壳聚糖2-位NH_2的修饰及其对理化性能的影响

Modification of Chitosan-2-NH_2 and its influence on characters

目的制备结构相似、键型不同的壳聚糖(CTS)-水杨酸(醛、酮)系列衍生物,考察不同修饰物对溶解度和对金属离子吸附作用的影响。方法一步法制备水杨酰基和水杨醛基壳聚糖衍生物,用化学检识、热分析等方法对其进行表征,用返滴定法测定对Pb2+和Zn2+等重金属离子的吸附作用。结果CTS-水杨酰基系列衍生物的溶解度高于CTS的溶解度,且接枝率越高,溶解度越大;CTS-水杨醛基系列衍生物的溶解度低于CTS,接枝率越高,溶解度越低。2个系列修饰物对金属离子的吸附作用都低于CTS,且接枝率越高,吸附作用越低。但酰基衍生物对金属离子的吸附能力高于西佛碱衍生物。接枝率在50%以上时,西佛碱衍生物对Pb2+和Zn2+的吸附能力几乎为零;酰基衍生物对Pb2+仍具有一定的络合作用。结论水杨酰基壳聚糖的溶解度高于水杨醛基壳聚糖,CTS的2-位NH保留1个氢原子有助于提高修饰物的溶解度;高接枝率的水杨酰基-壳聚糖有可能成为Pb2+的高效解毒剂。

OBJECTIVE To prepare series ramification of Chitosan-g-Salicylic acid and Chitosan-g- Salicylic aldehyde, which have similar structure and different bonds, and to examine the solubility of modifiers and the adsorption to Pb^2＋ and Zn^2＋, METHODS Ramification of Salicylic acyl- Chitosan and Salicylic aldehyde-Chitosan was separately prepared by one-step method, and was characterized by chemical methods and thermal analysis. The adsorption to Pb^2＋ and Zn^2＋ was examined by titration method. RESULTS Solubility of series ramification of Salicylic acyl- Chitosan was larger than that of Chitosan. The higher the graft ratio, the bigger the solubility. Solubility of series ramification of Salicylic aldehyde- Chitosan was less than that of Chitosan. The higher the graft ratio, the smaller the solubility. The adsorption of Chitosan-g-Salicylic acid and Chitosan-g- Salicylic aldehyde to Pb^2＋ and Zn^2＋ was smaller than that of Chitosan. The higher the graft ratio, the less the adsorption, but the adsorption of the former to Pb^2＋ was larger than the latter. CONCLUSIONS Solubility of series ramification of Salicylic acyl- Chitosan is larger than that of series ramification of Salicylic aldehyde- Chitosan. It is important that NH within Chitosan should be saved to increase the solubility when modified.