Influence of crosslinking agent content on structure and properties of glutaraldehyde crosslinked chitosan membranes

The crystallinity, swelling ratio as well as Cu2+ adsorption capacity of glutaraldehyde crosslinked chitosan membranes have been studied. The glutaraldehyde content is varied from 0 to 5. 0%. The lower glutaraldehyde content is, the smaller glutaraldehyde content interval changes. The results show that the crystallinity, swelling ratio and adsorption capacity reach the maximum when glutaraldehyde content in the membrane is 0. 25%. This phenomenon is different from that reported in literatures which shows the crystallinity and swelling degree are decreased with an increase of glutaraldehyde content. It is suggested that low- level crosslinking might be favorable to a more regular arrangement between chitosan molecular chains during membrane formation. Moreover, the increase of swelling ratio and adsorption capacity could be attributed to the increase of accessible amino group number while crosslinking taken place.