nonionic surfactants что это

nonionic surfactant

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nonionic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

nonionic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

Surfactant — A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue. In more technical terms, a… … Medical dictionary

non-ionic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

non-ionogenic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

nonionogenic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

non-ionic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

non-ionogenic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

nonionogenic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

Источник

nonionic surfactant

1 nonionic surfactant

2 nonionic surfactant

Тематики

3 nonionic surfactant

4 nonionic surfactant

5 nonionic surfactant

6 nonionic surfactant

7 nonionic surfactant

8 nonionic surfactant

9 nonionic surfactant

10 nonionic surfactant

11 неионогенное поверхностно-активное вещество

12 неионогенное поверхностно-активное вещество

См. также в других словарях:

nonionic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

nonionic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

Surfactant — A fluid secreted by the cells of the alveoli (the tiny air sacs in the lungs) that serves to reduce the surface tension of pulmonary fluids; surfactant contributes to the elastic properties of pulmonary tissue. In more technical terms, a… … Medical dictionary

non-ionic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

non-ionogenic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

nonionogenic surfactant — nejoninė aktyvioji paviršiaus medžiaga statusas T sritis Standartizacija ir metrologija apibrėžtis Aktyvioji paviršiaus medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant;… … Penkiakalbis aiškinamasis metrologijos terminų žodynas

non-ionic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

non-ionogenic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

nonionogenic surfactant — nejoninė paviršinio aktyvumo medžiaga statusas T sritis chemija apibrėžtis Paviršinio aktyvumo medžiaga, nedisocijuojanti į jonus. atitikmenys: angl. non ionic surfactant; nonionic surfactant; non ionogenic surfactant; nonionogenic surfactant rus … Chemijos terminų aiškinamasis žodynas

Источник

Nonionic Surfactant

The third group is nonionic surfactants that carry no charge.

Related terms:

Proceedings of the International Conference on Colloid and Surface Science

1 Introduction

Nonionic surfactants have an advantage to ionic surfactants that one can obtain surfactants with wide variety of hydrophile-lipophile balance (HLB) by changing molecular structures, especially hydrophilic moiety. As for polyoxyethylene-type nonionic surfactants, the HLB is adjusted by changing the polymerization degree of the polyoxyethylene group. Due to this advantage, wide variety of surfactant aggregates both with positive and negative curvatures is observed in a phase diagram as a function of HLB number of surfactant in water/polyoxyethylene-type surfactant systems [ 1-3 ].

Sucrose fatty acid esters are environment-friendly surfactants and are widely used for food, cosmetics, medicines, etc. Different from conventional nonionic surfactants, the HLB of sucrose fatty acid esters can be controlled by changing the number of fatty acid residues attached to a sucrose ring from 1 to 8. It is very interesting to investigate how the phase behavior and the self-organized structures in a water/sucrose fatty acid ester system are changed as a function of its number of attached fatty acid residue.

In this context, phase diagram of a water/sucrose dodecanoate system was constructed as a function of HLB of surfactant and the self-organized structures were analyzed based on the small-angleX-ray scattering (SAXS) data.

Introduction to Zeolite Science and Practice

2.1.1.3 Nonionic surfactants

Nonionic surfactants are available in a wide variety of different chemical structures. They are widely used in industry for their attractive characteristics, like low cost, nontoxicity and bio-degradability. Nonionic surfactants have rich phase behaviors and low CMT values and are becoming more and more popular and powerful in the synthesis of mesoporous solids. Figure 4 lists the classical commercial nonionic surfactants.

Paving with asphalt emulsions

13.3.2.3 Solubility of nonionic surfactants: cloud point

The nonionic surfactant is water soluble through hydrogen bonds formation of hydrophilic moieties with water. As the temperature is raised, it reaches the point at which large aggregates of the nonionic surfactant separate out into a distinct phase. The temperature at which the phase separation occurs is referred to as the cloud point. The surfactant molecules partition into the oil phase above the cloud point, and a large amount of water is solubilized in the oil phase near this temperature ( Shinoda and Ogawa, 1967 ). Polyoxyethylene (CH₂CH₂O)_n moieties of the nonionic surfactant range from 3 or 4 to 40 or more. The cloud point increases almost linearly with n: the longer the polyoxyethylene chain, the higher the cloud point. Nonionic surfactants used in asphalt emulsion generally have cloud points above the boiling point of water, which is an issue only when emulsifying high softening-point asphalts at high temperatures ( James and Logaraj, 2002 ).

Abrupt changes in application properties occur below the Krafft point of ionic and above the cloud point of nonionic surfactant solutions. For example, asphalt emulsion used for chip seal application is sometimes manufactured using the cationic emulsifier with a Krafft point near 60 °C, and the emulsion should be stored and tested above this temperature to prevent premature breaking.

NMR Studies of Nonionic Surfactants

1 Introduction

In addition to thermodynamic equilibrium phases, one can form metastable structures such as unilamellar vesicles by sonication 12 or a temperature jump, 13 multi-lamellar vesicles (MLVs) “onions” 14 by applying shear, or macroscopically oriented liquid crystalline phases by exposing the sample to a strong magnetic field. 15

NMR has been one of the main experimental methods for investigating nonionic surfactant systems. Starting from the mid-1980s, the main techniques have been 2 H quadrupole splittings to study phase behaviour, 16 1 H diffusion experiments to characterize micelles 17 and microemulsions, 18 and 13 C relaxation to investigate surfactant dynamics. 7 In the past few years, nonionic systems have been studied using advanced NMR techniques such as diffusion–diffusion exchange, 19 separated local field, 20 and spectroscopic imaging, 21 providing additional information on length scales from nano- to millimetres.

There are excellent previous reviews on both nonionic surfactants 22 and NMR studies of surfactants in general. 23–27 The scope of the present review is applications of NMR to aqueous systems with research grade C_mE_n nonionic surfactants. We exclude compounds with n above 10, since these substances more resemble hydrophobically modified poly(ethylene glycol) than surfactants, as well as commercial products such as Brij, Triton, and Tween. Studies of mixed systems containing co-surfactants, hydrocarbons, lipids, polymers, or solid surfaces are included. In terms of NMR techniques, we have the intention to be comprehensive but concise, covering the wide range of methods that have been applied for studying self-aggregation, microstructure, and molecular dynamics in nonionic surfactants: from imaging and diffusion to relaxation and solid-state NMR.

The remainder of this review is organized as follows. We start by briefly outlining the relevant NMR theory and the basic relations between the NMR observables and molecular structure and dynamics. Subsequently, we present some of the NMR pulse sequences. The main part of the review deals with applications of NMR to nonionic surfactant systems focusing on the models used for extracting structural and dynamic information from the NMR data.

Surface Tension

20.3.2.4 Non-Ionic Surfactants

Non-ionic surfactants are surfactants that have polar head groups that are not electrically charged (see Fig. 20.18 ). They usually rely on a functional group able to deprotonate but only to a very low degree. Thus the substance does not act as a good Brønsted acid but provides decent solubility in polar solvents, e.g., water. In general, the solubility of non-ionic surfactants is not as good as the solubility of ionic surfactants, but they do not change the pH of the solution. Their CMC is usually higher than those encountered in ionic surfactants, which may be an advantage as it allows more surfactant to be mixed into a solution without running the risk of (potentially) undesired micelle formation.

In general, alcohols are good candidates for such head groups. Alcohols are weak acids with decent solubility in aqueous solutions. Primary alcohol groups bound to unpolar aliphatic tails or cyclic or aromatic structures are generally good candidates for non-ionic surfactants. Non-ionic surfactants are important substances for cell biology as they are mild and do not break protein/protein interaction while still providing the potential to dissolve unpolar compounds, e.g., bilayer membranes. This makes them suitable, e.g., for disrupting cell membranes, a process referred to as (cell) lysis.

Alkylphenyl Ethers of poly(ethylene glycol). Alkylphenyl ethers of poly(ethylene glycol) are a very common group of non-ionic surfactants. One of the most prominent members of this surfactant family is Triton, which is a polar oligo(ethylene glycol) tail bound to an alkylphenol that acts as the hydrophobic head. The number following the name indicates the length of the polar tail. There are also reduced forms of Triton based on a cycloalkane. These are referred to as Triton (reduced).

Several other alkylphenyl ethers are used as surfactants that mainly differ by the side groups of the benzene ring. For example, nonoxynol-9 uses a n-nonane hydrophobic tail and has been used as an ingredient for shampoos and creams.

Alkylethers of poly(ethylene glycol). Besides alkylphenyl ether, alkylethers of poly(ethylene glycol) are also commonly used non-ionic surfactants. They consist of a poly(ethylene glycol) chain with varying lengths to which an aliphatic hydrocarbon chain is attached (often n-dodecane). Typical examples of this surfactant family include octaethylene glycol monododecyl ether and pentaethylene glycol monododecyl ether.

Alkylethers of poly(propylene glycol). Another alternative to using poly(ethylene glycol) is poly(propylene glycol). Its alkylethers are also commonly used non-ionic surfactants. For example, poly(propylene glycol) is less hydrophilic than poly(ethylene glycol) and can often be combined with poly(ethylene glycol) to form surfactants as well. The group of polymers referred to as poloxamer, poly(ethylene glycol)/poly(propylene glycol)/poly(ethylene glycol) block copolymers, can also be used as surfactants of this family.

Alkylethers of glycerol. Likewise, glycerol can be used as hydrophilic head in non-ionic surfactants. Usually, it is partly esterified with long-chained fatty acids, e.g., lauric acid, resulting in glycerol monolaurate.

Derivatives of ethanolamine. Several derivatives of ethanolamine can be used as surfactants. These are usually amids obtained by reacting ethanolamine with long-chained fatty acids, e.g., lauric acid. The resulting surfactant is a secondary amine. These surfactants are often referred to as cocamide surfactants because mostly fatty acids from coconut oil are used. A typical example is lauramide monoethylamine. An alternative to ethanolamine is diethanolamine, which is also reacted with a fatty acid to obtain a tertiary amine. Typical examples of such surfactants are 2-dimethylaminoethanol and polyethoxylated tallow amine.

Sugar-Based Surfactants. This group of non-ionic surfactants uses hydrophilic sugars to which hydrophobic tails are bound. One common substance of this class is n-dodecyl-β-D-maltoside, a member of the maltoside surfactants so named because the sugar unit used is maltose. An example of a pyranoside surfactant is n-octyl-β-D-thioglucopyranoside. This class uses pyranose as the sugar unit. Examples of the glycoside surfactants are octyl glucoside, decyl glucoside, and lauryl glucoside. An example of a polysugar surfactant is digitonin.

Another very important group of sugar-based surfactants are the Tween surfactants, most notable Tween 20 and Tween 80. These surfactants are based on a sorbitan sugar, which is why they are commonly referred to as polysorbate surfactants. Three oligo(ethylene glycol) side groups of varying lengths are bound to the sugar increasing the hydrophilicity of the head group. This structure forms the core of all Tween surfactants. They deviate in the hydrophobic tail, which is a fatty acid coupled via an ester to four oligo(ethylene glycol) tail. In Tween 20 this fatty acid is lauric acid; in Tween 80 it is oleic acid.

Miscellaneous. Several hydrophobic substances to which several hydroxy groups are appended can also be used as surfactants. If these compounds are of lower molecular weight, they are usually unsaturated in order to ensure sufficient hydrophobicity. A typical example is 2,5-dimethyl-3-hexyne-2,5-diol. There is also a class of fluorinated surfactant based on perfluorinated alcohols. The most common representatives of this class are the Zonyl FSO surfactants.

EOR mechanisms of wettability alteration and its comparison with IFT

9.6.5 Monolayer adsorption by nonionic surfactants

The use of surfactants in the finishing of technical textiles

9.3.2 Non-ionic surfactants

Non-ionic surfactants do not ionize in aqueous solution because their hydrophilic group is of a non-dissociable type, such as alcohol, phenol, ether, ester or amide. A large proportion of these non-ionic surfactants are made hydrophilic by the presence of a polyethylene glycol chain, obtained by polycondensation of ethylene oxide. They are known as polyethoxylated non-ionics. In the past decade glucoside (sugar-based) head groups have been developed because of their low toxicity. The polycondensation of propylene oxide produces a polyether which is slightly hydrophobic. This polyether chain is used as the lipophilic group in the group known as poly-EOpolyPO block copolymers. These surfactants have the following characteristics:

Ester linkage to solubilizing groups

Ethylene oxide condensates

Their behaviour when added to water (HLB range) is:

Chemistry of chemical admixtures

9.5.7 Non-ionic surfactants

Non-ionic surfactants are mostly based on EO, and are usually referred to as ethoxylated surfactants. Tadros (2005) distinguishes the following classes:

alkyl phenol ethoxylates

fatty acid ethoxylates

sorbitan ester ethoxylates

fatty amine ethoxylates

ethylene oxide–propylene oxide copolymers (also known as polymeric surfactants).

There are also multihydroxy products, such as:

glycerol and polyglycerol esters

glucosides and polyglucosides

Considering their application in concrete, non-ionic surfactants have the advantage of good compatibility with all other types of surfactants. Because of their non-ionic nature these surfactants do not show strong adsorption onto charged surfaces. In terms of undesired loss of surfactant at the solid–liquid interface, this means that more surfactant remains available to saturate the liquid–vapour interface of the air bubbles created through mixing, and less surfactant is needed compared to their analogous ionic surfactants for a given air void surface to be created in concrete.

The main disadvantage of non-ionic surfactants is their inability to properly stabilize the air system they are creating, mitigating coalescence and bubble coarsening. In particular, unlike anionic surfactants, they cannot directly form salts with electrolytes of the cement pore solution at the liquid–vapour interface, while charged heads of ionic surfactants form a shell-like structure with increased rigidity through precipitation (for example lime soap).

This may be the reason why non-ionic surfactants are rarely used as a single compound in AEAs ( Ziche and Schweizer, 1982 ) and are mostly found in mixtures with surfactants of different natures ( Bour and Childs, 1992; Hill et al., 2002; Budiansky et al., 1999, 2001a,b; Wombacher et al., 2014; Berke et al., 2002 ). In this sense they can be considered as having mainly a supporting function in formulated admixtures, as discussed in Chapter 15 ( Mantellato et al., 2016 ).

In this role of cosurfactants they increase the solubility of ionic surfactants and reduce the tendency of the ionic surfactant to adsorb at the solid–liquid interface. In the case of contamination with unburnt carbon in blended cements containing fly ash, some non-ionic surfactants may serve as sacrifice material because they are good carbon dispersers.

Ethoxylated fatty acids and their amines are referred to as single-component air entrainers ( Ziche and Schweizer, 1982 ). Their application is in cementitious material with rather high stiffness (plaster). Air entrainment in concrete for pavers is another field of application for non-ionic surfactants as a single component.

An example of a commercially available surfactant is coconut fatty amine with a number of EO units between 2 and 20.

In Berke et al. (2002) a triblock polyoxyalkylene copolymer surfactant has been claimed for use in AEAs. This has the general formula:

R₁; R₂: C1–C7 alkyl group, C5–C6 cycloalkyl group or aryl group

with a molar mass between 8000 and 12,000 g/mol and an HLB between 20 and 30.

This polymeric surfactant is claimed to show good performance in concrete that contains a surfactant of the same nature used as an SRA.

In Budiansky et al. (1999, 2001a,b) a polymeric surfactant with explicit compatibility with an oxyalkylated SRA is introduced. In particular, the surfactant has a di-block structure:

with preferences on:

and a molar mass of M > 2000 g/mol. The SRA used in combination is dipropylene-tert-butyl ether (DPTB).

This preferred structure results in a range of 14.2 air entrainer either consistently reduces air entrainment or requires disproportional high dosages. In Berke et al. (2002) this compatibility issue was solved using a polymeric non-ionic surfactant alone. However, the AEA of Budiansky et al. (1999, 2001a,b) contains not only a di-block polymeric surfactant but also a betaine-based surfactant.

Non-ionic polymeric surfactants have a major advantage with respect to other non-ionic surfactants, that is having a high degree of freedom for tailoring the overall size and HLB of the molecule, as well as the location of the hydrophilic/hydrophobic groups and their distribution.

A good example of this flexibility is provided by the above mentioned block copolymers. The triblock copolymer surfactant can be seen as an amphiphile containing two hydrophilic portions (EO units) and a hydrophobic group (propylene oxide-PO-units) between them, whereas the di-block polymeric surfactant has one hydrophilic block and one hydrophobic.

Proceedings of the International Conference on Colloid and Surface Science

2.1 Materials

The nonionic surfactants used were polyoxyethylene cetyl ethers, C16En (HLB values: 3 for n = 2, 7 for n = 5, 11 for n = 10, and 14 for n = 20), polyoxyethylene stearyl ethers, C18En (HLB values: 3 for n = 2, 7 for n = 6, 11 for n = 11, and 14 for n = 20), and polyoxyethylene hexadecyl ethers, C6-C10En (HLB values: 7 for n = 5, 11 for n = 10, and 14 for n = 20), polyoxyethylene isostearyl ethers, C7-C11En (HLB values: 7 for n = 5, 10 for n = 10, and 14 for n = 20). They were commercial products (Nihon Emulsion Co., Ltd., Japan). Sodium tetraoxyethylene alkyl sulfate, C_nAES (n = 12,16,and 18), anionic surfactants, were synthesized in our laboratory. Ethanol, diethylene glycol monobutyl ether and n-hexane were purchased from Kanto Chemical Co., Inc. (Japan). LPG was a commercial product, a mixture of n-butane and isobutane supplied by Taiyo Ekika Gas Co. (Japan).

Emulsions: Structure Stability and Interactions

2.1 Phase behavior of water/polyoxyethylene nonionic surfactant/oil systems: general aspects

(Reproduced by permission from Ref. 5 ).

(Reproduced by permission from Ref. 25 )

The surfactant R₁₂EO₆ is mainly water soluble and in the surfactant-water binary system forms a micellar solution (Wm) up to 40 wt% surfactant. In the presence of oil the Wm phase coexists with an excess oil phase (O). At higher surfactant concentrations, there are several regions with liquid crystalline phases of different structure.

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