Polyvinyl carbazole

Structural formula
General
Surname	Polyvinyl carbazole
other names	PVC
CAS number	25067-59-8
Monomer	N- vinyl carbazole
Molecular formula of the repeating unit	C 14 H 11 N
Molar mass of the repeating unit	193.24 g mol −1
Type of polymer	Thermoplastic
Brief description	white to yellow
properties
Physical state	firmly
density	1.18-1.20 g · cm −3 ; 1.84 g cm −3 (amorphous)
Melting point	> 320 ° C
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Polyvinyl carbazole ( abbreviation : PVK ) is a white-yellowish, temperature-resistant, thermoplastic material produced from the monomer N- vinyl carbazole by radical polymerization . It is photoconductive and therefore the basis for photorefractive polymers and organic light-emitting diodes .

history

Polyvinylcarbazole was discovered by chemists Walter Reppe (1892–1969), Ernst Keyssner and Eugen Dorrer and patented by IG Farben in the USA in 1937 . PVC was the first polymer whose photoconductivity was known. Starting from this, from the 1960s onwards, further such polymers were specifically searched for.

Extraction and presentation

Polyvinyl carbazole is obtained from N- vinyl carbazole by radical polymerization . There are different ways of conducting the reaction. It can be produced by suspension polymerization at 180 ° C using sodium chloride and potassium chromate as a catalyst . Alternatively, AIBN can be used as a radical starter and a Ziegler-Natta catalyst .

properties

Physical Properties

PVC can be used up to temperatures of 160–170 ° C and is therefore a temperature-resistant thermoplastic. The electrical conductivity changes depending on the exposure, which is why PVK is one of the semiconductors or photoconductors . The polymer is extremely brittle, but the brittleness can be reduced by copolymerization with a little isoprene .

Chemical properties

Polyvinyl carbazole is soluble in aromatic hydrocarbons , halogenated hydrocarbons and ketones . In contrast, it is resistant to acids , alkalis , polar solvents and aliphatic hydrocarbons . The addition of PVC to other plastic compounds increases their temperature resistance.

use

Display based on organic light emitting diodes

The use of PVC extends to special areas due to its high price and special properties. It is used in insulation technology, electrophotography (e.g. in copiers and laser printers), in organic light-emitting diodes and photovoltaic devices. In addition, PVC is a well-researched component in photorefractive polymers and thus plays an important role in holography . Another application is the production of boil-proof copolymers with styrene .

Individual evidence

1. ↑ ^{a b c d e f g} Hans-Dieter Jakubke, Ruth Karcher (coordinators): Lexicon of Chemistry in three volumes, Spektrum Verlag, Volume 3, Heidelberg 1999, ISBN 3-8274-0381-2 , p. 92.
2. ↑ ^{a b c d e f g} George Wypych: Handbook of Polymers . Elsevier, 2016, ISBN 978-1-927885-11-6 , pp. 643–645 ( limited preview in Google Book search).
3. ↑ Data sheet poly (9-vinylcarbazole) from Sigma-Aldrich , accessed on July 30, 2019 ( PDF ).
4. ↑ ^{a b c} Naoto Tsutsumi: Molecular design of photorefractive polymers. In: Polymer Journal . No. 48, 2016, pp. 571-588, doi: 10.1038 / pj.2015.131 .
5. ↑ Patent US2072465 : Production of polymeric N-Vinyl compounds. Registered on July 10, 1935 , published on March 2, 1937 , applicant: IG Farbenindustrie Aktiengesellschaft, inventors: Walter Reppe, Ernst Keyssner, Eugen Dorrer (priority July 24, 1934 in Germany). ‌
6. ↑ Hans-Georg Elias: Poly (N-vinylcarbazole) In: Hans-Georg Elias (Ed.): Makromoleküle (= industrial polymers and syntheses. Volume 3). Wiley-VCH, Weinheim, 2001, ISBN 3-527-29961-0 , p. 211 ( limited preview in Google book search).