polybutylene terephthalate

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| IUPACName = Poly(oxy-1,4-butanediyloxycarbonyl-1,4-phenylenecarbonyl)

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| CASNo = 24968-12-5

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| Properties_ref =[http://www.britannica.com/EBchecked/topic/468341/polybutylene-terephthalate Polybutylene-terephthalate] on Britannica

| Formula = (C₁₂H₁₂O₄)_n

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Polybutylene terephthalate (PBT) is a thermoplastic engineering polymer that is used as an insulator in the electrical and electronics industries.{{Cite journal|last1=De Vos|first1=Lobke|last2=Van de Voorde|first2=Babs|last3=Van Daele|first3=Lenny|last4=Dubruel|first4=Peter|last5=Van Vlierberghe|first5=Sandra|date=2021-12-05|title=Poly(alkylene terephthalate)s: From current developments in synthetic strategies towards applications|url=https://www.sciencedirect.com/science/article/pii/S0014305721005747|journal=European Polymer Journal|language=en|volume=161|pages=110840|doi=10.1016/j.eurpolymj.2021.110840|bibcode=2021EurPJ.16110840D |issn=0014-3057|hdl=1854/LU-8730084|hdl-access=free}} It is a thermoplastic (semi-)crystalline polymer, and a type of polyester. PBT resists solvents, shrinks very little during forming, is mechanically strong, is heat-resistant up to {{nowrap|150 °C}} (or {{nowrap|200 °C}} with glass-fibre reinforcement), and can be treated with flame retardants to make it noncombustible. It was developed by Britain's Imperial Chemical Industries (ICI).{{cite journal | journal=Le Moniteur de l'Automobile | page= 10 | title=BL passe la 3ème vitesse | trans-title = BL puts it into third | last=Renaux | first=Jean-Jacques | location=Brussels, Belgium | language=fr | volume=34 | number=764 | date=1983-03-10 | ref = mon764 | publisher=Editions Auto-Magazine }}

PBT is closely related to other thermoplastic polyesters. Compared to PET (polyethylene terephthalate), PBT has slightly lower strength and rigidity, slightly better impact resistance, and a slightly lower glass transition temperature. PBT and PET are sensitive to hot water above {{nowrap|60 °C}} (140 °F). PBT and PET need UV protection if used outdoors, and most grades of these polyesters are flammable, although additives can be used to improve both UV and flammability properties.

PBT is produced by the polymerization of 1,4-butanediol and terephthalic acid.{{Cite web |date=2023-06-01 |title=Polybutylene terephthalate (PBT) {{!}} Britannica |url=https://www.britannica.com/science/polybutylene-terephthalate |access-date=2023-11-24 |archive-url=https://web.archive.org/web/20230601202255/https://www.britannica.com/science/polybutylene-terephthalate |archive-date=2023-06-01 }}{{Cite web |date=2023-11-24 |title=Polybutylene Terephthalate PBT and Butanediol – Chemical production and investment cost {{!}} S&P; Global |url=https://www.spglobal.com/commodityinsights/en/ci/products/chemical-technology-pep-polybutylene-terephthalate-1997.html |access-date=2023-11-24 |archive-url=https://web.archive.org/web/20231124155828/https://www.spglobal.com/commodityinsights/en/ci/products/chemical-technology-pep-polybutylene-terephthalate-1997.html |archive-date=2023-11-24 }}