EXCLUDED-VOLUME EFFECT OF POLYMETHYL METHACRYLATE SOLUTIONS

Osmotic pressures of polymethyl methacrylate solutions in acetone and in benzene are examined over a wide range of concentration (0<v 2<0.17). The data are used to evaluate the thermodynamic parameter B appearing in the excluded-volume parameter z. The behavior of αη3 = [η]/[η]0 over a wide range of z (0<z<8) are compared to the theoretical predictions. The dependence of αη8 on s seems to be approximately described by the modified Flory-Fox relation αη 5-αη3= 1 03z. The observed dependence of h(S) = 2A2/NAB on 2 for polymethyl methacrylate solutions is very close to the result for polystyrene solutions. It is found that logA(2) is not a linear function of logz2 over a sufficiently wide range of z2(0<z<8).