Polyvinylcarbazole (PVK) is a temperature-resistant[2] thermoplastic polymer produced by radical polymerization from the monomer N-vinylcarbazole. It is a photoconductive polymer and thus the basis for photorefractive polymers and organic light-emitting diodes.[3]
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| Names | |
|---|---|
| Other names
Poly(vinylcarbazole); Poly(N-vinylcarbazole); Poly(9-vinylcarbazole)
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| Identifiers | |
CompTox Dashboard (EPA)
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| Properties | |
| (C14H11N)n | |
| Melting point | > 320 °C[1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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History
editPolyvinylcarbazole was discovered by the chemists Walter Reppe (1892-1969), Ernst Keyssner and Eugen Dorrer and patented by I.G. Farben in the USA in 1937.[4][1] PVK was the first polymer whose photoconductivity was known. Starting in the 1960s, further polymers of this kind were sought.[3]
Production
editPolyvinylcarbazole is obtained from N-vinylcarbazole by radical polymerization in various ways. It can be produced by suspension polymerization at 180 °C with sodium chloride and potassium chromate as catalyst.[2] Alternatively, AIBN can also be used as a radical starter or a Ziegler-Natta catalyst.[1]
Properties
editPhysical properties
editPVK can be used at temperatures of up to 160 - 170 °C and is therefore a temperature-resistant thermoplastic. The electrical conductivity changes depending on the illumination. For this reason, PVK is classified as a semiconductor or photoconductor. The polymer is extremely brittle, but the brittleness can be reduced by copolymerization with a little isoprene.[5]
Chemical properties
editPolyvinylcarbazole is soluble in aromatic hydrocarbons, halogenated hydrocarbons and ketones.[1] It is resistant to acids, alkalis, polar solvents and aliphatic hydrocarbons.[2] The addition of PVK to other plastic masses increases their temperature resistance.
Use
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Due to its high price and special properties, the use of PVK is limited to special areas.[2] It is used in insulation technology,[2] electrophotography (e.g. in copiers and laser printers),[3] for the fabrication of polymer photonic crystals,[6] for organic light-emitting diodes and photovoltaic devices.[1] In addition, PVK is a well researched component in photorefractive polymers and therefore plays an important role in holography. Another application is the production of cooking-proof copolymers with styrene.
See also
editReferences
edit- ^ a b c d e Wypych, George (2016). Handbook of Polymers (in German). Elsevier. pp. 643–645. ISBN 978-1-927885-11-6.
- ^ a b c d e Hans-Dieter Jakubke, Ruth Karcher (Koordinatoren): Lexikon der Chemie in drei Bänden, Spektrum Verlag, Band 3, Heidelberg 1999, ISBN 3-8274-0381-2, S. 92.
- ^ a b c Tsutsumi, Naoto (2016). "Molecular design of photorefractive polymers". Polymer Journal. 48 (5): 571–588. doi:10.1038/pj.2015.131..
- ^ US-Patent Nr. 2,072,465 pdfpiw.uspto.gov: Production of polymeric N-Vinyl compounds. Priorität 24. Juli 1934, veröffentlicht am 2. März 1937, Anmelder: I.G. Farbenindustrie Aktiengesellschaft, Erfinder: Walter Reppe, Ernst Keyssner, Eugen Dorrer.
- ^ Elias, Hans-Georg (2001). "Poly(N-vinylcarbazol)". Makromoleküle (Industrielle Polymere und Synthesen Volume 3). Weinheim: Wiley-VCH. p. 211. ISBN 3-527-29961-0.).
- ^ Lova, Paola; Megahd, Heba; Stagnaro, Paola; Alloisio, Marina; Patrini, Maddalena; Comoretto, Davide (2020-06-15). "Strategies for Dielectric Contrast Enhancement in 1D Planar Polymeric Photonic Crystals". Applied Sciences. 10 (12): 4122. doi:10.3390/app10124122. ISSN 2076-3417.