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The aqueous swelling kinetics of a series of crosslinked chitosan (cr‐CS) with glutaraldehyde (GA) interpenetrating polyether hydrogels have been studied as functions of pH, the N‐deacetylation degree of chitosan, the amount of crosslinking agent, the electrolyte composition in solution, temperature, and gel composition. Based on these results, the swelling mechanism of the hydrogels was discussed. The release profiles of chlorhexidini acetas from the semi‐IPN were also investigated. © 1994 John Wiley & Sons, Inc.

ABSTRACT:Grafting a temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), onto porous polyethylene (PE) membranes by UV irradiation was investigated. A wide range of graft yields (5-449%) was achieved by varying irradiation time (20 -240 min) and monomer concentration (1.2-3.6 wt %). Characterization by XPS and SEM shows that the graft polymers are located both on the external surfaces as well as inside the pores of the membranes. Diffusional permeation experiments show that two distinct types of temperature responses were observed, depending on the graft yield; permeability increases with temperature in low graft yield membranes, while permeability decreases with temperature in high graft yield membranes. A mechanism explaining the dual valve functions of the graft membrane is proposed based on the location of the graft polymers on the membrane. It was also observed the permeability response exhibits a maximum with permeant molecular weight.

SYNOPSISThis article deals with a novel, semi-interpenetrating polymer network (semi-IPN) , composed of crosslinked chitosan (cr-CS) with glutaraldehyde (GA) and polyether. The pH responsibility of swelling data shows that swelling reaches a maximum at pH = 3.19 and a minimum at pH = 13. The concentration of chitosan acetic acid solution, the amount of crosslinking agent, and polyether, have effects on the swelling behavior of the network. Stimulating-response of the semi-IPN, induced by abrupt changes of pH between 1 and 13, is discussed as well. 0

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