Dielectric and mechanical characterization of PVC composites with ground tire rubber

The mass manufacture of tires and the difficulty for their elimination or storage constitutes a serious environmental problem. At present, several methods for the recycling of tires are used, such as mechanical crushing, in which the steel vulcanized rubber and the fibers are separated; this rubber is being used in numerous applications like pavements, insulators, footwear, etc. This study proposes a second option for obsolete tires, demonstrating their utility as dielectrics. In order to do so, ground tire rubber (GTR) has been combined with polyvinyl chloride (PVC), to obtain a composite of a polymeric matrix reinforced with GTR. In order to determine the behavior of this composite material, the electrical and mechanical tests are presented as well as, more briefly, microstructure and thermal analyses, undertaken for the various mixtures of PVC with GTR (concentrations of 0%, 5%, 10%, 20%, 40%, 50%, and 70% GTR), and three GTR particle size categories (<200 μm, 200—500 μm, and >500 μm), in a range of temperatures that varied from 30° C to 130° C, and with frequencies from between 1 × 10 ^-2 Hz and 3 × 10 ⁶ Hz. The dielectric tests have allowed for an analysis of dielectric constant, dielectric loss factor, dielectric modulus, etc. On the other hand, the mechanical analysis has involved the Young’s modulus, tensile strength, elongation at break, and toughness. Mechanical and dielectric results point out that below 20% of GTR the material features for mechanical or electrical applications are not significantly altered.