Well Dispersive TiO2 Nanoparticles as Additives for Improving the Tribological Performance of Polyalphaolefin Gel Lubricant

The dispersibility of TiO2 nanoparticles in polyalphaolefin (PAO) are improved by the interaction between the chemically modified TiO2 (denoted as TTO) and 1-methyl-2,4-bis (N-octadecylurea) benzene (MOB) gelator. Tribological tests show the outstanding friction-reducing and antiwear performances of PAO10–MOB–TTO under the common friction condition and higher temperature friction condition, respectively. The lubricating property of PAO10–1% MOB–0.5% TTO is further enhanced after UV irradiation for 40 min, which might be attributed to the photocatalytic effect of TTO under UV. The physical adsorption film is enhanced by the immobilization function of MOB. The chemical reaction film including various organic oxides and nitrides are produced for the active element in TTO and MOB. The antiwear performance is further improved by the “mending effect” of TTO with the good dispersibility. The combined effects of various factors promote the excellent lubricating performances of PAO10–1% MOB–0.5% TTO.