Recent Advances in Catalytic Chemical Recycling of Polyolefins

Polyolefins and especially polyethylenes (LLDPE, LDPE and HDPE) and polypropylene (PP) contribute a great deal to the growing amounts of plastic waste with a combined production share of almost 50 % by mass. While being almost universally applicable, they are mainly used for short-lived packaging materials that constitute over 60 % of annual post-consumer plastic waste. Thus, disproportionately high amounts of polyolefins end up as post-consumer waste (PCW) and waste management strategies for these particularly inert plastics are needed. This necessity has promoted a great research effort dealing with valorization of these discarded but, nevertheless, valuable materials. This review aims to highlight the scientific advances made in chemical polyolefin recycling in recent years, focusing, though not exclusively, on catalytic processes to recycle polyolefin waste by various means at more moderate temperatures compared to pyrolysis such as deconstructing the polymer with the objective of upcycling in mind or by catalytic transformation to give access to functional chemicals.