Every year, millions of tires end up in landfills, creating an environmental crisis with far-reaching consequences.
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 a fifth of them being discarded into 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 U.S. Department of Energy-funded study, “Deconstruction of Rubber via C–H Amination and Aza-Cope Rearrangement,” recently published in Nature and led by Dr. Aleksandr Zhukhovitskiy, William R. Kenan, Jr. Fellow and assistant professor in the Department of Chemistry at UNC-Chapel Hill, introduces a novel chemical method for breaking down rubber waste. This pioneering 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.
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: de-vulcanization, which breaks sulfur cross-links but weakens the polymer’s mechanical properties, and cleavage of the polymer backbones using oxidative or catalytic methods, which often result in complex, low-value byproducts. Neither approach provides an efficient, scalable solution for repurposing rubber waste.
Read more at University of North Carolina at Chapel Hill
Photo Credit: Berger-Team via Pixabay
