Effect of graphene oxide and ionic liquid on the sliding wear and abrasion resistance of injection molded PMMA nanocomposites

Abstract

New polymethylmethacrylate (PMMA) nanocomposites containing 0.5 wt% graphene oxide (GO), or 1.5 wt% graphene oxide modified with the ionic liquid (IL) 1-octyl-3-methylimidazolium tetrafluoroborate (GOIL) have been processed by extrusion and injection molding to obtain PMMA+GO and PMMA+GOIL, respectively. Raman microscopy and mapping show that the additives align parallel to the flow close to the exterior surfaces, with an almost perpendicular orientation in the central core region. Reciprocating sliding tests have been carried out on the exterior surfaces and also on the surface of core sections of the injected parts. GO prevents surface damage, showing negligible wear on both section surfaces under sliding parallel and perpendicular to the injection flow. In contrast, the performance of PMMA+GOIL depends on the sliding direction. Under multiple scratching, both GO and GOIL reduced residual depth values and increased the viscoelastic recovery of PMMA, thus reducing permanent surface damage. PMMA+GOIL shows the highest viscoelastic recovery and the lowest complex viscosity values. Wear mechanisms are discussed as a function of materials properties, nanofiller type, and orientation and sliding direction.

Keywords

• nanocomposites
• nanomaterials
• material testing
• graphene oxide
• ionic liquid