Tribological properties of polymeric aryl phosphates grafted onto multi-walled carbon nanotubes as high-performances lubricant additive

•Multi walled carbon nanotubes-polymeric aryl phosphates (MWCNT-PAPs) was successfully synthesised.•MWCNT-PAPs showed exceptional stability in PAG base oil.•The tribological behaviour of MWCNT-PAPs was investigated at elevated temperature.

Herein polymeric aryl phosphates (PAPs) were grafted on the surfaces of multi-walled carbon nanotubes (MWCNT) to prepare the nanocomposites of multi-walled carbon nanotubes-polymeric aryl phosphates (MWCNT-PAPs), which is conducive to improve oil dispersibility of MWCNT in the presence of PAPs. The tribological properties of MWCNT-PAPs dispersion in polyalkylene glycol (PAG) base oil were investigated by an oscillating reciprocating tribometer for steel/steel contacts at 150 °C, and the results showed that MWCNT-PAPs could dramatically improve the friction reduction and anti-wear performances of base oil. XPS analysis indicated that a boundary lubrication film was formed on the wear surfaces during friction and wearing process, and the film might contribute to the excellent tribological performances of MWCNT-PAPs in PAG at elevated temperature.