THE EFFECT OF COMPOSITION OF THE RANDOM C OPOLYMERS BASED ON TRANS-1,4-POLYBUTADIENE ON THEIR ABILITY TO CRYSTALLIZE AND TENDENCY TO MESOMORPHISM

The structure and phase composition of the random copolymers based on mesomorphic trans-1,4-polybutadiene containing different amount of vin yl groups (2-41%) were studied at various temperatures by X-ray diffra ction and DSC. As the amount of defect units in the polymer increases, the temperatures of the phase transitions crystal-mesophase and mesop hase-melt decrease, thus leading to a more narrow temperature range co rresponding to the mesomorphic state. At a concentration of 1,2-units of about 30%, the copolymer loses the ability to form the mesophase. U pon further increase in the content of 1,2-units (35-40%), the polymer no longer crystallizes. The phase diagram of the copolymer was constr ucted in the coordinates the temperature of phase transitions-composit ion.