DEPENDENCE OF MOLECULAR-WEIGHT AND CONCENTRATION OF REACTIVE SIDE-CHAINS ON THE MECHANICAL-PROPERTIES OF CURED BROMINATED POLY(4-METHACRYLOYLOXYSTYRENE) DERIVATIVES

Brominated poly(4-methacryloyloxystyrene) derivatives with different m olecular weights and different concentrations of reactive side chains were synthesized. They were heated with radical initiator to be highly crosslinked products. Free volume of cured products increased with mo lecular weight of the starting materials. The thermal expansion coeffi cient and peak temperature of beta-dispersion became lower with increa sing free volume of the cured products. These results may be attribute d to the dependence of molecular weight on the balance between intermo lecular and intramolecular reactions. Many intramolecular reactions ma y lead to loop formation, when the molecular weight of the starting po lymer is high.