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Liquid crystalline polyfumarates, 2 Polymerization of fumarates with two mesogenic groups per unit
Author(s) -
Jähnichen Klaus,
Voigt Dieter,
Jehnichen Dieter,
Rätzsch Manfred
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021961020
Subject(s) - mesogen , copolymer , polymerization , polymer chemistry , monomer , materials science , styrene , polymer , maleimide , liquid crystal , liquid crystalline , composite material , optoelectronics
The paper describes synthesis and characterization of some new side‐chain liquid crystalline polymers (SCLCP) obtained by homo‐ and copolymerization of fumarates with two mesogenic groups per unit. The homopolymerization of spacerless bis[4‐(4‐butoxy‐benzoyloxy)phenyl] fumarate ( 1 ) did not take place due to steric hindrance of the propagation reaction by the bulky phenyl benzoate groups. The radically induced polymerization of the fumarates with spacer between fumaric unit and the mesogenic groups was performed in bulk. At the polymerization temperature the monomers were isotropic. During polymerization the mixtures became turbid due to phase separation of the isotropic monomer and the resulting polymerization products which formed a liquid crystalline (lc) phase. The molecular weights of the obtained homopolymers were relatively low and depended on spacer length. Transfer reactions to the monomer occurred to a considerable extent. The homopolymers showed an enantiotropic S A phase. This was confirmed by X‐ray measurements. A model for the arrangement of the polymer backbones in the smectic phase is given. Copolymerization of bis{6‐[4‐(4‐butoxybenzoyloxy)benzoyloxy]hexyl} fumarate (4) with styrene yielded copolymers 6 with different percentages of styrene. All copolymers formed an enantiotropic S A phase. With increasing percentage of styrene the transition to the isotropic state was shifted toward lower temperatures.