Functional polymers and sequential copolymers by phase-transfer catalysis. 15. Thermotropic copolyethers based on 4,4′-dihydroxybiphenyl,bisphenol a and 1,9-dibromononane

Thermotropic liquid crystalline (LC) copolyethers have been synthesized from 1,9-dibromononane, a nonmesogenic bisphenol (4,4′-isopropylidenediphenol BPA]) and a mesogenic bisphenol (4,4′-dihydroxybiphenyl HB]) by a two-phase (organic solvent—aqueous NaOH) phase-transfer catalyzed polyetherification. LC polyethers were obtained for copolymers containing as much as 70 mol % BPA. Optical polarizing microscopy and DSC have revealed smectic mesomorphism for all the copolyethers. The influence of both copolymer composition and microstructural changes, including the nature of the chain ends, upon the mesomorphic properties of these copolyethers have been discussed.