Dipole moments of styrene/4-vinylpyridine copolymers—I: Relation to the fraction of polar component

Mean-square dipole moments for styrene/4-vinylpyridine (S4VP) random copolymers were determined at five different temperatures, 25–60°C, in 1,4-dioxane solution. The dipole moment behaviour was examined with respect to the increase in mole fraction of the polar monomer, 4-vinylpyridine (4VP), in the copolymer. The behaviour observed was different from the general behaviour of similar copolymers. The temperature coefficient of the dipole moment ratio was found to be zero, within experimental error, in the temperature interval 25–60°C.