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Phase transitions of hydroxy‐telechelic side‐chain liquid crystalline polyethers and polyurethane networks derived thereof
Author(s) -
Reesink Johannes B.,
Picken Stephen J.,
Witteveen Arend J.,
Mijs Willem J.
Publication year - 1996
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.1996.021970322
Subject(s) - mesogen , mesophase , liquid crystal , side chain , polymer chemistry , monomer , crystallinity , polyurethane , alkoxy group , materials science , polymer , phase (matter) , glass transition , copolymer , substituent , phase transition , alkyl , chemistry , organic chemistry , liquid crystalline , composite material , optoelectronics , physics , quantum mechanics
Hydroxy‐telechelic polymers with side‐chain mesogenic groups have been prepared from epoxy monomers using a BF 3 /1,6‐hexanediol initiating system. Homopolymers showed either nematic or smectic A and C phases, depending on the length of the alkoxy substituent on the aromatic mesogenic group. In copolymers both nematic and smectic phases could be observed, depending on composition. Liquid crystallinity was found to be retained after crosslinking with a triisocyanate at temperatures below the clearing temperature of the mixture. On the other hand, the mesophase was found to disappear on rapid cooling after a certain degree of crosslinking above the clearing temperature, only to reappear after a period of heating above the glass transition temperature.