pH值对壳聚糖/羧甲基壳聚糖水凝胶溶胀行为的影响

利用壳聚糖与羧甲基壳聚糖制备了一系列新型的水凝胶，研究了pH值对水凝胶溶胀度、微观结构和基团结构的影响．结果表明，壳聚糖与羧甲基壳聚糖水凝胶的溶胀行为和微观结构均表现出pH值敏感性，但随着羧基的引入，水凝胶的最低溶胀度从pH7．O移向pH3．O．红外光谱证明，水凝胶的pH敏感行为是由基团结构的变化引起的．

Effects of pH on the Swelling Behavior of Chitosan and Carboxymethyl Chitosan Hydrogels

Chitosan and its derivatives, carboxymethyl chitosan, were crosslinkered by glutaraldehyde to prepare hydrogel. The swelling degree measurement showed that the carboxyl groups made the hydrogel appearing different swelling behaviors, especially in that the lowest swelling degree appearing at pH 3.0 (chitosan hydrogel at pH 7.0). SEM showed that micromorphology of the external surface of the hydrogels were also affected by the carboxyl groups. At pH 7.0 the surface carboxymethyl chitosan hydrogel was compressed and had male profiles, but that of chitosan hydrogel appeared no pores but some fissure. FT-IR spectra of the hydrogels indicated that the difference in swelling behavior could be attribute to transformation of amino and carboxyl groups.