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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 molecular 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 molecular weight of the starting materials. The thermal expansion coefficient and peak temperature of β-dispersion became lower with increasing free volume of the cured products. These results may be attributed to the dependence of molecular weight on the balance between intermolecular and intramolecular reactions. Many intramolecular reactions may lead to loop formation, when the molecular weight of the starting polymer is high.