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.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
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)
关键词
正离子聚合
苯乙烯
聚苯乙烯
吡啶
Carbocationic polymerization, Styrene, Polystyrene, Pyridine
