An organic-inorganic composite was prepared by mixing silica emulsion with urethane acrylate anionomer (UAA) emulsion. The silica emulsion was prepared by sol-gel process, and stabilized by a steric stabilizer, polyvinyl pyrrolidone. UAA/silica composite film was made by an ultraviolet curing method. The mechanical and rheological properties of the UAA/silica composite were greatly improved. This composite also showed thermal stability during increase of temperature. Surface hardness was improved with increasing silica content up to proper amount of silica. However, in abrasive test, because UAA/silica composite film has a more abrasive contact area than UAA film, the former was abraded much more than the latter. In comparison to UAA film, the UAA/silica composite showed much smoother abrasive surface and less roughness. (C) 2000 John Wiley & Sons, Inc.