Rubber includes elastomers and thermosets characterized by large deformability and the capability to recover their shape upon removal of applied loads. Industrial rubbers divide into natural rubber (NR) and synthetic rubbers. The former derives from natural rubber latex, mainly constituted by poly(cis-1,4-isoprene), an unsaturated hydrocarbon produced by over 2,000 plant species.
Synthetic rubbers are synthesized monomers from petroleum-based hydrocarbons, and the most commonly produced are ethylene propylene diene monomer and styrene butadiene rubber, chloroprene, and isobutylene (EPDM, SBR, CR, and IS).
The demand for rubber products has grown steadily over recent years. Global NR production in 2018 amounted to almost 13.9 million metric tons, the vast majority of which (91%) was produced in Asia Pacific. Synthetic rubbers primarily produce tires, with overall demand reaching 3.9 billion units last year.
This conspicuous and ever-increasing rubber production demonstrates the versatility and the widespread application of this class of materials through compounding; but it also poses the challenge of how to manage the growing amount of various rubber wastes.
