表面活性剂浓度对泡沫体系稳定性的影响

主要探讨了在泡沫体系内,表面活性剂对泡沫稳定性的影响,以表活剂浓度为主要研究点,总结了不同表活剂浓度下气泡的聚并过程,还分析了液膜的排液过程,指出界面流变学因素以及表活剂高浓度情况下的胶束分层现象是影响泡沫稳定的主要因素.表活剂浓度低于CMC时,界面流变学因素起主要决定作用;表活剂浓度高于CMC时,胶团分层起主要决定作用.     

Influence of Salt and Surfactant on Copper Removal by Xanthan Gum-g-Itaconic Acid/Bentonite Hydrogel Composite from Water Using Fractional Factorial Design

A novel xanthan gum-g-itaconic acid/bentonite (XG-g-PIA/BET) hydrogel composite was synthesized using free radical polymerization in the presence of ammonium persulfate as initiator and N,N’-methylenebis(acrylamide) as crosslinker. The Fourier transform infrared spectroscopy spectra of XG-g-PIA/BET composite before and after adsorption gave strong evidence of the successful adsorbance of copper ions with COOH groups. Influence of the presence of three typical salts (NaCl, CaCl₂, and FeCl₃) and three types of surfactants including anionic (Brij 35), cationic (N-Cetyl-N,N,N-trimethyl ammonium bromide), anionic (sodium dodecyl sulfate), and their two-term interactions on copper ions adsorption capacity were investigated using 32 experiments with fractional factorial experimental design. The analysis of variance (ANOVA) showed that the fitted model had a significant p value (<0.0001), and except FeCl₃, all other variables present in the aqueous solution increased the copper adsorption capacity. In addition, there was no significant two-term interaction between different variables.     

Mechanism Study on the Severe Foaming of Rhamnolipid in Fermentation

Although the biosurfactant rhamnolipid has been previously characterized as having low foam ability, its fermentation is largely impeded by severe foaming. Hence, the investigation of this paradox is critically important for improving the mass production of rhamnolipid. Unexpectedly, the hydrophobic cell, instead of rhamnolipid, has been claimed to explain such severe foaming in rhamnolipid fermentation. This study tried to systematically investigate the severe foaming in fermentation, aiming to propose an effective strategy for foam control. The overflowing foam sustained a super high stability in terms of half‐time for over 30 min. The major product of rhamnolipid largely contributed to the severe foaming in the fermentation process whereas other products like cells elicited much more limited effects. Furthermore, the foam stability of the fermentation broth increased with rhamnolipid concentration and noticeably increased with agitation speed. In the classic Bikerman foam test system without stirring, rhamnolipid showed foam stability as low as Tween 20 which is well known for its poor foam stability. However, in a stirring Bikerman system, rhamnolipid exhibited a foam stability almost as high as sodium dodecyl sulfate (SDS) at 10 g/L and even surpassed SDS at a higher concentration of 20 g/L. Hence, the extraordinarily increased foam stability of rhamnolipid with both agitation and concentration could explain the severe foaming at its late‐stage fermentation when rhamnolipid‐rich solution is mechanically agitated.     

Surfactant Recovery from Water Using a Multistage Foam Fractionator: Effect of Surfactant Type

Abstract

The purpose of this study was to investigate the recovery of surfactants using a multistage foam fractionator for three types of surfactants: cationic (cetyl pyridinium chloride, CPC); anionic (sodium dodecyl sulfate, SDS); and nonionic (polyoxyethylene(20 Princen , H.M. ; Mason , S.G. ( 1965 ) Shape of a fluid drop at a fluid-liquid interface I. Extension and test of two-phase theory . J. Colloid Sci. , 20 ( 2 ): 156 – 172 . [Google Scholar]) sorbitan monolaurate, Span80). The studied system was operated at a constant temperature of 25°C with a surfactant concentration in the range of 50 to 100% of CMC (critical micelle concentration). For any surfactant system, the enrichment ratio of surfactant increased with increasing foam height and number of stages but decreased with increasing effects of the air flow rate and feed concentration. For all studied surfactants, the removal efficiency of the surfactant was not significantly affected by changing the air flow rate, foam height, and feed concentration in the studied ranges. An increase in the number of stages showed a great improvement of both the enrichment ratio and the removal fraction for all three types of surfactants. In a comparison among the three studied surfactants, the separation performance, in terms of the enrichment ratio and removal was found to lie in the following order: CPC >Span80 > SDS, which can be explained by the foamability and foam stability of each surfactant.     

化学镀钴液中钴(Ⅲ)的分光光度测定

研究了钴（Ⅲ）－１－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）及溴化十六烷基三甲铵（ＣＴＭＡＢ）体系测定钴。钴与ＰＡＮ二元配合物摩尔吸光系数可达９４～１０３Ｌ·ｍｏｌ－１·ｃｍ－１，加入表面活性剂后，钴与ＰＡＮ生成三元配合物，摩尔吸光系数值提高到２１２～１０４Ｌ·ｍｏｌ－１·ｃｍ－１，钴含量在０～２５μｇ／５０ｍｌ范围内符合比耳定律，方法应用于测定化学镀钴液中钴的测定。     

Parameter Design of a Coaxial Cable Insulation Manufacturing Process Using Axiomatic Design and the Taguchi Method

In modern industries, the development of communication mediums requires high-frequency communication networks in which signal reduction by dielectric loss is increased. Accordingly, the need for an insulator with low permittivity also has grown, making the production of highly foamed insulators now necessary. Considering the mechanical and electrical properties of such insulators, benefits can be seen in multiresponse problems with higher densities of uniform-specific cell size.

In this paper, we describe the applicability of a highly foamed polyolefin extrusion process to the manufacturing of insulation for coaxial cable. Moreover, a combination of axiomatic design and the Taguchi method was utilized for solving the multiresponse problem. Through this technique, we propose a new method for optimizing multiresponse problems. Development of manufacturing processes for insulating coaxial cable, and responses for each process variable, become possible with this method.     

Study of Foaming Properties and Effect of the Isomeric Distribution of Some Anionic Surfactants

Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized method very similar to the Ross–Miles foaming tests to identify which surfactants are suitable for applications requiring high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the critical micellar concentrations and at 25 °C for both the samples.

Drawbacks of Surfactant Presence on the Dissolution and Mechanical Properties of Detergent Tablets: How to Control Interfaces by Surfactant Localization

The aim of this study is to limit the hurdles generated by the presence of a surfactant, i.e., sodium dodecyl sulfate (SDS), in effervescent detergent tablets containing a chlorine provider. The results are highlighted by investigating the tablet’s functional characteristics (mechanical strength, disintegration time). A second objective is to increase the surfactant content of the tablet in order to improve the cleaning properties of the detergent formula without retaining the previous drawbacks. For low tablet porosity, mechanical properties are damaged by the presence of 2% of SDS and while disintegration through an erosion mechanism is slowed down. Experimental evidence indicated that these phenomena are associated with the coexistence of SDS and sodium dichloroisocyanurate (DCCNa). Their separation by locating SDS in the tablet core was encouraging but had limited value due to the slow dissolution of the SDS core. The problem was solved when 2% SDS was concentrated on one face of the tablet; however, a higher concentration induced a delayed disintegration due to the progressive erosion of SDS, which behaved as a massive solid. The coating of the tablet with SDS was beneficial because the dissolution of the film delayed effervescence and consequently disintegration. Neither coating the SDS particles with cellulosic film nor including them in zeolite was an appropriate solution. On the other hand, segregating SDS and DCCNa by placing them in separate layers of the tablet produced very conclusive results when microcrystalline cellulose and an effervescent system were added to the SDS. Furthermore, this bilayer tablet allowed the SDS content to be increased while a satisfactory tensile strength and a low disintegration time were retained.

制备凝胶色谱在聚氨酯匀泡剂组成分析中的应用

用制备凝胶渗透色谱分离聚氨酯匀泡剂的混合组分,并对分离的组分进行了凝胶色谱、红外光谱等分析。对两个混合组分的聚氨酯匀泡剂的剖析结果进行了讨论。     

Influence of Process Parameters on the Mechanical and Foaming Properties of PP Polymer and PP/TALC/EPDM Composites

In this study, PP and Talc/EPDM/PP composite materials are used. Foaming process is achieved by a conventional injection molding method. The influence of injection pressure and melting temperature on the average cell dimension, cell number, skin layer thickness, foam density and mechanical properties of investegated foam materials were evaluated. It is observed that cell density is increased by the increment of injection pressure. However, the values of skin layer thickness, density, cell diameter and charpy impact strength are decreased. In addition, the values of skin layer thickness, cell density, density and impact strength are increased with the increment of melting temperature.     

卫生洁具清洗剂中表面活性剂含量检测方法探析

采用GB/T 13173-2008《表面活性剂洗涤剂实验方法》中7洗涤剂中总活性物含量的测定方法,对已知配比的有机酸、无机酸、表面活性剂等复配的卫生洁具清洗剂进行表面活性剂含量的检测,测量值均远高于配方理论值,文章分析了检测误差的原因,提出了优化检测方案.结果表明,改进后的方法测量误差低,检测结果稳定可靠.     

表面活性剂增容PVC／SBR共混体系力学性能研究

通过冲击试验，应力－应变试验研究了表面活性剂用量，液体石蜡用量，注体石蜡用量，橡胶含量对ＰＶＣ／ＳＢＲ共混材料力学性能的影响。同时对表面活性剂增容ＰＶＣ／ＳＢＲ共混材料的形变机理进行了初步探讨。     

混炼工艺对NBR/PVC发泡材料性能的影响

研究了密炼和开炼两种混炼方式及不同的密炼温度对丁腈橡胶(NBR)/聚氯乙烯(PVC)发泡材料性能的影响。结果表明,混炼温度相同时,密炼工艺比开炼工艺的塑化共混效果更好,胶料的门尼黏度更高,发泡材料性能更优;在130～160℃的密炼温度范围内,密炼温度为150℃时得到的发泡材料密度最低、硬度较高。     

塑料挤出口模优化设计方法研究

在分析挤出模设计特点的基础上,提出了一种基于智能反馈/FEA相耦合的挤出模多目标优化设计方法,并指出了其实现的关键技术     

组合式干燥系统的分段优化设计方法

提出了分离过程的分段设计法：将一个任务分解为多个子任务,根据各个子任务的不同特点进行设计. 对干燥过程进行优化设计,以年费用最小为目标,将干燥过程表示为最多3段的超结构,每段有2个干燥设备可以选择,给出了单元和过程系统的模型和经济模型. 实例研究结果表明,当物料含水量大于物料在该条件下的临界含水量时,宜采用两段干燥的方法,将回转圆筒干燥器和流化床干燥器组合进行干燥;当物料含水量低于临界含水量时,宜采用一段干燥,将物料直接放入流化床干燥器进行干燥.     

聚氯乙烯／木粉发泡复合材料性能影响因素分析

对影响聚氯乙烯／木粉复合材料性能的因素,包括PVC树脂分子结构、木粉处理工艺、加工润滑剂的选择等,进行了分析。指出木粉的加入对该复合材料起一定阻燃作用。     

PVC/木粉发泡复合材料的性能影响因素分析

PVC（PW）/木粉复合材料的研制？生产和应用对于寻求实体木材的替代品和利用木材加工残余物具有重要意义,也是塑料回收再生利用的有效途径之一。PVC（PW）/木粉复合材料的优点主要是力学强度高、耐强酸碱腐蚀性强和经济环保。对复合材料的性能影响因素进行了分析,并对PVC/木粉复合材料研究和探索的方向和趋势进行概述。     

热变性对蛋白质结构及泡沫行为的影响

以牛血清白蛋白(BSA)和鸡蛋白蛋白(albumin)为模型蛋白,研究了热变性对蛋白质起泡性能和分子结构的影响. 结果表明,热变性后的BSA起泡能力下降,泡沫稳定性有增强的趋势. 热变性使BSA分子表面巯基含量下降,分子之间发生缔合,表面疏水性下降. 而albumin在热变性后的起泡能力及泡沫稳定性都大大提高,热变性使albumin分子展开,表面巯基含量增加. 实验证明,蛋白质分子的表面疏水性是决定其起泡能力的重要因素之一,蛋白质分子之间的相互作用对泡沫的稳定性有很大的影响.     

Predicting and Controlling the Effect of Solubilized Flavor Oil on Foam Properties of Surfactant through Study of the Adsorption Activity and Configuration

In the wide application of foam products, the effect of oil additive on foam property is a critical issue that has gained increasing attention; the effect on foam induced by various flavor oils is still a puzzling question, and relative study is rare. In this article, a series of typical flavor oils were studied for their effects on the foam properties of sodium dodecylsulfate. Measurements of foamability, foam stability, foam elasticity, and surface activity were taken; meanwhile, molecular dispersion and interfacial arrangement behavior of surfactant and oil molecules were explored by molecular dynamics simulation. Through a combination of macroscopic phenomenon and microscopic information, how flavor oils with different chemical structures affected the foaming properties of surfactants was demonstrated, and an evaluation scheme for predicting the level of influence on foam properties by different flavor oils was constructed. This investigation may help better understand the role of flavor oils in foam systems and provide a theoretical foundation for optimizing the application of flavor oils in relevant industries.     

Colloid‐Enhanced Ultrafiltration of Chlorophenols in Wastewater: Part IV. Effect of Added Salt on the Surfactant Leakage in Surfactant Solutions and Surfactant–Polymer Mixtures

Abstract

The critical aggregation concentration (cac) in surfactant–polymer mixtures approximates a lower limit to the surfactant concentration in the permeate (surfactant leakage) in polyelectrolyte micellar‐enhanced ultrafiltration. Here, the cac was measured at different salinities by using surface tension measurements. It was found that the cac increases slightly with the addition of simple salt, then the cac value decreases at higher salt concentration. The critical micelle concentration (CMC), which approximates surfactant leakage in micellar systems (no polymer), decreases monotonically with increasing salinity for ionic surfactants. The surfactant leakage in colloid‐enhanced ultrafiltration (CEUF) processes is investigated by using a dialysis method in the presence of three phenolic solutes with various degrees of chlorination: 2‐monochlorophenol (MCP), 2,4‐dichlorophenol (DCP), and 2,4,6‐trichlorophenol (TCP). Cetylpyridinium chloride (CPC) or n‐hexadecylpyridinium chloride is used as a cationic surfactant; and sodium poly(styrenesulfonate) (PSS) is used as an anionic polyelectrolyte. The effect of salinity and type of colloid is focused on here. In the absence of added salt, the cac can be over an order of magnitude less than the CMC, as can be surfactant leakage with added polymer. The added salt reduces the surfactant leakage in the micellar solution due to CMC reduction in the presence of electrolyte. In the surfactant–polymer mixture, the surfactant leakage is dramatically affected by salinity.