Polystyrene Nanospheres Modified with a Hydrophilic Polymer Brush through Subsurface‐Initiated Atom Transfer Radical Polymerization as Biolubricating Additive

Hydration lubrication plays an important role including the cartilage of an organism. Here, polystyrene nanospheres modified with a hydrophilic polymer through subsurface‐initiated grafting as a biolubricating additive is proposed. The material provides good tribological performance when subjected to high load. Compared with surfaced‐initiated grafting polymer brushes, subsurface initiation can form much thicker hydration layers to obtain a lower friction coefficient and better mechanical properties for withstanding prolonged shearing forces with less measurable damage. The polymer brushes penetrate through the covalent network of the polystyrene nanospheres providing a match in mechanical properties between them, so that the additives obtain more excellent lubricity in an aqueous environment under shear pressure, which is expected to become a promising artificial joint biolubricating additive.     

Enhancement of biodegradability of lubricants by biodegradation accelerants

The influence of a phosphor–nitrogen modified fatty acid, an amide fatty acid and tributyl phosphate, on biodegradation of a mineral oil and a high‐viscosity polyalphaolefin (PAO‐10) was studied. The results indicate that the phosphorous and nitrogenous compounds as biodegradation accelerants greatly promote biodegradation of unreadily biodegradable mineral oil and PAO‐10, due to the activation of enzymes in the body of microbes and the microbial growth of specific microbes. Copyright © 2008 John Wiley & Sons, Ltd.