Cure and mechanical properties and abrasive wear behavior of natural rubber, styrene–butadiene rubber and their blends reinforced with silica hybrid fillers

This work investigated the mechanical properties of natural rubber (NR), styrene–butadiene rubber (SBR) and NR/SBR blends filled with silica hybrid filler, and their abrasive wear behavior against different counterface materials. The silica hybrid filler included bagasse ash silica (BASi) and precipitated silica (PSi). The BASi content used was 0, 5, 10 and 15 phr, which was incorporated into rubber compounds filled with 20 phr PSi. The wear behaviors of NR, SBR and their blends were examined using an in-house built abrader in a pin-on-plate (POP) configuration; they were tested against various counterface materials, including steel, concrete, and fabric materials under dry and wet conditions. The results suggested that BASi could be used as co-reinforcing filler with PSi for SBR and NR/SBR compounds, resulting in an improvement in the dispersive and distributive properties of PSi agglomerates in the rubber matrix, as indicated by an increase in tensile strength and elongation at break. However, this was not the case for the NR system. The BASi/rubber composites demonstrated greater abrasive wear resistance against a fabric counterface than against steel and concrete counterfaces, respectively. In the case of a fabric counterface, the addition of BASi tended to greatly increase the specific wear rate of the rubbers due to the detachment of fabric and BASi particles acting as three-body abrasive wear. In addition, all rubber composites abraded against steel, concrete and fabric under wet conditions showed less wear than composites under dry condition, except for SBR rubber composites on a concrete counterface.