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Review

Devulcanization Technologies for Recycling of Tire-Derived Rubber: A Review

University of Applied Sciences FH Technikum Wien, A-1200 Vienna, Austria
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Materials 2020, 13(5), 1246; https://doi.org/10.3390/ma13051246
Received: 20 January 2020 / Revised: 27 February 2020 / Accepted: 2 March 2020 / Published: 10 March 2020
(This article belongs to the Special Issue Recent Advances in Rubber Recycling)
In general, composite materials are difficult to recycle. Tires belong to this class of materials. On top, one of their main constitutents, vulcanized rubber, is as elastomer, which cannot be remolten and hence is particularly challenging to put to a new use. Today, the main end-of-life routes of tires and other rubber products are landfilling, incineration in e.g., cement plants, and grinding to a fine powder, generating huge quantities and indicating a lack of sustainable recycling of this valuable material. True feedstock recycling is not feasible for complex mixtures such as tires, but devulcanization can be done to reactivate the cross-linked polymer for material recycling in novel rubber products. Devulcanization, i.e., the breaking up of sulfur bonds by chemical, thermophysical, or biological means, is a promising route that has been investigated for more than 50 years. This review article presents an update on the state-of-the art in rubber devulcanization. The article addresses established devulcanization technologies and novel processes described in the scientific and patent literatures. On the one hand, tires have become high-tech products, where the simultaneous improvement of wet traction, rolling resistance, and abrasion resistance (the so-called “magic triangle”) is hard to achieve. On the other hand, recycling and sustainable end-of-life uses are becoming more and more important. It is expected that the public discussion of environmental impacts of thermoplastics will soon spill over to thermosets and elastomers. Therefore, the industry needs to develop and market solutions proactively. Every year, approximately 40 million tons of tires are discarded. Through the devulcanization of end-of-life tires (ELT), it is possible to produce new raw materials with good mechanical properties and a superior environmental footprint over virgin products. The devulcanization process has become an interesting technology that is able to support the circular economy concept. View Full-Text
Keywords: rubber devulcanization; sustainability; recycling; twin screw extruder; feedstock recycling; magic triangle; elastomer rubber devulcanization; sustainability; recycling; twin screw extruder; feedstock recycling; magic triangle; elastomer
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MDPI and ACS Style

Markl, E.; Lackner, M. Devulcanization Technologies for Recycling of Tire-Derived Rubber: A Review. Materials 2020, 13, 1246. https://doi.org/10.3390/ma13051246

AMA Style

Markl E, Lackner M. Devulcanization Technologies for Recycling of Tire-Derived Rubber: A Review. Materials. 2020; 13(5):1246. https://doi.org/10.3390/ma13051246

Chicago/Turabian Style

Markl, Erich, and Maximilian Lackner. 2020. "Devulcanization Technologies for Recycling of Tire-Derived Rubber: A Review" Materials 13, no. 5: 1246. https://doi.org/10.3390/ma13051246

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