离子对壳聚糖/果胶聚电解质复合物溶胀性及微观结构的影响研究

Effects of Ions on Swelling Properties and Microstructure of Chitosan and Pectin Polyelectrolyte Complexes

本文将壳聚糖、果胶在含有六种不同离子的溶液环境中复合,考察离子种类及浓度对壳聚糖/果胶聚电解质复合物(PEC)得率、溶胀度(水及模拟环境中)、红外光谱及微观结构的影响。离子价态对PEC得率的影响为:三价离子>二价离子>一价离子;离子浓度低时,离子浓度促进PEC得率增加,离子浓度高时,离子浓度抑制PEC得率增加。离子种类不同,PEC的溶胀过程不同,复合环境中含有FeCl3和Fe2(SO4)3的PEC在水中具有最大、最小溶胀度,分别为56.87±0.63和9.21±0.13;含有MgSO4和Fe2(SO4)3的PEC在胃肠模拟液中具有最大、最小溶胀度,分别为361.74±6.21和28.01±0.66。红外光谱结果表明添加离子并未影响PEC中NH3+/COO-键的形成。扫描电镜结果显示PEC呈海绵多孔状,添加离子后PEC孔壁厚度增加9.76±1.03%至334.19±5.12%不等,表面更加光滑,而孔隙状态因离子种类不同而不同。研究表明PEC得率、溶胀度及微观结构受到离子影响,但其交联方式不变。

Chitosan/pectin polyelectrolyte complexes （PECs） were obtained when chitosan and pectin was mixed within 6 different kinds of ion solutions. The influences of ion type and concentration on certain characteristics such as complex yield, swelling patterns both in water and in vitro, FT-IR spectra and microstructure of the aforementioned PECs were studied. The order of ionic valence on PEC yield was trivalent ions 〉 divalent ions 〉 univalent ions. PEC cross-linking was promoted by the low ion concentration but prohibited by high ion concentration. The addition of FeCl3 led to a maximum in swelling degree of 56.87±0.63 in water while the minimum swelling degree of 9.21±0.13 was obtained when added with Fe2（SO4）3. The addition of MgSO4 resulted in a greatest swelling degree of 361.74±6.21, while a lowest swelling degree of 28.01±0.66 with the addition of Fe2（SO4）3 was achieved in the simulated gastro-intestinal transit solutions. FT-IR analysis indicated that ions had no effect on hybrid NH3＋/COO- in PECs. SEM results showed that the chitosan/pectin PECs formed a sponge-morphic microstructure. The thickness increased from 9.76±1.03 % to 334.19±5.12%, and the layer became smooth with the interaction of ion. The porosity of PECs depended on different ions. Research showed that the addition of ions could influence the PEC complex yield, swelling ratio and microstructure, but showed little effect on PEC cross-linking pattern.