THE EFFECT OF MOLECULAR-MASS AND ANNEALIN G ON STRUCTURE OF THERMOTROPIC TERNARY LIQUID-CRYSTALLINE COPOLYESTER

The effect of molecular mass and thermal treatment on structure and ph ase composition of liquid-crystalline ternary rigid-chain copolyester was studied in a wide temperature range by means of temperature X-ray analysis and differential scanning calorimetry (DSC). A correlation be tween copolymer molecular mass and fractional content of two crystalli ne phases, the total content of which in the annealed samples was as h igh as 40 +/- 5% despite a random structure of the copolyester studied , was established. One of the two crystalline modifications was found to be characteristic of the polymer samples with minimal molecular mas s. As the length of macromolecules increases, fractional content of th is component decreases, whereas the content of the second modification in the system increases. More precise estimates on the parameters of the unit cells of two crystalline modifications for the samples with m inimal and maximal molecular masses, which were enriched with first or second crystalline phase, respectively, were found. On long annealing at temperatures above the glass transition point, the phase microsepa ration showed irreversible character.