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Effect of chemical cross‐linking under elongation on shape restoring of poly(vinyl alcohol) hydrogel
Author(s) -
Hirai Toshihiro,
Maruyama Hidetoshi,
Suzuki Takashi,
Hayashi Sadao
Publication year - 1992
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.1992.070460815
Subject(s) - vinyl alcohol , isotropy , glutaraldehyde , materials science , elongation , self healing hydrogels , anisotropy , aqueous solution , polyvinyl alcohol , chemical engineering , boiling , composite material , chemistry , polymer chemistry , polymer , organic chemistry , ultimate tensile strength , optics , physics , engineering
An anisotropically swollen hydrogel of poly(vinyl alcohol) (PVA) was found to be able to restore an isotropic physical shape by restoring isotropic physical cross‐links induced by anisotropically distributed chemical cross‐links. The anisotropic chemical cross‐links were introduced in the isotropic physical gel by cross‐linking with glutaraldehyde under elongation. The physical gel was made from the PVA aqueous solution by repetitive freezing and thawing. The chemically cross‐linked gel had kept its original shape and physical properties despite the chemical treatment under strain. However, by the heat treatment in boiling water, the gel changed its form anisotropically depending on the strain applied in the chemical treatment. The anisotropically swollen gel was deswollen in methanol and then reswollen in water. The reswollen gel took back its original isotropic shape, suggesting that the anisotropic chemical cross‐links thus introduced in the gel have a memory effect on the restoration of isotropic physical cross‐links. © 1992 John Wiley & Sons, Inc.