Dilute solution properties of poly(vinyl acetate). II. Experimental tests of theories for the excluded volume effect in chain polymers in therms of the limiting viscosity number‐molecular weight relationship

Viscosimetric tests are applied to examine the validity of the existing equations for the excluded volume in terms of experimental data. The PTITSYN equation is adequate to describe the excluded volume effect if combined with a semi‐empirical relation between two expansion factors α and α η for the end‐to‐end distance and the hydrodynamic radius, respectively, i. e. , α 2.43 = α η 3 . This combination is found to be equivalent with: for 0.330ċBċA −3 M 1/2 = Z > 0.03. The temperature dependence of K for the system PVAc/methanol is −2.7ċ10 −3 /°C. The unperturbed dimension varies slightly with the chemical structure of the solvent. The parameter B is directly proportional to (1−Θ/T), from which we obtain B 0 = 6.7 3 ċ10 −27 Up to (Θ + 35)°C. A comparison of B with A 2 for the system, PVAc/acetone shows the consistency of interchain and intrachain interactions. The maximum exponent ν in [η] = KM ν is predicted to be 0.9.