Petroleum-base-lube oils are non-biodegradable and their continuous use results in environmental pollution. Comparatively, vegetable oils are biodegradable, less toxic and renewable hence, their use as base stock for lubricant production will not only serve as viable alternatives but also help in avoiding environmental deterioration. This paper compares the properties of soybean and castor oils as potential sources for synthesizing bio-lubes when mixed separately with styrene as additive. Styrene was used because of its advantageous polymeric behavior. Samples of soybean and castor oils were mixed with different volumes of the additive at 50oC. Fluid properties were determined with emphasis on viscosities of the oils. For the castor oil samples, their viscosities compare with those of standard oils at 40 oC and at 100 oC. These values show that soybean samples can replace base oils used in SAE15W - SAE20 monograde lubricant while castor oil samples can replace the SAE50 - SAE60 lubricants.
Keywords: Additive; Biodegradability; Comparative analysis; Vegetable oils; lube oil