One of the many reasons polyurethanes are used is their excellent wear resistance, outperforming steel at times as high as 8 to 1. For this reason they have been used in the mining industry, the transportation industry, in processing equipment as well as in many other industries.
About polyurethane, I can say the high abrasion property is due the combination of two polymer chains in its structure: rigid and flexible chains. These chains agroup in domains. Rigid chains are responsable to mechanical resistance and flexible is responsable to other properties, as abrasion resistance. It's because the recovery ability of this flexible chain.