Green Approaches in Rubber Recycling Technologies: Present Status and Future Perspective

As a consequence of massive production and consumptionof rubbers,rubber blends, and rubber composites for myriad applications, elastomericproducts have enormously accumulated and become an environmental threat.The disposal and burning of rubber wastes have been banned becauseof environmental and economic reasons. By contrast, a great deal ofattention has been directed toward strategies enabling recycling andreuse of rubbers. Basically, conventional recycling methods sufferfrom several drawbacks such as the formation of dust, fumes, and toxicgases in the air, as well as contamination of underground water resources.Thus, green and sustainable formulations and processing methods nowadaysare of priority and importance. Taking advantage of sustainable developmenthorizons, scientific and technological aspects of waste rubber managementsuch as processing techniques, properties of the resulting products,industrial applications, and compatibilization with other materialssuch as thermoplastics, thermosets, and rubbers are herein reviewedand discussed. A particular emphasis is placed on reactive extrusionas a highly flexible in situ compounding method enablinginnovations and taking care of sustainability concerns. Finally, thecurrent status of green rubber recycling and future opening doorsahead of this technology are highlighted. Reactive extrusion as an authoritative technology for greenrubber recycling enables production of sustainable value-added secondarywaste rubber-based products.