Characterization of Microwave-Devulcanized Composites of Ground SBR Scraps

The recycling of waste rubber has considerable significance in terms of environmental protection and energy conservation. Considering that most of the relevant literature is concerned with tire recycling, the objective of this study is to develop and characterize styrene-butadiene rubber composites containing only industrial rubber scraps devulcanized by microwave. The styrene-butadiene rubber extruded profile scraps were collected and ground under ambient conditions. The obtained powder styrene-butadiene rubber-r was physically, thermally, and chemically characterized. From the devulcanized styrene-butadiene rubber-r two composites were prepared, varying the exposure time of the powder in the microwave (3 and 4 min). These composites were compared to a control sample supplied by the industry from which the styrene-butadiene rubber extruded profile scraps were collected. Vulcanization parameters were determined by oscillatory disk rheometry. Vulcanized composites were characterized by crosslink density and physical-mechanical properties (Shore A hardness, tensile and tear strength, and compression set) before and after a postcure process. The mechanical properties of the compositions were ∼25% for tensile strength and 41% for tear strength compared to the control sample. The results for the crosslink density verified those for the mechanical properties of the composites.