Chemical recycling and upcycling of polymeric materials

Advancing the sustainable development of the polymer industry requires establishing a comprehensive life-cycle technological framework encompassing raw material sourcing, production, utilization, and end-of-life management. This paper highlights the importance of developing cost-effective recycling and upcycling technologies for polymer waste, which can reduce reliance on non-renewable fossil resources and mitigate associated environmental pollution. Particular emphasis is placed on discussing current methods and strategic approaches for the chemical recycling and upcycling of waste polymeric materials. For existing polymeric materials, waste management strategies must shift from merely focusing on “reducing waste pollution” to a paradigm of “recreating value from waste”. Research should prioritize novel principles and methodologies that enable “closed-loop” and/or “upcycled” recovery (i.e., “Recycling” and/or “Upcycling”), fostering the development of green, low-carbon recycling technologies capable of producing output with competitive market value. This not only reduces fossil energy consumption but also minimizes environmental pollution from waste. For newly designed and synthesized polymer materials, recyclability must be considered alongside material performance. There are two primary pathways proposed. The first involves designing and synthesizing entirely new polymers that offer both targeted performance and inherent chemical recyclability, preferably repeatable chemical recyclability—“Repeatably Chemically-Recyclable Polymers”. The second focuses on chemically modifying existing polymers by introducing features such as comonomers or reversible crosslinks to facilitate chemical recycling/repeatable chemical recyclability, while maintaining or even enhancing their original performance or adding new functionalities. For single-use polymeric products, complete environmental degradability should also be integrated into material design. The designed polymer molecules should integrate necessary performance, ease of chemical recycling/repeatable chemical recyclability, and complete biodegradability in nature (“Repeatably Chemically-Recyclable Biodegradable Polymers”). This can address all potential scenarios after disposal, ensuring that waste is either recycled or assimilated by the natural environment—a key direction for single-use polymer products. Through the complementary and coordinated implementation of these strategies alongside other recycling approaches, the polymer industry can progress toward a sustainable, green, and low-carbon future.