The frictional properties of rigid and plasticized PVC have been measured as a function of temperature, speed of test, applied load, and plasticizer content. It was found that the data could be correlated by the simple equationF=F*[1−exp(−kf)], whereFis the frictional force,F* is a limiting frictional force dependent upon temperature and composition, andfis the applied normal force. The constantsF* andkcould be correlated with the tensile strength and the bulk modulus, respectively. A mechanism of polymer frictional behavior is proposed.