The Wear of Polymers by Transfer to Hard, Rough Surfaces

摘要

A surface topography characterization system consisting of a talysurf 4 profilometer, Zonic analog-to-digital converter and Fast Fourier Transform (FFT), and a Tetronix 4051 minicomputer was interfaced to an IBM 370 digital computer. Software for the computation of several surface parameters and for wear models have been written. Single traversal wear experiments were performed on a pin-on-disk machine at sliding velocities less than 1 cm/s. Experiments run at a constant bearing area ratio showed no difference in the wear rates of PVC and PCTFE while the wear rates of LDPE were less than both on ground surfaces. The presence of a vapor deposited film of poly (chloro-p-xylylene) did not affect the wear of PVC and PCTFE but reduced the wear of LDPE. A wear model was developed which correctly predicted the decrease in wear rate which occurs as the surface voids fill up with polymer debris, and the maximum wear which occurs as the bearing area ratio is increased. Multiple traversal wear experiments were run at sliding velocities up to 1.4 m/s using LDPE and PVC pins on steel disks. PVC with a molecular weight of 40000 had higher wear rates than 70000 MW PVC except when calculated temperatures exceeded the glass transition temperature. A pin-on-disk wear machine was fabricated with a speed range from 3 to 4400 rpm, a test chamber with temperature controlled up to 300 C, an a low inertia pneumatic loading piston. (Author)