【作者】 王欢；

【导师】 郭明；

【作者基本信息】 塔里木大学 ， 生物化学与分子生物学， 2010， 硕士

【摘要】 纤维素(Cellulose)是一种极具应用潜力和发展前途的可再生资源。本论文采用高碘酸钠对棉纤维分子中葡萄糖基环上C2和C3位的相邻仲羟基进行选择性氧化,得到双醛纤维素(Dialdehyde cellulose, DAC)。通过化学滴定法测定DAC中醛基含量,并讨论了三种滴定方法及反应机理,确定了最佳滴定方法为碱消耗法。进而,以双醛纤维素(DAC)和甘氨酸(Glycine, Gly)为原料,以对硝基苯甲醛(p-nitrobenzaldehyde, p-NBD)为接枝桥梁,利用希夫碱(Schiff base)反应,设计并合成新型的纤维素基希夫碱类衍生物—双醛纤维素接枝甘氨酸希夫碱(DAC-g-Gly)。详细研究了(DAC-g-Gly)的优化合成条件,其收率为86.1%,取代度可达11.4%。利用X射线衍射(XRD)、红外光谱(IR)、固体核磁共振波谱(CP/MAS 13C NMR)和扫描电子显微镜(Scanning electron microscope, SEM)技术表征了中间产物(DAC)和最终产物(DAC-g-Gly)的结构,确认了合成的化合物为预期产物。热重(TG)和示差扫面量热(DSC)分析中间产物(DAC)和最终产物(DAC-g-Gly)热性能结果表明,棉纤维经高碘酸钠氧化后整体结构发生降解,但是纤维素在接枝对氨基苯甲醛甘氨酸希夫碱(p-ABD-Gly-Schiff base)后,DAC的热稳定性得到增强。同时,对棉纤维、氧化棉纤维和氧化纤维素接枝甘氨酸进行了霉菌生物降解性能实验,利用扫描电子显微镜(SEM)观测了棉纤维、氧化棉纤维和氧化纤维素接枝甘氨酸经过木霉菌不同时间降解后的表观形貌,表明产物有良好的生物降解性能;利用活性淤泥法对DAC-g-Gly进行了降解试验,双指示剂滴定法处理活性淤泥降解DAC-g-Gly的结果表明,合成产物DAC-g-Gly在中性淤泥状且具有自然活性的土壤中,经四周时间,降解率达9.91%左右。更多还原

【Abstract】 Cellulose is a kind of regenerative material with great potential and promising application. In order to obtain dialdehyde cellulose (DAC), the cotton fiber is selectively oxidized with NaIO4 and adjacent hydroxy groups of C2, C3 in glucose units of cotton fiber.The aldehyde compostion in DAC was obtained by titration and three titration methods and mechanisms have been discussed to conclude the optimum method is alkali consumption method. Based on the schiff base reaction, using the DAC and Glycine (Gly) as the reactant and p-nitrobenzaldehyde (p-NBD) as grafting bridge, a novel cellulose based schiff base ramification□dialdehyde cellulose grafting glycin (DAC-g-Gly) was designed and synthesized. The optimum synthesis conditions of DAC-g-Gly were studied in detail. The yield and degree of substitution of DAC-g-Gly achieved were 86.1% and 11.4% respectively. The structure of intermediate product (DAC) and end product (DAC-g-Gly) were carefully characterized by X-ray diffraction analysis (XRD), FT-infrared spectroscopy (FT-IR), Cross polarization magic angle spin NMR (CP/MAS NMR) and Scanning electronic microscope (SEM). It was confirmed that the compounds which were synthesized were the expected product.Thermo gravimetric analysis (TG) and Differential Scanning Calorimetry (DSC) measurement indicated that the cotton fiber oxidized with NaIO4 was degraded during the oxidation reaction. It was also confirmed the grafting reaction enhanced the thermal stability of DAC.Simultaneously, the Scanning Electronic Microscope (SEM) revealed that the surface topography of the samples changed notably after the Trichoderma spp contaminated. It was also denoted that the biodegradation performance was enhanced evidently by oxidation and grafting reaction. The result of active silt degradation was performed by bi-indicator titration, showing that the degradation rate of DAC-g-Gly reached about 9.91% in litmusless silt-form soil possessing natural activity after four weeks.更多还原