Polyurethane chemistry is complex, but the basics are relatively easy to understand. Polyurethanes are formed by reacting a polyol (an alcohol with more than two reactive hydroxyl groups per molecule) with a
diisocyanate or a polymeric isocyanate in the presence of suitable catalysts and additives. Because a variety of diisocyanates and a wide range of polyols can be used to produce polyurethane, a broad spectrum of materials can be produced to meet the needs for specific applications.
Polyurethanes exist in a variety of forms, including flexible foams, rigid foams, chemical-resistant coatings, specialty adhesives and sealants, and elastomers.