Solution properties of poly(methyl methacrylate) in methyl methacrylate, 1. Viscosities from the dilute to the concentrated solution regime

Abstract

AbstractThe viscosities of samples of poly(methyl methacrylate), PMMA, with narrow molecular weight distributions and with molecular weights in the range 1,75·104 < M̄w < 1,60.106 were measured in methyl methacrylate, MMA, as solvent at 20, 40, and 60°C in the dilute and in the semi‐dilute concentration regime. By extrapolation to zero polymer concentration the limiting viscosity numbers and therefrom the Mark‐Houwink‐Kuhn‐Sakurada parameters for PMMA in MMA were obtained. In addition, unperturbed dimensions were determined from dilute solution viscosity data. Together with some published results for more concentrated solutions of PMMA in MMA the viscosities of the semi‐dilute systems were analysed in terms of scaling theories. It was found that irrespective of temperature, polymer concentration, and molecular weight all data could be quite well fitted by a single master curve when the relative viscosity η/η0 was plotted as a function of the product of the intrinsic viscosity and mass concentration [η]·c. No sharp transitions between different concentration regimes were observed, however, and the scaling law exponents for the entangled solution are significantly higher than predicted by theory.