EFFECT OF ZINC STEARATE AND PARAFFINIC OIL ON PROPERTIES OF CARBON-BLACK FILLED EPDM-BASED IONIC THERMOPLASTIC ELASTOMER

Both paraffinic oil and zinc stearate act as plasticizers for carbon b lack filled zinc sulfonated EPDM of high ethylene content. While paraf finic oil plasticizes the backbone chain and functions at ambient cond itions, the plasticizing ability of zinc stearate is observable only a t high temperatures (that is, > 129 degrees C, melting point of zinc s tearate) and it plasticizes the ionic domains of the ionomer. The blac k filled compound containing both plasticizers shows the lowest viscos ity. The thermoplastic elastomeric nature of the compounds is evident from the retention of stress-strain properties even after three cycles of repeated mixing and moulding.