Microbial Desulfurization of Ground Tire Rubber by sp.: A Novel Technology for Crumb Rubber Composites

This study focused on the microbial desulfurization of ground tire rubber (GTR) by sp. that was selected from coal mine soil and had sulphur oxidizing capacity. GTR was immersed in the medium co-cultured with the sp. for 20 days. The growth curve of sp. during co-cultured desulfurization with GTR was measured and the surface chemical groups of GTR before and after desulfurization were analyzed. The crosslink density, mechanical properties, dynamic mechanical properties, and morphology of fracture surface of SBR composites filled with GTR or DGTR were studied to evaluate the microbial desulfurization effect. The results showed that GTR had low toxicity to sp., so sp. was able to maintain a high biomass. After desulfurization, not only a rupture of conjugated C=C bonds, but also a reduction of sulfur content had happened to GTR. The sol fraction of GTR increased from its original 4.69-8.68% after desulfurization. Desulfurated ground tire rubber (DGTR) sheets had better physical properties, and higher swelling values than GTR sheets. The DMA results showed that SBR/DGTR composite had a reduction of molecular chain friction resistance during glass transition region and a decrease of glass transition temperature. SEM photograph further indicated a good coherency interface between DGTR and the rubber matrix.