供热水系统CTAC减阻流体减阻与传热性能研究

对不同工况下不同浓度和配比的CTAC减阻流体在二维流道中的减阻性能和传热性能进行了试验测试。结果表明,在减阻流体流动达到临界雷诺数之前,传热性能下降率随雷诺数的增大逐渐增大,在达到临界雷诺数之后,传热性能急剧增强;传热性能下降率与减阻率变化趋势相同;减阻流体的温度梯度在过渡层比水大,在湍流核心区比水小。     

Synthesis,Structure Characterization and Biological Activity of Co (II), Cu (II), and Zn (II) Complexes with (Z)‐3‐((3‐hydroxybenzylidene)amino)pyridin‐1‐ium 4‐(dodecan‐4‐yl)benzenesulfonate Surfactant

(Z)‐3‐((3‐hydroxybenzylidene)amino)pyridin‐1‐ium4‐dodecylbenzenesulfonate anionic surfactant and its cobalt, copper and zinc complexes were synthesized (I, I‐Co, I‐Cu and I‐Zn). The chemical structures of it were characterized by elemental analysis, FTIR, ¹H‐NMR, UV–Vis spectroscopy and atomic adsorption. The effects of the chemical structures of the synthesized anionic surfactant and the type of transition metals on the surface activity are presented in this paper. The thermodynamic parameters show that adsorption and micellization processes are spontaneous. The results of biological activity measurements showed that the synthesized compounds have a great efficiency against gram positive (Bacillus subtilis and Staphylococcus aureus), gram‐ negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and fungi (Candida albicans and Aspergillus niger) as well as the sulfate reducing bacteria (Desulfomonas pigra). The complexation of the anionic surfactant with Co²⁺, Cu²⁺ and Zn²⁺ increase the antimicrobial activity values.     

Polymer‐Cationic Surfactant Interaction: 1. Surface and Physicochemical Properties of Polyvinyl Alcohol (PVA)‐S‐Alkyl Isothiouronium Bromide Surfactant Mixed Systems

Surface properties of polyvinyl alcohol (nonionic polymer) and three synthesized cationic surfactants, namely, S‐alkyl isothiouronium bromide at different mole fractions of 1:9, 3:7, 5:5, 7:3, and 9:1, were investigated. The values of the surface parameters were discussed according to the type of interaction between the cationic surfactant and type of polymer studied. The S‐alkyl isothiouronium bromide surfactant molecules are positively charged molecules, and the PVA chains contain hydroxyl groups that are partially negatively charged centers. The comparison between the surface properties of the individual cationic surfactants and their mixture with PVA polymer showed that the mixed systems have some advantages over the individual cationic surfactants.     

Rheological Properties of Quaternary Ammonium Gemini Surfactants in Aqueous Solution

The rheological properties and time effect of a quaternary ammonium salt gemini surfactant C_n‐s‐C_n?2Br solution were measured. The rheological properties were markedly different at various concentrations of the surfactant C₁₂‐2‐C₁₂?2Br solutions. When the alkyl chain of C_n‐2‐C_n?2Br solution is 14 or 16, the rheological properties of the solution exhibit fluid dilatancy very similar to C₁₂‐2‐C₁₂?2Br solutions. However, when the length of the spacer is four or six, C₁₂‐s‐C₁₂?2Br solutions exhibit Newtonian fluid behavior and are quite different from the C₁₂‐2‐C₁₂?2Br solution. A C₁₂‐2‐C₁₂?2Br solution at a high concentration shows negative thixotropy and time dependency.     

Properties of a Binary System Containing Anionic and Cationic Gemini Surfactants

Surface tension, fluorescence, and dynamic light scattering were used to investigate the properties of a binary surfactant system comprising an anionic gemini surfactant (DLMC) and cationic gemini surfactant (II‐12‐EO₂). Surface tension measurements afforded the critical micelle concentration (cmc) of the mixture and the values are all lower than those of pure constituent surfactants. For the mixtures of II‐12‐EO₂/DLMC, the micelle aggregation number decreases with the increase of II‐12‐EO₂, and the micropolarity of the micelle is lowest when the molar fraction of II‐12‐EO₂ is 0.5; the hydrodynamic radius (R_h) of the mixed micelle first increases and then decreases with the addition of II‐12‐EO₂, and larger micelles are obtained when the molar fraction of II‐12‐EO₂ is 0.5 or 0.7.     

Micellar and Interfacial Behavior of Mixed Systems Containing Glycoside‐Based Surfactant and Cationic Didecyldimethylammonium Chloride

The behavior of binary mixtures of glycoside‐based surfactants in combination with didecyldimethylammonium chloride (DDAC) has been studied using surface tension measurements. The three glycoside‐based surfactants are nonionic decyl glycoside (APG), nonionic dodecyl ethoxy glycoside (AEG) and anionic disodium dodecyl ethoxy glycoside citrate (AEG‐EC). Lower critical micelle concentrations (CMC) and minimum molecular area (A_min) values were obtained for all the mixed systems. The pC₂₀ values of APG/DDAC and AEG‐EC/DDAC mixtures are larger than pure surfactants, while the values of AEG/DDAC are between those of AEG and DDAC. Interactions between the monomers have also been investigated by determining the interaction parameters. Negative β_m and β_s values indicate synergistic effects in both the mixed micelle and monolayer formation. For different mixed systems, interaction in the mixed micelle formation becomes stronger in the order: AEG/DDAC < AEG‐EC/DDAC < APG/DDAC. The degree of synergism in the mixed monolayer formation follows the order: AEG/DDAC < APG/DDAC < AEG‐EC/DDAC.     

Increased Emulsion Stability for Reverse Y‐Shaped Sugar‐Based Surfactants

A series of reverse Y‐shaped surfactants containing aromatic and aliphatic linkers to combine two short hydrocarbon chains and one carbohydrate head group was prepared. Liquid crystalline behavior, air–water interfacial properties, and efficiency as an emulsifier was investigated for each reverse Y‐shaped surfactant. All reverse Y‐shaped surfactants mediated higher emulsion stabilities for water‐in‐oil compared to common typical reference surfactants, reflecting an improved ability to cope with a curvature towards water. The introduction of a benzene ring into the linker substantially increased the affinity of the surfactant for hydrophobic media, resulting in improved emulsion stability for both water‐in‐oil and oil‐in‐water.     

抗静电腈纶用纳米金属氧化物的分散工艺研究

选择氧化锌(Zn O)、铝掺杂氧化锌(AZO)、氧化锡锑(ATO)以及ATO包覆硫酸钡(Ba SO4)4种纳米粉体抗静电剂球磨分散得到其水相悬浮液,利用喷雾共混的方法制备改性聚丙烯腈(PAN)纺丝原液,进行湿法纺丝,研究了表面活性剂种类、研磨工艺对纳米粉体在水相中沉降性的影响,以及改性PAN纤维的抗静电性能。结果表明:采用自制的非离子/阴离子表面活性剂复配物(FCY)作为分散剂,FCY质量分数(相对于纳米粉体)为2%,研磨时间3 h,纳米粉体的水相分散效果好,分散工艺对4种纳米粉体均有很好的适用性;ATO改性PAN纤维具有较好的抗静电效果,当添加ATO质量分数为2.0%时,PAN纤维的体积比电阻为3.1×109Ω·cm,具有耐久性,可以满足抗静电织物对原料的要求。