Lone and Combine Effect of Accelerated Irradiation and Thermal Aging Stressors on Silica Reinforced Ethylenepropylenediene Monomer Rubber 

Abstract The aim of this study was to determine the affect of irradiation and thermal accelerated aging (i.e. equivalent to 8years) on Ethylenepropylenediene Monomer (EPDM) rubber contained silica as a filler and also grafted in polymeric matrix. For this purpose, accelerated thermal aging was performed at T = 123°C for 15 days. Whereas, accelerated i.e. short term irradiation aging was done separately under thermal neutron flux in research reactor for 3.6 hrs. The combine affect of thermal aging before and after irradiation was also studied. The results revealed that irradiation promoted crosslinking in EPDM rubber, while thermal aging preferably induced secissioning in silica grafted network chain structure. The further study revealed that irradiation after thermal aging have a propensity to cure the adverse effects of temperature by increase of crosslink density and elimination of pores which made the polymeric matrix more dense as observed by structural (XRD, pole density, FTIR) and microscopic (SEM) Analyses. However, in converse order i.e. thermal aging after irradiation aggravated detrimental effects on EPDM rubber due to prevailing scissioning over crosslinking in polymeric chain structure.