Rolling Friction of Polymeric Materials. II. Thermoplastics

Abstract

The results of rolling friction studies of several thermoplastics provide additional evidence for the correlation of such friction with dynamic mechanical losses in polymeric materials. Among the polymers discussed are polymethyl methacrylate, polytetrafluoroethylene, polyethylene, nylon, polyvinyl chloride, polyvinyl acetate, and polystyrene. The effects of spin and other deviations from pure rolling are demonstrated for polymethyl methacrylate, polytetrafluoroethylene, and nylon by varing the experimental parameters. In essentially pure rolling, the dependence of friction on temperature illustrates the importance of the extent of crystallinity in polytetrafluoroethylene, the amount of branching in polyethylene, and the concentration of plasticizer in polyvinyl chloride. In the latter effect, it is found that the temperature at which the rolling friction goes through a maximum varies linearly with plasticizer content.