Friction and Deformation of Polymers

Abstract

The deformation caused to the surface of polymers by hard hemispheres of different radii was observed and the friction between the hemisphere and the plate was measured. The deformation produced was deduced from Newton’s rings and grooved track. Hertz’s equation was found to give the size of the contact circle. Wave-like deformation was observed near the contact region. When a tangential force is applied, the deformation increased on one side of the contact region and decreased on the other side. Two types of sliding contact were observed. One was attributed to the retarded elasticity and the other to the frictional heating. From the former, the retardation time was obtained. The production of grooved tracks was attributed to the non-recoverable deformation. The deformation was discussed in connection with the friction and the wave-like deformation of polymer surface was suggested as the source of frictional resistance.