MEAN-SQUARE RADIUS OF GYRATION AND DIPOLE MOMENT OF POLY(METHYLPHENYLSILOXANE) CHAINS

Abstract

The mean-square radius of gyration 〈S2〉, the mean-square dipole moment 〈D2〉, the mean-square end-to-end distance 〈R2〉 and their temperature coefficients of unsymmetrical disubstituted poly(methylphenylsiloxane) (PMPS) chains, as a function of stereochemical structure, confomational energies and length of polymers, were studied by using an improved configurational-confomational statistical method based on the rotational-isomeric-state theory. It is found that the increase in isotacticity of PMPS chains causes a significant decrease in the unperturbed dimensions and increase in their temperature coefficients. This correlation of the properties of PMPS and its stereochemical structure is different from that of vinyl monosubstituted polystyrene and disubstituted poly(α-methylstyrene) chains. Dependence of the characteristic ratio of 〈S2〉 on conformational energy Eω′ of C6H5…C6H5 four-bond interactions increases markedly with the degree of isotacticity increasing, the dependence on the conformational energy Eδ...