Friction reducing effect of multiply adsorptive organic polymer

The relationships among molecular structures of multiply adsorptive organic polymers, their friction reducing effects and the properties of boundary films formed on surfaces were investigated using polymethacrylates (PMAs) as model additives in order to set guidelines for designing new effective additives for reducing friction. It was found that PMAs can reduce friction by forming adsorbed boundary films that retain structures similar to that of PMA additives on rubbed surfaces. The friction reducing effects of PMAs became larger with increasing molecular weight and increasing adsorptive polar groups. It is speculated that the enhanced friction reducing effects were caused by increasing the coverage of the boundary films formed on the surfaces and by decreasing solid contact between opposing surfaces.