Phase Separation in Polymer Solutions under Extension

The results obtained recently by the authors during investigation of the phase behavior of polymer solutions under uniaxial tension are reviewed. The main attention is given to the dilute solutions of unentangled semiflexible macromolecules. The effect of the solution extension rate on the coil–stretched coil transition for semiflexible chains is considered, and stability of the system of stretched coils is analyzed in terms of their segregation followed by formation of the concentrated polymer phase. The spinodal and binodal of the system are determined depending on temperature and extension rate. The kinetics of solution segregation to polymer and solvent, where three stages, namely, (i) spinodal decomposition accompanied by the formation of regions with increased and reduced polymer contents, (ii) formation of the microfibrillar network, and (iii) network collapse yielding separation of the solvent from the polymer phase are identified, is described.     

碳添加剂对聚丙烯腈溶液流变性影响的研究

以碳纳米管(MCNT)和碳黑(CB)为添加剂,采用溶液共混的方法,讨论了添加剂浓度、放置时间、温度、剪切速率对聚丙烯腈溶液的表观黏度及黏流活化能(ΔΕη)的影响。结果表明:随着MCNT含量的增加,聚丙烯腈溶液的黏度先增大后减小,添加1.0%MCNT时,聚丙烯腈溶液的黏度最大,活化能也同时达到最大;随着碳黑含量的增加,黏度与活化能都随之增加,但增加幅度不大。两种PAN溶液都属于明显的切力变稀的非牛顿流体,随着剪切速率的增加,黏度下降;但在高切变速率(>800s-1)时,黏度几乎不变。     

Influence of Some Organic Additives on the Extractive Separation of Americium(III) by Sulfoxides

Abstract

The solvent extraction behavior of americium(III) from aqueous nitrate media by two long-chain aliphatic sulfoxides has been examined systematically in the presence of several water-miscible organic solvents to study their possible synergistic effect on metal ion extraction. Methanol, ethanol, n- and isopropanol, n-butanol, dioxane, acetone, as well as acetonitrile, were employed as the organic component of the mixed (polar) phase. These additives affected the extraction to varying degrees. Extractability of Am increased 5 to 10-fold with increasing concentration of some of these additives, with the maximum enhancement being observed in the presence of acetone or acetonitrile. However, alcohols are generally very poor in this respect. Possible reasons for such behavior are briefly discussed. The distribution of several common contaminants was also investigated at the optimum condition for americium extraction.     

有机磺酸盐添加剂对电镀硬铬性能的影响

以有机磺酸盐作为镀硬铬添加剂,在钢铁基材上电镀硬铬,研究有机磺酸盐硬铬添加剂在最佳含量下对阴极电流效率、沉积速度、镀层硬度和微裂纹的影响.结果表明:在CrO3为250 g/L、H2SO4为2.5 g/L、Cr3+为3.2 g/L,温度为55±2℃,Jk为55 A/dm2,有机磺酸盐硬铬添加剂最佳含量为4 g/L工艺条件...     

Separation of Organic Compounds from Surfactant Solutions: A Review

Abstract

This review summarizes the recent development in separation of emulsified organic compounds from surfactant solutions for surfactant reuse and/or surfactant‐contaminant disposal. Three major principles have been employed for separating organic compounds and/or surfactants from aqueous solutions, namely, organic compound inter‐phase mass transfer, surfactant micelle removal, and manipulation of surfactant solution phase behavior. Details of these principles and their applications are discussed, with the advantages and limitations of each separation method compared. Separation based on mass transfer of the organic compounds into a secondary phase is currently more practical than the others. Finally, two major issues requiring further research are identified.     

Organic Additives and Electrolytes as Cloud Point Modifiers in Octylphenol Ethoxylate Solutions

Cloud point measurements of nonionic surfactant Triton X-100, an octylphenol ethoxylate, were carried out in the absence and presence of various organic additives such as n-alkanols (methanol, ethanol, propanol and butanol), glycols (ethylene glycol, diethylene glycol and triethylene glycol), glycol ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether (EGMBE)) and electrolytes (LiCl, KCl, NaF, NaCl, NaBr, NaI, MgCl₂ and AlCl₃). The combined effect of these organic additives and electrolytes on cloud point (CP) measurement was also investigated. The effect of nature of cation, anion and valency of cation on CP is also reported. Among the n-alkanols and glycol ethers as additives, n-butanol and EGMBE were found to decrease the CP while all other additives increase the cloud point. The addition of electrolytes (LiCl, NaCl and KCl) to the solution of Triton X-100 (TX-100) decreases the CP but the rate of decrease in CP with concentration does not follow the lyotropic series of effect. Sodium halides (except NaI) also decrease the CP and the rate of decrease follows the lyotropic series of effect even in the presence of organic additives. NaI is a water structure breaker, hence it increases the cloud point. Further, cations of increasing valency lessen the depression in CP of TX-100 with the rate of decrease in CP following the order Na⁺ > Mg²⁺ > Al³⁺ even in the presence of organic additives.

Aggregation and Phase Separation Phenomenon of Amitriptyline Hydrochloride Under the Influence of Pharmaceutical Excipients

The interaction between the amphiphilic drug amitriptyline hydrochloride (AMT) and the nonionic surfactants used in drug delivery has been investigated. Herein, we report the micellization behavior of AMT in presence of ethoxylated alkyl phenols in aqueous medium and the clouding phenomenon in the absence and presence of different nonionic surfactants in buffer solution. The values of critical micelle concentration (CMC) of AMT obtained using the conductivity method, decrease as nonionic surfactant concentration increases. With an increase in temperature, the CMC first increases and then decreases. At 303.15 K, the maximum CMC values were obtained with or without nonionic surfactant. The results obtained indicate attractive interactions (synergism) between the two mixing amphiphiles in solution. The experimentally obtained critical micelle concentration (CMC) values are always lower than ideal CMC values. Micellar mole fraction (X₁) values, calculated by different proposed models, show the contribution of nonionic surfactant concentration. At a fixed drug concentration (50 mmol kg^?1) and pH (=6.7) nonionic surfactants show continuous increase in cloud point (CP). Increase in drug concentration and pH, in the presence of fixed amounts of nonionic surfactant, increases and decreases the CP, respectively.     

有机添加剂对ZrO2流延生坯性能的影响

有机添加剂是流延料浆的关键组元,它们对料浆和流延生坯的性能有很大的影响.文章用流延法制备了YSZ电解质薄膜,并对生坯的力学性能进行了研究,分析了各有机添加剂对生坯力学性能的影响,最终提出了提高生坯及烧结体质量的方法.     

有机相变蓄冷材料中碳纳米管添加剂性能实验研究

针对有机相变蓄冷材料导热系数低、传热性能差的缺点,采用向其中添加碳纳米管,通过超声分散法及添加分散剂制备稳定分散液来改善其导热性能。对分散剂的种类、碳纳米管的质量浓度、超声时间和分散剂的浓度对碳纳米管分散稳定性的影响及添加碳纳米管对导热性能的影响进行了实验研究。研究结果表明,分散剂对碳纳米管悬浮液的稳定性具有关键作用,十二烷基苯磺酸钠(SDBS)是一种比较理想的分散剂,碳纳米管稳定分散悬浮液的最佳制备条件为:碳纳米管质量浓度0.4 g/L;分散剂SDBS质量浓度0.2 g/L;超声时间80 min。通过在有机相变蓄冷材料加入碳纳米管可以有效增大其导热系数。     

Reverse Osmosis Separation of Some Organic Acids from Their Aqueous Solutions

Abstract

Cellulose acetate membranes were characterized as previously described and were found to reject 91.7% of sodium chloride. The reverse osmosis separation behavior of benzoic, 2-chlorobenzoic, 2-nitrobenzoic, 2-hydroxybenzoic, and 2-aminobenzoic acids as a function of pH was studied. Experimentally obtained pK_a values are compared with literature values. The calculated polar substituent constant σ* values for the o-substituents were also found to agree with literature values.     

化学组成对铁红分相釉的影响

以钾长石、骨灰、三氧化二铁、煅烧滑石、石英、高岭土为原料制备铁红分相釉.探究SiO2/Al2 O3摩尔比、Fe2 O3-P2 O5组成引起的釉面性状变化.结合XRD以及扫描电镜(SEM)和能谱分析,对铁红釉的分相和析晶进行定性和定量的分析.研究结果表明:当SiO2/Al2 O3摩尔比为10,Fe2 O3/P2 O5摩尔比为2时,釉表面为分散规则大红花.SEM和EDS显示釉中存在液相分离而带来的组分不均匀的现象,主要表现为Fe元素组分的差异;经XRD结果证实,在富铁相中析出的红色晶体为Fe2 O3.     

Mixed Micellar and Interfacial Studies of Triblock Copolymers with Amphiphilic Drug Ibuprofen in Aqueous Urea Solutions

Mixed micellar and surface properties of non-ionic triblock copolymers (Pluronic® P123 and F68) and non-steroidal anti-inflammatory drug Ibuprofen (IBF) have been evaluated in aqueous urea (100 mM) solutions with the help of surface tension and fluorescence measurements at 298.15 K. Various bulk and surface parameters such as critical micelle concentration (CMC) of the mixtures, micellar mole fraction (X), interaction parameter (β) and free energies were calculated using Clint, Rubingh, Rosen and Maeda models. In aqueous solutions, all the mixtures show synergistic interactions and are more in mixtures of IBF with P123. These interactions decrease in presence aqueous urea solution due to breaking of water structure surrounding the hydrophobic moieties by urea molecules resulting in delayed mixed micellization. Micellar aggregation number (N_agg) obtained from the steady state fluorescence quenching indicate that the participation of triblock copolymer is more than the drug IBF in mixed micelle formation. Stern-Volmer constant (K_SV), dielectric constant (D_exp), and micropolarity (I₁/I₃) have also been evaluated and their contribution in the mixed micellar systems have been discussed.     

Effect of Mobile Phase Additives on the Resolution of Four Bioactive Compounds by RP-HPLC

The use of mobile phase additives enhances the separation and resolution of the bioactive compounds on the C₁₈ column. Chlorogenic acid, caffeic acid, rutin, and scoparone from Herba Artemisiae Scopariae were investigated as the target compounds. Acetic acid, triethylamine, inorganic salts, and several ionic liquids were added as mobile phase additives into methanol/water (40:60, v/v). The result revealed that a mobile phase with 0.01 mol/L of ionic liquid [BMIM][BF₄] enabled the optimum separation of the four target compounds.     

Effect of Organic Additives on Electrochemical Surface Precipitation and Polymorphism of CaCO3

The inhibition effect of three organic additives on the precipitation and polymorphism of CaCO₃ deposited on gold surfaces was investigated using electrochemical and microscopic techniques. Additives, two polyacrylic acid (PAA) polymers with different molecular weights (Mw 2100, Mw 30,000), and 1,2,4,5‐benzenetetracarboxylic acid (BTCA), were either added to the solution before or during deposition. In the presence of 100 ppm of one of the three additives in solution, almost no scale was observed on the surface for at least 24 hours. In the presence of lower concentrations of PAA Mw 2100, only distorted calcite crystals were obtained while with PAA Mw 30,000 the polymorph was spherical vaterite. A mixture of calcite and vaterite was observed with the BTCA additive. Addition of the polymers inhibits further nucleation and growth even if added after partial deposition of CaCO₃ while BTCA has no effect once nucleation has started. The results indicate that the inhibit ion effect of the PAA polymers is due to adsorption on the electrode surface while the effect of BTCA is related to chelation of calcium ions in solution.     

软段结构对水性聚氨酯微相分离的影响

以异佛尔酮二异氰酸酯(IPDI)、1,6-己二异氰酸酯(HDI)和聚四氢呋喃醚二醇(PTMG)、聚碳酸-1,6-己二醇酯二醇(PCDL)、聚己二酸-1,6-己二醇酯二醇(PHA)为原料,采用预聚体法合成了一系列水性聚氨酯(WPU)乳液。通过红外光谱(IR)、热重(TGA)、X-射线衍射(XRD)、动态机械性能(DMA)和拉伸测试等方法研究不同多元醇对所合成的WPU薄膜软、硬段微相分离及其热性能、结晶性和机械性能影响。结果表明,氢键作用对WPU的微相分离有明显影响;微相分离程度大的聚醚型WPU热稳定性、结晶性、柔韧性、低温塑性比微相分离程度小的聚碳酸酯型WPU好;聚碳酸酯型WPU膜的拉伸强度和模量更大。     

Synergistic Silver Extraction from Hydrochloric Acid Solutions with Triisobutylphosphine Sulfide in the Presence of Organic Proton-Donor Additives

Silver chloride extraction from hydrochloric acid solutions with triisobutylphosphine sulfide (CYANEX 471, L) in the presence of organic proton-donor additives (HR) was studied. Both alkyl-, bromo-, nitro-substituted phenols, and organic acids of various structures were used as additives. A new synergistic effect (S) was found to take place in the presence of the additives. The degree of the synergistic effect in the systems containing phenols decreases in the series 4-nitrophenol > 4-bromophenol > 4-tert-butylphenol > 2,6-dimethylphenol > 2-methyl-6-cyclohexylphenol > 2,6-bis(tert-butyl) phenol. In the systems containing organic acids, the following series is observed: dinonylnaphthalenesulfonic acid (DNNSA) > 4-tert-butylphenol > caprylic acid > di(2-ethylhexyl)phosphoric acid > bis(2,4,4-trimethylpentyl)phosphinic acid. Based on the analysis of the extraction data and the IR and NMR spectra of the extracts, it was concluded that an increase in the silver extraction with CYANEX 471 in the presence of HR is due to the formation of the compound [AgCl?2L?HR] in the organic phase. It was shown that a mixture of CYANEX 471 and 4-tert-butylphenol can be used for the highly selective extraction of silver from hydrochloric acid solutions containing metal impurities (Ni, Cu, Co, Zn, Fe(III), and Na). The mixtures of CYANEX 471 with alkylphenols or DNNSA, in which the high synergistic effects (S ≥ 10 and ≥ 50, respectively) take place, can efficiently be used for processing different industrial silver chloride solutions.     

有机添加剂对电沉积Fe-Co-Ni合金的影响

通过测定阴极极化曲线和电沉积试验，研究了有机添加剂对电沉积铁－钴－镍合金的影响。认为含硫有机添加剂通过在电极表面的吸附，促进或延缓金属离子的还原反应，而络合剂则通过选择性络合阳离子，起稳定电解液、调节合金组份的作用。     

Phase Characterization of Lead Zirconate Titanate Obtained from Organic Solutions of Citrates

Lead zirconate titanate (PZT) with several Zr/Ti ratios was prepared by the organic solution of citrates of the respective cations. The Rietveld method was applied to perform quantitative analysis of the coexisting phases. The ratio of tetragonal/rhombohedral phases increased with calcination temperature. For the composition where Zr/Ti = 53/47, the tetragonal quantity varied from 25% to 35% for temperatures ranging from 600° to 800°C. For the powder with Zr/Ti = 57/43, only the rhombohedral phase was observed after calcination at 700°C. For the powder with Zr/Ti = 49/51, only the tetragonal phase was observed after calcination at 800°C. The amount of tetragonal phase was controlled in Zr/Ti = 55/45 by seeding the powder with the tetragonal phase of PZT.