Scientists pioneer chemical process to repurpose rubber waste

Summary

Overview of the strategy for rubber deconstruction. a, Proposed route for achieving deconstruction of vulcanized polybutadiene. R is either H, ammonium or hydrated form of aldehyde. b, Mechanism of 2-aza-Cope rearrangement/deconstruction of aminated model polymer. Credit: Nature (2025). DOI: 10.1038/s41586-025-08716-6 Every year, millions of tires end up in landfills, creating an environmental crisis with far-reaching consequences. In the United States alone, over 274 million tires were scrapped in 2021, with nearly 20% of them being discarded in landfills. The accumulation of these waste materials presents not only a space issue but also introduces environmental hazards, such as chemical leaching and spontaneous combustion. While pyrolysis—a process that chemically recycles rubber through high-temperature decomposition—is widely used, it generates harmful byproducts like benzene and dioxins, posing health and environmental risks. A study titled "Deconstruction of Rubber via C–H Amination and Aza-Cope Rearrangement," published in Nature, introduces a novel chemical method for breaking down rubber waste. This technique utilizes C–H amination and a polymer rearrangement strategy to transform discarded rubber into valuable precursors for epoxy resins, offering an innovative and sustainable alternative to traditional recycling methods. The research was led by Dr. Aleksandr Zhukhovitskiy, William R. Kenan, Jr. Fellow and Assistant Professor in the Department of Chemistry at UNC-Chapel Hill. Rubber, including the synthetic kind used in tires, is composed of polymers cross-linked together into a three-dimensional network that behaves as a tough, flexible material. Recycling these materials is difficult due to the extensive cross-linking within the polymer structure, which gives rubber its durability but also makes it resistant to degradation. Traditional methods for breaking down rubber focus on two main approaches: devulcanization, which breaks sulfur cross-links but weak...