A team of researchers from the University of Huelva has developed an environmentally-friendly
lubricating grease based on ricin oil and cellulose derivatives, according to
the journal Green Chemistry. The new formula does not include any of the
contaminating components used to manufacture traditional industrial lubricants.
"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% biodegradable", José María Franco, a chemical engineer at the
University of Huelva and co-author of the study published recently in Green
Chemistry, tells SINC.
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 says 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 imply more problems from an
environmental perspective.
Millions of tonnes of hydraulic and industrial oils, and others from
machinery, are discharged each year into rivers, the sea and fields.
Mineral-based oils can contaminate groundwater for more than 100 years, and can
prevent the growth of trees and prove toxic to aquatic life.
Only partial solutions have been found to date for this problem, such as
substituting mineral oil for vegetable ones, but no alternatives had been found
to the metallic thickeners, which are also highly polluting. The new green
grease provides an answer, although the scientists admit that "more research is
needed" in order to perfect its lubricating and anti-wear performance.
Franco tells SINC that the new material "has a similar level of mechanical
stability to that of traditional greases, and it is highly temperature
resistant, with rheological properties (viscosity) that do not change greatly,
although we have observed that the material is expelled in large quantities when
subjected to large inertial forces at high temperatures". When this substance is
used in bearings, it is important that it is not easily shed. This will reduce
the lubrication frequency, thus maintaining the ideal functioning conditions for
machinery for a longer time.
The researchers will continue to investigate this aspect in order to find a
way of balancing the use of biodegradable ingredients to manufacture the grease
while also optimising its lubricating capacity.
In any case, the scientists have proved that "oleogels" based on cellulose
derivatives are not only environmentally friendly, but are also advantageous in
that they are easier to process, and that manufacturing them requires simpler
technology than that used to make conventional greases.
