Study On The Synthesis And Properties Of Oil-based Biolubricants For Low Teperature

Natural vegetable oil is able to be used as substrate for producing bio-lubricant and substituting traditional lubricant partly due to its renewability,bio-degradation and favorable property.Natural vegetable oil consists mostly of triglyceride which mainly divided into 16-C fatty acid(Palmitic acid,PA)and 18-C fatty acid(Oleic acid,OA).Modification of natural vegetable oil's chemical structure is essential to the utilization in bio-lubricant production because of its poor property in direct using as lubricant.Various properties such as hydrolytic stability,oxidation stability,low-temperature mobility and viscosity-temperature can be improved by designated chemical modification according to fatty acid types in natural vegetable oil.Glycerol was substituted by trimethylolpropane(TMP)in synthesis of polyester base oil and the oxidation stability of product is better than natural vegetable oil due to absence of ?-H in TMP.With optimized condition of OA:TMP of 3.6:1 and catalyst loading of 2.0%at 140? for 3 h,trimethylolpropane easter's yield was 92.43%and pour point,viscosity and pyrolysis point reached-27?,156 and 335?,respectively.Epoxidation and ring-opening reaction was conducted by using saturated fatty acid as nucleophile for isomerization of unsaturated fatty acid and hence generated branched structures were able to enhance the oxidation stability and performance at low temperature.The epoxidation and ring-opening reaction condition was optimized as acid:alcohol of 2:1 with catalyst loading of 2.0%at 100? for 25 h.In addition,properties of three types of branched fatty acid ester lubricant were analyzed in accordance with modification of dissociative hydroxyls with three branched fatty acid.It revealed that 16-C fatty acid modified branched esters performed the best with viscosity,flash point and pour point of 168,283? and-39? and minimum friction factor and wear scar diameter of 0.12 and 0.25 mm,respectively.Based on the epoxidation and ring-opening reaction,branched alcohols served as nucleophile introducing ether bonds into product and reducing pour point and enhancing hydrolytic stability.Isomerization of epoxy groups with isopropanol was conducted in this work and obtained esters were characterized with pour point,flash point and viscosity of-31?,254? and 137,respectively.Finally,these obtained esters were added into mineral based lubricant for high frequency reciprocating friction test and results indicated that these added synthesized esters were able to improve lubricant's anti-friction property and reduce its wear scar diameter and friction factors.