Isopropyl-branched lard and its potential application as a bio-based lubricant

Regular lard (RL) was chemically modified into isopropyl-branched lard (BL). The isopropyl group was introduced into the triglyceride structure via a reaction of carbon-carbon double with isopropyl bromide in presence of ethylaluminum sesquichloride. The reaction was confirmed with gas chromatography-mass spectroscopy, nuclear magnetic resonance, infrared spectroscopy. The physical, tribological and chemical properties of the RL, BL and their blendings in polyalphaolefin (PAO) and high-oleic sunflower oil (HOSuO) were investigated. The BL exhibited better solubility both in HOSuO and PAO than RL. Compared to RL, BL exhibited higher density, viscosity, improved oxidative stability and cold flow properties both as a neat material and blendings in HOSuO or PAO. However, BL displayed lower viscosity index (197 vs. 162) compared to RL. Both RL and BL displayed similar lubricity as HOSuO and showed potential such as a good lubricity additive in PAO even in small amounts (similar to 10 wt%). This study reveals introducing alkyl branching into lard can lead to improved physico-chemical properties and lubrication performance.