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

Abstract

ABSTRACT:The synthesis and characterization of poly(4-hydroxystyrene) (PHS) and poly(4-vinylphenol) (PVPh) by the polymer modification route are reported. Polystyrene prepared by free-radical and anionic polymerization was acetylated quantitatively to poly(4-acetylstyrene) (ACPS) with acetyl chloride and anhydrous aluminum trichloride in carbon disulfide. The acetylation worked equally well in a mixture of 1,2-dichloroethane (DCE) and nitrobenzene containing largely DCE. The extent of the acetylation was estimated by 1 H NMR. The oxidation of ACPS was carried out with various oxidizing agents and reaction conditions. The peracetic acid oxidation in chloroform resulted in quantitative oxidation to poly(4-acetoxystyrene) (APS) as estimated by 1 H NMR spectroscopy. The treatment of APS with hydrazine hydrate in dioxane resulted in the formation of PVPh. Deacetylation occurred with equal versatility in a mixture of aqueous sodium hydroxide and tetrahydrofuran. All the polymers were characterized via gel permeation chromatography, IR, UV, 1 H NMR, and 13 C NMR spectroscopic techniques. This is the first report on the synthesis of ACPS, APS, and PHS of reasonably narrow molecular weight distributions or otherwise by the polymer modification route.

Synthesis of Partially Protected Block Copolymers Based on 4-Hydroxystyrene Using NMRP and a Sequence of Polymer Analogous Reactions

“…As already mentioned above protected 4-hydroxystyrene monomers can be polymerized in a controlled fashion by means of different radical polymerization techniques like NMRP, ATRP, and RAFT or by anionic polymerization. Because of unavoidable transfer reactions the direct radical polymerization of unprotected 4-hydroxystyrene provides polymers with very broad molecular weight distributions (MWD) and shows poor control over their molar masses. – Because of the protic phenolic OH groups the direct anionic polymerization of unprotected 4-hydroxystyrene is also not practicable. Therefore, only protected 4-hydroxystyrene monomers can be applied for anionic or controlled radical polymerization techniques.…”

Linear or Branched Polyethylenes from Supported Aryloxytitanium(IV)−Cyclopentadienyl Complexes

“…Poly(styrene-r-4-hydroxystyrene) (HPS) 9 of 70 000 M w having 0.3 mol % of hydroxyl groups was prepared for use as the macroligand. The reaction of complexes 1-4 (Figure 1) with HPS in toluene at 60 °C for 2 days (Scheme 1, reaction stoichiometries are in Table 1) forms a viscous reaction mixture that ultimately results in a polymeric gel having low solubility in toluene.…”

Synthesis of poly(N‐isopropylacrylamide) with a low molecular weight and a low polydispersity index by single‐electron transfer living radical polymerization

“…The hydrolysis of PAS to PHS was confirmed by NMR spectroscopy. 1 H‐NMR (500 MHz, DMSO‐d 6 ), δ: 8.8–9.1 (br, OH), 6.1–6.7 (m, Ar‐H), 1.6–1.8 (br, CH), 1.2‐1.5 (br, CH 2 ) 30–33…”