Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Fabrication and tribological assessment of epoxy nanocomposites reinforced with Gr, GO, and rGO. Combined mechanical mixing and ultrasonication ensure dispersion, followed by Raman/FTIR characterization and pin-on-disk wear testing, highlighting the role of transfer layer formation in tribological performance.

ABSTRACT
This study investigated the tribological properties of epoxy nanocomposites reinforced with graphene (Gr), graphene oxide (GO), and reduced graphene oxide (rGO) at concentrations of 0.15 and 0.6 wt%. Comprehensive structural characterization was performed using SEM, EDX, XRD, FTIR, and Raman spectroscopy to evaluate nanoparticle morphology, chemical composition, and crystal structure. Pin-on-disk wear tests assessed friction coefficient and weight loss under controlled conditions. SEM analysis revealed planar layered structures in Gr, while GO and rGO exhibited wrinkled morphologies due to oxygenated functional groups. EDX confirmed pure carbon composition (100%) in Gr, with oxygen content of 44.82 wt% in GO and 34.62 wt% in rGO. XRD analysis demonstrated interlayer distances of 0.34 nm, 0.78 nm, and 0.61 nm for Gr, GO, and rGO, respectively. FTIR and Raman spectroscopy confirmed stronger matrix interactions in GO due to functional groups, while Gr maintained superior structural order. Tribological testing revealed that Gr at 0.6 wt% exhibited optimal performance with 41.67% reduction in friction coefficient and 77.78% decrease in weight loss compared to neat epoxy. This superior performance is attributed to the well-ordered sp2 layered structure and inherent lubricating properties of graphene. GO performed weakest, while rGO demonstrated intermediate behavior. These findings provide insights for designing epoxy nanocomposites with enhanced tribological properties for industrial applications.