KU Leuven disseminated the fourth project MOOC, about “Polyurethane in the landscape of polymer recycling”. You can watch it on youtube.
Plastic waste is processed by a variety of techniques comprising incineration, pyrolysis, dissolution/precipitation, mechanical recycling and chemical recycling.
Incineration allows for the recovery of thermal energy but also requires extensive scrubbing of exhaust gasses and produces greenhouse gasses. Pyrolysis involves the thermal decomposition of plastic at elevated temperatures in an inert atmosphere. The product mixture comprises a wide range of hydrocarbons requiring further processing by cracking. Dissolution and precipitation processes require the use of non-toxic and easily recoverable solvents to produce plastic granulates for product manufacturers and accounts for less than 1% of plastic waste. Mechanical recycling results in lower quality plastics (also known as downcycling) and accounts for 12% of annual plastic waste.
Chemical recycling requires the dissolution and depolymerization of polymers to constituent chemical materials for virgin grade producers and accounts for less than 1% of the plastic waste. An innovative process for the chemolysis of end-of-life polyurethane mattresses is being developed as part of the PUReSmart project, with the goal of recycling the two main components comprising the polyol and the isocyanate. Concurrently, an intelligent sorting process is being developed for separating the various polyurethane foams from end-of-life mattresses.