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Effect of organized assemblies, part VII: adsorption behavior of polyoxyethylated nonyl phenol at silica - cyclohexane interface and its efficiency in stabilizing the silica - cyclohexane dispersion / Pramila K. Misra in Industrial & engineering chemistry research, Vol. 48 N° 7 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3403–3409 Titre : Effect of organized assemblies, part VII: adsorption behavior of polyoxyethylated nonyl phenol at silica - cyclohexane interface and its efficiency in stabilizing the silica - cyclohexane dispersion Type de document : texte imprimé Auteurs : Pramila K. Misra, Auteur ; Uma Dash, Auteur ; Ponisseril Somasundaran, Auteur Année de publication : 2009 Article en page(s) : pp. 3403–3409 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polyoxyethylated  nonyl  phenol  Silica-cyclohexane  interface  Cyclohexane  decreases  Silica-water  dispersion  Oxyethylene  units Résumé : The adsorption behavior of a series of nonionic polyoxyethylated nonyl phenol surfactants having same hydrocarbon chain length but varying oxyethylene chain has been studied spectrophotometrically at the silica−cyclohexane interface. The adsorption density is found to be independent of the number of oxyethylene units throughout the adsorption isotherms, except at higher surface coverage, where the adsorption density decreases with the increase in the number of oxyethylene units. The settling rate of the silica particles in cyclohexane decreases with the increase in adsorption density as well as oxyethylene chain length. On the other hand, the sediment volume decreases with the increase in the adsorption density, with a minimum for the surfactant having the least number of oxyethylene units. Surfactants with a longer oxyethylene chain partitions preferentially to the bulk solvent at higher concentrations, as a result of the change in the polarity of the medium. On the basis of adsorption density, settling rate, and sediment volume data, a model for the mechanism of stabilization of silica−cyclohexane dispersion has been proposed. The aromatic ring of the surfactant is assumed to be anchored on the silica surface through specific interaction with silanol hydrogen, while its nonyl and oxyethylene chains are suspended in the bulk cyclohexane solution. The protruding oxyethylene chain offers a strong steric resistance for particle−particle association leading to the stabilization of the silica−water dispersion. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801283f [article] Effect of organized assemblies, part VII: adsorption behavior of polyoxyethylated nonyl phenol at silica - cyclohexane interface and its efficiency in stabilizing the silica - cyclohexane dispersion [texte imprimé] / Pramila K. Misra, Auteur ; Uma Dash, Auteur ; Ponisseril Somasundaran, Auteur . - 2009 . - pp. 3403–3409. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 7 (Avril 2009) . - pp. 3403–3409 Mots-clés : Polyoxyethylated  nonyl  phenol  Silica-cyclohexane  interface  Cyclohexane  decreases  Silica-water  dispersion  Oxyethylene  units Résumé : The adsorption behavior of a series of nonionic polyoxyethylated nonyl phenol surfactants having same hydrocarbon chain length but varying oxyethylene chain has been studied spectrophotometrically at the silica−cyclohexane interface. The adsorption density is found to be independent of the number of oxyethylene units throughout the adsorption isotherms, except at higher surface coverage, where the adsorption density decreases with the increase in the number of oxyethylene units. The settling rate of the silica particles in cyclohexane decreases with the increase in adsorption density as well as oxyethylene chain length. On the other hand, the sediment volume decreases with the increase in the adsorption density, with a minimum for the surfactant having the least number of oxyethylene units. Surfactants with a longer oxyethylene chain partitions preferentially to the bulk solvent at higher concentrations, as a result of the change in the polarity of the medium. On the basis of adsorption density, settling rate, and sediment volume data, a model for the mechanism of stabilization of silica−cyclohexane dispersion has been proposed. The aromatic ring of the surfactant is assumed to be anchored on the silica surface through specific interaction with silanol hydrogen, while its nonyl and oxyethylene chains are suspended in the bulk cyclohexane solution. The protruding oxyethylene chain offers a strong steric resistance for particle−particle association leading to the stabilization of the silica−water dispersion. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801283f