Friction and wear behavior of PTFE coatings modified with poly (methyl methacrylate)

To achieve self-lubricating coating of polymer-based composite coatings with low coefficient of friction (COF) and high wear resistance, the core-shell structure was introduced via a seeded emulsion polymerization to improve wear resistance and self-lubricating properties of the coating. The effect of polytetrafluoroethylene (PTFE) encapsulated by polymethylmethacrylate (PMMA) shell on its wear resistance and lubricating properties under reciprocating dry friction was investigated. The experimental results revealed interesting examples of: the wear rate of PTFE coating was decreased from 232 x 10(-6) mm(3)/Nm to 1.04 x 10(-6) mm(3)/Nm and the COF decreased from 0.081 to 0.069. During reciprocating sliding tests, the results show that a continuous, uniform and thin PTFE/PMMA composite film is transferred to the GCr15 steel ball surface. It was demonstrated that the improved lubricating performance was associated with the dispersion effect from core-shell structure, which has a characteristic size in the nanometer range, and composite thus possess a much higher uniformity and higher dispersivity of reinforcement phase than do composite obtained by the conventional filling method.