Chemical recycling of polyolefin wastes: recent advances and insights into recycling routes

Polyolefin wastes have caused severe environmental problems due to their chemical stability and slow natural degradation. Developing upcycling techniques for these carbon- and hydrogen-rich materials—transforming them into high-value products such as fuel oil, naphtha, olefins, aromatics, carboxylic acids, and functional polymers—not only addresses plastic pollution but also promotes resource circularity, thereby advancing the circular economy. Researchers have made significant efforts in chemical recycling of polyolefin wastes, yielding innovative strategies to tackle issues including high temperatures, large energy consumption, uncontrolled chain scission, and wide distributions with low-value products. However, some recycling strategies remain overoptimistic, for they overlook the practical aspects (e.g., high separation costs and unfavorable application prospects), which are critical for “circular recycling”. This review focuses on the application prospects of chemical recycling routes for polyolefin wastes, with an emphasis on avoiding costly separation while producing products with relatively high market demand and value. We systematically examine recent advances in recycling routes from polyolefin wastes to fuels (e.g., liquid fuels and naphtha), olefins, aromatics, carboxylic acids, and recycled polymers, and evaluate the challenges that face in achieving “upcycling” and “circularity”.