Dynamic Imine Bonds in Tire Tread Compounds: A Pathway to a Circular Economy and Reduced Waste

The tire industry is in constant transformation toward the development of more sustainable products while maintaining high performance. Nowadays, one of the most used strategies is the implementation of the circular economy (CE) model, based on the reuse of products, recycling, and conservation of natural resources. One of the main goals of introducing the CE model is to reduce the amount of end of life tires (ELTs) that accumulate every year. For this, improvement in the recycling process of these products is of great importance. To face this challenge, this research aims to improve the recyclability of rubber by a novel approach to apply dynamic imine bonds for the silica–rubber coupling in tire tread compounds as an alternative to the state-of-the-art silica/silane covalent coupling. The formation of this new coupling using an imine bond was achieved by the reaction of an amine and different aromatic aldehydes. Rubber compounds with this new coupling system show a decrease in the wet grip indicator but improved mechanical performance, rolling resistance, superior fatigue behavior, and a high potential for recycling compared with the state-of-the-art compounds.