Surfactants, non-ionic

All types of conventional non-ionic surfactants have at one time or another been recommended for use in polyester and, in certain instances, in polyether polyurethanes. However, the predominant surfactants used today are the silicones. These materials are block or graft copolymers or polydimethyl siloxanes and polyalkylene oxides. The polyether part is usually a copolymer of propylene and ethylene oxides. Variations in the commercially available surfactants are in the molecular weight and the weight ratio of the two blocks, the ratio of ethylene oxide to propylene oxide in the polyether portion, and the type of link between the silicone and 

The commercially dominant cell-size control additives for microcellular urethanes are at present silicone surfactants, which when added in small quantities serve several purposes. With the addition of silicone three basic problems are overcome  

Silicones therefore influence the cell structure and consequently the physical properties of the foam. However, adding too much silicone does not give any further improvements. The optimum quantity is dependent upon the constituents, foaming conditions, mixing efficiency, etc. 

Non-ionics are second major surfactant class used in preparation and are manufactured in different forms. Non-ionic surfactants do not contain an ionisable group and have no electrical charge (Table 4.2). The most important non-ionic detergents TABLE 4.2 

Non-ionic Surfactants that Bear an Electrically Neutral Charge 

Sorbitan ester-EO Sorbitol esters Sorbitol ester-EO EO fatty acid PO fatty acid Fatty alkanol amides 

Ethoxylated primary alcohol Ethoxylated nonyl phenol Ethoxylated thio-ethers 

Ethoxylated fatty acids Ethoxylated fatty amide 

Cassidy and Niro [13] have applied high-speed liquid chromatography combined with infrared spectroscopy to the analysis of polyoxyeihylene surfactants and their decomposition products in industrial process waters. Molecular sieve chromatography combined with infrared spectrometry give a selective method for the analysis of trace concentrations of these surfactants. These workers foimd that liquid-solid chromatography and reversed phase chromatography are useful for the characterisation and analysis of free fatty acids. 

Okada [14] used indirect conductiometric detection of poly(oxyethy-lene) surfactants following chromatographic separation. 

---

Recent publications indicate the cloud-point extraction by phases of nonionic surfactant as an effective procedure for preconcentrating and separation of metal ions, organic pollutants and biologically active compounds. The effectiveness of the cloud-point extraction is due to its high selectivity and the possibility to obtain high coefficients of absolute preconcentrating while analyzing small volumes of the sample. Besides, the cloud-point extraction with non-ionic surfactants insures the low-cost, simple and accurate analytic procedures. 

CONCENTRATING OF THE MICRO-ADMIXTURES FROM AQUA SOLUTIONS OF THE NON-IONIC SURFACTANTS... 

METHODOLOGICAL ASPECTS OP CLOUD POINT PRECONCENTRATING OF MICRO-ADMIXTURES BY PHASES OF NON-IONIC SURFACTANTS Doroschuk V.O. 

The study of the mechanism of cloud point micellar extractions by phases of non-ionic surfactant (NS) is an aspect often disregarded in most literature reports and, thus, is of general interest. The effective application of the micellar extraction in the analysis is connected with the principled and the least studied problem about the influence of hydrophobicity, stmcture and substrate charge on the distribution between the water and non-ionic surfactant-rich phase. 

THE CLOUD-POINT EXTRACTION OF ALIPHATIC AMINES INTO THE NON-IONIC SURFACTANT-RICH PHASES... 

A new generation of mesoporous silica (SG) materials obtained by sol-gel technique where polymers and ionic or non-ionic surfactant act as stmcture - directed templates is widely developed during last year s. Final materials can be synthesized as thin films and used as sensitive elements of optical and electrochemical sensors. 

In the present work it was studied the dependence of analytical characteristics of the composite SG - polyelectrolyte films obtained by sol-gel technique on the content of non-ionic surfactant in initial sol. Triton X-100 and Tween 20 were examined as surfactants polystyrene sulfonate (PSS), polyvinyl-sulfonic acid (PVSA) or polydimethyl-ammonium chloride (PDMDA) were used as polyelectrolytes. The final films were applied as modificators of glass slides and pyrolytic graphite (PG) electrode surfaces. 

SILICA BASED THIN FILMS OBTAINED BY SOL-GEL TECHNOLOGY IN THE PRESENCE OF NON-IONIC SURFACTANTS AND MODIFIED WITH POLYELECTROLYTE... 

Low temperature sol-gel technology is promising approach for preparation of modified with organic molecules silica (SG) thin films. Such films are perspective as sensitive elements of optical sensors. Incorporation of polyelectrolytes into SG sol gives the possibility to obtain composite films with ion-exchange properties. The addition of non-ionic surfactants as template agents into SG sol results formation of ordered mechanically stable materials with tunable pore size. 

The aim of the present work was optimization of synthesis of SG -polymeric cation exchanger composite films by sol-gel technology in the presence of non-ionic surfactants and their application for detenuination of Zn (II) as phenanthrolinate (Phen) complex. 

SG sols were synthesized by hydrolysis of tetraethyloxysilane in the presence of polyelectrolyte and surfactant. Poly (vinylsulfonic acid) (PVSA) or poly (styrenesulfonic acid) (PSSA) were used as cation exchangers, Tween-20 or Triton X-100 were used as non- ionic surfactants. Obtained sol was dropped onto the surface of glass slide and dried over night. Template extraction from the composite film was performed in water- ethanol medium. The ion-exchange properties of the films were studied spectrophotometrically using adsorption of cationic dye Rhodamine 6G or Fe(Phen) and potentiometrically by sorption of protons. 

Non-ionic surfactants used in detergents, paints, herbicides, pesticides and plastics. Breakdown products, such as nonylphenol and octylphenol, are found in sewage and industrial efffuents Products of combustion of many materials Widely used as plasticisers for PVC. Common environmental pollutants... 

The substitution of water-borne versions of these primers is increasing as environmental restrictions on the use of organic solvents become stricter. These are generally aqueous emulsions of epoxy novolac or phenolic based resins stabilized by surfactants [34]. Non-ionic surfactants are preferred, as they are non-hygroscopic in the dried primer films. Hygroscopic ionic surfactants could result in excessive water absorption by the primer film in service. 

An application of an LC-SFC system has been demonstrated by the separation of non-ionic surfactants consisting of mono- and di-laurates of poly (ethyleneglycol) (23). Without fractionation in the precolumn by normal phase HPLC (Figure 12.18 (a)) and transfer of the whole sample into the SFC system, the different homologues coeluted with each other. (Figure 12.18(b)). In contrast with prior fractionation by HPLC into two fractions and consequent analysis by SFC, the homologues in the two fractions were well resolved (Figures 12.18(c) and 12.18(d)). 

The apparent difference seems to be due to the difference in the binding constants of the complexes to micelles which is much larger in the lipophilic 38c than in the hydrophilic 38b complex27 . A somewhat different, but not an unusual micellar effect is observed in the case of the non-ionic surfactant Triton X-100 as shown in... 

The change in surface wettability (measured by the contact angle) with concentration for the three surfactants is plotted in Fig. 2.54 (Zhang and Manglik 2005). The contact angle reaches a lower plateau around the CMC where bilayers start to form on the surface. Wettability of non-ionic surfactants in aqueous solutions shows that the contact angle data attains a constant value much below CMC. Direct interactions of their polar chain are generally weak in non-ionics, and it is possible for them to build and rebuild adsorption layers below CMC. The reduced contact an-... 

For example, for alkyl (8-16) glycoside (Plantacare 818 UP) non-ionic surfactant solution of molecular weight 390 g/mol, an increase in surfactant concentration up to 300 ppm (CMC concentration) leads to a significant decrease in surface tension. In the range 300 < C < 1,200 ppm the surface tension was almost independent of concentration. In all cases an increase in liquid temperature leads to a decrease in surface tension. This surface tension relaxation is a diffusion rate-dependent process, which typically depends on the type of surfactant, its diffusion/absorption kinetics, micellar dynamics, and bulk concentration levels. As the CMC is approached the absorption becomes independent of the bulk concentration, and the surfactant... 

Baillie, A.J. et al.. The preparation and properties of niosomes-non-ionic surfactant vesicles, J. Pharm. Pharmacol., 37, 863, 1985. 

By the enzymatic esterification of diglycerol with lauric acid, the corresponding monolaurate ester is obtained [84]. This is an important industrial reaction for the cosmetic, pharmaceutical and feed industries, since this ester is used as biodegradable non-ionic surfactant. In recent years, the synthesis of this and other polyglycerols with fatty acids has attracted growing interest in industry, leading also to a demand for enantiomerically and isomerically pure products. 

As alternatives to amphiphilic betaines, a wide range of cationic, anionic, and non-ionic surfactants including environmentally benign sugar soaps have been successfully used as colloidal stabilizers [201]. Electrochemical reduction of the metal salts provides a very clean access to water soluble nanometal colloids [192]. 

Gutfelt et al. (1997) have evaluated various ME formulations as reaction media for synthesis of decyl sulphonate from decylbromide and sodium sulphite. The reaction rate was fast both in water-in-oil and in bicontinuous ME based on non-ionic surfactants. A comparison was made with this reaction being conducted in a two-phase. system with quats as phase-transfer catalyst but was found to be much less efficient. However, when two other nucleophiles, NaCN and NaNOj, were used the PTC method was almost as efficient as the ME media. It seems that in the case of decyl sulphonate there is a strong ion pair formation between the product and the PTC. The rate in the ME media could be further increased by addition of a small amount of a cationic surfactant. 

The raw materials used in a particular product may present some challenges to the formulation chemist when selecting the most appropriate preservative. Problem ingredients may act as microbial nutrients, preservative inactivators or preservative adsorbers and careful testing and assessment of the preservative system is necessary in these cases. One notable example of this is the inactivation of parabens esters by certain non-ionic surfactants. 

Combinations of Phenoxyethanol and Parabens- This is used as a second option and where the pH can be controlled to ideally 6 and below and wherever possible restricting the amount of non-ionic surfactants. The total Phenonip type combination not exceeding 0.7%. 

---