Chemical recycling via precision depolymerization: fundamentals, design principles, and emerging frontiers for circular polymer systems

초록

Ranging from traditional food packaging, clothing, and furniture to modern small and large electronic devices and automobiles, plastics serve to fulfill diverse demands in our daily lives. However, global plastic waste generation is dramatically increasing, currently standing at approximately 150 million metric tonnes annually. While some regenerated plastics by mechanical process can be reused as their parent plastics, cost and energy savings are limited by multiple preliminary processes such as plastic sorting, shredding, washing, and drying. Moreover, continuous mechanical process degrades the physical properties of the materials. In this context, chemical recycling is emerging as a promising alternative method due to its high efficiency, simpler preliminary steps, reduced reliance on fossil resources, and conversion of plastic waste into valuable chemicals. This review provides a state-of-the-art overview of contemporary chemical recycling of polymeric materials toward circular economy via i) depolymerization: "from polymers to small valuable molecules" and ii) closed-loop cycles: "from polymers to monomers, then back to polymers", by encompassing traditional/advanced depolymerization chemistries and the remaining challenges. These recycling approaches are contextualized within key design principles, chemistries, specific recycling case studies, and industrial aspects related to distinct polymeric materials.

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