Polymer degradation into the bore of the pipe, and fuel leakage and fire may follow. The problem of ozone cracking can be prevented by adding anti-ozonants to the rubber before vulcanization. Ozone cracks were commonly seen in automobile tire sidewalls, but are now seen rarely thanks to these additives. On the other hand, the problem does recur in unprotected products such as rubber tubing and seals. The polymers are susceptible to attack by atmospheric oxygen, especially at elevated temperatures encountered during processing to shape. Many process methods such as extrusion and injection moulding involve pumping molten polymer into tools, and the high
Rubber toughening of waste rubber from car tires has sparked interest in finding uses for this discarded rubber. The rubber can be turned into a fine powder, which can then be used as a toughening agent for polystyrene. However, poor miscibility between the waste rubber and polystyrene will weaken the material. This problem requires the use of a compatibilizer (see "compatibilization") in order to reduce interfacial tension and ultimately make rubber toughening of polystyrene effective. A polystyrene/styrene-butadiene copolymer acts to increase the adhesion between the dispersed and continuous phases. Rubber toughening Rubber toughening is a process in which rubber nanoparticles are interspersed