Abrasion

The ability to withstand wear typically cased by mechanical action

Polyurethane’s abrasion resistance is a key performance advantage of polyurethane. It’s why you find polyurethane used in so many applications that experience high wear. Examples include bushings, bearings, wheels, sprockets, and wear liners.

Abrasion occurs when one surface slides over another – also called two-body abrasion. Or sliding abrasion occurs between two surfaces separated by dry particles or slurry – also called three-body abrasion. In both, localized areas of high strain occur at the interface and create minute tears in the surface. Polyurethane with a low coefficient of friction and a high tear strength resists sliding abrasion.

Polyurethane’s abrasion resistance is typically measured in units of mass or volume loss, or as a percentage thereof. A correlation between test results and service performance is often quite difficult to establish. Tests generally accelerate wear rates to make testing durations more practical. But in the field, the same components would be gradually worn over a long period of time. The accelerated wear rates of tests generate extra heat that is not representative of the operation. Heat build-up within polyurethane reduces its performance. Therefore, abrasion tests are more useful for comparing materials than for predicting polyurethane’s in-service performance.