Study of graphene nanolubricant using thermogravimetric analysis

Thermal degradation of graphene based mineral oil lubricants was studied using thermogravimetric analysis (TGA). As-synthesized graphene sheets of 8, 12, 60 nm thick, engine-oil formulation of API standard 20W50 SN/CF, SJ/CF and base mineral oils 150, 500, 2100 SUS were used for synthesizing various test samples. FTIR, XRD, FESEM, EDX, zeta potential and UV-vis spectrophotometry was used to characterize graphene and nanolubricants. Thermal gravimetric analysis (TGA) revealed that the weight loss in the presence of graphene could be delayed by more than 20 degrees C. Resistance to oil degradation depends strongly on graphene nanoparticle size, concentration and heating rates. Moreover, with the addition of graphene, SN/CF oil formulation shows better enhancement than SJ/CF under most parameters. The reasons for this phenomenon could be attributed to graphene's large surface area, stable dispersion and Brownian motion of graphene flakes.