Review on disposal, recycling and management of waste polyurethane foams: A way ahead

Abstract

With the burning issue of air, land and water pollution, the premonition of looking forward towards a future devoid of any kind of oil and gas reserves has caused a paradigm shift towards recycling, recovery of any synthetic polymer and also to dispose them off environmentally. Among them are plastics such as polyethylene terephthalate and poly vinyl chloride. Polyurethane (PU) is also under the scanner to dispose of or recycle it environmentally and sustainably. PU is at present the sixth most utilized polymer all over the world with a production of nearly 18 million tonnes per annum, which roughly estimates a daily production of PU products of greater than a million of cubic metres. Its thermostable nature is one of the major reasons for its higher preference over other polymers. This review article discusses the current disposal and technologies available to recycle waste PU foams and also sheds some light on some additional work being done in the field to upgrade the existing technology. Interestingly, some methods mentioned here are probably undergoing scale-up trials runs by now. Currently, the most researched and studied ones are mechanical recycling and glycolysis. But microbial and enzymatic disposal methods can be turned into full-scale industrial recycling processes in the near future. Additionally, we can see an archetypal shift from traditional oil-based sources to the agrarian sources.

Recycling of polyurethanes: where we are and where we are going

“…It is possible to exploit such living microorganisms as bacteria and fungi to biodegrade polyurethane wastes, including postconsumer materials: 29,[85][86][87] because of the interaction with the microorganisms, either under aerobic or anaerobic conditions, the macromolecular chains are shortened, and the molecular weight of the polymer significantly decreases. Further, according to the adopted experimental conditions, it is possible to achieve the full mineralization of the biodegraded polymer.…”

Down-Cycling Sustainability of Flexible Polyurethane Foam in Improving Asphalt Performance through a Proper Pyrolysis Approach

“…Waste flexible polyurethane foam (FPUF) has become a growing problem worldwide. , The typical appearance and cross-linked skeleton structure of FPUF are shown in Figure a. FPUF has long been recognized as an important class of polymeric materials with excellent physical, chemical, and mechanical properties (low density, good elasticity, shock absorption, thermal insulation, etc.)…”

Evaluation of composites based on virgin rubber/devulcanized rubber reinforced with chemically and radiation activated polyurethane scrap for possible applications

“…Many methods were developed to reutilize the WPU, such as biological degradation, mechanical treatment, re-bonding using adhesives, and chemical treatment. 4 Mechanical processing is the most straightforward and efficient way to recycle WPU. It involves converting solid waste into flakes, granules, or powder.…”