UNUSUAL CRYSTALLIZATION AND MELTING PROCESSES OF AN OPTICALLY ACTIVE POLYOLEFIN:ISOTACTIC POLY((S)-4-METHYL-HEXENE-1)  

作　　者：Annamaria Buono JrjengRuan AnnetteThierry Peter Neuenschwander Bernard Lotz 

机构地区：[1]Institut Charles Sadron and Dipartimento di Chimica,Universita di Napoli Federico Ⅱ,Via Cynthia 5,Napoli,Italy,Institut Charles Sadron(CNRS-ULP),6,Rue Boussingault,67083 Strasbourg,France,Institut Charles Sadron(CNRS-ULP),6,Rue Boussingault,67083 Strasbourg,France,Institute for Polymers,ETH Zentrum,CNB E 93.2,Universitaetstrasse 6,CH-8092 Zurich,Switzerland,Institut Charles Sadron(CNRS-ULP),6,Rue Boussingault,67083 Strasbourg,France

出　　处：《Chinese Journal of Polymer Science》2005年第2期165-170,共6页高分子科学（英文版）

摘　　要：Polyolefins that bear a chiral side chain(typically an isobutyl group)experience a so-called macromolecularamplification of chirality:the chiral side-chain induces a slight preference for either tg or tg(?) main chain conformation.Thisslight conformational bias is amplified cooperatively along the chain,and results in preferred chirality of the main chainhelical conformations.As a result,these polymers display a liquid-crystal(LC)phase both in solution and,in the melt as atransient phase on the way to crystallization.The existence of two processes(melt-LC and LC-crystal transitions)results inunconventional behaviors that were first analyzed by Pino and collaborators back in 1975.These polymers also offer a meansto test the structural consequences of recently introduced crystallization schemes.These schemes postulate the formation of atransient liquid-crystal phase as a general scheme for polymer crystallization.Polyolefins that bear a chiral side chain(typically an isobutyl group)experience a so-called macromolecularamplification of chirality:the chiral side-chain induces a slight preference for either tg or tg(?) main chain conformation.Thisslight conformational bias is amplified cooperatively along the chain,and results in preferred chirality of the main chainhelical conformations.As a result,these polymers display a liquid-crystal(LC)phase both in solution and,in the melt as atransient phase on the way to crystallization.The existence of two processes(melt-LC and LC-crystal transitions)results inunconventional behaviors that were first analyzed by Pino and collaborators back in 1975.These polymers also offer a meansto test the structural consequences of recently introduced crystallization schemes.These schemes postulate the formation of atransient liquid-crystal phase as a general scheme for polymer crystallization.

关 键 词：Liquid crystalline polyolefins CRYSTALLIZATION Melting Amplification of chirality. 

分 类 号：O631[理学—高分子化学]