ISSN:
1573-904X
Keywords:
thermosensitivity
;
hydrogels
;
N-isopropylacrylamide
;
interpenetrating polymer networks
;
surface deswelling
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The swelling in water, as a function of temperature, of two series of N-isopropylacrylamide (NIPA Am) polymer networks was studied. In the first series, n-butylmethacrylate (BMA) was copolymerized with NIPA Am, and in the second, polytetramethylene ether glycol (PTMEG) was incorporated into NIPAAm network as a chemically independent interpenetrating network. With increasing BMA content in the poly(NIPAAm-co-BMA) network, the gel collapse point was lowered and the gels deswelled in a more gradual manner with increasing temperature. In the interpenetrating polymer networks (IPN) system, the gel collapse point was not significantly changed by the amount of incorporated PTMEG. In DSC thermograms of swollen samples, the shape and onset temperature of the endothermic peak corresponded to the gel deswelling behavior and gel collapse point. The temperature dependence of equilibrium swelling in water was shown to be a function of the gel composition in both network series. The synthesized networks formed a dense surface layer as the temperature increased past the gel collapse point. This dense layer retarded water efflux and thereby resulted in water pockets at the membrane surface.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1015871732706
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