Chemical Upcycling of Biodegradable Plastic Waste: A Critical Review

Biodegradable plastics (BPs) have emerged as a promising, sustainable, and alternative to traditional ones. It is essential to concentrate on BPs waste recycling and upgrading. Chemical upcycling approach not only retains the intrinsic carbon value of the polymers, but also offers broad adaptability and high conversion efficiency across diverse types of BPs through precise reaction condition optimization. This review systematically summarizes the factors influencing BPs conversion and the mechanisms of various chemical conversion techniques. The advantages and limitations of various conversion technologies, such as pyrolysis, hydrolysis, alcoholysis, electrocatalysis, and photocatalysis, were evaluated across five dimensions, including product value, selectivity, conversion rate, cost, and carbon emissions. Pyrolysis can produce high-value products, but it is limited by high energy consumption and low selectivity. Hydrolysis and alcoholysis, both mature and reliable technologies, offer high selectivity and conversion efficiency but require optimized conditions for effective implementation. Electrocatalysis and photocatalysis appear as promising technologies for waste-to-resource conversion, aligning well with green development goals. However, both require further advancements in catalyst design and reaction optimization. Future research should focus on integrating multiple technologies, enhancing catalyst efficiency, improving pretreatment processes, and refining reaction modeling to create more sustainable and cost-effective BPs upcycling strategies. This work aims to provide theoretical support and guidance for waste plastic upcycling.