壳聚糖接枝改性单羧基棉织物的结构及性能

采用HNO3/H3PO4-NaNO2氧化体系选择性氧化棉织物得到单羧基纤维素，然后与壳聚糖溶液酰胺交联反应，使壳聚糖化学键合单羧基棉织物。研究HNO3/H3PO4-NaNO2氧化时间对单羧基棉织物羧基含量、断裂强力及壳聚糖接枝后棉织物增重率的影响，得出氧化时间在45min时，壳聚糖接枝棉织物的最大增重率为5.52%。运用固相CP/MAS 13C NMR、FT-IR、SEM和XRD等测试分析，结果表明，HNO3/H3PO4-NaNO2体系将棉纤维葡萄糖单元中C6位伯羟基选择性氧化成羧基，壳聚糖分子中的氨基与氧化棉织物上的活性羧基反应形成C-N酰胺化学键，壳聚糖在织物表面共价交联成膜。壳聚糖接枝反应后，单羧基棉织物的结晶度从65.37%下降到60.86%，壳聚糖改性棉织物的断裂强力、白度及毛细效应有所减小，但折皱回复角明显提高。

Structure and properties of monocarboxyl cotton fabrics by graft modification with chitosan

Abstract: Cotton fabrics were selectively oxidized by HNO3/H3PO4-NaNO2 mediate system to obtain the monocarboxyl cellulose, and then chitosan bonded with monocarboxyl cotton fabric through the amide reaction in chitosan solution. Effects of oxidation time of HNO3/H3PO4-NaNO2 on carboxyl content, breaking strength of oxidized cotton fabrics and weight gain of cotton fabric grafted chitosan were studied and the maximum weight gain of 5.52% was obtained when the oxidation time was chosen as 45min. The analysis of CP/MAS 13C NMR, FT-IR, SEM and XRD demonstrated that the primary hydroxyl at C6 site in glucose units of cotton cellulose was selectively oxidized to carboxyl group by HNO3/H3PO4-NaNO2 system, subsequently the amido bond of C-N was formed between amino groups in chitosan and active carboxyl groups on oxidized cotton fabrics and chitosan covered on the surface of oxidized cotton fabrics by the covalent bond. After chitosan graft reaction, the crystallinity of monocarboxyl cotton fabric decreased from 65.37% to 60.86%, and the breaking strength, whiteness and capillary effect of chitosan grafted cotton fabrics slightly reduced, whereas the wrinkle recovery angle of modified fabrics significantly increased.