A Review on Devulcanization of Waste Tire Rubber

Abstract

Rubber has become an indispensable material for the technological
development of civilization, including simple balloon and complex rocket
propellant. Rubber Industry worldwide is using on an average 50% of raw
materials. These materials were mostly petroleum-based, except natural
rubber (NR), steel cord and bead wire. Using of these petroleum-based raw
materials not only depletes natural resources, but also produces more extreme
environmental hazards. The waste tire rubber problem is of great magnitude
and has far reaching environmental and economic implications. There are
some ways for recycling of rubber, such as reclaiming technology, surface
treatment, grinding and pulverization technology, devulcanization technology.
Methods of devulcanizing rubber (or elastomers) have been researched almost
since the time of the discovery of the rubber/sulfur vulcanization process. By
devulcanization process the cross-links in the structure of rubber are broken
and devulcanized rubber can be revulcanized into a raw material for rubber
industry, which is a highly valued form of waste rubber. This study provides a
review of the recent advances in understanding of methods of recycling rubber
and claims that the capacity of thermomechanical and mechanochemical
devulcanization methods of recycling waste tire rubber can be improved in
future studies.