A thermotropic liquid crystal, 4,4＇-dibutylazobenzene, added in a 1% weight proportion to thermoplastic materials, polystyrene (PS) and styrene acrylonitrile (SAN), gives, after molding the mixture at 150 degrees C and 22 MPa, a new family of polymers with an improved resistance to sliding dry wear against steel as tested in a pin-on-disc tribometer. Variable load, sliding speed, and distance tests were performed to establish the range of conditions under which the wear-resistance improvement is maximum.