What are Polyurethanes?
Contrary to the generality of plastic materials, which have well-defined and known properties, the versatility of polyurethanes is so great and the field of applications so vast that allows polyurethanes to be present and used in countless applications in our every day life. Polyurethanes exist as soft materials in the foams of mattresses and sofas and also in rigid materials such as skateboard wheels or surfboards. They are marketed in the oily form (thermoplastics), in water-based lilies, solvent-based (paints, varnishes), without solvents (pre-polymer) or in gel. They are used both in construction applications (adhesives, sealants) and biometric applications. Polyurethanes are a huge market that goes from "commodities" to market niches.
Despite the disparate characteristics, there is something in common in all these products: a chemical group called urethane. The beginning of the success story of polyurethanes dates back to 1957, when Otto Bayer studied and developed the polyurethane synthesis line. In a more technical way it is said that the urethane group results from the reaction between a hydroxyl group (OH) and an isocyanate (NCO).
Chemically when a molecule contains a hydroxyl group (OH group) it is said that this molecule belongs to the family of alcohols. A molecule containing several OH groups is usually called a polyol. If a molecule possessing an OH (hydroxyl) group "finds" a molecule with an isocyanate group (NCO) then the 2 molecules react to form a single molecule with a urethane group.