Enhancing fatigue properties of styrene butadiene rubber composites by improving interface adhesion between coated aramid fibers and matrix

Abstract

This paper details a new method for characterizing the interfacial bonding performance of short-fiber reinforced rubber composites and its correlation with fatigue properties. Meanwhile, the experimental study of interfacial damage during the fatigue process is presented. Aramid fiber (AF) was modified with an aqueous solution of lithium chloride and then coated with butadiene styrene vinyl-pyridine rubber latex (VPL) or maleated polybutadiene liquid rubber (MLPB). Subsequently, the coated AF was introduced into a butadiene styrene rubber (SBR) matrix to fabricate reinforced butadiene styrene rubber/carbon black/aramid fiber (SBR/CB/AF) composites. Atomic force microscopy (AFM) was employed to identify the flexible interface layer of the SBR composites. After 30,000 fatigue cycles, the modulus of the interface layer was obviously reduced to below that of the SBR matrix, which produced hysteresis of the reinforcing effect of AF due to concentrated damage in the interface layer. The relative debonding energy (RDE) is innovatively introduced to characterize the interfacial adhesion performance. A higher RDE value can lead to the interface layer absorbing more deformation work and a longer fatigue life of the composite. SBR reinforced by T-AF/MLPB, with its high modulus interface, has the longest fatigue life, corresponding to the highest RDE value.