溶剂法纤维素-甲壳素共混材料的发展现状

介绍了黄原酸盐法、氢氧化钠-尿素-硫脲、NaOH-硫脲、NaOH-尿素、离子液体、三氟乙酸、N,N-二甲基乙酰胺-氯化锂、N-甲基吗啉-N-氧化物等溶剂体系对纤维素-甲壳素溶解的最新进展及各自的优缺点,以期能全面了解纤维素-甲壳素以及甲壳素衍生物共混材料的未来发展趋势。     

溶剂法纤维素-甲壳素共混材料的发展现状

介绍了黄原酸盐法、氢氧化钠-尿素-硫脲、NaOH-硫脲、NaOH-尿素、离子液体、三氟乙酸、N,N-二甲基乙酰胺-氯化锂、N-甲基吗啉-N-氧化物等溶剂体系对纤维素-甲壳素溶解的最新进展及各自的优缺点,以期能全面了解纤维素-甲壳素以及甲壳素衍生物共混材料的未来发展趋势。     

甲壳素／纤维素共混粘胶纤维的抗菌性能研究

研究表明，甲壳素／纤维素共混粘胶纤维对大肠杆菌、金黄色葡萄球菌、白色念珠菌都有很好的抑菌能力。采用振荡烧瓶试验法测定样品的抑菌率，发现甲壳素的抑菌率与基准样品抑菌率的差值都大于有关卫生标准，而又经多次水洗也不影响其抑菌性。     

聚乙烯醇/淀粉共混材料研究进展

综述了近年来聚乙烯醇/淀粉共混材料的研究进展,主要介绍此类生物可降解性环境友好材料的制备方法,包括溶液流延法、挤出法以及模压法,以及增塑剂、交联剂、淀粉改性、纳米改性等对共混材料性能的影响,并对此类新材料的应用前景和发展方向进行了展望。     

用 FTIR研究纤维素/聚乙烯醇共混物结晶性

将纤维素(Cell)和聚乙烯醇(PVA)分别溶于二甲基亚砜-四乙基氯化铵(DMS(?)-TEAC)混合溶剂中,混和后(Cell/PVA=100/0—0/100)在玻璃板上铸膜,乙醇为固化剂.薄膜在硅油中热处理。用傅里叶变换红外光谱仪(FTIR)研究了共混物薄膜的结构特性.结果表明,共混物各组分分子间无化学键缔合。将结晶吸收带1369cm~(-1)(Cell)和1143cm~(-1)(PVA)与参考吸收带2887cm~(-1)(Cell)和2908cm~(-1)(PVA)之比定义为结晶度指数。发现各组分的结晶度指数均随其含量增加而增大,并随另一组分含量增加而减小,说明共混物薄膜中两组分大分子间有较强的相互作用。因此可以推断,在非晶区 Cell 与 PVA 是混溶的,而晶区是不混溶的.热处理使共混物薄膜中两组分的结晶度都增大。     

海藻酸钠/水溶性甲壳素共混纤维的制备和性能研究

用自制的湿法纺丝机制备了海藻酸钠/水溶性甲壳素共混纤维,并用红外光谱和扫描电镜对其进行了表征,且对纤维进行了单纤维拉伸测试和吸水性能测试。结果表明:共混纤维中确实有水溶性甲壳素的存在;从纤维的表面形态可以看出在轴向上有明显的筋状结构;拉伸结果表明共混纤维的平均断裂强度为16.25cN/tex,线密度为2.47dtex;共混纤维对水和盐水的吸收率都不高,但比纯海藻酸钙纤维的略高。     

聚乳酸/乙酸丙酸纤维素复合材料共混研究

采用双螺杆挤出工艺制备聚乳酸(PLA)/乙酸丙酸纤维素(CAP)简单共混复合材料。通过力学性能、吸水性、扫描电子显微镜、动态热机械分析和热重分析等手段,研究了CAP用量对复合材料拉伸强度、微观形态及松弛行为的影响。结果表明,随着CAP用量的增加,其拉伸强度出现峰值,加入CAP使复合材料具有较好的力学性能,同时没有影响PLA的链段运动。     

甲壳素及其衍生物的研究进展

综述了甲壳素及其衍生物的最新研究进展，并结合自己的工作论述了它们的性质特点、制备方法以及作为功能性材料的应用等方面的发展情况、存在问题和发展趋势。     

9：1的纤维素／甲壳素黄原酸酯溶液流变性能的研究

探讨了9：1的纤维素／甲壳素黄原酸酯共混溶液流变性能的影响因素，如溶液浓度和温度对共混溶液非牛顿指数、结构粘度指数、零切粘度等的影响。随着溶液浓度的增加和温度的降低，纤维素／甲壳素黄原酸酯溶液的非牛顿指数随之减小，而结构粘度指数、零切粘度随之增大。溶液的粘流活化能高于传统的粘胶。     

纤维素膜、纤维素功能材料及纤维素医用材料的发展

概述了纤维素膜、纤维素功能材料及纤维素医用材料的发展状况,指出纤维素膜、纤维素功能材料及纤维素医用材料是纤维素科学发展的重要方向之一,成为当代新材料的一个重要组成部分,具有极为广阔的发展和应用前景。     

Structure and Properties of Cellulose Films Reinforced by Chitin Whiskers

Cytocompatible nanocomposite films are prepared by blending α‐chitin whiskers and cellulose solution in NaOH/urea. Structure and properties of the chitin/cellulose composite films are characterized by FT‐IR, XRD, ¹³C NMR, SEM, UV‐Vis, TGA, and tensile tests. The results reveal that the chitin whiskers are dispersed homogeneously, leading to good miscibility and properties of the chitin/cellulose composite films. By varying the chitin whisker content, the tensile strength and elastic modulus of the films can be controlled. HeLa and T293 cells are seeded onto the surfaces of the nanocomposite films, showing that the composite films were nontoxic to both cell types and that the addition of chitin whiskers promotes cell adhesion and proliferation.

     

Cellulose/chitin films blended in NaOH/urea aqueous solution

Regenerated cellulose/chitin blend films (RCCH) were satisfactorily prepared in 6 wt % NaOH/4 wt % urea aqueous solution by coagulating with 5 wt % CaCl₂ aqueous solution then treating with 1 wt % HCl. The structure, miscibility, and mechanical properties of the RCCH films were investigated by infrared, scanning electron microscopy, ultraviolet spectroscopies, X‐ray diffraction, tensile test, and differential scanning analysis. The results indicated that the blends were miscible when the content of chitin was lower than 40 wt %. Moreover, the RCCH blend film achieved the maximum tensile strength in both dry and wet states of 89.1 and 43.7 MPa, respectively, indicating that the tensile strength and water resistivity of the RCCH film containing 10–20 wt % chitin was slightly higher than that of the RC film unblended with chitin. Structural analysis indicated that strong interaction occurred between cellulose and chitin molecules caused by intermolecular hydrogen bonding. Compared to the mechanical properties of chitin film, those of the blend films containing 10–50 wt % chitin were significantly improved. This work provided a novel way to obtain directly chitin material blended in the aqueous solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1679–1683, 2002     

甲壳质的应用研究现状

甲壳质无色、无毒、无味、耐晒、耐热、耐腐蚀,具有吸附性、吸收性、和亲和性等优良特性。文章主要综述了国内外甲壳质在农业、工业、医学上的开发和应用进展情况及甲壳质的应用前景。     

Conserved Active Site Architecture Between Bacterial Cellulose and Chitin Synthases

Glycosyltransferases (GTs) are a large and diverse group of enzymes responsible for catalyzing the formation of a glycosidic bond between a donor molecule, usually a monosaccharide, and a wide range of acceptor molecules, thus, playing critical roles in various essential biological processes. Chitin and cellulose synthases are two inverting processive integral membrane GTs, belonging to the type-2 family involved in the biosynthesis of chitin and cellulose, respectively. Herein, we report that bacterial cellulose and chitin synthases share an E-D-D-ED-QRW-TK active site common motif that is spatially co-localized. This motif is conserved among distant bacterial evolutionary species despite their low amino acid sequence and structural similarities between them. This theoretical framework offers a new perspective to the current view that bacterial cellulose and chitin synthases are substrate specific and that chitin and cellulose are organism specific. It lays the ground for future in vivo and in silico experimental assessment of cellulose synthase catalytic promiscuity against uridine diphosphate N-acetylglucosamine and chitin synthase against uridine diphosphate glucose, respectively.     

吸水膨胀型软质聚氯乙烯/ 羧甲基纤维素共混物的研究

采用扫描电子显微镜等仪器测试并研究了聚氯乙烯(PVC)/羧甲基纤维素(CMC)共混物的结构与性能。结果表明:随着吸水树脂含量的增加,共混物的吸水率和体积膨胀率增大,拉伸强度和断裂伸长率降低;随着水浸泡时间的增加,拉伸强度和断裂伸长率降低;吸水后PVC/CMC共混物中CMC分散相粒径明显增大,与基体树脂界面相互作用下降。     

Interfacial Properties of Ethyl Cellulose/Cellulose Acetate Blends by HPLC

The high performance liquid chromatography method (HPLC) with ethyl cellulose/cellulose acetate (EC/CA) blends and EC as column packing material, and small molecular weight compound as probe molecules was employed to measure the retention volume (VR) and equilibrium distribution coefficient (K) of both inorganic and organic solutes. The interfacial separation properties of EC/CA blends were characterized by the HPLC data. The effects of the blends on the interfacial adsorption properties, hydrophilicity, affinity, polar and non-polar parameters of EC membrane materials were studied subsequently. The research results indicate that the interfacial adsorption properties and hydrophilicity of EC have been improved by solution blending with CA. The alloys are superior to EC in the separation efficiency for non-dissociable polar organic solute. The EC/CA alloy (80:20, w) is suitable for desalting and desaccharifying.     

甲壳素研究进展与应用

甲壳素是地球上的第二大再生资源,具有生理适应性、可完全分解性、多功能反应性、立体结构与手性、可再生性与亲水性。近年来,甲壳素在生物医用和环境友好功能材料方面取得了一些进展;由甲壳素经化学降解和酶解而生成的甲壳低聚糖也广泛应用在医药品、农用化学品、保健食品及化妆品中;甲壳素降解后生成的氨基葡萄糖也应用于生化试剂及医药中间体的合成。其他包括许多品种的甲壳素衍生物均在工业、纺织、食品行业和环保方面获得广泛应用。     

纤维素氨基甲酸酯的合成研究进展

纤维素氨基甲酸酯(CC)是一种再生纤维素产品,被视为黏胶工艺中纤维素磺酸酯最有潜力的替代产品。对CC的发展过程、研究现状、合成方法和应用性能进行介绍,对酯化反应中所使用的纤维素溶剂进行分类和总结,并详细介绍离子液体作为无副产物纤维素溶剂的研究进展。