Evaluation of sunflower oil as a multifunctional lubricating oil additive

The function of additives is either to enhance an already-existing property of the base fluid or to add a new property. Viscosity index improvers, antifoaming agents, emulsifiers, demulsifiers, and pour point depressants are examples of different kinds of additives. Most of the present day additives are synthetic acrylate based. But with increasing environmental awareness, the research in the area towards the synthesis of multifunctional biodegradable lubricating oil additive is increasing day by day. Hence, in our present work chemistry of biodegradable multifunctional lubricating oil additive based on vegetable oil (sunflower oil) has been investigated. In the present work solvent-free synthesis of homopolymer of sunflower oil was performed by two different ways; microwave irradiation method and thermal method using benzoyl peroxide as initiator. Characterization of the polymers was done by spectral (NMR, IR), GPC and viscometric analysis and finally performance evaluation was tested by standard ASTM methods. Performance evaluation as pour point depressant, viscosity modifier or viscosity index improver and antiwear in different base oils (BO1, BO2) was carried out by standard ASTM methods. Shear stability and oil thickening property of the polymers have also been investigated and reported here. Thermal stability of the polymers was determined by thermogravimetric analysis. A comparison of their performances has also been reported. The additive prepared by microwave-assisted method showed better viscosity index and pour point values as compared to thermally prepared additive. Thus, polymerized sunflower oil may be used as a potential biodegradable lube oil additive and hence the microwave-assisted protocol may be considered as a cost-effective greener approach for synthesis of lube oil additive.