阳离子羟乙基纤维素溶液黏度性能的研究

以羟乙基纤维素（HEC）为原料,2-氯-4,6-二（N,N-二甲基-N-苄基1,3-丙二胺）1,3,5-均三嗪为改性剂,制备出不同取代度阳离子羟乙基纤维素。同时探讨了取代度及其浓度、阳离子及其浓度、转子转速、温度、pH值对阳离子羟乙基纤维素（CHEC）的黏性行为的影响。结果表明,阳离子羟乙基纤维素溶液黏度随着CHEC浓度增大、温度的升高、pH值的增加而减小。同一CHEC质量浓度下,取代度越高,转子的转速降低,黏度增大。CHEC在K₂SO₄溶液中的黏度总低于MgSO₄溶液中黏度;随着阳离子浓度的增加,CHEC溶液的黏度降低。     

新型阳离子羟乙基纤维素醚的合成

以羟乙基纤维素为原料、2-氯-4,6-二（N,N-二甲基-N-苄基-1,3-丙二胺）-1,3,5-均三嗪（BT）为改性剂,合成新型季铵盐阳离子羟乙基纤维素醚,讨论了影响产物取代度的主要因素。结果表明：在异丙醇稀释剂中,NaOH和改性剂的物料量比为1．2：1,改性剂和羟乙基纤维素的物料量比为1．5：1,反应温度为95℃、反应时间为5h时,产物的取代度最高达0．24。     

阳离子纤维素在二合一洗衣液中的柔顺和去污性能研究

将阳离子改性纤维素应用于二合一洗衣液,考察阳离子改性纤维素的分子结构对二合一洗衣液配方的柔顺和去污性能的影响。结果表明,阳离子改性纤维素易于形成透明二合一洗衣液配方,并且具有提高织物柔顺性、蓬松度、同时保持良好吸水性的功效。阳离子取代度对柔顺和去污性能的影响不大;疏水取代度越低,柔顺性能越好,去污性能越差;分子量越高,柔顺性能越好,去污性能越差。     

离子液体中羟丙基纤维素的合成

使用离子液体1,3-二乙基咪唑磷酸二乙酯盐([EEIM][DEP])为反应溶剂主组分来溶解微晶纤维素进行羟丙基化衍生,微晶纤维素和醚化剂在离子液体中均可形成均相,通过碱化、醚化、酸化及洗涤等步骤制备得到不同取代度的羟丙基纤维素。考察了碱化反应温度、反应原料摩尔比、醚化反应时间及酸化剂的种类对羟丙基纤维素产品的收率和摩尔取代度的影响,并采用红外、核磁、TGA等手段对产品结构进行了表征。     

香蕉纤维素在离子液体中的均相改性

以香蕉纤维素为原料,1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)离子液体为反应介质,乙酸酐为酯化剂,在不加任何催化剂条件下,实现了香蕉纤维素的均相改性。研究了反应时间、反应温度以及乙酸酐与纤维素葡萄糖单元的摩尔比对产物取代度的影响。结果表明,其最优条件为:反应温度为80℃,反应时间为4h,乙酸酐与纤维素葡萄糖单元的摩尔比为5∶1。采用傅里叶变换红外光谱仪(FTIR)、核磁共振氢谱(1HNMR)、热重分析仪(TGA)和扫描电镜(SEM)对其进行表征。结果表明产物的FTIR和1HNMR谱图中有明显的乙酰基特征峰;TGA和SEM表明产物纤维素醋酸酯的热稳定性较原纤维素有所提高,并失去了原纤维状。     

一种合成季铵盐阳离子瓜尔胶的新方法

以瓜尔胶胚乳片为原料,3-氯-2-羟丙基三甲基氯化铵为阳离子醚化剂,在水媒介中合成阳离子瓜尔胶。利用FTIR光谱对阳离子瓜尔胶进行结构表征。通过正交试验研究碱的用量、阳离子醚化剂用量、反应温度、反应时间对产物的取代度的影响。结果表明,在胚乳片为100 g,NaOH为12 g,3-氯-2-羟丙基三甲基氯化铵为50 g,45~50℃反应60 min条件下,可以得到取代度0.08的季铵盐瓜尔胶,其中碱量和阳离子醚化剂用量对产物取代度影响较大。     

季铵型低取代度阳离子淀粉的合成

以玉米淀粉及3-氯-2-羟丙基三甲基氯化铵(CTA)为原料,采用水法制备低取代度季铵型阳离子淀粉,讨论了醚化剂用量、NaOH用量、反应温度、反应时间等对取代度的影响。结果表明,最佳合成条件为:淀粉50 g,醚化剂用量3 g,NaOH用量为0.77 g,反应温度40℃,反应时间2 h,制备的阳离子淀粉取代度可达0.079。     

微波辅助离子液体法对纤维素的均相改性研究

以离子液体1-丁基-3-甲基咪唑氯盐（BMIMCl）为溶剂,采用微波辐射代替常规的加热技术,对纤维素进行均相改性研究。首先进行微波辐射下纤维素在离子液体中的溶解,研究微波辐射温度和溶解时间的影响;其次进行纤维素与氯乙酰氯在微波辅助离子液体中的均相乙酰化研究,利用FT-IR、1H-NMR对聚合物进行了表征,探讨微波辐射功率、反应温度、反应时间和氯乙酰氯用量对纤维素取代度的影响。结果表明,微波加热有利于纤维素溶解和酯化,辐射时间和温度提高均会增加纤维素溶解量,酯化剂用量和微波辐射时间对反应影响较大。     

阳离子壳聚糖的干法制备

以Na0H为催化剂，N-(2，3-环氧丙基)三甲基氯化铵(GTAMc)为阳离子化试剂，干法制备了高取代度的阳离子壳聚糖。研究了Na0H用量、阳离子化试剂用量、反应时间和反应温度对得率和季铵化度的影响。当壳聚糖为100g，GTMAc用量为282g时，最佳反应条件为1gNaOH、反应温度80℃、反应时间3h。在此条件下，反应得率为92％，季铵化度为95％。     

阳离子纤维素抗菌薄膜材料的制备及性能研究

将抗菌单体3-氯-2-羟丙基-三甲基氯化铵(ETA)接枝在纤维素上制得阳离子纤维素,再利用NaOH/硫脲混合水溶液为溶剂,在冰冻条件下溶解所制得的阳离子纤维素,以CaCl2/HCl水溶液为凝固剂,从而得到新型共价键型固相接触抗菌膜。并用IR、XRD、SEM、拉伸、抑菌圈等测试方法对阳离子纤维素膜的结构和性能进行了测试,表明所制得阳离子纤维素膜抗菌性好,并具有良好的机械性和降解性。     

羧甲基纤维素阳离子化衍生物的研究现状

羧甲基纤维素阳离子化改性是制备性能优良的天然两性高分子的重要方法之一。文章综述了迄今为止羧甲基纤维素阳离子化改性所用的阳离子单体的主要类型及其接枝的若干主要途径,其中包括自由基型接枝共聚、高分子侧基反应、聚合后功能化等三大类。     

Preparation of betaine‐modified cationic cellulose and its application in the treatment of reactive dye wastewater

Betaine‐modified cationic cellulose was prepared through the reaction of cellulose with betaine hydrochloride by an efficient one‐step dry method. Dicyandiamide was used as a dehydrating agent to promote the formation of ester bonds between the reactants. Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy were used to characterize the cellulose betainate. Experiments showed that at a molar ratio of the cellulose glucose unit, betaine hydrochloride to dicyandiamide, of 1:1:0.5 at 150°C for 3 h, the degree of substitution of the cationic group reached 0.80. The adsorption of simulated C. I. Reactive Red 24 and C. I. Reactive Red 195 wastewater on the cationic cellulose was carried out, and the effects of the adsorbent dose, initial dye concentration, and salt concentration on the dye removal efficiency were investigated. The equilibrium adsorption isotherm data of the cationic cellulose exhibited a better fit to the Langmuir isotherm model than the Freundlich one. The experimental results suggest that the prepared cationic cellulose materials show potential application for reactive dye wastewater treatment. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40522.     

微晶纤维素醋酸酯的合成与工艺研究

以微晶纤维素为原料,浓硫酸为催化剂,制备了一系列不同取代度的纤维素醋酸酯。研究了反应时间、温度、原料配比、催化剂用量对取代度和产率的影响,并通过红外图谱进行了表征。结果表明：随着反应时间、反应温度、原料配比和催化剂用量的增加,产物取代度增大,但产率降低。在温度为85℃,时间为10min,浓硫酸用量为1mL,醋酸酐与微晶纤维素的用量比为25∶1的最佳合成条件下取代度接近3,与理论值相符合。     

阳离子纤维对活性染料X-BR吸解行为研究

用阳离子纤维吸附水溶液中的阴离子活性染料X-BR,从吸附条件和吸附动力学2方面研究了阳离子纤维对阴离子染料的吸附情况,比较了不同条件下阳离子纤维的吸附及解吸性能.结果表明,在阳离子纤维浸入含染料水溶液中的吸附与解吸的研究中,染料溶液初始含量越大,吸附速率常数越大,吸附符合伪2级动力学模型;染料水溶液中含有电解质如NaCl、Na_2SO_4对吸附过程有一定影响;随着阳离子纤维吸附量的增加,NaOH溶液含量增加,解吸率随之增加.     

Adsorption of bark derived polyphenols onto functionalized nanocellulose: Equilibrium modeling and kinetics

This article describes the kinetics and capacity of adsorbing condensed conifer tannins onto cationic cellulose nanocrystals (CCNCs). Batch adsorption experiments were carried as a function of pH, contact time, and initial tannin concentration with constant cationic cellulose nanocrystal concentration (0.01%). The adsorption process was highly pH dependent as adsorption capacities ranged from 13.2 mg/g to 112.7 mg/g at pH of 3–10. The amount of tannin adsorbed per unit mass of the cationic cellulose nanocrystals increased with increasing of tannin concentration until equilibrium was attained. The experimental data followed the Langmuir adsorption model, and the maximum experimental and theoretical adsorption capacities for the cationic nanocrystals reached 1,008 mg/g and 1,111 mg/g, respectively. The kinetics of adsorption was described best by the pseudo-second-order kinetics indicating a chemisorption process. The inherent adsorption has interesting applications for CCNC-complexes with natural polyphenolics in green chemical applications for adhesives, adsorbents, preservatives, and packaging materials.     

Derivatization of cellulose in lithium chloride and N-N-dimethylacetamide solutions

The derivatization of cellulose in mixtures of lithium chloride and N,N-dimethylacetamide (LiCl/DMAc) is described. A wide range of cellulose derivatives, including cellulose esters, carbamates, sulphonates and ethers, have been synthesized in homogeneous solution using the LiCl/DMAc solvent. In most cases, a high degree of substitution was achieved, and the degree of substitution could be controlled accurately. Compared to current heterogeneous synthesis of cellulose derivatives, reactions conducted in homogeneous solutions of LiCl/DMAc have many advantages: (1) reactions may be conducted at moderate temperatures; (2) less reagent is required; (3) less degradation of the cellulose occurs; and (4) substitution is uniformly controllable.     

A new and simple way of preparing polycation‐grafted fibrous cellulose

A new way of producing polycation‐grafted fibrous cellulose for its use as a retention aid in the papermaking process was conceived. It consists of adding, under intense stirring, to a cellulose fibers suspension at a basic pH a cationic polyacrylamide dissolved in water. As the cellulose fiber's surface is negatively charged because of its more or less acid groups, the cationic polymer adsorbs on it. The cationic‐grafted cellulose fibers are very similar to the cellulose fibers used in papermaking, since the polymer is (on a micrometer scale) homogeneously grafted on them as a film. It could so be used to increase the retention of the negatively charged fillers, fibers, and pigments during the process, without altering the properties of the resulting sheet of paper. The amount of polymeric grafts depends on the quantity of anionic groups on fiber's surface and varies monotonically with the grafting temperature and polyacrylamide's concentration in the blend. The grafted fibrous cellulose is well stable, even in drastic media and for lower M_w grafts, and the amount of grafted polymer also depends on the concentration and characteristics of fiber's suspension. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3149–3157, 2006