Devulcanization of styrene butadiene rubber by microwave energy: Effect of the presence of ionic liquid

International audience; In this study, styrene butadiene rubber (SBR) was devulcanized using microwave irradiation. In particular, effectof ionic liquid (IL), pyrrolidinium hydrogen sulfate [Pyrr][HSO4], on the devulcanization performance was studied. It wasobserved that the evolution of the temperature reached by rubber powder exposed to microwave irradiation for differentenergy values was favored by the presence of ionic liquid [Pyrr][HSO4] significantly over the whole range of themicrowave energy values. Beyond the threshold point of 220 Wh/kg, the soluble fraction after devulcanization sharplyincreased with increasing devulcanization microwave energy. For the powder mixed with [Pyrr][HSO4], the increase wasmore significant. Furthermore, the crosslink density was observed to decrease slowly with the microwave energy up to220 Wh/kg, beyond which the crosslink density decreased significantly for the rubber impregnated with IL. For the rubberwith IL, significant and continuous increase in Tg with microwave energy values was observed in comparison with the SBRwhere no change in transition temperature was observed. Mechanical shearing of rubber gums in the two-roll mill favoredthe devulcanization process, which indicated that the combination of mechanical loading with microwave energy and IL isan efficient procedure allowing an optimal devulcanization of rubbers.