Thesis (M.Sc.)--Chulalongkorn University, 1993

Sulfurized palm oil as a lubricant additive was synthesized by sulfurized reaction at temperature 200 oc for 2 hours. The reaction yielded the polysulfide as a product. It was discovered that the sulfurized palm oil which contained 10-15 % by weight of total sulfur had a good physical property especially in load carrying capacity. The factor which affected the efficiency of extreme-pressure property of film on the metal surface were amount of sulfurized palm oil, concentration of sulfurized palm oil and viscosity of base oil. Regarding to the amount and concentration of sulfurized palm oil, the higher the concentration and amount, the higher the load carrying weight, the higher the corrosion took place. In application, the optimum concentration of total sulfur of sulfurized palm oil in base oil was not exceed 0.5 % by weight.