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。     

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。     

聚乳酸/纤维素及其衍生物共混复合材料的研究进展

介绍了聚乳酸(PLA)/纤维素、PLA/天然植物纤维、PLA/纤维素酯和PLA/纤维素醚共混复合材料最新的研究进展,综述了复合材料在相容性、分散性、力学性能和降解特性等方面存在的优点和缺点,为此类共混复合材料的进一步研究指明方向。     

健康环保的甲壳素服装面料

甲壳素是一种具有抗菌、保健、环保的天然纤维素材料。用其加工的纤维和面料具有很多独特的性能。主要介绍了用甲壳素对面料进行的各种改性整理,指出甲壳素将会有更广泛的应用空间。     

新型仿生化纤维的制备与纤维性能评价

为提高纤维素纤维和壳聚糖纤维的生物相容性能并保持纤维原有的力学机械强度,在其单纤维纺丝溶液中添加原胶原蛋白、丝素蛋白、甲壳素等,经湿法纺丝,考察了各种混合纤维的密度、直径、纤度、强度、伸长率等性能的变化。研究结果表明:壳聚糖纤维中混合原胶原蛋白后,纤维纤度增加,但对纤维的伸长和强度影响不大;当原胶原蛋白含量达10%时,纤维伸长率最大。纤维素纤维因添加了丝素后,强度、伸长下降,但添加第三组分甲壳素后表现出优异的机械性能。扫描电镜对混合纤维的形貌分析证实了生物材料与甲壳素、壳聚糖及纤维素间存在着良好的共混相容性,对纤维性能起到改善的作用。     

甲壳素-壳聚糖的抑菌性能研究进展

甲壳素是一种仅次于纤维素的第二大天然高分子聚合物,是一种可再生资源。概略的记述了目前甲壳素及其脱酰衍生物?壳聚糖的特性以及其在抑菌方面的研究进展。     

天然高分子材料在改性水性聚氨酯中的应用

介绍了甲壳素／壳聚糖、淀粉和纤维素等天然高分子材料的特点。综述了天然高分子材料在改性水性聚氨酯方面的研究进展。展望了天然高分子材料的应用前景。     

甲壳素——壳聚糖的抑菌性能研究进展

甲壳素是一种仅次于纤维素的第二大天然高分子聚合物，是一种可再生资源。记述了目前甲壳素及其脱酰衍生物——壳聚糖的特性以及其在抑菌方面的研究进展。     

天然胶乳共混改性的研究进展

概述天然胶乳/天然高分子(包括壳聚糖、淀粉、纤维素和丝素蛋白质)共混、天然胶乳/合成胶乳共混、天然胶乳/合成乳液共混和天然胶乳/纳米材料共混等不同改性方法的研究进展.由于天然胶乳制品的耐油、耐老化等性能不佳,为扩大天然胶乳使用范围,有必要对胶乳进行物理改性或化学改性,使天然胶乳朝高性能化方向发展.     

甲壳素开发应用的新进展

甲壳素作为一种资源丰富的天然高分子化合物,具有广泛的用途。本文对该领域研究和发展的新动向进行了分析和展望。     

甲壳质在农业上的开发及应用

甲壳质是地球上最丰富的天然高分子化合物之一在农业上具有广阔的应用前景,对甲壳质及其衍生物独特的作用机理及应用于农业的重要领域进行了述评。     

生物基绿色涂料的研究进展

植物油、纤维素、甲壳素等生物基材料,由于其原材料来源丰富、挥发性低、无毒性、生物相容性和生物可降解性良好,成为理想的可再生绿色资源。植物油的主要成分为甘油三酸酯,其包含脂肪酸长链;可以通过化学方法对脂肪酸进行羟基化、环氧化、甘油醇解、马来酸酐化等处理。因此,植物油基聚合物材料已经广泛地应用于醇酸树脂、环氧树脂、丙烯酸酯树脂以及聚氨酯涂料等方面。纤维素和甲壳素是自然界中最广泛的生物多糖大分子,利用它们含有的羟基或是经过化学改性处理后可以发展新型的生物基材料。本文综述了这几类生物基可再生资源在涂料中的研究和发展趋势。     

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.     

纤维素与甲壳素常压酸催化液化生成小分子化学品的机理研究进展

在过去的二十年里,利用常压催化液化法将木质生物质尤其是纤维素转化为小分子化学品的研究已经取得了一定的成果,近年来,常压催化液化法开始被应用于甲壳素生物质向小分子化学品转化的研究,极大地丰富了液化产物的种类尤其是含氮小分子化学品的类型。本文对常压下酸催化的纤维素与甲壳素在不同溶剂中液化生成的小分子化学品进行了总结,并重点对其液化机理的研究进展进行了阐述。提出了纤维素与甲壳素液化制备小分子化学品及机理研究中存在的一些问题及解决途径的建议,并对甲壳素的液化研究进行了展望。     

Intensifying chitin hydrolysis by adjunct treatments – an overview

Chitin is, after cellulose, the most abundant organic natural polysaccharide on Earth, being synthesized as a dominant component in the exoskeletons of crustaceans, among other sources. In the processing of seafood for human consumption, between 40 and 50% of the total raw material mass is wasted, causing a significant problem for the environment owing to its slow degradation. Efforts to find uses for chitin derivatives, particularly their oligomers, have intensified since these chemicals are highly functional and offer a wide range of applications, especially as antimicrobial agent. As a consequence, some adjunct treatments, either chemical or physical in nature, have been employed to assist acid and enzymatic hydrolysis. This work provides a detailed review of the methods employed to intensify the formation of chitin oligomers, particularly focusing on the adjunct treatments used (microwave, ultrasonication, steam explosion and gamma irradiation), and an evaluation of the yield and characteristics of the oligomers formed. Adjunct treatments are more suitable for enzymatic hydrolysis since these treatments modify the chitin structure, and enhance the hydrolysis rate and yield of the oligomers, under milder reaction conditions. For future research, it would be worth trying pre‐treatments like the application of high‐pressure to chitin in order to lower its crystallinity. © 2017 Society of Chemical Industry     

The preparation and properties of cellulose/chitin blend filaments

The focus of this article is the preparation and characterization of cellulose/chitin blend filaments obtained from cellulose/chitin xanthate blend solution over the experimental blend ratio, i.e., 2.89% and 6.46% (w/w) chitin content. The addition of chitin xanthate into cellulose xanthate leads to an increase of intermittence rate and the blend solution has good filtering property. Scanning electronic microscope photos shows that there exist grooves on the filaments surface, which are becoming coarse with increasing chitin content. The mechanical properties of the spun blend filaments is much higher than that of Crabyon® fiber, which proves that the viscose method we adopt here is an efficient way to prepare cellulose/chitin blend filaments with satisfactory mechanical properties and processing property. Based on the data from X‐ray, sonic velocity, equilibrium regain rate, and accessibility, it is concluded that the degree of crystallinity, modulus, degree of orientation, density, equilibrium regain rate, and accessibility of blend filaments decreases with increasing chitin content in the blend filaments in the experiment scope. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

天然高分子静电纺纳米纤维的研究进展

介绍了静电纺丝的原理及利用静电纺丝方法制备天然高分子纳米纤维的最新研究进展,主要介绍了海藻酸钠、天然纤维素、透明质酸、明胶、胶原蛋白、甲壳素及其衍生物等几种主要的天然高分子静电纺纤维的研究进展,并指出它们在生物医学领域的重要应用。     

Rheological properties of cellulose/chitin xanthate blend solutions and properties of the prepared fibers

The focus of this article is the rheological properties of cellulose xanthate, chitin xanthate, and their blend solutions with cellulose/chitin blend weight ratios of 9.5 : 0.5, 9 : 1, 8 : 2, and 5 : 5 (mostly 9 : 1 blend solutions). The preparation and properties of fibers from 9 : 1 blend solutions and cellulose xanthate solutions are also discussed. The non‐Newtonian index of the investigated solutions was found to vary in the following order: chitin < cellulose < 9.5 : 0.5 blend < 9 : 1 blend < 8 : 2 blend < 5 : 5 blend. Showing a tendency contrary to that of the non‐Newtonian index, the structure viscosity index varies in the following order: chitin > cellulose > 9.5 : 0.5 blend > 9 : 1 blend > 8 : 2 blend > 5 : 5 blend. For 5–9 wt % 9 : 1 blend solutions, increasing the solution temperature aids the improvement of the fluidity of 9 : 1 blend solutions in the temperature range of 10–40°C. The zero shear viscosity decreases in an index manner with the solution temperature increasing. The 7–8 wt % 9 : 1 blend solutions have good filtering and rheological properties and are ideal for spinning fibers. The mechanical properties of blend fibers spun from 7% 9 : 1 blend solutions are lower than those of pure cellulose and are much higher than those of Crabyon fiber, and they still reach the national criteria and fit the need for further processing. This proves that the viscose method which we have developed here is an efficient way of preparing cellulose/chitin blend fibers with satisfactory mechanical properties and processing properties. Scanning electron microscopy photographs show that the surface of 9 : 1 blend fibers is coarser than that of pure cellulose fibers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008