Estudio de la microestructura del caucho de neumático como herramienta para diseñar elastómeros autorreparables

Abstract

In this work, the potential of rubber from end-of-life tires (ELT) and in powder form as an effective reinforcement for self-healing styrene-butadiene rubber (SBR) compounds has been studied. For this purpose, the evolution of the microstructure of tire rubber with the grinding and devulcanization was studied in order to relate the microstructure to the mechanical and healing properties of self-healing SBR composites. Tire rubber particles with different microstructures obtained by different grinding technologies (cryogenic and water jet) and through devulcanization (thermo-mechanical) were taking into consideration. The results showed: (a) the importance of grinding technology on the microstructure of ground tire rubber (GTR) and; (b) the influence of GTR microstructure and devulcanized product (dGTR) characteristics on the mechanical performance and healing ability of SBR composites. It was concluded that the higher the specific surface area and the higher the percentage of free polymer chains, as a result of devulcanization, the better the mechanical performance and the higher the healing ability. This strategy allowed obtaining an overall repair efficiency > 80%, in terms of global mechanical recovery (tensile strength and elongation at break), when adding 30 phr of dGTR. These results open a new opportunity for ELT rubber in a technical and novel application, as a reinforcement of self-healing rubbers to achieve a balance between mechanical and healing properties