Selective devulcanization of ground tire rubber by choline-based deep eutectic solvents for high-performance recycled materials

Waste tire rubber poses significant environmental challenges due to its non-biodegradability and complex crosslinked structure.In this sense, this study aims to examine the utilization of deep eutectic solvents (DESs) in the desulfurization process of ground tire rubber (GTR).A range of hydrogen bond donors (HBDs), including ethylene glycol, malonic acid, imidazole, toluene sulfonic acid, and urea, were combined with choline chloride, which serves as a hydrogen bond acceptor (HBA), to synthesize deep eutectic solvents.Subsequently, these DESs are used in the modification of rubber devulcanization processes.Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Horikx analysis were used to confirm the occurrence of devulcanization.The studies confirmed that the devulcanization process was selective in nature, effectively reducing random chain scission while maintaining the integrity of the polymer.Furthermore, the vulcanizates obtained post-treatment demonstrated enhanced properties, including increased tensile strength, modulus, tear strength, hardness, and durability, with ethylene glycol-based DES (DES-E) exhibiting the most pronounced enhancements.