Mechanical Properties of Substances of High Molecular Weight. VIII. Dispersion of Dynamic Rigidity and Viscosity in Concentrated Polyvinyl Acetate Solutions

The dynamic rigidities and viscosities of concentrated solutions of polyvinyl acetate in 1,2,3-trichloropropane have been obtained from transducer and wave propagation measurements. Two polymer samples with number-average molecular weights of 140,000 and 840,000 were studied in the lower audiofrequency range at concentrations from 3 to 40 percent and temperatures from −3 to 41°C. For each sample, when the reduced dynamic rigidity G′T0/Tc and the reduced dynamic viscosity η′/η were plotted against the reduced frequency, ωηT0/Tc, all the data superposed to give two composite dispersion functions. The distribution of Maxwellian relaxation times can be derived from the dispersion of either G′ or η′, and the two calculations are in reasonable agreement.