Blends of ultrasonically devulcanized tire-curing bladder and butyl rubber

The devulcanization of the butyl rubber based tire-curing bladder was carried out with a grooved barrel ultrasonic extruder. The devulcanized rubber was blended at different ratios with the carbon black filled virgin butyl rubber and cured. The rheological and mechanical properties, as well as gel fraction and crosslink density of the revulcanized rubber and vulcanizates of blends have been measured. The blend of ground tire-curing bladder and carbon black filled butyl rubber has also been prepared for comparison purpose. Compared to the blend containing the ground rubber, compounding of the blends containing the devulcanized bladder were easier and their vulcanizates had smoother surface. In addition, the vulcanizates containing devulcanized tire-curing bladder and virgin rubber showed substantially improved mechanical properties than the vulcanizate of the devulcanized rubber alone.