Abstract: To synthesize two Boron and Nitrogen-containing soybean oil additive (abbreviated as BNS-1 and BNS-2), boron and nitrogen were introduced into the soybean oil molecules through chemical modification. The influence of BNS-1 and BNS-2 on biodegradability and lubricity of rapeseed oils were studied. The morphologies and chemical species of the worn surfaces were investigated by scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The results showed that BNS-1 and BNS-2 had little influence on the biodegradability of rapeseed oil. They possessed good anti-wear and friction-reducing properties, as well as extreme pressure properties. The friction-reducing properties of BNS-2 were better than those of BNS-1, however, its anti-wear properties were worse than BNS-1. The mechanism is that the electron-deficiency boron reacts with high reaction active nitrogen element at high temperature from friction, forming tribo chemical films, resulting in improved tribological properties.

Key words: soybean oil, boron and nitrogen, biodegradation, friction and wear