Friction

The ratio of the friction force between two bodies and the normal force pressing those bodies together

Low polyurethane coefficient of friction is desirable for applications that want sliding to occur. Example applications include slide bearings, bushings and wear liners. On the other hand, high polyurethane coefficient of friction is desirable for applications that want minimal slippage between surfaces. An example of this type of application is a drive wheel.

The coefficient of friction between two bodies depends on system variables like the materials of both bodies, their surfaces’ roughness, and the relative velocity between the bodies. For polyurethane, its hardness is also a key factor. In addition to changing hardness, urethane’s coefficient of friction can also be modified by including additives in the formulation.