CRYSTALLINE AND LIQUID-CRYSTALLINE PROPERTIES OF POLYESTERS OF PHENYL-SUBSTITUTED 4,4'-BIPHENOL .2. COPOLYMERS WITH 4-HYDROXYBENZOIC ACID

The results of X-ray diffraction, DSC, and optical microscopy are presented for a series of four copolyesters of either 3-phenyl-4,4'-biphenol (MPBP) or 3,3'-diphenyl-4,4'-biphenol (DPBP) with either terephthalic acid (TA) or 2,6-naphthalenedicarboxylic acid (NDA) and 30 mol % of p-hydroxybenzoic acid (HBA). The properties of the copolyesters resembled those of the Xydar family of polymers. The X-ray diffraction patterns of oriented samples drawn from the nematic phase of three of the four copolymers showed a series of aperiodic intensity maxima on the meridian, orientation, or fiber direction, which, in general terms, are consistent with that expected from a random sequence of monomers.