ReaxFF simulations reveal how ZnO affects carbon black production from waste tires

Converting waste tires into valuable carbon materials offers a promising route for recycling rubber waste. However, additives originally incorporated into tires can influence the pyrolysis chemistry and affect the yield and quality of the recovered carbon black. Understanding these effects at the molecular level is important for optimizing the recycling process.

In a recent Fuel study, researchers combined pyrolysis experiments with reactive molecular dynamics simulations using ReaxFF to investigate the influence of zinc oxide (ZnO), a common additive in tire rubber. The simulations tracked chemical bond breaking and formation during thermal decomposition, providing insight into how ZnO changes the reaction pathways leading to carbonaceous products.

The results indicate that ZnO-associated oxygen promotes bond cleavage and the opening of aromatic rings, disrupting the formation of stable carbon structures. These molecular-level observations help explain the experimentally observed reduction in carbon black yield and structural order in the presence of ZnO.

By connecting reactive molecular dynamics with experimental pyrolysis results, the study demonstrates how ReaxFF can reveal the chemical mechanisms behind material formation and support the optimization of waste-to-value recycling processes.