Frequency dependence of the complex dielectric constant of sodium carboxymethyl cellulose

The dielectric constant, ε′, and dielectric loss, ε″, were determined for three solid carboxymethyl cellulose samples having different levels of substitution and different degrees of polymerization over a frequency range of 0.1 – 10 000 kHz at temperatures from 10–60°C. In contrast to the two relaxation processes, γ and β, previously observed in native cotton cellulose, only one relaxation process within a frequency range of 0.1 – 1 kHz was identified. It was found that the dielectric properties do not only depend on the degree of substitution, but also on the weight-average degree of polymerization and uniformity of distribution.     

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.     

提高羧甲基纤维素钠酸黏比的研究

以乙醇为溶剂,精棉、氯乙酸和氢氧化钠为原料,加入价廉的、对人体无害的添加剂来加深碱化与醚化反应的深度,可制备出高酸黏比(小试达1.00左右)的羧甲基纤维素钠(CMC)。运用数理统计与正交试验法研究了物料配比、添加剂种类与用量、反应温度、反应时间以及其它强化碱化与醚化深度的多种因素,从而确定了提高CMC酸黏比的优化反应条件,为中试与扩大试验提供了参考的依据。     

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.     

废纸制备羧甲基纤维素的研究

以废纸为原料制备羧甲基纤维素(CMC),探讨了分散剂组成、碱化温度、时间、碱用量和醚化剂用量、醚化温度、时间对产品粘度的影响。结果表明,当废纸、氢氧化钠和醚化剂的质量比为1 0∶0 9∶1 2,以85%的乙醇水溶液为分散剂,35℃碱化90min,75℃醚化150min时,生成的CMC质量最好,取代度>0.6,有效成分>85%,水分<10%,氯化物<4%,其2%水溶液的粘度>500mPa·s。     

Influence of wood pulp quality on the structure of carboxymethyl cellulose

The quality of carboxymethyl cellulose (CMC) prepared from different wood-derived market pulps is examined. The pulps represent kraft and sulfite qualities with different levels of hemicellulose (1.5–22.8 wt %), intrinsic viscosity (391–780 mL g⁻¹), and content of extractives (0.04–0.13 wt %). The pulps are carboxymethylated in aqueous medium at three different levels of sodium hydroxide concentration, resulting in three levels of degree of substitution (DS), 0.3, 0.7–0.8, and 1.3–1.4 (according to nuclear magnetic resonance spectroscopy and high-performance liquid chromatography). CMC with DS 0.7–0.8 is found to be near the limit for water solubility and the resulting ranking for that solubility is shown to be correlated to DS. The DS is found to be impaired by a high content of impurities and high degree of Cellulose II in the pulp. The sulfite pulps yield CMC with the best solubility in water. A high level of extractives does not interfere with reactivity. Moreover, it is found that impurities, such as lignin and xylan, inhibit thickening behavior even at high DS, and that the ratio of substitution on Position 3 is a measure of the xylan content, which suggests that this position in xylan has extremely high reactivity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47862.     

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。     

Micellar solutions of amphipathic copolymers based on carboxymethyl cellulose

A novel family of amphipathic copolymers based on carboxymethyl cellulose (CM‐cellulose) has been synthesized through ultrasonic irradiation. Their micellar conformation in aqueous solution was studied by dynamic laser scattering, environmental scanning electron microscopy and gel permeation chromatography. The results show that conformation of copolymer molecules is totally different from that of CM‐cellulose because of the introduction of the surface active macromonomers. Due to the influence of hydrophobic character and molecular weight, different amphipathic copolymers have different micellar conformations, such as cylindrical, spheroidal or ellipsoidal micelles. In the range of concentration tested, the normalized first‐order autocorrelation function g⁽¹⁾(τ) of a copolymer of CM‐cellulose and poly(ethylene oxide) dodecyl ether acrylate does not fit a single‐exponential decay, indicating a polydisperse system and the existence of species of different shapes and size. At different concentrations, the hydrodynamic radii of micelles (R) almost distribute into two regions of smaller and larger size. With increasing copolymer concentration, the region of smaller R remains in the range 30–100 nm and is considered to represent monomolecular micelles, while the larger R region increases gradually with concentration, which means that polymolecular micelles increase in size. © 2003 Society of Chemical Industry     

羧甲基纤维素制备高吸水性树脂的研究

以羧甲基纤维素(CMC)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为原料,用过硫酸钾为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,经接枝共聚制备高吸水性树脂,讨论了反应时间、丙烯酸中和度、引发剂用量等对反应的影响。结果表明,最优工艺条件为:CMC、AA、AMPS的量分别为1,8,3.5 g,引发剂量为0.15 g,交联剂量为0.02 g,AA中和度为80%,在50℃下反应2 h。所得产物吸水倍率为580 g/g,吸水速率为80 g/m in。     

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。     

Studies on the Synthesis of 2,2′,4,4′,6,6′-Hexanitrostilbene

The synthesis of 2,2′,4,4′,6,6′-hexanitrostilbene by oxidative coupling of 2,4,6-trinitrotoluene in the presence of metal catalysts has been studied. The effects of reaction parameters on product yields have been evaluated and mechanisms for the reaction are proposed.     

Methyl acrylate/N-phenylmaleimide copolymers, 1. Synthesis of copolymers and effect of copolymer composition on huggins constant KH

This paper deals with the synthesis of methyl acrylate/N-phenylmaleimide copolymers having different compositions, (mole fractions of N-phenylmaleimide for the four copolymers MP-1, MP-2, MP-3, and MP-4 are 0.0664, 0.3905 and 0.5445, respectively) by free radical solution polymerization in cyclohexanone using azoisobutyronitrile as an initiator. The compositions of the copolymers have been determined by elemental analysis. The variation of the Huggins constant K_H with composition for the copolymers in three solvents, methyl ethyl ketone, dimethylformamide and cyclohexanone is described. K_H is found to be dependent both on solvent and composition of the copolymers.     

The effect of sodium carboxymethyl cellulose on synthetic detergent systems

Summary Certain forms of sodium carboxymethyl cellulose have been shown to be highly effective as synthetic detergent promoters. Formulations containing a sodium alkyl aryl sulfonate type of synthetic detergent, alkaline salts and a type of sodium carboxymethyl cellulose developed for high detergency promoting properties surpass high quality fatty acid soaps in both carbon soil removal and whiteness retention on cottons. Methods having a relatively high order of precision for the evaluation of detergency have been presented in detail. By these methods two fundamental characteristics of detergency—as applied to the laundering of cotton fabrics may be independently measured.     

Metal chelates with some cellulose derivatives. Part I. Preparation and characterization of chromium (III)–carboxymethyl cellulose complexes

A systematic spectrophotometric study on the complexation of chromium (III) ion with sodium carboxymethyl cellulose (CMC) was carried out. The effects of the degree of substitution (DS) of the polymer, the concentrations of Cr(III) and CMC solutions, the pH and temperature on the complex formation were studied in the aqueous state. CMC complexes with Cr(III) were characterized by elemental analysis, magnetic moment and spectral (Vis and IR) data. The results showed that CMC (L) chelated to the metal ion according to the formula CrL₂ · 2H₂O. The ligand field parameters, namely D_q, B and β were calculated; the β-values indicate strong covalency in the ligand σ bond. The IR spectra revealed that the chelating sites of CMC are not only the carboxymethyl groups, via the ether- and the carboxyl-oxygen atoms, but also the secondary hydroxyl groups.     

Investigation of the action of flame retardants in cellulose. I. Investigation of the flame retardant action of 2,2′-oxybis(5,5-dimethyl-1,3,2-dioxaphosphorinane-2,2′-disulfide) in cellulose

Pyrolysis experiments were performed in high vacuum and under reduced air pressure (100 Pa). The volatile products of pure cellulose and cellulose containing various amounts of flame retardant 2,2′-oxybis (5,5-dimethyl-1,3,2-dioxaphosphorinane-2,2′-disulfide), i.e., Sandoflam 5060 of Sandoz AG, were studied by means of gas chromatography in combination with mass spectroscopy. The volatile products were characterized with infrared spectroscopy. The studied revealed that the incorporation of the flame retardant enhanced the water release and shifted the onset of this reaction to lower temperature. On the basis of these findings an explanation for the mechanism of flame retardancy in generated cellulose fibers modified with this particular flame retardant is attempted. From experiments with different residual air pressure the influence of oxygen on the primary processes of the pyrolytic degradation of cellulose is being discussed.     

Detergency and foaming properties of the system alkylarylsulfonate-soap-sodium carboxymethyl cellulose

Summary A study has been made of the detergency and foaming characteristics of a ternary system comprising a sodium alkylarylsulfonate, a medium titer soap derived from tallow and coconut oil, and sodium carboxymethyl cellulose under average conditions prevailing in household laundering. The carbon soil removal and whiteness retention properties of unbuilt soap are equalled or exceeded in compositions containing approximately five parts soap to one part alkylarylsulfonate, with a minor portion of CMC. Measurements made in a transparent cylindrical washer indicate that the decrease of foam height due to adsorption on fabric and hard water is much greater with soap than with alkylarylsulfonate. This results in greater foam volumes with alkylarylsulfonate than with soap at concentrations less than 0.2%, in water of hardness equivalent to 96–114 ppm. CaCO₃. Sodium carboxymethyl cellulose, when used with soap and alkylarylsulfonate in the proportions desirable for improvement of detergency, does not affect foaming properties significantly. When soap is the major ingredient in mixtures of soap and alkylarylsulfonate, foam height is critically dependent on concentration. When alkylarylsulfonate predominates, high foam levels are obtainable at low concentrations. The data reported permits selection of compositions from the ternary system for formulation with builders such that excellent detergency characteristics may be obtained under average conditions prevailing in household service, with high foaming characteristics as desired for agitator-type machines, or with moderate, controllable foaming for cylinder machines. Presented at the 43rd annual meeting, American Oil Chemists' Society, Houston, Tex., April 29, 1952.     

Characterization and DC electrical conductivity of the composite films containing polyaniline‐carboxymethyl cellulose

New polymer composites containing polyaniline‐carboxymethyl cellulose (PANI‐CMC) were prepared via the polymerization of aniline hydrochloride using different concentration (wt%) of sodium CMC using ammonium persulfate as an oxidant. The thermal stability and embedded crystallinity of the composites were investigated using thermogravimetric and X‐ray diffraction analysis method, respectively. The electrical properties of the composites were examined using temperature‐dependent DC conductivity within 300–500 K. As compared to pure polyaniline the composites with increasing CMC in the PANI‐CMC composites shows the enhancement in the higher crystallinity and thermal stability, and higher electrical conductivities under equivalent conditions. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

山东某硫铁矿烧渣硫酸浸出液制备铁红工艺研究

为了以山东某硫铁矿烧渣硫酸浸出液制备铁红,采用氨水调节溶液pH值,与碳酸氢铵协同沉淀铁离子,沉淀物焙烧制备铁红。结果表明,浓氨水用量为10 mL,碳酸氢铵用量为2 g时,铁离子沉淀率达到97.18%;沉淀物焙烧时间为1.0 h,焙烧温度为800℃,获得铁红Fe_2O_3含量约98.76%,根据氧化铁颜料标准(GB T 1863—2008),为A级铁红,颜料索引号为颜料红101(77491)。     

交联羧甲基纤维素吸附阳离子染料的动力学和热力学特性

以取代度为0.82的羧甲基纤维素钠[CMC(0.82)]为原料,通过固相合成法制备取代度为0.43的交联羧甲基纤维素[CCMC(0.43)],将其应用于对碱性品红(BF)和亚甲基蓝(MB)的吸附,分析吸附动力学和热力学特性。动力学研究结果表明,在CCMC吸附MB(BF)实验中,吸附90 min后,吸附基本达到饱和;吸附过程符合准二级动力学模型。液膜扩散为染料扩散的控速步骤。热力学研究结果表明,Langmuir吸附等温式拟合度更好,CCMC(0.43)对MB(BF)的吸附作用为单分子层吸附,且为优惠吸附,吸附过程是自发进行且为放热过程。用红外光谱(FTIR)和热重(TGA)等手段表征CCMC。     

羧甲基纤维素包覆天然石墨性能的研究

本实验研究了羧甲基纤维素(CMC)包覆对天然石墨电化学性能的影响。通过XRD、恒电流充放电测试手段研究了不同包覆量对该复合材料结构和电化学性能的影响。结果表明:羧甲基纤维素裂解炭对天然石墨有较好的包覆作用,并且能够有效的阻止石墨在充放电过程中发生层状剥落现象,从而有效的提高复合炭材料的循环稳定性,其中5%树脂包覆量的复合材料在循环50次之后可逆容量是310.9 mAh.g-1,比天然石墨高50 mAh.g-1,并保持了首次可逆容量的97.1%。