Dielectric relaxation time of PVAc in terms of hole fraction calculated from the theory of Simha-Somcynsky

Abstract

The relaxation behavior of chain molecular systems in terms of the free volume has been an ongoing significant approach to comprehend the structural defect connection. Using the recently proposed free volume model, we have investigated the relaxation time of the α-relaxation process of PVAc (polyvinyl acetate) as a function of the hole fraction−the so-called “thermo-occupancy” function−for a broad range of temperatures (320–460 K) and pressures (0–300 MPa). The model is based on merging the equilibrium theory of Simha-Somcynsky on the transport theory of the Eyring Significant Structure. We have discussed and compared this model with the current free volume model. The former is superior and more consistent than the latter. However, we have explored the derivative of the logarithm of relaxation with respect to the hole fraction, named relaxiholibility, which measures how the relaxation time changes with the hole fraction.