A family of polymers made by a condensation reaction of an organic isocyanate with a compound containing a hydroxyl group, such as glycol. Polymers of this type (ester type) were first made in 1937 by Otto Bayer at I.G.Farben. During W.W.II, Germany made brush bristles and filtration fabrics from Perlon U, an early polyurethane. In the 1950's another type of polyurethane using an ether starting compound (ether type) was used to produce elastomeric polyurethane fiber called spandex. Spandex has elastic characteristics similar to natural rubber. In addition to fibers, elastomeric polyurethanes are used for sealants, adhesives, films, and automobile bumpers. Polyurethanes can be rigid or soft, thermosetting or thermoplastic. Additionally, they react with isocyanates to produce a foamed resin. Polyurethane resins are also used as coatings where they provide excellent hardness, gloss, and resistance to weathering, abrasion, acids, and alkalis. Flexible and rigid polyurethane foams are used for insulation, furniture, mattresses, laminates, carpet cushions, upholstery, soundproofing, flotation devices, packaging, and filtration.
Synonyms and Related Terms
PUR; poliuretano (Esp.); polyuréthane (Fr.); poliuretano (It.); poliuretano (Port.); spandex; elastane
Examples: Perlon® U [Ger.]; Lycra® [DuPont];
Coatings are resistant to weathering, abrasion, acids and alkalis.
Attacked by aromatic solvents, chlorinated solvents, ozone, and nitrogen oxides.
Spot test for detection: dimethyl amino benzaldehyde in glacial acetic acid - positive reaction gives bright yellow color (Roff et al 1971)
Hazards and Safety
Urethane burns with a bright flame producing a sharp odor and toxic fumes.
Potential degradation products are hydrogen cyanide and ammonia.
Polyether type urethanes are very susceptible to light degradation.
Polyester type urethanes are very susceptible to degradation at high humidities.
Chlorine bleach may cause degradation.
W.J.Roff, J.R.Scott, J.Pacitti (compilers) Handbook of Common Polymers:Fibres, Gilms, Plastics and Rubber Cleveland: CRC Press, Butterworth & Co., 1971.
[[media:|Physical Properties for Selected Thermoplastic Resins]]
- External source or communication Comment: C&ENews Aug 2004 - first developed by Otto Bayer in 1937.
- Encyclopedia Britannica, http://www.britannica.com Comment: "Polyurethane." Encyclopædia Britannica. 18 Aug. 2004 .
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