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Synthesis of Liquid Crystalline Epoxy Oligomers: Effect of Molecular Weight on the Phase Behavior
Author(s) -
Liu Weichang,
Carfagna Cosimo
Publication year - 2001
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/1521-3927(20010901)22:13<1058::aid-marc1058>3.0.co;2-c
Subject(s) - differential scanning calorimetry , oligomer , mesogen , epichlorohydrin , epoxy , materials science , polymer chemistry , liquid crystal , phase (matter) , copolymer , crystallography , polymer , chemistry , organic chemistry , liquid crystalline , composite material , physics , optoelectronics , thermodynamics
A series of epoxy‐terminated liquid crystalline oligomers with different molecular weights having α ‐methylstilbene as the mesogenic unit were synthesized and characterized by means of 1 H NMR and FT‐IR spectroscopy, differential scanning calorimetry (DSC), polarized‐light optical microscopy (POM) and X‐ray diffraction. The effect of the initial ratio between epichlorohydrin and diol on the molecular weight was not significant enough to change the thermal behavior of the oligomers essentially. The copolymerization of epoxy‐ and hydroxyl‐terminated comonomers yielded high‐molecular weight oligomer, whose enantiotropic liquid crystalline character was proved by means of DSC, POM and X‐ray diffraction.