Degradation of Postconsumer Thermoset Rubbers via Photo-Oxidation

Despite advancements in blending systems and processing technologies that enhance the durability of commodity rubbers, the recycling of postconsumer vulcanized rubbers remains a significant challenge due to the insolubility of cross-linked networks and catalyst poisoning caused by various additives. In this study, we present a highly reactive and broadly compatible degradation strategy based on photoinduced oxidative cleavage of C═C bonds using substoichiometric amounts of nitroarenes. This method minimizes interference from additives and accommodates a wide range of rubber compositions, enabling efficient degradation of both synthetic and natural rubbers. The degradation yields aldehyde-terminated oligomers, which can be further converted to value-added hydroxy-terminated polymers. The system exhibits excellent efficiency in degrading postconsumer thermoset rubber products, including tires, gloves, and stoppers, demonstrating strong practical applicability. Furthermore, the method was successfully extended to certain plastics, further broadening its potential for polymer recycling.