Etude du comportement d'une série de polystyrènes linéaires dans des mélanges de solvants

Abstract

Abstract The preferential solvation of anionically polymerised polystyrene by different solvent/non solvent mixtures (CCl 4 /CH 3 OH, C 6 H 6 /CH 3 OH, dioxane/CH 3 OH, C 6 H 6 /Heptane) was studied by light scattering. The parameter λ′ of preferential solvation depends on molecular weight M according to where λ′ ∞ is the preferential solvation at infinite molecular weight and A a quantity characteristic for the composition of the mixed solvent. A increases with decreasing thermodynamic goodness of the solvent mixture. The above equation can be derived semi‐empirically by assuming that the solvent composition near the chain depends on the density of chain segments. This hypothesis furthermore explains the observed anomalous behavior of the intrinsic viscosity/molecular weight relationship below molecular weights of about 160,000 in solvent/non solvent mixtures.