Greener grease

A team of researchers from the University of Huelva in Spain has developed environmentally-friendly lubricating grease based on ricin oil and cellulose derivatives.

’The objective of this research was to develop a product that could be used as a lubricating grease but that was made only from natural materials and was therefore 100 per cent biodegradable,’ said José María Franco, a chemical engineer at the University of Huelva.

Environmentally-friendly greases are ’oleogels’ that use cellulose derivatives from plants and ricin oil (from a bush in the Euphorbiaceae family) as a lubricant base. Franco said these new formulations are an alternative to traditional lubricating greases, which create pollution that is difficult to combat once discharged into the environment.

Lubricants used in industry are made from non-biodegradable components, such as synthetic oils or petroleum derivatives, and thickeners made with metallic soaps or polyurea derivatives (a family of synthetic polymers). These are currently the best performers, but they also present environmental problems.

Only partial solutions have been found to date for this problem, such as substituting mineral oil for vegetable oil, but no alternatives had been found to the metallic thickeners, which are also highly polluting. The new green grease provides one answer, although the scientists admit that more research is needed to perfect its lubricating and anti-wear performance.

The new material has a similar level of mechanical stability to that of traditional greases, and it is highly temperature resistant, with rheological properties such as viscosity that do not change greatly. Although the researchers have observed that the material is expelled in large quantities when subjected to large inertial forces at high temperatures.

The researchers plan to continue to investigate this aspect of the material to find a way to optimise its lubricating capabilities.

Their research was recently published in the journal Green Chemistry.