秸秆CMC的流变性能及在姜黄素染发中的应用

以废弃小麦秸秆为原料,采用硝酸-乙醇法提取秸秆纤维素,再通过醚化反应制备了不同取代度的秸秆羧甲基纤维素(CMC)。采用DHR-2流变仪研究了CMC水溶液的流变性能,最后将CMC应用在姜黄素染发中,并与市面上常用的增稠剂比较。结果表明,CMC水溶液为假塑性流体,具有剪切稀化的性质,其体系黏度随平均取代度(DS)、质量分数的增大而增加;CMC水溶液的线性黏弹区为应变小于70%的区域,其范围几乎不受CMC质量分数的影响;CMC水溶液体系黏度随剪切速率的阶跃改变而发生阶跃变化,具有良好的触变性。CMC能使姜黄素易于上染,对毛发损伤小,染后毛发色泽鲜艳饱满,且保持了较好的毛发强度和色牢度。     

糠醛渣制备羧甲基纤维素的研究

以糠醛渣为原料,采用Milox法提取纤维素,经漂白处理后制备羧甲基纤维素(CMC),对纤维素提取工艺、漂白工艺及CMC的合成进行了初步研究。实验结果表明,纤维素提取工艺优化条件:甲酸80mL,过氧化氢14mL,反应时间2.5h—2.5h—2.5h,反应温度80℃—95℃—80℃;漂白工艺条件:可选择过氧化氢10mL,氢氧化钠质量浓度2.5g/L,反应温度45℃,反应时间60min。制得的CMC的取代度为0.901 2,黏度为45mPa·s。     

蔗渣再生纤维素制备高取代度羧甲基纤维素钠的研究

先以NaOH/H2O2水溶液对蔗渣进行预处理,再用预冷至-12℃的7%NaOH/12%尿素水溶液对预处理蔗渣进行分离,获得结构蓬松的蔗渣再生纤维素。以蔗渣再生纤维素为原料,以氯乙酸钠为醚化剂,在85%乙醇水溶液中,采用一次碱化、二次醚化的工艺,制备了羧基取代度达1.45的羧甲基纤维素钠(CMC)。利用红外光谱(FTIR)、扫描电镜(SEM)、X-射线衍射(XRD)、热重分析(TGA)等手段对样品的结构进行了表征,并研究了羧甲基纤维素钠样品的黏度性能。     

不同碱金属氢氧化物对纤维素羧甲基化的影响

以不同碱金属氢氧化物(NaOH,KOH)为碱化剂,利用淤浆法合成CMC,对纤维素的碱化及羧甲基化进行了研究。结果表明,NaOH质量分数为25%,纤维素达到最大的润胀,KOH质量分数在20%~35%,纤维素的润胀率出现平台区;同一质量分数下,纤维素在NaOH溶液中的润胀率和吸附碱量都比在KOH中高;CMC的取代度随NaOH用量的增加急剧增加,而随KOH量的增加较为缓慢;取代度相近时,羧甲基纤维素钾的耐酸性和耐盐性比羧甲基纤维素钠差。     

改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素复合高吸水性树脂的制备和性能研究

以改性聚天冬氨酸（KPAsp）、丙烯酸(AA)和羧甲基纤维素(CMC)为原料,采用水溶液聚合法合成改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素(KPAsp/PAA/CMC)复合高吸水性树脂。通过红外光谱（FTIR）、热重分析(TGA)和扫描电镜（SEM）对产物组成结构、热稳定性和表面形态进行表征。探讨了CMC和AA用量对复合高吸水性树脂吸液性能的影响,结果表明当m(CMC)/m(AA)/m(KPSI)=0.15:3:1时,树脂的吸液性能最佳,在去离子水和0.9% NaCl溶液中的吸水倍率分别达到830 g/g和130 g/g。研究了不同组成KPAsp/PAA/CMC吸水性树脂的盐敏感性、温度敏感性和pH敏感性,以及树脂在人工血、人工尿和不同浓度乙醇水溶液的吸液性能,结果表明复合树脂盐敏感性提高,在盐溶液中的吸液倍率为NaCl>FeCl3>CaCl2;低临界溶解温度(LCST)比KPAsp提高了15℃;在溶液pH=5和pH=9出现了两吸液高峰;在人工血和人工尿中的吸液倍率最大为211 g/g和142 g/g,在50%的乙醇水溶液中吸液倍率最大为295 g/g。     

改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素复合高吸水性树脂的制备及其性能

以聚琥珀酰亚胺(KPSI)、丙烯酸(AA)和羧甲基纤维素(CMC)为原料,采用水溶液聚合法合成改性聚天冬氨酸/聚丙烯酸/羧甲基纤维素复合高吸水性树脂(KPAsp/PAA/CMC)。通过红外光谱(FTIR)、热重分析(TGA)和扫描电镜(SEM)对产物的结构、热稳定性和表面形态进行表征。探讨了CMC和AA用量对复合吸水性树脂吸液性能的影响,结果表明,当m(CMC)∶m(AA)∶m(KPSI)=0.15∶3∶1时,树脂的吸液性能最佳,在去离子水和质量分数0.9%的NaCl水溶液(生理盐水)中的吸液倍率分别达到843 g/g和130 g/g。研究了不同组成KPAsp/PAA/CMC吸水性树脂的盐敏感性、温度敏感性和pH敏感性,以及树脂在人工血、人工尿和不同体积分数乙醇水溶液的吸液性能,结果表明,复合树脂盐敏感性提高,在盐溶液中的吸液大小顺序为NaClFeCl_3CaCl_2;低临界溶解温度(LCST)比KPAsp提高了15℃;在溶液pH=5和pH=9出现了两吸液高峰;在人工血和人工尿中的最大吸液倍率为211 g/g和142 g/g,在体积分数为50%的乙醇水溶液中的最大吸液倍率为295 g/g。     

废弃玉米芯高效提取并改性为羧甲基纤维素的研究

利用废弃玉米芯提取纤维素并制备羧甲基纤维素(CMC),以提高玉米芯高值化利用.本研究采用酸水解法处理玉米芯,提取纤维素并改性为羧甲基纤维素,探究玉米芯提取并改性为羧甲基纤维素的最佳工艺.本研究以乙醇为溶剂,先从玉米芯中提取纤维素,经先碱化后醚化后得到羧甲基纤维素.通过单因素试验,探讨了碱化和醚化条件对CMC产品得率和取...     

以尿素为活化剂制备 聚阴离子纤维素的工艺及其性能研究

聚阴离子纤维素生产工艺有捏合法、淤浆法、均相法等。本文采用捏合法,以尿素为纤维素活化剂,酒精为溶剂制备了聚阴离子纤维素,并对其在钻井泥浆中的应用性能进行了研究。研究发现:在反应体系中加入6%的尿素,可以有效提高聚阴离子纤维素的取代度,改善取代均匀性;碱化温度控制在20～25℃,可以改善反应的均匀性;反应期间加入尿素、提高产品取代度(DS)均可有效降低泥浆滤失量。     

2-羟基-3-烯丙氧基丙基羟乙基纤维素的制备及温度敏感性能

利用醚化反应将烯丙基缩水甘油醚(AGE)接枝到羟乙基纤维素骨架上,制备出系列具有温度敏感性的2-羟基-3-烯丙氧基丙基羟乙基纤维素(HAPEC)。HAPEC的最低临界溶解温度(LCST)可通过改变疏水基团的取代度进行调节。当HAPEC的取代度从1.30增加到2.71时,LCST从64.3℃降低到28.5℃。通过荧光光谱、动态光散射法(DLS)考察了HAPEC在水溶液中的自组装行为,并测定了临界胶束浓度(CMC)。结果表明,HAPEC在水溶液中可自组装形成胶束,并且CMC随着HAPEC取代度的增大而减小。当HAPEC的取代度从1.11增加到2.71时,CMC从0.145 g/L下降至0.021 g/L。参照ASTMD 5988—03标准并利用SEM测试了HAPEC的生物降解度及降解前、后HAPEC样品形貌的变化。HAPEC具有良好的生物降解性,降解90 d后,其形貌变化明显,生物降解程度可高达36.5%。     

(会议论文）2-羟基-3-烯丙氧基丙基羟乙基纤维素的制备及温度敏感性能

利用醚化反应将烯丙基缩水甘油醚(AGE)接枝到羟乙基纤维素骨架上,制备出系列具有温度敏感性的2-羟基-3-烯丙氧基丙基羟乙基纤维素(HAPEC)。HAPEC的最低临界溶解温度(LCST)可通过改变疏水基团的取代度进行调节。当HAPEC的取代度从1.30增加到2.71时,LCST从64.3℃降低到28.5℃。通过荧光光谱、动态光散射法(DLS)考察了HAPEC在水溶液中的自组装行为,并测定了临界胶束浓度(CMC)。结果表明,HAPEC在水溶液中可自组装形成胶束,并且CMC随着HAPEC取代度的增大而减小。当HAPEC的取代度从1.11增加到2.71时,CMC从0.145 g/L下降至0.021 g/L。参照ASTMD 5988—03标准并利用SEM测试了HAPEC的生物降解度及降解前、后HAPEC样品形貌的变化。HAPEC具有良好的生物降解性,降解90 d后,其形貌变化明显,生物降解程度可高达36.5%。     

Homogenous carboxymethylation of cellulose in the NaOH/urea aqueous solution

In this work, the carboxymethylation of cellulose in the alkaline cellulose solvent, 7 wt% NaOH/12 wt% urea aqueous solution, was investigated. Carboxymethyl cellulose (CMC) samples were characterized with FT-IR, NMR, HPLC, and viscosity measurements. Water-soluble CMC with DS = 0.20–0.62 was prepared from both Avicel cellulose and cotton linters. Thus, carboxymethylation of cellulose in NaOH/urea leads to a polymer with the lowest DS value for water solubility (0.20) of CMC known. The total DS of CMC could be controlled by varying the molar ratio of reagents and NaOH to AGU and the reaction temperature. Structure analysis by means of HPLC after complete depolymerization showed that the mole fractions of the different carboxymethylated repeating units as well as those of unmodified glucose follow the simple statistic pattern. A distribution of the carboxymethyl groups at the level of the AGU in the order O-6 > O-2 > O-3 was determined. The results were similar with findings for CMC obtained by totally homogeneous reaction of cellulose in aqueous solvents such as Ni[tris(2-aminoethyl)amine](OH)₂.     

Characteristics of water-soluble fiber manufactured from carboxymethylcellulose synthesis

Carboxymethylcellulose (CMC), which is water-soluble fiber at room temperature, was manufactured from cellulose in this study. Experimental parameters included reaction temperature, time, concentration of NaOH, and monochloroacetic acid. In mercerization and etherification, the solubility and DS increased when NaOH (or MCA) concentration increased, and maximum solubility and DS were achieved when NaOH or MCA was 30%. The effect of MCA concentrations was larger than that of the NaOH concentration on DS. Tensile strength of the CMC fiber was affected and decreased by an increase in reaction time, reagent concentration and reaction temperature increase. Tensile strength also decreased by NaOH and MCA. However, low decrease of tensile strength was observed in near neutral region.     

Experimental study on carboxymethylation of cellulose extracted from Posidonia oceanica

The production of carboxymethylcellulose (CMC) from bleached cellulose pulps obtained from Posidonia oceanica was explored. The optimal reaction conditions were studied for the carboxymethylation of cellulose in organic liquids. The carboxymethylation reaction was carried out with NaOH and monochloroacetic acid (MAC) as the reagent. Different alcohols were compared in terms of the degree of substitution (DS). The highest DS was obtained with n‐butanol. For this alcohol, the effects of the temperature, alkali concentration, and MAC concentration were studied. The reaction was also carried out in three consecutive steps. The resulting CMC had a DS of about 2.75. The functionalization of cellulose was checked using FTIR spectroscopy and ¹³C‐NMR. The X‐ray analysis showed that the crystalline structure of cellulose decreased when the DS increased and the structure was totally amorphous in high DS material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1808–1816, 2006     

Synthesis and characterization of carboxymethyl cellulose powder and films from Mimosa pigra

Mimosa pigra peel was sun‐dried for 2 days and then ground before being boiled with 30%w/v sodium hydroxide (NaOH) at 100°C for 3 h, washed and then dried at 55°C to constant weight. The cellulose was then synthesized using different NaOH concentrations and monochloroacetic acid (MCA) in isopropyl alcohol (IPA). Effects of various NaOH concentrations on degree of substitution (DS), viscosity and thermal of carboxymethyl cellulose from Mimosa pigra peel (CMC_m) were investigated. The increasing of NaOH concentration resulted in increasing DS and viscosity. However, viscosity of CMC_m decreased as temperature increased. Thermal properties were studied using differential scanning calorimetry (DSC). The melting point of the samples decreased as %NaOH increased. The effects of various NaOH concentrations in CMC_m synthesis on the mechanical properties and water vapor permeability (WVP) of the CMC_m films were investigated as well. With increasing NaOH concentrations (30–50%) were also found to result in improved mechanical properties. However, when the level of NaOH concentration was 60%, the mechanical properties of the CMC films decreased. This result indicates that the highest mechanical properties were found for 50% NaOH‐synthesized CMC_m films. The WVP of the CMC_m films increased as %NaOH increased. In addition, the CMC_m films were tested to determine the effect of glycerol as a plasticizer on the mechanical properties. Increasing the amount of glycerol showed an increase in elongation at break but also led to a decrease in tensile strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Inter- and intra-molecular ionic interactions of polyampholyte: Carboxymethyl-2-diethylaminoethylcellulose

Carboxymethyl-2-diethylaminoethylcellulose (CM-DEAE cellulose) was prepared by etherification of carboxymethylcellulose with diethylaminoethyl chloride in a NaOH solution. The behaviour of CM-DEAE cellulose in aqueous solution was studied by viscosity and GPC measurements. The degree of substitution (DS) and existing states of DEAE substituents were examined by the use of proton NMR, and those of the CM substituents were observed with FT-IR. The results reveal that the reduced viscosity and apparent molecular size of CM-DEAE cellulose vary with the concentration of sodium chloride and changes in pH and DS. These phenomena can be explained in terms of inter- and intra-molecular ionic interactions.     

Preparation of sodium carboxymethyl cellulose from paper sludge

BACKGROUND: This paper describes the reuse of paper sludge, an industrial solid waste, for the preparation of sodium carboxymethyl cellulose (CMC). The process includes pretreatment, basification and etherification. RESULTS: The optimal pretreatment condition involved the addition of 6.7% hydrochloric acid to the paper sludge for 30 min at 70 °C. The order of factors influencing the effect of reaction was: etherification temperature > sodium hydroxide dose > basification temperature > etherification time > sodium chloroacetate dose. The optimal preparation condition of CMC was: m_papersludge: m_{sodiumhydroxide}: m_{sodiumchloroacetate} = 0.9:0.8:1.15; basification at 40 °C; etherification at 60 °C for 1 h. Under these conditions, certified CMC with viscosity less than 20 mPa· s, DS more than 0.50 and purity more than 90% was produced. The results of Fourier transform infrared (FTIR) and X‐ray diffraction (XRD) spectra analyses indicated that the product has characteristics of high degree of substitution (DS) and low crystallinity. The coated paper using CMC prepared from paper sludge as a water retention agent can meet the quality standards of GB/T 10335.1‐2005. CONCLUSION: Preparation of CMC from paper sludge can be considered a feasible alternative, generating value‐added product and contributing to solving environmental problems resulting from paper sludge. Copyright © 2008 Society of Chemical Industry     

Preparation and characterization of sodium carboxymethyl cellulose from cotton stalk using microwave heating

BACKGROUND: This paper describes the use of cotton stalk, an agricultural waste, for the preparation of sodium carboxymethyl cellulose (CMC) using microwave heating. The study includes the optimization of pre‐treatment and preparation processes, and the characterization of product. RESULTS: The optimal cotton stalk pre‐treatment condition involved the addition of 12% alkali to extract cellulose for 6 min at a microwave power of 200 W using the ratio of cotton stalk to solvent 1:9, giving 87.52% cellulose. Response surface methodology was applied to optimize the preparation of CMC, with the best conditions for preparation predicted by the model: $m_{\rm {cotton stalk cellulose}}:m_{\rm {sodium hydroxide}}:m_{\rm {sodium chloroacetate}} = {1.0:1.1:1.2}$ with etherification at 195.5 W of microwave power for 1.97 min. Under these conditions, CMC with degree of substitution (DS) 0.77, viscosity 498.0 cps and purity 92% was produced. The results of Fourier transform infrared (FT‐IR) spectroscopy indicated that the product had the characteristics of a high DS. Scanning electron microscopy showed that the particles were nearly clava in shape with length ranging from about 12–100 µm. The product met the quality standards of GB/T1904‐2005. CONCLUSION: Preparation of CMC from cotton stalk using microwave heating can shorten the processing time and may be considered a feasible alternative, contributing to solving environmental problems resulting from cotton stalk. Copyright © 2011 Society of Chemical Industry     

高粘耐盐性羧甲基纤维素工艺机理的研究

研究了制备数甲基纤维素（CMC）过程中加入四硼酸钠的工艺方法，研究表明，用这一工艺制得的CMC溶液质量明显改善，取代度（DS）0．8左右的CMC，2％水溶液粘度提高60％，用溶液透明度表示的取代基分布均一性提高。CMC的耐盐性用盐粘比（HS）表示，对四硼酸钠做交联和CMC溶液耐盐性的机理进行了解释。结果表明，加入3％－7％四硼酸钠微交联的CMC较未交联CMC的盐粘比提高30％－50%。