The interaction of urea with the generic class of poly(2-hydroxyethyl methacrylate) hydrogels.

Citation data:

Journal of biomedical materials research, ISSN: 0021-9304, Vol: 18, Issue: 6, Page: 671-84

Publication Year:
1984
Usage 8
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Citations 12
Citation Indexes 12
Repository URL:
http://scholarsmine.mst.edu/chem_facwork/1479
PMID:
6544769
DOI:
10.1002/jbm.820180608
Author(s):
Pinchuk, Leonard; Eckstein, Eugene C.; Van-De-Mark, Michael R.
Publisher(s):
Wiley; Wiley-Blackwell
Tags:
Materials Science; Engineering; Chemistry
article description
Work reported here shows that, contrary to reports in the literature, hydrogels made from pure poly(2-hydroxyethyl methacrylate), pHEMA, at crosslinker content greater than 0.15 mol % do not swell above the usual equilibrium values of 39-42% water content in aqueous urea solution. However, hydrogels containing small (impurity) amounts of methacrylic acid (MAA) do swell dramatically (approximately 90%) in dilute urea solution, but not directly due to the urea. The urea decomposes to produce ammonium ions, thus raising the pH of the solution. Ionization of MAA occurs above pH 6, causing electrostatic interactions within the gel. The grossly swollen state of these gels represents an internal equilibrium among forces due to rubber elasticity, polymer-polymer/solvent affinity, and electrostatic interactions.