吡啶类试剂调节H_2O/TiCl_4引发苯乙烯正离子聚合研究  

CARBOCATIONIC POLYMERIZATION OF STYRENE WITH H_2O/TiCl_4 INITIATING SYSTEM IN THE PRESENCE OF PYRIDINE AND ITS DERIVANTS

作　　者：冉奋[1] 吴一弦[1] 邱迎昕[1] 黄丽[1] 武冠英[1] 

机构地区：[1]北京化工大学教育部'可控聚合反应科学与技术基础'重点实验室,北京100029

出　　处：《高分子学报》2006年第1期164-167,共4页Acta Polymerica Sinica

基　　金：国家自然科学基金资助项目(基金号20474006)

摘　　要：The carbocationic polymerization of styrene（St） initiated by H2O/TiCl4 system was conducted at-60℃ in dichloromethane（CH2Cl2）/hexane（n-Hex）（50/50 V/V） in the presence of pyridine（Py）,2-methyl pyridine（MPy） and 2,6-dimethyl pyridine（DMPy）.A desirable polymerization process with a relative slow polymerization rate and PS products with relatively narrow molecular weight distribution（MWD,Mw/Mn ca.1.8） were obtained.Py and its derivants and/or their complexes with Lewis acid TiCl4 interact with the growing chain end to reduced its 'cationicity' and thus to decrease the polymerization rate,suppress chain transfer and termination reactions and narrow MWD.The experimental results also show that the monomer conversion as well as the molecular weight of polymer products increased but MWD almost kept unchanged with polymerization time.The number-average molecular weight of polymer increased linearly with monomer conversion but the line did not pass through the origin.Abstract The carbocationic polymerization of styrene （St） initiated by H2O/TiCl4 system was conducted at - 60℃ in dichloromethane （CH2 Cl2 ）/hexane （n-Hex） （50/50 V/ V） in the presence of pyridine （Py）, 2-methyl pyridine （MPy） and 2,6-dimethyl pyridine （DMPy）. A desirable polymerization process with a relative slow polymerization rate and PS products with relatively narrow molecular weight distribution （MWD, M./M, ca. 1.8） were obtained. Py and its derivants and/or their complexes with Lewis acid TICl4 interact with the growing chain end to reduced its ＂cationicity＂ and thus to decrease the polymerization narrow MWD.The experimental results also show that rate, suppress chain transfer and termination reactions and the monomer conversion as well as the molecular weight of polymer products increased but MWD almost kept unchanged with polymerization time. The number-average molecular weight of polymer increased linearly with monomer conversion but the line did not pass through the origin.

关 键 词：正离子聚合 苯乙烯 聚苯乙烯 吡啶 

分 类 号：O631.5[理学—高分子化学]