Thermal degradation of γ-irradiated poly(vinyl chloride)

The thermal degradation of unstabilized poly(vinyl chloride) irradiated with γ-rays has been investigated by dynamic thermogravimetry in a nitrogen atmosphere. The overall effect of irradiation is to render PVC more susceptible to thermal degradation. The change in activation energy of degradation with dose showed a behavior parallel with the change of intrinsic viscosity with dose. The minimum and maximum E_a values were found to correspond with the minimum and maximum observed on [η] versus dose curves. This behavior indicates an inverse relationship between the rate of thermal degradation and molecular size.