Journal of Polymer Science Part A: Polymer Chemistry, Vol.44, No.6, 1877-1889, 2006
Vinyl-terminated side-chain liquid-crystal line polyethers containing mesogenic benzylideneaniline moieties
The synthesis of two vinyl-terminated side-chain liquid-crystalline poly-ethers containing benzylideneaniline moieties as mesogenic cores was approached in two different ways: by chemically modifying poly(epichlorohydrin) with suitable mesogenic acids or by polymerizing analogous glycidyl ester or glycidyl ether derivatives. In all the conditions tested, the first approach led to materials in which the imine group was hydrolyzed. The second approach led to the desired polymers PG2a and PG2b, but only from the glycidyl ether derivatives and when the initiator was the system that combined polyiminophosphazene base t-Bu-P-4 and 3,5-di-t-butylphenol. These polymers were chemically characterized by IR and H-1 and C-13 NMR spectroscopies. The estimated degrees of polymerization ranged from 30 to 36. The liquid crystalline behavior of the synthesized polymers was studied by differential scanning calorimetry, polarized optical microscopy (POM) and X-ray diffraction. Both polymers behave like liquid crystals and exhibited a single mesophase, which was recognized as a smectic C mesophase, probably with a bilayer arrangement, i.e., a smectic C-2 mesophase. The crosslinking of both polymers was performed with dicumyl peroxide as initiator, which led to liquid crystalline thermosets. POM and X-ray diffraction confirmed that the mesophase organization mantained on the crosslinked materials. (c) 2006 Wiley Periodicals, Inc.
Keywords:anisotropic thermosets;crosslinking;liquid-crystalline polymers;polyethers;ring-opening polymerization