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Ionomeric polyurethanes of pyridinium type with side azobenzene groups
Author(s) -
Buruiana Tinca,
Buruiana Emil C.
Publication year - 2002
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.11071
Subject(s) - azobenzene , polyurethane , polymer chemistry , chromophore , photoisomerization , materials science , polymer , photochemistry , azo compound , pyridinium , diol , chemistry , isomerization , organic chemistry , catalysis
New polyurethane cationomers synthesized by a two‐step substitution postreaction of urethane hydrogen atoms with nitroazobenzene groups were studied. As a starting polymer, a polyurethane based on poly(tetramethylene oxide)diol, isophorone diisocyanate, and 2,6‐bis(hydroximethyl)pyridine was used. After a preliminary metalation of the above polymer with natrium hydride, by reaction of polyurethane N ‐sodate with 4‐nitro‐4′(β–iodoethylurethane)azobenzene, chromophoric groups between 2.85 and 10.53 wt % could be incorporated instead of hydrogen. Such polymers partially functionalized with azobenzene and further quaternized with methyl iodide led to the formation of pyridinium polyurethane cationomers N ‐modified with nitroazo groups. The photosensible properties of the azobenzene chromophore in a polymer solution and film state indicated important differences in their photoresponse. In the polymer solution, the trans – cis photoisomerization of the chromophore is accompanied by an irreversible photobleaching effect, while under the same UV irradiation conditions, the ionomeric films exhibited an enhanced photostability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1240–1247, 2002