Influence of crosslinking density on the tribological behavior of norbornene-based polymeric materials

Abstract

► The tribological properties of ring opening metathesis polymerization (ROMP) thermosetting polymers have been evaluated as a function of crosslinking density. ► Both the friction and wear against a spherical Si 3 N 4 and a conical diamond probe were affected by crosslinking. ► The material without the crosslinker (CL-0) showed the highest friction coefficient against Si 3 N 4 . ► Reciprocating wear tests have confirmed that all materials, except CL-0, show resistance to wear against Si 3 N 4 under the given loading conditions. ► All samples exhibited abrasive wear by the sharp diamond probe. ► The abrasive wear depth was observed to decrease with increasing crosslinking density. In this study, the friction and the wear behavior of norbornene-based polymers prepared by ring-opening metathesis polymerization (ROMP) reaction are evaluated as a function of the crosslinking density. Tribological measurements were performed using a ball-on-flat reciprocating microtribometer. Friction and wear experiments under dry sliding were evaluated using a 1.2 mm radius Si 3 N 4 spherical probe as well as a 100 μm radius conical diamond probe with a 90° cone angle. Wear experiments were conducted at constant normal loads for 100–500 reciprocating cycles. Wear depths were estimated from wear grooves using a contact profilometer, and scanning electron microscopy was used to elucidate deformation mechanisms in the various samples. Correlation between the crosslinking density and the wear behavior were observed.