新型阳离子化羟乙基纤维素的合成与应用研究

以羟乙基纤维素(HEC)为基体原料、二甲基二烯丙基氯化铵(DMDAAC)为阳离子化单体,NaOH为改性剂,过硫酸钾(KPS)为引发剂,采用自由基接枝共聚合成了新型阳离子化羟乙基纤维素,并将其用于陶瓷料浆解凝剂研究。探讨了合成条件对产物分散高岭土料浆性能的影响。结果表明,羟乙基纤维素与阳离子接枝单体的摩尔比3.3%,引发剂与阳离子接枝单体比为2%,反应温度为75℃,反应时间为4h时,含水量为30%的高岭土料浆中添加0.5%的阳离子化羟乙基纤维素,用涂-4杯测定陶瓷料浆流动时间平均为25.4s,高于相同条件下传统解凝剂的流动性。     

超声波辅助阳离子羟乙基纤维素的合成研究

利用超声波辅助合成了阳离子羟乙基纤维素。结果表明,醚化过程中使用超声波,反应时间比传统湿法缩短一半,反应效率提高15%。通过红外、核磁等对产物的结构进行表征并用高效凝胶过滤色谱测定了其分子量及其分布。增稠性能实验表明,阳离子羟乙基纤维素具有很好的增稠效果。     

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。     

含硼非均相体系中纤维素阳离子化反应的优化

在含有硼化合物（BC）的异丙醇（iPA）-H₂O非均相体系中,以3-氯-2-羟丙基三甲基氯化铵（CTA）为醚化剂,对棉短绒纤维素（Cel.）进行阳离子化反应。采用正交实验确定了影响阳离子纤维素取代度（DS）的因素,并对反应进行了优化,并采用¹H-NMR对产物的结构进行了确认。结果表明,按m(Cel.)∶m(iPAⅠ)∶m(iPAⅡ)∶m(30% NaOH)∶m(50% CTA)∶m(BC)= 100∶1000∶400∶296∶696∶20的配比,室温25 ℃活化处理60 min,50 ℃恒温反应4 h,产物取代度DS达到0.54。     

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。     

用异丙醇精制高取代度羟乙基纤维素的研究

高取代度羟乙基纤维素可利用异丙醇溶液进行精制，根据高取代度HEC中灰分及其在异丙醇中的溶解速度和溶解度不同，通过实验确定了最佳的精制工艺条件：洗涤次数为2次，每次洗涤时间为20min，洗涤液用量为每克HEC需10mL异丙醇溶液，每次洗涤时洗涤液的用量均相同。本实验还设计了产品及废洗涤液中异丙醇回收的实验装置，具有很好的工业参考价值。     

羟乙基纤维素接枝聚合及衍生基团取代值的测定

利用三甲基硅(TMS)基团改性保护技术,成功制备了羟乙基纤维素接枝聚己内酯(HEC-g-PCL)聚合物;利用红外光谱及核磁共振波谱对合成产物进行了结构验证;利用化学滴定法测定了原料HEC的醚化取代度,通过1H-NMR确定了中间产物的取代度及聚己内酯接枝侧链的重复单元数,并测定了终产物接枝聚己内酯侧链的接枝率和ε-己内酯接枝效率。研究结果有助于对反应历程的探讨。     

高取代度羟乙基纤维素精制工艺研究

研究了高取代度羟乙基纤维素(H-HEC)的精制工艺。根据H-HEC在丙酮水溶液中的溶解特点,考察了在洗涤过程中影响产品灰分的因素,并通过实验确定了最佳的工艺条件。结果表明,采用质量分数75%的丙酮溶液作为洗涤溶剂,在常温下(<45℃),连续洗涤2次,每次洗涤20min,每次溶剂使用量与粗H-HEC的比为8mL:1g,过滤、干燥、粉碎后产品的最终灰分的质量分数≤5.0%。产品外观雪白、流散性好,洗涤过程中不溶解、易分离,H-HEC和溶剂的损失少,操作简单。     

Thermotropic behavior of hydroxyethyl cellulose acetate

Thermotropic behavior of hydroxyethyl celloulose acetate (HECA) was studied by polarizing microscopy, DSC, and X-ray diffraction. It was found that HECA was an anisotropic liquid between the temperature from 130 to 185°C on heating, and when the temperature was over 185°C, it became isotropic. In cooling, however, mesophase began to form at about 165°C. The transformation temperature decreased with decreasing molecular weight and the temperature region of transformation decreased with decreasing the distribution of the molecular weight for HECA. The kinetic ability of tranformation appeared the maximum with molecular weight. The HECA liquid crystal is cholesteric and the distance between layers of ordered molecular chains was enlarged when HECA was transformed from liquid crystalline glass to the liquid crystalline state. © 1994 John Wiley & Sons, Inc.     

羧甲基纤维素钠和羟乙基纤维素在日化产品中的应用

羧甲基纤维素钠(CMC)和羟乙基纤维素(HEC)是纤维素醚类产品中使用范围最广的产品,它们是纤维素链上葡萄酐单元的羟基与醚化基团(氯乙酸或环氧乙烷)反应而成的。其水溶液是非牛顿性流体,黏度随剪切速率变化而与时间无关。溶液的黏度随浓度增大迅速增加,是使用范围最广的增稠剂和流变助剂。介绍了CMC和HEC的分子结构、合成制备、溶液特性和在日化产品应用的配方。     

羟乙基纤维素开发利用前景广阔

介绍了羟乙基纤维素的一般性质、应用和生产方法以及国内外生产情况。并对市场需求做了预测,指出只要羟乙基纤维素质量好而稳定,价格进一步降低,国内的潜在市场将达2500～3500t／a。     

Study of rheological behavior of hydrophobically modified hydroxyethyl cellulose

Hydrophobically modified hydroxyethyl cellulose (BD‐HAHEC) was synthesized by the macromolecular reaction of hydroxyethyl cellulose (HEC) with bromododecane (BD). Study of the effects of polymer concentration, shear rate, temperature, and electrolytes on the rheological behavior of BD‐HAHEC indicated that the polymers had high viscosity, excellent viscosity retention in brine water, good thermal stability, and surface activity. Furthermore, investigation of the micromorphology of BD‐HAHEC solutions revealed the close relationship of rheological behavior and a hydrophobically associating effect. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3346–3352, 2006     

Photoinitiated graft copolymerization of hydroxyethyl methacrylate onto cotton cellulose

The photoinitiated graft copolymerization of hydroxyethyl methacrylate (HEMA) onto cotton cellulose was studied using uranyl nitrate (UN) and ceric ammonium nitrate (CAN) photoinitiators. Optimization of various parameters of the graft-copolymerization reaction viz., time, temperature, initiator, and monomer concentration, was carried out. The optimized conditions of grafting were employed to cotton samples swollen in zinc chloride as well as sodium hydroxide. Graft add-on was found to be dependent on the nature of substrate and the concentrations of monomer and photoinitiator. UN was found to be the better photoinitiator, giving higher grafting with HEMA. The grafted samples showed initially decrease and then marginal increase in the moisture regain with increase in graft add-on. The dye uptake of both direct and reactive dyes decreased with increase in graft add-on.     

Photosensitized grafting of acrylamide and hydroxyethyl methacrylate onto cellulose

The photoinitiated copolymerization of acrylamide and hydroxyethyl methacrylate onto cellulose substrates, from acetone/water solutions, was studied using isopropyl thioxanthone as the photoinitiator. The graft copolymerization was carried out over a range of monomer and photoinitiator concentrations. Grafting is shown to be dependent on the nature of the monomer and the concentration of monomer and photoinitiator. In the case of acrylamide, it was found that there is an optimum concentration of the photoinitiator for grafting to occur effectively. The kinetics of graft copolymerization were studied in some detail and the results are considered.