A practical route for the preparation of poly(4-hydroxystyrene), a useful photoresist material

The synthesis and characterization of poly(4-hydroxystyrene) (PHS) and poly (4-vinylphenol) (PVPh) by the polymer modification route are reported. Poly styrene prepared by free-radical and anionic polymerization was acetylated quantitatively to poly(4-acetylstyrene) (ACPS) with acetyl chloride and anh ydrous aluminum trichloride in carbon disulfide. The acetylation worked equ ally well in a mixture of 1,2-dichloroethane (DCE) and nitrobenzene contain ing largely DCE. The extent of the acetylation was estimated by H-1 NMR. Th e oxidation of ACPS was carried out with various oxidizing agents and react ion conditions. The peracetic acid oxidation in chloroform resulted in quan titative oxidation to poly(4-acetoxystyrene) (APS) as estimated by H-1 NMR spectroscopy. The treatment of APS with hydrazine hydrate in dioxane result ed in the formation of PVPh. Deacetylation occurred with equal versatility in a mixture of aqueous sodium hydroxide and tetrahydrofuran. All the polym ers were characterized via gel permeation chromatography, IR, UV,H-1 NMR, a nd C-13 NMR spectroscopic techniques. This is the first report on the synth esis of ACPS, APS, and PHS of reasonably narrow molecular weight distributi ons or otherwise by the polymer modification route. (C) 2000 John Wiley & S ons, Inc.