Nano-silica greases based on alkylnaphthalene base oils with various side chain and their rheological behaviors and tribological properties

Nano-silica grease (NSG), an innovative lubricant, is commonly synthesized using base oil thickened with SiO 2 , the choice of appropriate base oil is crucial for obtaining superior performance NSG. Herein, a series of alkylnaphthalene (AN) base oils with different side-chain lengths were synthesized through the alkylation reaction between naphthalene and α-olefin. We first reported the synthesis of NSGs based on the AN base oils, and investigated the influence of the synthetic AN base oils on the rheological behaviors and tribological characteristics of the resulted NSGs. The results indicated that the structural strength of the grease increased as the alkyl chain length rose because it reinforced the contact between the alkylnaphthalene base oil and nano-silica thickener. Meanwhile, tribological tests were conducted to examine the effect of various AN base oils on the lubricating performance of the formed NSGs. The tested results showed that increasing the side chain length of the AN could elevate the friction-reducing and anti-wear properties of the NSG.