纤维素衍生物

纤维素衍生物１概况我国纤维素衍生物工业已有数十年历史,除硝酸纤维素和粘胶纤维已有相当规模的大、中型厂外,羧甲基纤维素近年来已发展至数十家中小型厂,形成了年产２万ｔ以上的规模。但醋酸纤维素尚不足５０００ｔ／ａ规模。我国纤维素衍生物与国外相比,不论在品种...     

纤维素基重金属离子吸附材料研究进展

针对近年来利用纤维素及其衍生物制备高吸附材料的热点,概述了纤维素基重金属离子吸附材料(离子交换型纤维素吸附材料和离子螯合型纤维素吸附材料)的研究现状。     

新型纤维素衍生物--纤维素氨基甲酸酯概述

本文叙述了纤维素氨基甲酸酯的研究历程、性能及应用,并对其合成工艺和发展前景进行了分析。     

纤维素及其衍生物的应用

综述了纤维素及其衍生物产品在化学工业、生物医药、环境保护等领域内的应用情况。     

纤维素及其衍生物液晶

从纤维素及其衍生物的化学结构出发,综合论述了纤维素衍生物的合成方法,液晶态的形成理论,液晶性能及其在塑料中的应用。     

新型疏水性改性羧甲基纤维素衍生物

由不同百分比含量的十六烷（HDA）改性组分（每单元酸根含HDA0．9－6％）取代的新型疏水性羧甲基纤维素衍生物,是采用不同方法对羧基进行酰胺化作用而制得的。改性组分的百分比含量（HDA0通过电导滴定进行控制,并采用^13C核磁振波谱法对纤维素酶水解后的剂聚物进行定量测定。在干燥的二甲亚砚中经N,N′－双环已碳二酰胺（DCCI）活经的酸式CMC与十六碳胺耦合后,可达到最低的降解度（用GPS法制定）。在稀释的溶液范围内,粘度的降低是由于疏水性改性CMC衍生物分子内部的相互作用力所产生的分子链缩短所致。这些作用力由于离子强度增加而达到均衡。流变性测定结果表明HDA达到6％时表观粘度值增大,这是由于分子间相互作用力的存在抵消了剪切速率增加的影响,从而在半稀释浓度范围内超过叠加浓度（C^*p达到1．5g/l）。该特性采用一种中等剪切稀释效应来证明,它与未改性聚合物不同,后者的浓度直至C^*p达到5．3g/l时其粘度也表现出与剪切速率无关（牛顿流体性能）的特点。     

我国纤维素衍生物工业现状及发展

我国纤维素衍生物工业已有数十年历史,除硝酸纤维素和粘胶纤维已有相当规模的大、中型厂外,按甲基纤维素近年来已发展至数十中小型厂,形成了2万ua以上的生产规模。但醋酸纤维素尚不足0．5万Ua规模。我国纤维素衍生物与国外相比,不论在品种,产量,质量和价格上都有较大的差距。1纤维素酯类产品该类产品主要品种有硝酸纤维素、二醋酸纤维素、三醋酸纤维素、丁醋酸纤维素和丙醋酸纤维素。1．l硝酸纤维素虽然目前电影片基几乎全部为三醋酸纤维和涤纶树脂所代替,但硝酸纤维素由于价格低廉,尚有相当用量,而用于清漆、塑料和薄膜的硝酸纤…     

生产再生纤维素纤维的新溶剂研究进展

综述了近年来再生纤维素纤维新溶剂法生产技术的研究进展，主要介绍了目前研究较多的一些纤维素新溶剂体系，比较了不同溶剂体系的特点，简要分析了这些溶剂体系的工业应用前景。     

Melt spinning of thermotropic cellulose derivatives

The melt spinning of two thermotropic cellulose derivatives—trimethyl silyl cellulose and phenyl acetoxy cellulose—is described in this article. Removal of the substituents was facile, rapid, and essentially complete. Both the melt‐spun and regenerated fibers had banded textures typical of fibers spun from a liquid crystalline phase. The regenerated cellulose fibers had high strengths and moduli compared to viscose rayon and Lyocel cellulose fibers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 418–423, 2000     

疏水化水溶性纤维素衍生物

疏水化水溶性纤维素衍生物是一类既含疏水基又含亲水基的新型纤维素改性物,性能独特,应用前景广阔。综述了迄今用于其制备与表征的若干方法,包括引人长链烷基流水基、碳氟疏水基、多环芳基流水基的大分子反应制备方法和应用核磁共振、紫外光谱、裂解／气相色谱技术的表征方法;同时对其溶解、增稠、表面活性、吸附及荧光光谱等主要物性进行了简要总结。     

Preparation of cellulose derivatives containing carbazole chromophore

Cellulose derivatives containing long hydrocarbon side chains and the carbazole chromophore are prepared. N‐4′‐Bromobutylcarbazole is first synthesized from carbazole and 1,4‐dibromobutane. Alkylated carbazole is then reacted with cellulose acetate in dimethyl sulfoxide solution to produce cellulose ethers containing the desired chromophore. Polymers containing a mixture of alkyl side chains are also prepared by the subsequent addition of 1‐bromododecane to the reaction mixture. Characterization of the resulting cellulose derivatives by FTIR spectroscopy indicates that the deacetylation of cellulose acetate and the subsequent etherification are both complete. In addition, the incorporation of the carbazole chromophore is clearly shown by ¹H‐ and ¹³C‐NMR spectroscopy. Polymers of different carbazole content, ranging from 2.9 to 1.1 chromophores per anhydroglucose repeat unit, are obtained by varying the reaction conditions. Substitution is found to be controlled primarily by the quantity of alkylating agent introduced while variation of the reaction time has little effect. This method is used to prepare (dodecyl)_y(N‐4′‐carbazolylbutyl)_xcellulose, (decyl)_y(N‐4′‐carbazolylbutyl)_xcellulose, and (butyl)_y(N‐4′‐carbazolylbutyl)_xcellulose. Cellulose acetate can be replaced by (methyl)cellulose as the starting material to obtain analogous products. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2764–2772, 1999     

Diffusion of glucose derivatives in aqueous solutions of hydroxypropyl cellulose

The diffusion behaviour of glucose and three of its derivatives in aqueous solutions of hydroxypropyl cellulose was studied as a function of polymer concentration. A shearing type diffusion cell was used together with a schlieren optical system. The presence of polymer did not affect the diffusion of glucose. The derivatives, however, exhibited a linear decrease in diffusion coefficient with increasing polymer concentration. The results were discussed in terms of solvation and obstruction.     

纤维素的改性及应用研究进展

植物纤维素是天然的可再生资源, 对纤维素的改性利用一直是研究的热点。本文简要介绍了纤维素的结构与性质, 综述了纤维素的改性方法, 包括物理改性、化学改性和生物改性等, 其中化学改性是最主要的方法, 包括酯化、磺化、醚化、醚酯化、交联和接枝共聚等, 通常涉及其结构中羟基的一系列反应。通过改性, 引进了一系列离子型基团, 有利于增强纤维素的亲水性。经改性后的纤维素与之前相比, 结晶度和聚合度明显降低, 可及度明显提高, 无论物理性质还是化学性质都表现出更大的优越性。其后回顾了纤维素衍生物在食品、造纸以及建筑行业中的一些研究应用成果, 阐述了其在医药及废水处理等方面的研究进展, 并展望了纤维素衍生物的发展前景。     

Intrinsic viscosity of cellulose derivatives and the persistent cylinder model of Yamakawa

By using the chain model proposed by Yamakawa, intrinsic viscosity measurements allow characterization of cellulose derivatives in dilute solution by persistence length and hydrodynamic diameter as a function of different parameters such as temperature of solvents, degree of substitution and type of substituent.     

Structure and mechanical properties of cellulose derivatives/soy protein isolate blends

Biodegradable and biocompatible composites based on soy protein isolate (SPI) and various cellulose derivatives have been prepared, and the dependence of structures and mechanical properties on the content and species of cellulose derivatives for the composites were investigated by X‐ray diffraction, differential scanning calorimetry, scanning electron microscope, and tensile test. The selected cellulose derivatives, such as methyl cellulose (MC), hydroxyethyl cellulose (HEC), and hydroxypropyl cellulose, were miscible with SPI when the content of cellulose derivatives was low, and then the isolated crystalline domains, shown as the structures of network and great aggregate, formed with an increase of cellulose derivative content. The miscible blends could produce the higher strength, and even result in the simultaneous enhancement of strength and elongation for the HEC/SPI and MC/SPI blends. Meanwhile, the moderate content of great MC domains also reinforced the materials. However, the damage of original ordered structure in SPI gave the decreased modulus. Since all the components, i.e., cellulose derivatives and soy protein, are biocompatible, the resultant composites are not only used as environment‐friendly material, but the biomedical application can be expected, especially for the tissue engineering scaffold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

纤维素氨基甲酸酯的生产工艺研究

探讨了新型纤维素纤维原料纤维素氨基甲酸酯的生产工艺,指出当纤维素浆粕活化用氢氧化钠溶液质量分数为14％～16％,活化温度40～50℃,活化时间为30～40min,尿素与纤维素的质量比(2:1)～ (3:1),反应时间为2-3 h时,纤维素氨基甲酸酯可在氧氧化钠溶液中形成良好的稳定溶液,其过滤性好, 可直接用于纺丝。