A polyurethane (PUR and PU) is polymer composed of a chain of organic units joined by carbamate (urethane) links.
Polyurethane polymers are formed by combining two or several bi- or higher functional monomers. One contains two or more isocyanate functional groups (with formula –N=C=O) and the other contains two or more hydroxyl groups (with formula –OH). The alcohol and the isocyanate groups combine to form a urethane linkage:
- ROH + R'NCO → ROC(O)N(H)R' (R and R' are alkyl or aryl groups)
This combining process, sometimes called condensation, typically requires the presence of a catalyst. More complicated monomers are also used.
Polyurethanes are used in the manufacture of flexible, high-resilience 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; surface coatings and surface sealants; synthetic fibers (e.g., Spandex); carpet underlay; and hard-plastic parts (e.g., for electronic instruments).
Polyurethane is also used for the manufacture of hoses and skateboard wheels as it combines the best properties of both rubber and plastic.
Read more about Polyurethane: History, Chemistry, Raw Materials, Production, Health and Safety, Fungus, Manufacturing, Applications
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