Abstract
Improvement of comminuted vulcanizates from mechanically ground used passenger car tires has been achieved by the addition of sulfur, accelerator, and milling of the powder by an open roll. The rubber powder was mixed with rubber and then vulcanized. The vulcanization rate and the crosslink density of the rubber matrix for the composite has been studied.
The addition of sulfur and accelerator to the rubber powder increased the vulcanization rate of the rubber matrix in the composite. On the other hand, milling of the rubber powder by an open roll increased the crosslink density of the rubber matrix and decreased the size of the rubber powder in the composite. The physical properties of the composite is shown to be improved considerably by the above treatment.
The tensile strength of the composite is improved by the increased vulcanization rate and crosslink density of the matrix rubber. However, the tearing energy of the composite is contrary to the above behavior. The main reason is estimated to be due to the crosslink density of the matrix rubber.
