EFFECT OF IONIC CROSSLINKING AGENTS ON SWELLING BEHAVIOUR OF CHITOSAN HYDROGEL MEMBRANES

Physically crosslinked chitosan hydrogels were prepared by treating chitosan with sulfuric acid, trisodium citrate, sodium tripolyphosphate and sodium alginate, respectively. The chemical structure of modified chitosan hydrogels as well as unmodified one was analysed by FTIR spectroscopy and conclusions on the formation of the ionic crosslinks between protonated amino groups of chitosan and anionic functional groups of crosslinking agents were drawn out. The swelling behaviour of the membranes formed from modified and unmodified chitosan was studied in buffer solutions at various pH at 37 oC. It was observed that the swelling degree of chitosan hydrogel membranes depends both on pH of buffer solution as well as on the type of crosslinking agent.