词
动力学模型
机械活化淀粉
接枝共聚
反相乳液
接枝共聚速率
kinetics model
mechanically-activated starch
graft co-polymerization
inverse emulsion
graft co-polymerization rate
