摘要
以聚氧化四亚甲基二醇、4,4′ 二苯甲烷二异氰酸酯和己二胺为原料 ,利用高分子在溶液中基本形态是无规线团的特征 ,设计了一个含有分子内和分子间反应的交联聚合体系 ,由于分子内反应与分子间反应是一对竞争反应 ,使得交联过程得以控制 ,在溶液聚合体系中合成了可溶解的微凝胶 .在分子尺寸测定过程中 ,发现了这种高分子在溶液中非常容易形成分子簇 ,且分子簇的形成与解离处于不平衡之中 。
A polymerization system, which contains inter- and intramolecular reactions, was designed on the basis of the random coil type morphology of macromolecules in solutions. The polytetramethylene glycol, 4, 4'-diphenylmethane diisocyanate and hexanediamine were used to synthesize the soluble microgels in concentrated solutions successfully. Through varying the use level of the extender i.e. hexanediamine, a series of samples were obtained, namely 1200H-X, where 1200 stands for the molecular weight of soft segments, H stands for the extender and X is the ratio of the number of hydrogen of hexanediamine and that of end groups of the oligomer (from scheme 1) An our system two kinds of functional groups that can react with each other located in the same macromolecular chain, resulting in the existence of inter- and intramolecular reactions, which were a pair of competitive reactions. In the presence of the intramolecular reaction the intermolecular reaction was prevented from unlimited development,so the cross-linking process was controlled, producing the soluble and fusible microgels i.e. cross-linked macromolecules instead of cross-linked polymer macrogels. By using the technique of dynamic light scattering, the molecular dimensions of the samples in solution were measured at different concentrations, showing a sharp distinction of solution behavior between this kind of cross-linked macromolecules and other macromolecules such as the linear ones. It was found that this kind of macromolecules possessed cross-linked structure, which was affected by the use level of the extender: the less the extender was used, the more compact the cross-linked structure was. In solutions these macromolecules preferred to form molecular clusters. The formation and disassociation of molecular clusters was off balance, and the solution concentration had influence on the size of the molecular clusters.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2003年第5期673-678,共6页
Acta Polymerica Sinica
基金
吸附分离功能高分子材料国家重点实验室开放基金资助项目
