Dynamic mechanical properties of plasticized polyvinyl acetate

Abstract

The real and imaginary components of the complex compliance have been measured between 30 and 4500 cycles per second in the temperature range −11°C. to 40°C. for a 50% (by volume) solution of polyvinyl acetate in tri- m-cresyl phosphate. Results at all temperatures and frequencies superpose by the method of reduced variables to give the components at 25°C. over 7.5 decades of frequency, corresponding to the transition from rubberlike to glasslike consistency at this temperature. Values of the steady-flow viscosity have been measured between 0° and 41°C. and found to give nearly the same temperature reduction factors as found empirically from the dynamic measurements. Relaxation and retardation distribution functions have been calculated. By reducing these data to a common temperature for both plasticized and undiluted polymer, it is concluded that the presence of 50% diluent reduces the monomeric friction coefficient by a factor of 10 7. By reducing the data to a hypothetical reference state of unit density and unit steady-flow viscosity and combining them with previous data on solutions of the same polymer in 1,2,3-trichloropropane, the distribution function of mechanical relaxation times can be obtained at 25°C. over 13.5 decades of time. The distribution function is found to be similar in shape and location on the time scale to that obtained for polystyrene in decalin previously studied in this laboratory.