Аңдатпа
Abstract Intrinsic viscosities of fractions of the statistical copolymer of vinylpyrrolidone and methyl methacrylate (composition 42:58 mole percent) have been measured in the cross‐selective solvents, benzene and methanol, in mixtures of these solvents, as well as in chloroform, a solvent for both polymer components, and in mixtures of chloroform with methanol. The dependence of the intrinsic viscosity on the composition of the mixed solvent exhibits a maximum reflecting the destruction of secondary structures that exist in the selective solvents. The temperature dependence of the intrinsic viscosity, which has a maximum around 50‐60°C, has been studied in chlorobenzene between 10° and 100°C. The Mark‐Houwink‐Kuhn constants K and a, which do not change significantly with solvent composition, have been calculated. The values of the parameters Kθand σ, which depend on solvent composition similarly to the intrinsic viscosity, have also been determined. The results indicate marked changes of macromolecular conformation from the hypercoiled structure in a selective solvent to the random coil in mixed and nonselective solvents.