Thermal stability of PVC formulations gamma irradiated at different dose rates

•PVC formulations were crosslinked with gamma radiation.•Two different thermal stabilizing systems were used to Project PVC.•Two gamma dose rates were used to crosslink PVC formulations.•Non-toxic Ca/Zn stabilizing system has a lower activation energy (Ea).

Polyvinyl chloride (PVC) formulated with two different stabilizer systems (Ca/Zn stearates and dibasic lead phthalate) irradiated at 75 kGy at two different dose rates were studied in order to evaluate their effect in thermal stability. Samples were degraded in a TGA instrument at different heating rates and the activation energy (Ea) to dehydrochlorination was calculated using the Arrhenius method in accordance with ASTM E 1641-07. TGA evaluations show that temperature for HCl evolution is higher when increasing heating rate, as well as higher resistance to degradation, for irradiated lead formulations; however, after activation energies calculation the irradiated Ca/Zn formulations are more stable. The controversial results are due to the low initial stability of lead additives in PVC.