羧基壳聚糖酰胺接枝丝素材料的结构及性能

Structure and Properties of Silk Fibroin Materials with Amide Graft by Carboxylic Chitosan

通过HNO_3/H_3PO_4-NaNO_2体系选择性氧化制备了不同羧基度的氧化壳聚糖,研究了羧基壳聚糖接枝条件对丝素织物接枝率和服用性能的影响,利用红外光谱、扫描电镜、差示扫描量热对酰胺改性丝素纤维的分子结构进行了表征。结果表明,氧化壳聚糖羧基度和质量分数分别为45.46%与2%,接枝反应时间为2 h时,丝素织物接枝率达到9.26%。羧基壳聚糖通过酰胺化学键交联在丝素纤维表面,改性丝素的热稳定性提高。羧基壳聚糖接枝丝素织物的拉伸强度略有降低,改性丝素织物的白度下降46.70%,而折皱回复角提升61.74%,毛细效应增加39.21%,且在改性丝素分子中引入了羧基壳聚糖的聚阳离子氨基,9.26%接枝率的改性丝素对金黄色葡萄球菌和大肠杆菌的抑菌率分别为99.65%和94.59%,具有较高的抗菌活性。

Oxidized chitosan with different carboxyl contents were prepared by the selective oxidation of HNO3/H3 PO4-NaNO2 mediated system,the effects of grafting conditions of carboxylic chitosan on graft yield and physical properties of silk fibroin fabrics were investigated,and the molecular structure of modified silk fibroin fiber was characterized through FT-IR,SEM and DSC.Results show that the graft yield of fibroin fabric achieves the value of 9.26%,when the carboxyl content and concentration of oxidized chitosan are respectively 45.46% and 2%,and the graft time is 2 h.The carboxylic chitosan is integrated with the silk fibroin fiber surface via the amide chemical bond,and the thermal stability of grafted silk fibroin is improved.The tensile strength of grafted silk fabric slightly decreases and the whiteness of modified silk fabric drops 46.70%,whereas the wrinkle recovery angle and capillary affinity of grafted fibroin fabrics increase61.74% and 39.21%,respectively.Furthermore,the polycationic amino groups of carboxylic chitosan are introduced into the molecules of modified silk fibroin,so the modified fibroin fabric with the graft yield of 9.26% displays good antibacterial activity with the inhibition ratio of 99.65% against Gram-positive bacteria S.aureus and 94.59% against Gramnegative bacteria E.coli.