甘蔗渣制备高取代度羧甲基纤维素研究

提出一种一锅法制备高取代度羧甲基纤维素的方法,选用甘蔗制糖过程中产生的副产物甘蔗渣为主要原料,经碱浸泡、碱化及醚化合成了羧甲基纤维素,经单因素实验和正交试验探究得到最大取代度为0.3,且有良好的水溶性。利用红外光谱(IR)仪、X-射线衍射(XRD)仪、扫描电镜(SEM)仪及元素分析仪等设备对其进行了表征。证明所得产品为高取代度的羧甲基纤维素。     

毛竹笋壳制备羧甲基纤维素

以废弃毛竹笋壳为原料,经过4次加碱法制备出了羧甲基纤维素,并通过FTIR、XRD、TGA、SEM手段对原料与产品进行了表征。实验结果表明,制备羧甲基纤维素的最佳工艺条件为精制竹笋壳5 g,氢氧化钠5 g,氯乙酸6 g,85%乙醇溶液为溶剂,第1次碱化温度和时间分别为30 ℃和90 min,加入氢氧化钠总质量的80%,后3次碱化是在醚化过程中平均加入剩余20%的碱,醚化最终温度为70 ℃,醚化总时间为3 h。在此工艺条件下,所得到的羧甲基纤维素的取代度为0.9341,黏度为35 mPa?s。     

水媒法合成羧甲基纤维素工艺改进

实验室及工业生产上用水媒法制备羧甲基纤维素的最佳工艺条件为：原料配比为棉花：氯乙酸：３０％ＮａＯＨ＝５：６：２６，常温常压，反应约２ｈ。生产的羧甲基纤维素产品取代度高达０．８－２．２粘度可达１Ｐａ．ｓ－３Ｐａ．ｓ，且水溶性好而迅速。     

水媒法合成羧甲基纤维素工艺改进

实验室及工业生产上用水媒法制备羧甲基纤维素的最佳工艺条件为：原料配比（质量比）为棉花∶氯乙酸∶３０％ ＮａＯＨ＝ ５∶６∶２６,常温常压,反应约２ ｈ。生产的羧甲基纤维素产品取代度高达０．８～２．２,粘度可达１ Ｐａ·ｓ～３ Ｐａ·ｓ,且水溶性好而迅速。     

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...     

表面活性剂对碳化法制备白炭黑的影响研究

在碳化法制备白炭黑的过程中分别选用聚乙二醇6000、十二烷基苯磺酸钠、羧甲基纤维素等三种表面活性剂制备改性白炭黑。参察产品的性能，筛选合适的表面活性剂。     

植物秸秆制备羧甲基纤维素

提供了以植物秸秆为原料制备羧甲基纤维素的方法，并对其合成工艺条件进行了讨论。     

微波法合成羧甲基淀粉

本实验报道以木薯淀粉为原料，在微波下，采用干法制备羧甲基淀粉。系统地分析了淀粉经微波处理后的性能变化，研究了微波干法合成羧甲基淀粉的工艺条件，并探测了不同取代度产品与传统溶剂法产品所具有的不同性能，结果表明用微波法合成的羧甲基淀粉，其黏度更低、冻融稳定性更好，对Cu^2 、Fe^2 离子的吸附性能更强。     

稻草芦苇及其浆料制备羧甲基纤维素的比较

研究了直接由草粉或浆料制备羧甲基纤维素钠的溶剂适应性,并对产品的结构、粘度、取代度做了分析。结果表明,丙酮做溶剂时羧甲基纤维素合成的得率最高、取代度最大。草粉和草浆在丙酮溶剂中经过一次反应得到的羧甲基纤维素取代度均可达0.7以上。红外光谱表明,从草粉和从浆料制得的羧甲基纤维素样品结构上没有明显差别。以不同程度预处理的草粉为原料,可以得到取代度0.5~1.1之间的不同品质的羧甲基纤维素产品。     

汽爆玉米秸秆羧甲基纤维素的制备

秸秆是自然界中资源丰富的天然木质纤维素原料, 本研究以秸秆为反应原料,采用无污染蒸汽爆破技术活化预处理,然后进行羧甲基化反应,通过反应产物理化性质的不同实现秸秆的组分分离并制备出高附加值的羧甲基纤维素。实验结果表明：制备羧甲基纤维素的最优条件为液固比（ml∶g）18∶1,氢氧化钠∶氯乙酸钠(摩尔比)为4∶3,H₂O/底物（ml∶g）为1∶2,75℃反应2 h。在优化的反应条件下,从羧甲基化产物中可分离得到40.70%的羧甲基纤维素,其取代度可达0.91, 而且具有低黏的性质,并利用红外图谱和¹H NMR进行了分析表征;同时,还可从羧甲基化产物中分离出木质素组分,可进一步拓展其在工业方面的用途。相对于目前工业上普遍采用的α-纤维素含量较高的棉浆和木浆等反应原料,不仅原料和预处理成本大为下降, 工艺流程更为简单,而且还实现了秸秆的组分分离与全利用。     

Studies on carboxymethyl cellulose. Viscosity dependence on polymer concentration and electrolyte content

Viscosity behaviour of sodium carboxymethyl cellulose (NaCMC) in water has been examined. The data obtained are treated with Fuoss, Liberti-Stivala, Jones-Dole-Fuoss, and Yuan et al., empirical as well as semiempirical relations to understand the polyelectrolytic character of NaCMC. The results obtained are compared with other polyelectrolytes. The effect of added salt, like sodium chloride, on the viscosity of NaCMC solution also has been reported. Isoionic dillution experiments have been carried out to determine the degree of ionization of the polyelectrolyte, which reveals a little dependence of the degree of free counterions on the concentration of carboxymethyl cellulose (CMC) solutions. This leads to the conclusion that the polyion gets dilated because of the osmotic effect caused on diluting the polyelectrolyte solution. Furthermore, it has been found that the theory of Oosawa accounting the additivity rule adequately explains the viscosity behaviour of CMC in simple salt solutions.     

超低粘羧甲基纤维素钠的研制

以精制棉、氯乙酸、氢氧化钠和过氧化氢为原料,经过碱化、醚化、洗涤、干燥,制得羧甲基纤维素钠。同时,采用二步降粘法,在碱化及洗涤过程中加入过氧化氢,以降低纤维素钠的粘度,制得超低粘度的羧甲基纤维素钠。     

Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios, 97%:3%, 95%:5% and 93%:7%. The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various temperatures. The dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quantified with calibrated conductivity-concentration converting equation of sodium carbonate. The quantified dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured tablets. Therefore, it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet unchanged. The dissolution rate constant quantified with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain significant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate constant. The results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level, the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.     

相转移催化法纤维素羧甲基化工艺研究

研究了以棉短绒（精制棉）为原料、氯乙酸为醚化剂,合成羧甲基纤维素钠。探索了纤维素在碱化、醚化阶段的反应机理。考察了渗透剂、氢氧化钠溶液浓度及其用量、醚化时间4种因素对所合成羧甲基纤维素钠的水溶液粘度的影响。通过检测醚化后羧甲基纤维素钠的取代度和2%水溶液的粘度,确定了最佳工艺条件：碱化温度为30~35℃,碱化时间为50 min,醚化温度为70~75℃,醚化时间为70 min,碱溶液浓度为25%,渗透剂添加量为3%。此条件下制备的羧甲基纤维素钠,水溶液浓度为2%时,粘度达到600~650 MPa.s,取代度为0.530~0.560。     

Research on the Influence of the Type of Surfactant and Concentrator in Aqueous Dispersion of Pigments

This work reports tests performed to evaluate the stability of aqueous dispersions of inorganic oxide pigments with different specific surface areas, with the use of anionic and non-ionic surfactants and concentrators. Color mixtures of oxide compounds of blue, green, olive and brown with the unit cell spinel structure were used as pigments. The sodium salt of sulfosuccinic acid monoester, oxyethylenated nonylphenol and ethoxylated derivatives of lauryl alcohol, fatty alcohol and fatty amine were used as surfactants. The concentrators used were: poly(vinyl alcohol), the sodium salt of carboxymethyl cellulose as well as a water-based polyurethane oligomer. The highest dispersion efficiency was found for dispersed systems in which surfactant and concentrator were incorporated in the formula. The one containing the sodium salt of carboxymethyl cellulose or polyurethane oligomer with ethoxylated saturated fatty alcohol or fatty amine was found to be the most efficient. It was discovered that a higher dispersion efficiency corresponds to pigments with larger specific surface. The efficiency is also found to improve when the concentrator is an acrylic polymer or copolymer made up of two acrylic species. In this case, the concentrator interaction with the surfactant is more effective if the value of its boundary viscosity number is higher. This observation confirms the existence of interactions between macro-chains of the concentrator and surfactant molecules forming micelles with the pigment particles.     

On the low frequency dielectric behavior of carboxymethyl cellulose and its sodium salt

A dielectric dispersion and frequency loss peak within the low frequency range 0.05–1 kc/s and at temperatures of 283–333 K was observed in the case of the sodium salt of carboxymethyl cellulose and absent in the case of its acid form. The critical frequency of the dielectric absorption was independent of molecular weight and of the presence of low moisture content. The results obtained show that the variation with temperature of the dielectric constant is exponential at low frequency only in the case of the sodium salt of carboxymethyl cellulose. The significance of the results is discussed.     

疏水化水溶性两性纤维素接枝共聚物CGAO的合成及其水溶液的粘度性能

通过丙烯酰胺（AM）及甲基丙烯酰氧乙基二甲基辛基溴化铵（ADMOAB）与羧甲基纤维素钠（Na－CMC）进行接枝共聚制备了疏水化水溶性两性纤维素接权共聚物（CGAO）。用红外光谱与元素分析对CGAO的组成进行了分析。考察了CGAO的组成、浓度及无机盐对其水溶液粘度行为的影响。发现组成对粘度有直接的影响;水溶液粘度随共聚物的浓度增加而增大存在一临界聚合物浓度（cp）,cp与其组成紧密相关;在低的无机盐浓度时,溶液的粘度随无机盐浓度增加而降低,进一步增加无机盐浓度时,溶液粘度随无机盐浓度增加而提高,显示出了这种疏水化水溶性两性聚电解质特有的耐盐增粘性能。     

Effects of chemicals and blending petroleum coke on the properties of low-rank Indonesian coal water mixtures

In this study, the effects of different chemical additives including dispersant and stabilizer on the solid loading, viscosity, rheological behaviour and static stability of coal water mixtures have been investigated. In the experiments, naphthalene sulfonate formaldehyde condensate (NSF) was selected as dispersant and carboxymethyl cellulose sodium salt (CMC-Na) and nano-stabilizer were employed as stabilizers. An Indonesian low-rank coal, taken from Berau, East Kalimantan, was used for the study. To obtain high-loaded slurry, Liaohe petroleum coke was used to blend with Indonesian coal sample. The results of the experiments showed that adding chemical additives and blending Liaohe petroleum coke can effectively improve the slurryability of Indonesian low-rank coal.     

福建毛竹制备羧甲基纤维素及其结构和性能表征

以福建毛竹为原料,经过四次加碱法制备羧甲基纤维素（CMC）,并通过FTIR、XRD、TGA、SEM手段对原料与产品的结构和性能进行表征。结果表明,制备CMC的最佳工艺条件为：精制毛竹5g,氢氧化钠6g,氯乙酸6g,乙醇质量分数为85％,第一次碱化温度为30℃,时间为90min,氢氧化钠加入量为总质量的80％;后三次碱化是在醚化过程中平均加入剩余20％的碱,醚化最终温度为70℃,醚化总时间为3h。在此工艺条件下,所得到的CMC的取代度为0．9137,黏度为37mPa·s。