Physical recycling of Polyethylene terephthalate (PET): principles, challenges, and advances in dissolution-precipitation methods

Polyethylene terephthalate (PET) is a high-volume thermoplastic whose post-consumer accumulation requires recycling technologies capable of retaining polymer value while enabling industrially viable circularity. Although mechanical recycling remains the dominant route, repeated thermo-mechanical processing can reduce molecular weight and compromise material performance. Solvent-based physical recycling by dissolution–precipitation (D–P) offers a complementary strategy for selective PET purification without intentional backbone cleavage. This review critically examines PET physical recycling technologies, with emphasis on D–P process pathways, polymer–solvent interactions, precipitation mechanisms, and solvent/antisolvent selection. Mechanical, chemical, and D–P routes are compared in terms of product quality, process complexity, selectivity, solvent toxicity, recovery, and scalability. Recent progress in low-toxicity, bio-based solvents, solvent screening methods, and regeneration strategies is discussed to assess the feasibility of D–P recycling as an industrially relevant route for PET circularity.