Influence of Devulcanization and Revulcanization of Ground Tire Rubber in Dynamic Mechanical Properties of Blends Ground Tire Rubber/High Density Polyethylene

Ground tire rubber (GTR) was devulcanized in a system comprised of a conventional microwave oven adapted with a motorized stirring system with speed control by 5.5 minutes. Blends composed of GTR/high density polyethylene (HDPE) were prepared in a twin-screw extruder with two feeders at 180 degrees C. The blends were produced in different concentrations, and both the effect of devulcanization and the dynamic revulcanization of GTR phase in the dynamic mechanical properties of the blends were analyzed. As main results, the devulcanization of GTR phase changed the crystallinity of HDPE phase of some blends, possibly because of changes in sizes of particles of devulcanized GTR and its distribution in the matrix. Concerning the revulcanization of the elastomeric phase, generally, it was observed the shift of the glass transition temperature (T-g) peak of the GTR to higher temperatures, and reduction in the area under the peak of tan delta for the T-g of the same phase, as a result of the restriction on the mobility of the GTR by dynamic revulcanization.