Synthesis and characterization of side-chain liquid-crystalline poly(ether ester)s having p-substituted biphenyl mesogenic side groups

✍ Scribed by Ben-Ruey Liaw; Ching-Chuan Chen

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 480 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199810)36:14<2439::aid-pola2>3.0.co;2-o

✦ Synopsis

Several novel mesogenic spiro-orthoester monomers such as 1,6,10trioxaspiro [4,5]decanes 4, containing biphenyl mesogens at the C-8 positions of the fiveand six-membered spirocyclic ring, through the alkylene spacers of different lengths were prepared by condensation reaction of the corresponding biphenyl mesogenic 1,3-propanediol 3 with 2,2-diethoxytetrahydrofuran, with 50 -75% yields. Through cationic double ring-opening polymerization, carried out with boron trifluoride etherate as an initiator (5 mol % vs. monomer) in bulk at 150°C, spiro-orthoester monomers 4 afforded a novel class of side-chain thermotropic LC polymers with a poly(ether ester) as the main chain 8. The liquid-crystalline properties of the spiro-orthoester monomers and the resulting polymers were examined by differential scanning calorimetry and optical polarized microscopy. Biphase separation was observed in the side-chain liquidcrystalline poly(ether ester)s upon annealing in the broad isotropic region.