Effect of chemical structure on the wear behaviour of polyurethane-urea elastomers

摘要

The wear behaviour of a series of polyurethane-urea elastomers of two hardness levels, 83/90 ShoreA, made with two different curatives and a range of stoichiometries was studied using two differentmethods. In a high-speed slurry erosion test, wear was higher in the harder polymers but in a DrySand Rubber Wheel test, the softer polymers underwent greater wear. This change in rankings of thepolymers was associated with a change in the wear mechanism from cutting and gouging in the slurrytest to a fatigue mechanism in the Dry Sand Rubber Wheel test. In both wear tests and for the twolevels of hardness tested, polymers cured with MBOCA were more wear-resistant than those curedwith ETHACURE which was linked to a higher level of crosslinking in the MBOCA polymers.Decreasing the stoichiometry of the softer 83 Shore A ETHACURE polymers introduced crosslinksinto these polymers and there was a corresponding increase in the wear resistance. High surfacetemperatures occurred in the high speed slurry tests, and these probably resulted from hysteresis inthe polymers. Softening of the polymers may also have contributed to the variation in performance ofthe different polymers.