Main-chain copolyester structure, liquid

To date, reports of investigations on the gas transport properties of main chain liquid crystalline polymers appear to have been limited to the work conducted in our laboratory. Chiou and Paul (4.) have briefly described the transport parameters of an extruded film of an LCP having a similar structure to the commercial product Vectra. This copolyester belongs to the family of napthylene thermotropic polymers (NTP s) commercialized by Hoechst-Celanese Corp. whose synthesis and properties have been described previously (iLS.). Transient permeation experiments were conducted with a series of gases. The effective... 

Preparation of Main Chain Liquid Crystalline Polymers (MCLCPs) Table 8. Representation of some typical structures of polyesters and copolyesters. 

Guezala et al. [420] studied the viscoelastic behaviour of solutions of the thermotropic main chain liquid crystalline X7G (see Fig. 160), Le. a copolyester (M 20 kg/mol) of poly(hydroxy benzoic acid) (60%) and poly(ethylene tere-phthalate) (40%) in m-cresoi the material used is non-random with respect to chain structure and domains of poly(hydroxy benzoic acid) have been reported. Solutions were studied, varying in concentration from 2.5 to 45 wt%. Special care was taken to avoid water absorption, because in its presence degradation and/or trans terification might occur. 

The influence of mesomorphic polymer components on the morphological, physical, and rheological properties of blends with polyester, polyamide, polycarbonate, and polyolefin matrix has been investigated in several cases [115]. Studies on blends of PET, PBT, PC, PS with main chain liquid crystal polymers and copolymers of various type (including flexible LC copolyesters and wholly aromatic LC copolyesters) showed that the phase transitions and properties were largely dependent on the chemical structure, molar mass, processing conditions, and concentration of components [132-134]. Generally, these systems displayed phase separation in the molten... 

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