Nonionic surfactant INDEX

The difficulty with HLB as an index of physicochemical properties is that it is not a unique value, as the data of Zaslavsky et al. (1) on the haemolytic activity of three alkyl mercaptan polyoxyethylene derivatives clearly show in Table 1. Nevertheless data on promotion of the absorption of drugs by series of nonionic surfactants, when plotted as a function of HLB do show patterns of behaviour which can assist in pin-pointing the necessary lipophilicity required for optimal biological activity. It is evident however, that structural specificity plays a part in interactions of nonionic surfactants with biomembranes as shown in Table 1. It is reasonable to assume that membranes with different lipophilicities will"require" surfactants of different HLB to achieve penetration and fluidization one of the difficulties in discerning this optimal value of HLB resides in the problems of analysis of data in the literature. For example, Hirai et al. (8 ) examined the effect of a large series of alkyl polyoxyethylene ethers (C4,C0, Cj2 and C 2 series) on the absorption of insulin through the nasal mucosa of rats. Some results are shown in Table II. 

Living radical polymerizations in miniemulsions have also been conducted by de Brouwer et al. using reversible addition-fragmentation chain transfer (RAFT) and nonionic surfactants [98]. The polydispersity index was usually below 1.2. The living character is further exemplified by its transformation into block copolymers. 

Anon. (1991) Environmental and Human Safety of Major Surfactants. Volume 1 Anionic Surfactants. Part 1. Linear Alkylbenzene Sulfonates. Part 2. Alcohol Ethyl Sulfates. Part 3. Alkyl Sulfates. Part 4. Alpha Olgin Sulfonates. Volume 2 Nonionic Surfactants, Alcohol Ethoxylates and Alkylphenol Ethoxylates. Government Reports Announcements Index (GRA I). 

Emulsification is the process by which a hydrophobic monomer, such as styrene, is dispersed into micelles and monomer droplets. A measure of a surfactant s ability to solubilize a monomer is its CMC. Below the CMC the surfactant is dissolved in the aqueous phase and does not serve to solubilize monomer. At and above the CMC the surfactant forms spherical micelles, usually 50-200 soap molecules per micelle. Many properties, such as electrical conductivity, interfacial tension, surface tension, refractive index, and viscosity show a sudden decrease at the CMC (107). The CMC is temperature- and chain-length-dependent for a given class of surfactants (108). The CMCs of nonionic surfactants are higher than those of ionic surfactants (109). 

Figure 8 Effect of resorcinol (X) and phenol ( ) on phenol index values of nonionic surfactants.

Living free radical polymerizations were also carried out in miniemulsion systems via the reversible addition-fragmentation chain transfer mechanism [66]. The colloidal stability of miniemulsions is the key issue, and nonionic surfactants result in the best results. The polydispersity index of molecular weight distribution for the resultant miniemulsion polymer is generally smaller than 1.2. 

Chiu, Y. C., L. J. Chen, Refractive index of nonionic surfactant solutions containing polyoxyethylene mono-n-alkylether. Colloids Surf., 1989,41,239-244. 

An HPLC method optimized for scanning mixtures of unknown nonionic surfactants can be used for qualitative and semi-quantitative analyses (21). Use of a Cig column, a mobile phase of 90 10 methanol/water, and a refractive index detector allows detection of all major classes of nonionics except the EO/PO copolymers. These last can be determined using a Cg column and 100% methanol. 

HPLC under critical conditions is sometimes used for simple determination of a specific surfactant in a complex matrix, since the smaller number of individual peaks make quantification easier than for normal phase HPLC. Such a system may also be used for qualitative analysis of unknown mixtures of surfactants. For example, a reversed-phase C s column with a mobile phase of 90 10 methanol/water and refractive index detection is suggested for detection of almost every commercial nonionic surfactant. EO/PO copolymers require a Cg column and 100% methanol. Some sample cleanup is required prior to HPLC (89). 

Szymanowski, J., A. Voelkel, H. Szewczyk, Increments of the arithmetic retention index for nonionic surfactants with a polyoxyethylene chain, J. Chromatogr., 1986,360,43-52. 

Chem. Desaip. PEG 600 CAS 25322-68-3 EINECS/ELINCS 229-859-1 Uses Surfactant intermediate intermediate for fatty acid esters solubilizer, lubricant used in paper coating mixes antisticking agent oil resistor antistaL softener, humectanL and lubricant for textiles, metalworking Properties Pt-Co < 50 color clear paste m.w. 570-630 dens. 1.1257 g/ ml (20 C) vise. 64 cps f.p. 20-25 C flash pt. (PMCC) 210 C ref. index 1.4699 pH 5.5-7.0 (5% aq.) nonionic 100% act. 

Uses Emulsifier, thickener, wetting agent, dispersant, solubilizer, stabilizer for cosmetics and pharmaceuticals demulsifier in petrol, industry detergent ingred. antistat for polyethylene and resin molding powds. metal treatment emulsion polymerization surfactant in latex-based paints, aq.-based syn. cutting fluids and vulcanization of rubber Properties Colorless liq. m.w. 5500 ref. index 1.4613 water-sol. sp.gr. 1.04 vise. 850 cps HLB 15 cloud pt. 65 C (1%) pour pt. 18 C surf, tens. 40.3 dynes/cm (0.1%) nonionic 100% act. 

Uses Emollient for cosmetics lubricant for compressor, rubber, greases, textiles intermediate for prep, of resins, plasticizers, modifiers, and surfactants solvent for inks and dyes demulsifier solvent, softener, plasticizer for textile and paper coatings, NC coatings mold release agents and dye soivs. for vinyl resins antifoam in boiler water, latex processing, washing sol ns., paints, adhesives, saltwater evaporators Properties M.w. 520 (avg.) sp.gr. 1.023 (20/20 C) dens. 8.51 Ib/gal (20 C) vise. 100 SUS (38 C) pour pt. -51 C flash pt. (PMCC) 141 C ref. index 1.4491 (20 C) nonionic... 

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