Polyurethane

Polymer composed of a chain of organic units joined by carbamate (urethane) links

Polyurethane (often abbreviated as PUR and PU) is a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane refers to a group of polymers. Unlike polyethylene and polystyrene, polyurethanes can be produced from a wide range of starting materials, resulting in various polymers within the same group.

From Wikipedia, under CC BY-SA. More on occurri.