Synthesis and crosslinking of liquid-crystalline polyethers and vinyl-terminated biphenyl and naphthalene with pendant full-saturated aliphatic chains

Two series of vinyl-terminated, side-chain liquid-crystalline polyethers containing 4,4'-biphenyl and 2,6-naphthalene moieties as mesogenic cores with several contents of vinyl crosslinkable groups were synthesized by chemically modifying poly(epichlorohydrin) with mixtures of saturated and vinyl-terminated mesogenic acids. In most cases the degree of modification was over 90%. The polymers were characterized by chlorine analysis, IR and H-1 and C-13 NMR spectroscopies, viscometry, size exclusion chromatography/multi-angle laser light scattering, and thermogravimetric analysis. The liquid-crystal behavior of all the synthesized polymers was examined by differential scanning calorimetry, polarized optical microscopy (POM), and X-ray diffraction on mechanically oriented samples. The crosslinking of most polymers was done by peroxide-type initiators, which generally led to liquid-crystal elastomers. The mesophase organization was maintained on the crosslinked materials, as confirmed by POM and X-ray diffraction. (C) 2003 Wiley Periodicals, Inc.