ABSTRACT
150Waste tires and their deposition have been a serious environmental concern as they are resistant to moisture, oxygen, ozone, solar radiation, microbiological degradation, and so forth. Pyrolysis is an environment-friendly process for recycling used tires. The aim of this chapter is to present some studies on the effect that pyrolysis carbon black (PCB) has upon the curing and mechanical properties of styrene-butadiene rubber (SBR)-based composites, as well as to demonstrate a possibility for the surface modification of PCB, so that its ash content could be reduced. It has been established that modification of the PCB lowers its ash content two times and the zinc oxide concentration six times in its ash. The curing characteristics of the investigated SBR-based compounds are not affected significantly by that modification. The values of modulus100, tensile strength and Shore A hardness for the vulcanizates comprising modified PCB increase, while the elongation at break and residual elongation decrease slightly. The effects observed are related to the lowered ash content in PCB following its modification as well as to the dominating silica content in the remaining ash. Pyrolysis carbon black could substitute about 40-50% of conventional carbon black in the production of rubber goods requiring weaker mechanical properties. The results obtained have shown that the nature of the pyrolysis product studied is much closer to that of conventional semi-reinforcing carbon black.
