MODEL COMPOUND STUDIES OF THE DEVULCANIZATION OF RUBBER VIA PHASE TRANSFER CATALYSIS

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