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1.
近年适应石油化学工业的需要,聚氧乙烯(POE)型非离子表面活性剂的研究得以发展。桑村常彦等合成了一类均三嗪烷醚POE非离子表面活性剂,测定了它们的浊点和临界胶束浓度(CMC)。等合成了均三嗪胺醚POE非离子表面活性剂,测定了它们的  相似文献   

2.
《物理化学学报》1986,2(4):328-334
(1) 用γ-θ法研究C_8H_(17)SO_44Na、C_8H_(17)N(CH_3)_3Br及其1:1混合物在石蜡/水溶液界面上的吸附, 得到Langmuir型吸附等温线。 (2) 首次计算两表面活性剂在固/液界面吸附层中的分子相互作用参数, 并与它们在气/液、液/液界面吸附层中的数值相比较。 (3) 结果表明γ-θ法不仅简单、方便、样品用量少, 而且有获得信息多的特点, 用几毫升样品可得到有关体系表面性质的十多种数据。  相似文献   

3.
It is verified that a 1:1 correspondence exists between the sizes of a stable emulsion droplet prior to and subsequent to solidification through a chemical reaction.  相似文献   

4.
The critical micelle concentration of mixtures of anionic and nonionic surfactants was measured. The anionic surfactants were alkylbenzene sulfonates and the nonionic surfactants were polyoxyethylene nonylphenols and a polyoxy-ethylene alcohol. The effect of added electrolyte, the number of ethylene oxide units in the polyethoxylate, and the anionic alkyl chain length were studied. All systems showed substantial negative deviations (lower CMC) from ideal solution theory. The results can be represented by regular solution theory. Charge separation appears to be the source of the nonideality. This considers the reduction of electrostatic repulsion between the ionic surfactant head groups in the mixed micelle, due to the insertion of nonionic hydrophilic groups between these charged groups, to be the cause of enhanced micelle formation. The physical basis of regular solution theory was shown to be consistent with the charge separation effect.  相似文献   

5.
通过O-烯丙基化,全氟烷基化和还原3步过程在聚乙二醇分子中引入了全(多)氟烷基,合成了10多种全(多)氟烷基非离子型表面活性剂。  相似文献   

6.
研究了直接测定粘附张力、推算表面活性剂在低能固体表面上吸附的方法。与文献结果比较, 说明此法可行, 且较γ-θ法~[4]方便、准确、重复性好。研究了C_(12)H_(25)-SO_4Na、C_(16)H_(33)N(CH_3)_3Br、C_7F_(15)COONa水溶液与聚四氟乙烯、石蜡、甲基化玻璃、聚甲基丙烯酸甲醋界面上的粘附张力及吸附, 结果表明: (1)各种表面活性剂在四种固体上的饱和吸附量顺序皆为~ΓPTFE>~ΓAE>~ΓMG>~ΓPMMA与各固体对水粘附张力增加的顺序相同; (2)改善固体亲水性的能力, 对于碳氟固体, 碳氟表面活性剂优于碳氢表面活性剂, 对于碳氢固体则相反。  相似文献   

7.
A series of triblock nonionic surfactants with different Propylene oxide and ethylene oxide chain lengths were synthesized. The triblock nonionic surfactants and poly(ethylene glycols) with different molecular weight were used, to find the effects of polymer chain length and size of the micelles on the cloud point of the surfactants. Two possible models are considered on the basis of cloud point changes of the solutions, to describe the polymer- surfactant interactions. One model suggests that flocculation depletion for the polymer chains exist between two regular micelles. This provides the driving force for the neighboring micelles to approach each other and destabilize the colloidal system. The flocculation effect is more important for polymers with a shorter chain block the approach of the micelles, since there is no typical polymer-surfactant association formed but just simple small molecule associations in which the steric and solvation effects of the polymer chains make the inter-micelles interactions repulsive. The other model considers that intra-chain micelles of polysoap are formed among the surfactant monomers and long polymer chains. The bridging attraction between two intra-chain micelles in such structures can enhance the collisions among the micelles, due to the exchange of amphiphilic monomers among the neighboring micelles.  相似文献   

8.
New monodisperse nonionic surfactant molecules based on lysine with two different fatty acid chains in the hydrophobic part and one or two polyoxyethylene methoxy capped chain s (EOn-Me) in the hydrophilic head group were synthesized and their physicochemical and toxicity properties were compared to the symmetrical homologs with the same number of methylene groups in the acyl fatty chains. Our findings indicate that the asymmetry studied results in higher surface active properties and in a greater capacity for micellization when compared with their symmetrical analogs, albeit with a slight increase in toxicity.  相似文献   

9.
ABSTRACT

W/O/W and O/W/O multiple emulsions have been found in systems consisting of water, light mineral oil, and two nonionic surfactants (Span 80 and Tween 20).No specific order of addition of the components or pre-mixing was followed. Following gentle agitation at 25°, 35° and 45° for 48?hours, W/O/W emulsions were found at water contents above 30%, while 0/W/O emulsions generally appeared below 60% water.W/0 and 0/W emulsions, micellar phases and liquid crystalline phases were also observed at various compositions. The multiple emulsion regions decreased in size as temperature increased and the areas and positions of the other phases were also temperature dependent.  相似文献   

10.
盐酸溶液中阴离子表面活性剂在铝表面上的吸附   总被引:2,自引:0,他引:2  
用失重法研究了盐酸溶液中阴离子表面活性剂十二烷基磺酸钠(DSASS),十二烷基苯磺酸钠(DBSAS)以及十二烷基硫酸钠(SDS)在铝表面上的吸附作用,提出这种吸附作用与铝的失重量有关,且符合Lang-muir方程,计算出吸附热,吸附熵和吸附自由能等热力学参数。认为这种吸附主要靠静电作用,根据接触角的变化讨论了阴离子表面活性剂分子在铝表面上的吸附取向。  相似文献   

11.
土壤自溶液中吸附MoO_4~(2-)会影响植物生长。前人对这一吸附过程已作过一些研究。本文报导阴离子表面活性剂十二烷基硫酸钠(SDS),阳离子表面活性剂氯化十六烷基吡啶(CPC)和非离子表面活性剂吐温-20(TW-20)对Al_2O_3吸附MoO_4~(2-)的影响。 实验所用吸附剂为层析用中性Al_2O_3(上海五四农场化学试剂厂),SDS(化学纯,广东石岐化工厂),CPC(化学纯。上海试剂一厂),TW—20(试剂级),其余试剂均为分析纯,含钼液用Na_2MoO_4配制。  相似文献   

12.
卟啉类的光电极在分子固体液体接界光伏打电池工作中已得到研究。本文用阴离子型表面活性剂在固体表面上的特性吸附等温线来分析此种离子浓度对数函数与光伏打效应增长的关系,并研究了表面活性剂烷基链长、极性基、阳离子型表面活性剂及非离子型表面活性剂对光伏打效应增强的影响。内Helmholtz层结构与参量变化对光伏打效应也起重要作用。  相似文献   

13.
Effect of ethoxylated nonyl phenol type non-ionic and alkyl sulfate type anionic surfactants on the film formation process of poly (vinyl acetate) and poly (vinyl acetate-acrylate) latexes are discussed. HLB value of non-ionic surfactant is shown to affect glass transition temperature, minimum film formation temperature and rate of film coalescence of vinyl acrylic latexes. Higher HLB non-ionic surfactant appears to be more compatible than the lower HLB ones with the fairly polar vinyl acrylic latex and form a well coalesced film. Presence of sodium lauryl sulfate in the latex is observed to result in incompatible regions on the latex film surface, typical of two phase morphology. Influences of surfactants on the film formation process in the polar vinyl acrylic latexes are compared and contrasted with the available data on the effects of surfactants in styrene butadiene latexes. The findings are discussed in terms of adsorption and interaction behavior of surfactants at polar vinyl acrylic latex surfaces and current theories of latex film formation mechanisms.  相似文献   

14.
The adsorption and solution properties of cationic surfactants dodecylammonium chloride, tetradecylammonium chloride, and hexadecylammonium chloride, as well as hexadecyltrimtehylammonium bromide in pure and mixed states, were studied by surface tension and conductance measurements. The surfactants mixed non-ideally in both mixed monolayer and in the mixed micelles. The regular solution theory was used for evaluating the non-ideal interactions between molecules in adsorbed and micellar states. Similar values of the mixed monolayer and mixed micelle molecular interaction parameters in a mixture imply the molecules at the interface and in the mixed micelle have similar interactions. No synergism in surface tension effectiveness was observed. The adsorbed film at the air/water interface and mixed micelles were richer in more surface-active component.  相似文献   

15.
Solubilization of water and aqueous NaCl solutions in mixed reverse micellar systems of anionic surfactant AOT and nonionic surfactants in n-heptane was studied. It was found that the maximum solubilization capacity of water was higher in the presence of certain concentrations of NaCl electrolyte, and these concentrations increased with the increase of nonionic surfactant content and their EO chain length. Soluibilization capacity was enhanced by mixing AOT with nonionic surfactants. The observed phenomena were interpreted in terms of the stability of the interfacial film of reverse micellar microdroplet and the packing parameter of the surfactant that formed mixed reverse micelles.  相似文献   

16.
The adsorption of the cationic surfactant dodecyl trimethyl ammonium bromide (DTAB) and of the nonionic surfactant dodecyl octaethylene glycol ether (C12E8) on four different layer silicates and their influence on the sorption processes of the fungizide biphenyl were studied. Unexpectedly, no great differences were found in comparing the adsorption of the two surfactants on the basis of physicochemical investigations, although the adsorption mechanism up to monolayer formation is fundamentally different (ion exchange and physisorption). Thus, the plateau values of the adsorption isotherms and the molar enthalpies of displacement Δ 21h are of the same order of magnitude for both surfactants and the same basal spacing by intercalation is observed in the case of swelling clays. The isotherms of the hydrophobic contaminant biphenyl are of the linear Cl-type at all layer silicates and very low adsorption takes place approximately proportionally to the BET (N2) surface area. If the surface is weakly hydrophobized by surfactants (csurfactant<< critical;micelle concentration (CMC)), biphenyl adsorption is clearly increased. These processes can be adequately described using the distribution coefficients K and KOC (Henry coefficient related to the organic carbon content). KOC is hardly influenced by the type of layer silicate for DTA+-layer silicates, whereas the C12E8 layer silicate complexes generally show higher, but also different KOC values. If the surfactant concentrations are above the CMC, solubilization and adsorption compete for the pollutant molecules, which leads to a significant decrease in biphenyl adsorption.  相似文献   

17.
Surface modification by physical adsorption of a series of non-ionic surfactants including Tween 20, Tween 40, Tween 60, Tween 80 and Tween 85, was accomplished on polypropylene microporous hollow fiber and flat membranes. The adsorption curve of the membrane surface was analyzed by weight measurements and the typical results showed a twoplatform character similarly. Differences in the degree and curve shape of adsorption resulting from such factors as concentration, temperature, as well as water cleaning time were observed for Tween 85 among other Tweens. Attenuated total reflection - Fourier transform infrared spectroscopy analysis and field emission scanning electron microscopy observation showed that the adsorption of Tween on polypropylene microporous membrane (PPMM) is effective and occurs mainly in the pores of PPMMs at low adsorption amount, and on the membrane surface also at high adsorption value.  相似文献   

18.
大孔树脂对茄尼醇吸附行为的研究   总被引:2,自引:0,他引:2  
从6种大孔树脂中筛选出用于茄尼醇分离较好的树脂NKA,并进一步研究了其对茄尼醇吸附行为,结果表明,吸附等温线服从Langmuir方程和Freundlich方程,且吸附过程表现为优惠吸附.在温度为283~313K,吸附量为15~35mg/g的条件下,吸附焓变为-16.20~16.57kJ/mol,自由能变为.3.142~3.459kJ/mol,吸附熵变为-47.43~41.17J/mol.K.NKA树脂对茄尼醇吸附速率较快,吸附过程符合一级吸附动力学方程,吸附过程主要受液膜扩散控制.  相似文献   

19.
Abstract

The adsorption of polyoxyethylene mono soya bean fatty acid [Soy (EO)20,40 and 80] and polyoxyethylene (80) monolinoleate [Li(EO)80] onto Na-montmorillonite has been determined at 30°C. The adsorption isotherms of all the tested surfactants exhibit an L-shaped following the Langmuirian model. The experimental adsorption data are fitted to Langmuir adsorption equation, the maximum amount adsorbed, Γmax, and the minimum area occupied per molecule, Amax at the pseudo-plateau have been calculated. Γmax value increases with the increase in the number of ethylene oxide units following the order, Soy (EO)20 < Soy (EO)40 Soy (EO) ? Li (EO)80. Both Soy (EO)80 and Li (EO)80 nearly show the same adsorption behavior.  相似文献   

20.
The adsorption of a series of sodium polystyrene sulfonates with a narrow distribution of molecular weight and ethoxylated non-ionic surfactants ( NP-12, NP-40, NP-100 and C16E20 ) was investigated at carbon black-water interface. Adsorption isotherms of the Langmuir type were obtained for all the samples with negative adsorption free energies. The dependence of maximum of adsorption on molecular weight tor PSSNa was used to obtain information on the macromolecular conformation at the interface; surface geometry effects on adsorption conformation were analyzed using a simplified fractal approach. PSSNa does not adopt a flat conformation at the interface. Non-ionic surfactants ( NP-12, NP-40, NP-100 and C16E20 ) are adsorbed at the interface with the EO chains in a coil conformation.  相似文献   

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