摘要
TiCl4共引发异丁烯(IB)或苯乙烯(St)进行正离子聚合,聚合反应速率与共引发剂TiCl4之间可呈一级和二级动力学关系,这与TiCl4浓度([TiCl4])、单体浓度、亲核试剂的亲核性等多方面因素有关。单分子TiCl4与休眠分子链末端进行离子化反应并产生活性中心碳正离子和反离子TiCl5-,TiCl5-与另一个TiCl4分子进一步反应则形成双分子反离子Ti2Cl9-,导致TiCl4表现为二级动力学关系的机理。
The kinetics and mechanism of TiCl4 coinitiating cationic polymerization of isobutylene （IB） or styrene （St） were discussed in this paper. The reaction order with respect to TiCl4 could be either first-order or second-order due to the affection of the concentration of TICl4 or monomer, the donicity of electron donors, etc. And it has been suggested that the second-order dependency on TiCl4 was attributed to the dimeric gegenions which formed via monomeric TiCl4 ionizing a dormant tert-alkyl chloride chain end to create an activated chain with a monomeric gegenion TiCl5^- , and then the monomeric gegenion reacted with another molecule of TiCl4 to form the dimeric gegenion Ti2Cl9^- .
出处
《高分子通报》
CAS
CSCD
2006年第10期16-22,81,共8页
Polymer Bulletin
基金
国家自然科学基金资助项目(20474006)
关键词
正离子聚合
机理
动力学
异丁烯
苯乙烯
Cationic polymerization
Mechanism
Kinetics
Styrene
Isobutylene
