Model compound studies of the devulcanization of rubber via phase transfercatalysis

It has been estimated that 240 million automobile tires must be disposed of annually in the United States alone (Korte, 1988). Presently, most of thes e tires are not being recycled but are instead being stockpiled across the country. One of the difficulties in recycling the tires arises from the vul canized nature of the styrene-butadiene rubber (SBR). One route for recycli ng these tires is to cleave the sulfur crosslinks so that uncrosslinked cha ins can then be remolded into new tires and revulcanized. To date this rout e has not been shown to be completely feasible. This paper focuses on initial efforts to develop a low cost process using p hase transfer catalysis to cleave the sulfur crosslinks in vulcanized rubbe r via phase transfer catalysis (PTC). Model compounds as well as SBR were u sed to study the cleavage of both disulfide and monosulfide bond via PTC. A lthough the chemistry proved to be capable of cleaving sulfur bonds in mode l compounds, the work on SBR was inconclusive.