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ESR studies of chemically modified and photocrosslinked poly(vinyl alcohol) gels
Author(s) -
Uhlich Thomas,
Ulbricht Mathias,
Tomaschewski Georg,
Stösser Reinhard
Publication year - 1995
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.1995.070580920
Subject(s) - vinyl alcohol , polymer , solvent , polymer chemistry , materials science , alcohol , spin probe , chemical engineering , chemistry , organic chemistry , membrane , biochemistry , engineering
The hydrophilicity of poly(vinyl alcohol) (PVA) was lowered by acetalization with propionic aldehyde. After UV irradiation of pendent styrylpyridinium groups, these prepolymers form networks of different hydrophobicity depending on the degree of acetaization. PVA films containing different amounts of propionic acetals were doped with 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl. Then, the ESR spectra of the spin probe entrapped in the polymeric network were monitored while allowing different solvents to diffuse into the polymer. The rate of spin probe mobilization depends on the hydrophilicity/hydrophobicity of both the polymer network and the solvent. However, the modified polymers, even the more hydrophobic ones, are hydrophilic in comparison to “really” hydrophobic polymers. This is probably caused by the character of the parent polymer (PVA), unreacted hydroxy groups. S++uiations of the ESR spectra have shown that in polymers with a higher degree of acetalization domains of different hydrophobicity are built in which the spin probes have a different mobility. © 1995 John Wiley & Sons, Inc.