An Investigation on the EPDM Devulcanization in Co-rotating Twin Screw Extruder by Response Surface Methodology

Abstract

In this study the effects of barrel temperature, screw speed and the devulcanization agent content on ethylene-propylene-diene-monomer (EPDM) devulcanization were investigated using co-rotating twin screw extruder. A Box-Behnken design for three variables, at three levels, was chosen as an experimental design. Sol fraction and Mooney viscosity of devulcanized rubber and mechanical properties of revulcanizates were considered as the responses. Response Surface Methodology (RSM) was used for analyzing the result of the experiments. The results indicated that the sol fraction increased with increasing the barrel temperature and screw speed but the barrel temperature was more effective than screw speed upon devulcanization of EPDM. Mooney viscosity decreased with the increase of barrel temperature. Tensile strength of revulcanized rubber showed a maximum value with the rise of devulcanization temperature, while the elongation at break increased with the increase of the barrel temperature, screw speed and devulcanization agent content. The accuracy of the models was confirmed by the experimental data.