Tribological Investigation of Self-Healing Composites Containing Metal/Polymer Microcapsules

The tribological properties of epoxy composites containing metal microcapsules and polymer microcapsules were investigated systematically. Both metal microcapsules and polymer microcapsules showed obvious core shell structures. The diameter of metal microcapsules and polymer microcapsules was 200.7±44.5 μm and 185.2±44.2 μm with a corresponding core fraction of 23.5±1.3 wt% and 75.0±2.1 wt%, respectively. The epoxy composites containing metal microcapsules possessed higher compressive strength than that containing polymer microcapsules, but its compressive modulus remained stable relatively with microcapsule concentrations, comparing with the gradual decrease of compressive modulus of composites containing polymer microcapsules. Besides, the friction coefficient of epoxy composites containing polymer microcapsules (less than 0.1) was several times lower than that of epoxy composites containing metal microcapsules (around 0.55). The friction coefficients of epoxy composites containing polymer microcapsules were decreased under higher microcapsules concentrations, but that of epoxy composites containing metal microcapsules was increased with microcapsules concentrations. Although composites containing metal microcapsules had higher strength and modulus than that containing polymer microcapsules, its wear loss including wear depth and wear width was far more than the composites containing polymer microcapsules under different normal loads and velocities.