Excluded-Volume Effect of Polystyrene Solutions

Abstract

Osmotic pressures of moderately concentrated solutions of polystyrene in toluene are examined with the object of evaluating the free energy parameter B which describes the long‐range interactions between segments. The B value evaluated through an analysis of the data is used to estimate the excluded‐volume parameter, ${\text{z=0.330B(6〈s}}^2{〉}_0{\mathrm{/M)}}^{\text{−3/2}}{M}^{\text{1/2}}$ , for polystyrene solutions in which solvent is toluene. The behavior of α_η³=[η]/[η]₀ over a wide range of z(0<z<6) is compared to the theoretical predictions. It is found that α_η³ is not a linear function of z. The dependence of α_η³ on z seems to be described better by the recent Fixman relation than the Stockmayer—Fixman relation.