部分交联聚丙烯酰胺凝胶化反应中交联剂的影响

摘要

采用流变仪原位监测部分交联聚丙烯酰胺凝胶化反应过程,获得了部分交联聚页烯酰胺水凝胶(PG)模量与反应时间的关系,从而研究了聚合过程中的黏弹性行为.采用甲基丙烯酸二甲氨基乙酯(DA)作部分交联的交联剂,在DA含量从0.89％增加到3.38％的过程中,体系弹性模量均比黏性模量大约两个数量级,且在一定范围内,弹性模量随DA含量的增大而线性增加,说明DA主导了体系的弹性行为,在聚合反应中充当了交联剂的作用.利用Flory橡胶弹性理论建立起力学性能与分子结构的关系,可以推测出有效交联点密度(ne)和交联点之间的相对分子质量(Me)的理论值.与N,N'-亚甲基双丙烯酰胺(BIS)做交联剂的凝胶体系对比,PG体系内黏性模量显著大于BIS体系,且黏性模量随DA用量的增长而增长,说明体系具有良好的黏性行为,是其可以作为黏弹性驱油剂使用的主要因素.%The hydrogels reaction of the partially cross-linked polyacrylamide was investigated by rheometry. Relation between modulus of partially cross-linked polyacrylamide hydrogel and reaction time was gained. The viscoelastic behavior during the polymerization was investigated. With dimethylaminoethyl methacrylate (DA) as the crossing linking agent of partially cross-linked polyacrylamide, increasing the DA concentration from 0. 89% to 3. 38% , the elastic moduli ( G') were all twice magnitude orders of viscous modulus (G"). The elastic moduli linearly increased with the DA content increasing. This indicated that DA worked as a cross-linker and mainly determined the elasticity of the hydrogels. By establishing the relation between mechanical property and molecular structure through Flory theory, the active network link density (ne) and strand molecular weight (Me) were calculated. The viscous modulus ( G") was found to be larger than that of the hydrogel cross-linked by N, N'-Methylenebisacrylamide (BIS), indicating that the PC was much more viscous than the traditional hydrogels, which was responsible for its improve properties using as oil displacement agent.