Friction and wear studies of bulk polyetherimide

Polyetherimide, ULTEM 1000, was studied as a neat resin to investigate its friction and wear behaviour while sliding against mild steel, under unlubricated conditions on a pin on disc machine. Experimental parameters selected were different loads, sliding distances and counterface roughness. It was observed that, unlike other semicrystalline highly linear thermoplastics and some thermoplastic thermosetting polyimides, this polyimide does not transfer a film on the counterface under the conditions of the study. It seems that it wears mainly by a fatigue mechanism although crack propagation could not be observed in SEM micrographs of pin surfaces. The frictional coefficient was low as compared with other polyimides and varied with contact pressure from 0.4-0.22, although the initial value was high. The cycles required to initiate wear particles were approx 90 kcycles at 13 N cm exp --2 contact pressure. Once the wear started, the specific wear rate was high (K sub 0 = 10 exp --13 m exp 3 N exp --1 m exp --1 ). , , . 20 ref.--AA