Valorising Waste Plastics into Functional Materials and Industrially-Relevant Chemicals

Petroleum-based plastics are amongst the most versatile synthetic materials available today. They are produced in excess of 300 million tons a year and are ubiquitous in modern society due to their favourable combination of light weight, low cost and usefulness for a diverse range of applications. However, their existing life cycles are extremely linear, with most post-use plastics disposed unsustainably in landfills, incinerated or irresponsibly discarded in the environment, representing a huge loss of inherent material value. In recent years, these existing petroleum-based plastics are receiving increased attention as promising feedstock materials for production of functional polymers and chemicals essential for society. Herein, several examples of how plastics can be post-synthetically transformed into functional polymers will be described. These include upcycling waste poly(ethylene terephthalate) (PET) bottles into polymer electrolytes for energy storage, and synthesis of water-soluble antifungal polymers from polyethylene (PE). In addition, our recent methods for valorisation of waste polystyrene into benzoic acid, a commodity chemical with annual demand exceeding 500,000 tonnes, will be discussed. These proof-of-concept applications highlight the vast untapped potential for using waste plastics as a future source of raw material for producing high-value products for societal needs, ultimately reducing our collective reliance on petroleum sources for a more sustainable materials future.