Solving the Dichotomy between Self-Healing and Mechanical Properties in Rubber Composites by Combining Reinforcing and Sustainable Fillers

Abstract

The dichotomy between mechanical performance and repairability is a well-known fact in the self-healing field. One alternative to overcome this trade-off is the inclusion of reinforcing fillers. In this research, hybrid reinforced self-healing styrene-butadiene rubber (SBR) composites are developed by combining mechano-chemically modified ground tire rubber (mGTR) with carbon black (CB). The SBR matrix is systematically analyzed by means of dynamic mechanical analysis and broadband dielectric spectroscopy. The SBR composite reinforced with 20 phr mGTR and 20 phr CB maintains the healing efficiency of the unfilled SBR (80%) and improves its tensile strength by 300%, balancing perfectly well both properties. The healing efficiency is determined at different damage levels. The damage at the microscopic scale is easier to recover and does not depend on the presence of fillers, while the recovery at the macroscopic level clearly relies on the addition of filler, with more demanding healing conditions.