PVP is typically prepared by free radical polymerization of 4-vinylphenol or a protected form of 4-vinylphenol. The protected monomers can be prepared from 4-hydroxybenzaldehyde, by vinylation of phenols, or acylation of polystyrene followed by oxidation at room temperature. If poly(4-methoxystyrene) is produced, the methoxy group can be cleaved by treating it with trimethylsilyliodide. There are several patents on the synthesis of 4-hydroxystyrene due its importance in the development of photoresist materials. RAFT polymerization can be used to prepare well-defined PVP chains. This can be done by mediating free radical polymerization of acetoxystyrene, which is then followed by deacetylation. Nitroxide mediated polymerization can also be used to prepare polyacetoxystyrene, which can transformed in polyphenols by UV irradiation. ATRP can also be used for the preparation of defined block copolymers of PVP, by polymerization of 4-acetoxystyrene that is subsequently selectively hydrolysed.
