Polyurethane

Polyurethane is a polymer. Its name is often shortened to "PU" or "PUR". Polyurethane is made of organic units, which are joined by urethane. Polyurethane polymers are formed through step-growth polymerization. In this process, a monomer containing at least two isocyanate functional groups reacts with another monomer containing at least two hydroxyl (alcohol) groups in the presence of a catalyst.
Polyurethane is available with different levels of stiffness, hardness or densities. Examples for such materials are:
Polyurethanes are widely used in high resiliency flexible foam seating, rigid foam insulation panels, microcellular foam seals and gaskets, durable elastomeric wheels and tires, automotive suspension bushings, electrical potting compounds, high performance adhesives and sealants, Spandex fibers, seals, gaskets, carpet underlay, and hard plastic parts.
Polyurethane products are often called "urethanes". They should not be confused with the specific substance urethane, also known as ethyl carbamate. Polyurethanes are neither produced from ethyl carbamate, nor do they contain it.