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FR-4 (or FR4) is a NEMA grade designation for glass-reinforced epoxy laminate material. FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant (self-extinguishing). "FR" stands for "flame retardant", and does not denote that the material complies with the standard UL94V-0 unless testing is performed to UL 94, Vertical Flame testing in Section 8 at a compliant lab. The designation FR-4 was created by NEMA in 1968. FR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate grade with good strength to weight ratios. With near zero water absorption, FR-4 is most commonly used as an electrical insulator possessing considerable mechanical strength. The material is known to retain its high mechanical values and electrical insulating qualities in both dry and humid conditions. These attributes, along with good fabrication characteristics, lend utility to this grade for a wide variety of electrical and mechanical applications. Grade designations for glass epoxy laminates are: G-10, G-11, FR-4, FR-5 and FR-6. Of these, FR-4 is the grade most widely in use today. G-10, the predecessor to FR-4, lacks FR-4's self-extinguishing flammability characteristics. Hence, FR-4 has since replaced G-10 in most applications. FR-4 epoxy resin systems typically employ bromine, a halogen, to facilitate flame-resistant properties in FR-4 glass epoxy laminates. Some applications where thermal destruction of the material is a desirable trait will still use G-10 non flame resistant.

Article Title : FR-4
Article Snippet :are: G-10, G-11, FR-4, FR-5 and FR-6. Of these, FR-4 is the grade most widely in use today. G-10, the predecessor to FR-4, lacks FR-4's self-extinguishing
Article Title : Russell 1000 Index
Article Snippet :The Russell 1000 Index is a U.S. stock market index that tracks the highest-ranking 1,000 stocks in the Russell 3000 Index, which represent about 93%
Article Title : Color index
Article Snippet :In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature
Article Title : Nature Index
Article Snippet :The Nature Index is a database that tracks institutions and countries/territories and their scientific output since its introduction in November, 2014
Article Title : Results of the 2024 French legislative election by constituency
Article Snippet :resultats-elections.interieur.gouv.fr/legislatives2024/ensemble_geographique/84/01/0105/index.html https://www.resultats-elections.interieur.gouv.fr
Article Title : A Certain Magical Index
Article Snippet :A Certain Magical Index (Japanese: とある魔術の禁書目録(インデックス), Hepburn: Toaru Majutsu no Indekkusu) is a Japanese light novel series written by Kazuma Kamachi
Article Title : Jaccard index
Article Snippet :The Jaccard index, also known as the Jaccard similarity coefficient, is a statistic used for gauging the similarity and diversity of sample sets. It was
Article Title : Roland Bondonny
Article Snippet :February 2005, he committed suicide. http://programmes.france2.fr/faites-entrer-laccuse/index-fr.php?page=toutes-les-affaires-emission&id_rubrique=33 (in French)
Article Title : Results of the 2024 French legislative election in Alpes-Maritimes
Article Snippet :resultats-elections.interieur.gouv.fr/legislatives2024/ensemble_geographique/93/06/0601/index.html https://www.resultats-elections.interieur.gouv.fr
Article Title : Human Poverty Index
Article Snippet :economics Happy Planet Index (HPI) Human Development Index (HDI) Human Poverty Index country ranking in 2000 [fr] ISEW (Index of sustainable economic

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