Glycolysis: an efficient route for recycling of end of life polyurethane foams

Abstract

The increased applications of Polyurethane (PU) materials give rise to a higher amount of wastes, which have a devastating effect on the earth in turn; therefore, the management of end-of-life wastes is one of the most important issues in the modern world. Although incineration and landfilling are the most common procedure adopted for waste disposal, but both of them caused environmental problems such as air and soil pollution. Moreover, the former triggers global warming, and the latter causes water pollution making the problem worst. As a consequence, finding economical and environmentally friendly methods are a high priority topic for researchers to overcome this problem. Fortunately, recycling is an environmentally attractive solution, and there is an increased interest by the researchers in recycling PU wastes. Several recycling techniques for PUs have been described in the technical and scientific literature. Without any doubt, glycolysis reaction is one of the most important recycling method, especially for rigid and flexible PUs. In this review, glycolysis of waste polyurethane foam (PUF) materials with different glycols and catalysts, especially metallic ones were considered, and the effect of some additional parameters such as the nature of glycol, catalyst, temperature and material ratio were discussed too. In addition, a brief description on characterization of recycled products, and potential application of regenerated products is carried out.