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EN
From the large group of surfactants with branched chains, sulfosuccinate derivatives obtained based on 2-ethylhexyl alcohol were selected. The surfactant of reference was ethoxylated sulfosuccinate with an alkyl chain (C12-C14). Tests regarding foam-forming ability (V0) and foam stability (V10) for selected solutions of the three surfactants were performed. Foam stability of the solutions of sterically specific surfactants (P13, P14) decreased by up to a factor of ten as compared with the equivalent linear alkyl chain (P19). This was achieved with the high surface activity of the solutions of these compounds as represented by surface tension and wettability of the surface of the bearing steel. The consequence of the high surface activity of the compounds were low friction and wear in tribological tests at constant load and excellent anti-seizure properties. On the cooperating friction pairs, adsorption layers were formed, effectively separating the two materials and able to transfer the high loads [L. 3]. Summing up, there is the possibility of using solutions of sterically specific surfactants as model cutting fluids with low foaming ability.
PL
Z licznej grupy surfaktantów o rozgałęzionych łańcuchach wybrano pochodne sulfobursztynianowe otrzymane na bazie oksyalkinelowego alkoholu 2-etyloheksylowego. Surfaktantem odniesienia był etoksylowany sulfobursztynian posiadający łańcuch alkilowy (C12-C14). Wykonano testy określające zdolność pianotwórczą (V0) i trwałość piany (V20) wytypowanych roztworów trzech surfaktantów. Trwałość piany roztworów sterycznie specyficznych ZPC (P13, P14) zmniejszyła się nawet dziesięciokrotnie w stosunku do ich odpowiedników z liniowym łańcuchem alkilowym (P19). Efekt ten uzyskano przy wysokiej aktywności powierzchniowej roztworów tych związków, której miarą było napięcie powierzchniowe i zwilżalność powierzchni stali łożyskowej. Konsekwencją wysokiej aktywności powierzchniowej związków były niskie opory ruchu i zużycie w testach tribologicznych przy stałym obciążeniu oraz doskonałe właściwości przeciwzatarciowe. Na współpracujących tarciowo parach ciernych tworzą się warstwy adsorpcyjne skutecznie oddzielające materiały oraz przenoszące wysokie obciążenia. Reasumując, udokumentowano możliwość stosowania roztworów sterycznie specyficznych surfaktantów jako modelowych cieczy obróbkowych o niskiej pianotwórczości.
PL
W pracy przedstawiono wyniki badań reologicznych dla mieszaniny chlorku heksadecylotrimetyloamoniowego (HTAC) z dodatkiem salicylanu sodu (NaSal). Z analizy danych wynika, że kształt krzywych płynięcia zależy przede wszystkim od stosunku molowego Na-Sal/HTAC. Stężenie układu NaSal/HTAC, przy zachowanym stosunku molowym obu składników, wpływa głównie na zmiany ilościowe w przebiegu krzywych płynięcia.
EN
Rheological investigation results dealing with mixtures of hexadecyltrimethylammonium chloride (HTAC) and sodium salicylate (NaSal) in shear flow are presented in the paper. It was shown that a shape of flow curves depended mainly on the NaSal/HTAC molar ratio. The concentration of NaSal/HTAC system has a quantitative effect on the course of flow curves at the same molar ratio of both components used.
EN
In this paper, the measurement results of rheological behaviour of the surfactant solutions have been presented. The influence of pipe diameter and non-Newtonian behaviour index of the surfactant solutions on drag reduction phenomena were investigated. The results are presented in various, dimensionless co-ordinate systems. The influence of the Reynolds number definition on the shape and the position of the friction factor curve has been emphasised. The phenomena of drag reductions caused by high molecular polymers and surfactants have been compared.
EN
Nonionic surfactants containing a polyoxyethylene chain 1 and 2 dissolve well in aqueous solutions due to the hydration of the hydrophilic chains. All parameters e.g. temperature and electrolyte content, which affect the hydration change the solubility of nonionic surfactants in water. As a result, clouding of surfactant solutions is observed after heating them. The process is reversible and nonionic surfactants dissolve after cooling. Aqueous solutions of zwitterionic surfactants (3 and 4) also exhibit the cloud point phenomenon but in this case after cooling. The cloud point temperature depends on several parameters, including the hydrophobicity and polydispersity of surfactants. The presence of additional organic compounds, e.g. alcohols, fatty acids, etc., and type and content of electrolytes. Therefore, the cloud point can be easily modified to cause the clouding separated, e.g. by centrifugation. However, only the knowledge of the surfactant-water phase diagrams (Figs 1 and 2) permits the design of optimal conditions at which the surfactant-rich-phase is in equilibrium with almost pure water. Aqueous solutions of some b-cyclodextrine derivatives (Fig. 3) also exhibit the clouding phenomenon caused, however, by crystallisation. Nonionic surfactants dissolved in organic solvents complex small amounts of ion pairs. As a result, they are considered as open analogs of crown ethers. Aqueous solutions containing surfactants at concentrations above the critical micelle concentration solubilize various organic and inorganic substances, including chelating agents and chelates. Ions can be also sorbed by charged micelles. The spherical micelles of nonionic surfactants (Fig. 4) can be thus considered as dynamic analogs of crown ethers. Typical hydrophobic extractants/chelating agents used in hydrometallurgical processes are exceedingly large and scarcely soluble in aqueous solutions, including micellar solutions, to obtain high enough extractant concentrations. Because of that, hydrophilic complexing agents such as oxine., PAP, PAMP, etc. Are used. Special reagents exhibiting both amphiphilic and chelating properties (5 and 6) can be also used. In this case they act simultaneously as surfactants and chelating agents. The distributions coefficients of chelating agents (Tabs 1 and 2) and their metal complexes (Tab. 3) between the surfactant-rich phase and the aqueous phase are comparable to those observed in classical extraction systems. These are, however, lower in comparison to those obtained for hydrophobic industrial extractants. The recovery of metal ions from diluted aqueous solutions can be near 100% (Tab. 4). The system is also useful to recover various organic substances from aqueous solutions (Tab. 5) and from contaminated soil (Tab. 6). The technique has found already application for sample preconcentration, recovery of toxic substances from solutions and soils and separation of expensive biological materials.
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