Any of various thermoplastic polymers that contain urethane. Polyurethanes can vary widely in their flexibility and rigidity ? eraser-soft to bowling-ball-hard. They are typically used in resins, chemical-resistant coatings, elastomers, adhesives, fibers, and foams for padding and insulation. Polyurethanes can be obtained in cast sheets, bars, rods, and tubes, as well as in liquid forms in both water and oil-based formulas.Urethane is a crystalline compound that is used especially as a solvent, and as the basis for polyurethanes. "Urethane" and "polyurethane" are terms that tend to be used interchangeably to refer to the same set of materials.Based on their cost and physical properties ? their load-bearing capacity, as well as weather, abrasion, impact, wear and tear resistance ? polyurethanes have much to recommend them as alternatives to rubber, plastic, wood, metal, and other materials, in applications that have traditionally been filled by such materials, as proven by polyurethane's many uses in industrial situations.