Frictional behavior of polymers: the transition from static to kinetic conditions

Abstract

It is believed that the noise produced in squeaking dashboards is caused by the drop in friction force during the transition from static to kinetic conditions between the mating plastic components of the dashboard. The frictional behavior of a polymer determines whether there is a drop in friction force during this transition. This study investigates the frictional behavior of polymers under dry sliding conditions. Various compositions of ABS plastic along with Polypropylene were tested in a flat-on-flat configuration. There appears to be no consistent evidence of surface roughness effects on the magnitude of the drop in friction force. The surface roughness did have an effect on the frictional behavior of the polymers as did the material composition. A new test apparatus was designed to study the transition from static to kinetic conditions more closely. A computer model was developed to simulate this transition. The computer model was used to illustrate the effect of the friction-velocity curve on the frictional behavior of a surface interaction. A few conclusions are made about which friction mechanisms are in control of the polymer-on-polymer tribological system.