PVP is a white, hygroscopic powder with a weak characteristic
odor. In contrast to most polymers, it is readily soluble in water and
a large number of organic solvents, such as alcohols, amines, acids,
chlorinated hydrocarbons, amides and lactams. On the other hand,
the polymer is insoluble in the common esters, ethers, hydrocarbons
and ketones.
PVP is markedly hygroscopic. This property combined with outstanding film formation, initial tack and adhesion to different materials,
high capacity for complex formation, good stabilizing and solubilizing
capacity, insensitivity to pH changes, ready radiation-induced crosslinkability as well as good biological compatibility have made PVP one
of the most frequently used specialty polymers.
PVP is synthesized by free-radical polymerization of N-vinylpyrrolidone
in water or alcohols with a suitable initiator. By selecting suitable
polymerization conditions, a wide range of molecular weights can be
obtained, extending from low values of a few thousand daltons to
approximately 2.2 million daltons.