Production of rubber parts by tyre recycling without using virgin materials

A new recycling technology (namely ‘direct powder moulding’) is proposed to produce large rubber parts from spent tyres without any addition of virgin materials or linking agents. Rubber pads were produced by compression moulding of rubber powder mixtures which were obtained by mechanical grinding of ground tyre rubbers. In this study, the effect of different powder mixtures on the final performances of the moulded parts was evaluated. Starting from three initial size distributions of the rubber powder, other binary and ternary blends were prepared, for a total of 15 different powder distributions. All these rubber mixtures were compression moulded to produce large pads. Differential scanning calorimetry of the rubber powders was carried out as well as tensile tests and dynamic mechanical analyses on samples extracted from the pads. It was found that the rubber powder distribution strongly affects the mechanical performances of the recycled rubber moulded products.