EXCLUDED-VOLUME AND HYDRODYNAMIC PROPERTIES OF POLYSTYRENE IN NONIDEAL SOLVENTS

At 298 K, intrinsic viscosity, [eta], has been measured for fifteen po lystyrene, PS, samples of different relative molar masses M in pure to luene, T, and seven different binary solvents. These solvents were tol uene / methanol (MeOH) mixtures having different volume fractions of M eOH. The theta - composition for the binary solvent system was found t o be 77% T / 23% MeOH at 298 K. The dependance of excluded volume of p olymer molecules on M and the solvation power was demonstrated. A cons tant value of 0.633 nm for the effective unit length, b, was obtained under theta - condition. Meanwhile a non-constancy of b, obtained in c ase of thermodynamically good solvents, was attributed to the neglect of excluded volume effect.