Influence of contact pressure and sliding speed on the temperature and coefficient of friction in sliding contact between two PET samples

Original scientific paperThe use of polymeric materials has been growing steadily.A more extensive use of polymers as bearing materials will be made possible by a better knowledge of the properties of particular materials and their compatibility in a particular application.Poly(ethylene terephthalate) (PET) with the addition of Polytetrafluorethylene (PTFE) shows potential for being used as a material for machine parts rotating at lower loads due to its good ratio between manufacturing costs and mechanical properties.The use of PET in a PET/PET combination has been tested in three working points, with a lubricant applied once in each run and with three different values of sliding speed and of load.The change in temperature which occurs in the vicinity of the outlet zone of the contact at the end of the sliding path after 9 hour operation is presented.The applied method and temperature measurement are explained.The distribution of obtained maximum and average temperatures in the load range 9 ÷ 18 MPa and the sliding speed range 0,8 ÷ 2 m/s is shown for single working points.In addition, the effects of lubricant application on the increase in the magnitude of the load carrying capacity and on the decrease in the value of friction coefficient are shown in comparison with the reference values of temperature and friction coefficient in the dry contact operation.