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PVP (polyvinyl pyrrolidone, povidone, polyvidone) is a water-soluble polymer made from the monomer N-vinyl pyrrolidone:
Registry Numbers and Synonyms
CAS Number: 9003-39-8
Merck 13, 7783
1-Ethenyl-2-pyrrolidoinone homopolymer (IUPAC); Poly[1-(2-oxo-1-pyrrolidinyl)ethylene]; polyvidone; polyvinylpyrrolidone; PVP; 1-vinyl-2-pyrrolidinone polymer
PVP is soluble in water and other polar solvents. In water it has the useful property of Newtonian viscosity. When dry it is a light flaky powder, which readily absorbs up to 18% of its weight in atmospheric water. In solution, it has excellent wetting properties and readily forms films. This makes it good as a coating or an additive to coatings.
The monomer is carcinogenic and is extremely toxic to aquatic life. However the polymer PVP in its pure form is so safe that not only is it edible by humans, it was used as a blood plasma expander for trauma victims after the first half of 20th century.
It is used as a binder in many pharmaceutical tablets; being completely inert to humans, it simply passes through. PVP added to Iodine forms a complex; in solution it is known under the trade name Betadine.
PVP binds to polar molecules exceptionally well, owing to its polarity. This has led to its application in coatings for photo-quality ink-jet papers and transparencies, as well as in inks for inkjet printers.
PVP is also used in personal care products, such as shampoos and toothpastes, in paints, and adhesives that you have to moisten, such as old-style postage stamps and envelopes. It has also been used in contact lens solutions and in steel-quenching solutions. PVP is the basis of the early formulas for hair sprays and hair gels, and still continues to be a component of some.
Material Safety Data Sheet
A cross-linked form of PVP is also used as a disintegrant in pharmaceutical tablets. 1 A very similar polymer - polyvinyl polypyrrolidone (PVPP) - is used to bind impurities to remove them from solutions. Basically, PVPP is a more highly cross-linked version of PVP, which makes it insoluble in water. This means that it can be used to extract impurities by filtration. This polymer is used to filter bitter compounds from drinks and can even be taken as a tablet to absorb compounds causing diarrhoea. (Cf. bone char, charcoal.)