Synthesis and characterization of polystyrene-polyester liquid crystalline block copolymers

✍ Scribed by S. H. Wang; F. M. B. Coutinho; G. Galli; E. Chiellini

• Publisher: Springer
• Year: 1995
• Tongue: English
• Weight: 371 KB
• Volume: 34
• Category: Article
• ISSN: 0170-0839
• DOI: 10.1007/bf00423348

✦ Synopsis

Liquid crystalline (LC) block copolymers comprising polystyrene and LC polyester blocks were obtained by a three-step procedure. In a first step, hydroxyl-terminated oligoesters were obtained by polycondensation reaction of methylhydroquinone and 4,4'-dicarboxy-l,10dibenzoyloxydecane in pyridine solution in the presence of tosyl chloride and dimethylformamide. Hydroxyl-terminated oligoesters were then further polymerized with 4,4'-azo-bis(4-cyanopentanoyl chloride) to form azo-macroinitiators which, in a third step, were employed in the free-radical polymerization of styrene to form block copolymers. The thermal and LC properties of the copolymers are presented and discussed in terms of the dependence upon the molecular weight of the polystyrene block.