Investigation of surface modifications in ethylene propylene diene monomer(EPDM) rubber due to tracking under a.c. and d.c. voltages

In the present work, tracking phenomena has been studied with the ethylene propylene diene monomer (EPDM) material under the a.c. and d.c. voltages, w ith ammonium chloride/acid rain solution as the contaminant. It is noticed that the tracking time depends on the conductivity and flow rate of the con taminant. The physico-chemical analyses viz. wide angle X-ray diffraction ( WAXD), thermo-gravimetric differential thermal analysis (TG-DTA) and the di fferential scanning calorimetry (DSC) studies, were carried out and it was concluded that the tracking process is a surface degradation process. The t racking time is different for a.c. and d.c. voltages.