C6位选择性氧化竹浆纤维的壳聚糖改性处理

采用H_3PO_4/HNO_3-NaNO_2氧化体系对竹浆纤维C6位进行选择性氧化,然后与壳聚糖溶液交联反应制备生态的抗菌壳聚糖改性竹浆纤维。固相CP/MAS 13 C核磁共振分析显示,H_3PO_4/HNO_3-NaNO_2已将竹浆纤维C6位上的伯羟基选择性氧化成羧基,且红外光谱和扫描电镜测试表明,壳聚糖的氨基与氧化竹浆纤维分子上的羧基发生酰胺化反应,壳聚糖分子通过C-N化学键共价交联在竹浆纤维上,并在竹浆纤维表面形成壳聚糖薄膜。通过分析H_3PO_4/HNO_3-NaNO_2氧化和壳聚糖处理过程中竹浆纤维羧基含量、机械强力、壳聚糖含量等指标,得出最佳工艺参数。Kjeldahl定氮分析得出壳聚糖在氧化竹浆纤维上的最大含量为3.92%。壳聚糖接枝竹浆纤维的断裂强度变化不明显,但其断裂伸长率降低。抗菌试验结果显示,与壳聚糖处理的原竹浆纤维抗菌性相比,壳聚糖改性竹浆纤维对大肠杆菌和金黄色葡萄球菌的抗菌效果明显提高,抑菌率均在96%以上,且壳聚糖改性竹浆纤维具有良好的抗菌耐洗涤性能。

Treatment on C6 Selective Oxidation and Chitosan Coating of Bamboo Pulp Fibers

H3PO4/HNO3-NaNO2 mediated oxidation at C6 position of glucose and subsequent cross-link reaction with chitosan were performed to produce anti-bacterial bamboo pulp fibers.Solid-state CP/MAS 13C-NMR spectra analysis reveals that the oxidation occurs at the C6 primary hydroxyl groups of bamboo pulp cellulose.The amidization between chitosan and oxidized bamboo pulp fibers was confirmed by FT-IR spectroscopy and chitosan coated thin films on the surface of bamboo pulp fibers was detected by SEM.The content of chitosan in these modified fibers was up to 3.92％,detected by Kjeldahl method.The carboxyl group content,mechanical strength of the oxidized bamboo pulp fibers,as well as chitosan content in the chitosan grafted bamboo pulp fibers were examined in the modification processes,and the optimum parameters were achieved.The breaking strength of chitosan modified bamboo pulp fibers is not significantly changed,while the elongation at break of modified fibers is decreased.The antibacterial assay shows these oxidized bamboo fibers coated with chitosan have high antimicrobial activity (over 96 ％) against Escherichia coli and Staphylococcus aureus bacteria and better water resistance compared with those chitosan coated original bamboo pulp fibers.