class=skin-invert-image|thumb|right|Polyurethane synthesis: the urethane groups −NH−(C=O)−O− link the molecular units, resulting in a polymer consisting of an alternating chain of two monomers. thumb|A kitchen sponge made of polyurethane foam
class=skin-invert-image|thumb|right|Polyurethane synthesis: the urethane groups −NH−(C=O)−O− link the molecular units, resulting in a polymer consisting of an alternating chain of two monomers. thumb|A kitchen sponge made of polyurethane foam
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. This chemical variety produces polyurethanes with different chemical structures leading to many different applications. These include rigid and flexible foams, and coatings, adhesives, electrical potting compounds, and fibers such as spandex and polyurethane laminate (PUL). Foams are the largest application accounting for 67% of all polyurethane produced in 2016.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).