A new approach for reclaiming of waste automotive EPDM rubber using waste oil

The disposal of polymeric and especially rubber materials is an important global issue. In this work we have used disulfide oil (DSO), the oily waste produced in gas refineries, as a chemical agent for mechanochemical reclaiming of waste EPDM rubber at a specific operation condition. The devulcanization reaction was performed using different concentrations of DSO (5 and 7 phr) and different temperatures (220, 250 and 290 °C). The results confirmed the effectiveness of DSO in decreasing the crosslink density up to 73% at specific reaction conditions. Subsequently, two different portions of the devulcanized rubber (RR) (20 and 40 wt %) were blended with the virgin EPDM rubber to assess the reusability of the recycled product. Accordingly, replacing 40 wt% of RR had no effect on the scorch and the optimum curing time and similar curing rates were obtained. Moreover, the mechanical properties of the revulcanized blends were not worsened and surprisingly were improved in some cases including tensile strength and elongation at break up to 14% and 26% respectively. These results can be used to propose a new method for solving both rubber and disulfide oil disposal issues.