High-quality ground tire rubber production from scrap tires by using supercritical carbon dioxide jet pulverization assisted with diphenyl disulfide

Abstract

This study presents a high-quality ground tire rubber (GTR) production technology by using supercritical carbon dioxide jet pulverization. Diphenyl disulfide was incorporated as the devulcanization reagent during the pulverization process. The effects of rubber swelling on particle size distributions, shape characteristics, thermal degradation behaviors, and devulcanization behaviors of the acquired GTR were investigated. The results showed that fine pulverization of scrap tires can be achieved, along with a desired degree of rubber devulcanization. Rubber swelling or devulcanization was associated with the failure pattern of rubber under jet impact and was not beneficial for fine pulverization. Rubber devulcanization mechanisms included radical and oxidation-based reactions, both of which showed breakage selectivity of crosslinks. The excellent properties of the acquired GTR can help to achieve good dispersion and enhanced interfacial compatibility with the polymeric matrix. Therefore, supercritical carbon dioxide jet pulverization incorporated with diphenyl disulfide is a promising recycling technology for scrap tires.