Advanced adsorption for actives application / Lorna M. Kessel in SOFW JOURNAL, Vol. 133, N° 4 (04/2007)

[article]  inSOFW JOURNAL > Vol. 133, N° 4 (04/2007) . - p. 16-28 Titre : Advanced adsorption for actives application Type de document : texte imprimé Auteurs : Lorna M. Kessel, Auteur ; Benjamin J. Naden, Auteur ; Ian R. Tooley ; Tharwat F. Tadros Année de publication : 2007 Article en page(s) : p. 16-28 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adsorption Cosmétiques Dioxyde de titane Dispersions et suspensions Emulsions -- Emploi en cosmétologie Emulsions -- Stabilité Formulation (Génie chimique) Paramètres de solubilité Peau -- Soins et hygiène Polymères Produits antisolaires Rhéologie solvants Index. décimale : 668.5 Parfums et cosmétiques Résumé : The integration of colloid and cosmetic science has provided a sound basis on which to carry out true optimisation of consumer acceptable sunscreen formulations based upon particulate Ti02 which is of particular benefit in daily skin care formulation. Adsorption isotherms, dispersant demand and solids loading determinations enabled a model to be developed which related the rheology, stability and maximum efficacy of the dispersions to the structure of the adsorbed layer. It was found that both dispersion stability and dispersion rheology depended upon adsorbed amount Γ and steric layer thickness δ (which in turn depends on oligomer molecular weight Mn and solvency χ) but that in order to optimise formulation, the adsorption strength χ, must also be considered. The nature of interaction between particles, dispersant, emulsifiers and thickeners must be considered with regard to competitive adsorption and/or interfacial stability if a formulation is to deliver its required protection when spread on the skin. Note de contenu : - Steric stabilisation - Solubility parameters - Steric stabilisation continued - Materials and methods - Results and discussion - Competitive interactions in formulations - Tables : 1. Surface modified TiO2 powder - 2. Sunscreen emulsion formulations from dispersions of powders B and C - 3. Hansen and Beerbower solubility parameters for the polymer and both solvents Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30977 [article]

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Colloids in cosmetics and personal care / Tharwat F. Tadros / Weinheim [Germany] : Wiley-VCH (2008)

Titre : Colloids in cosmetics and personal care Type de document : texte imprimé Auteurs : Tharwat F. Tadros, Editeur scientifique Editeur : Weinheim [Germany] : Wiley-VCH Année de publication : 2008 Collection : Colloids and interface science series num. 4 Importance : XVI-321 p. Présentation : ill. Format : 25 cm ISBN/ISSN/EAN : 978-3-527-31464-5 Prix : 194 E Note générale : Index - Bibliogr. Langues : Anglais (eng) Catégories : Colloides Cosmétiques Hygiène Index. décimale : 668.5 Parfums et cosmétiques Résumé : The first modern approach to relate fundamental research to the applied science of colloids, this series bridges academic research and industrial applications, thus providing the information vital to both. Written by the very best scientists in their respective disciplines, the five volumes are edited by an internationally recognized expert on this topic. This volume describes the role of colloids in cosmetics and personal care, highlighting the importance of fundamental research in practical applications. Of interest to electrochemists, physical and surface chemists, materials scientists, and physicists. Note de contenu : - 1. Colloid aspects of cosmetic formulations with particular reference to polymeric surfactants + 2. Formulation and stabilization of nanoemulsions using hydrophobically modified inulin (polyfructose) polymeric surfactant - 3. Integrating polymeric surfactants in cosmetic formulations for the enhancement of their performance and stability - 4. Application of colloid and interface science principles for optimization of sunscreen dispersions - 5. Use of associative thickeners as rheology modifiers for surfactant systems - 6. Cosmetic emulsions based on surfactant liqid crystalline phases : structure, rheology and sensory evaluation - 7. Personal care emulsions based on surfactant-biopolymer mixtures : correlation of rheological parameters with sensory attributes - 8. Correlation of "body butter" texture and structure of cosmetic emulsions with their rheological characteristics - 9. Interparticle interactions in color cosmetics - 10. Starch-based dispersions - 11. IN vivo skin performance of a cationic emulsion base in comparison with an anionic system - 12. The impact of urea on the colloidal structure of alkylpolyglucoside-based emulsions : physicochemical and in vitro/in vivo characterization - 13. Models for the calculation of sun protection factors and parameters characterizing the UVA protection ability of cosmetic sunscreens Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27610

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Colloids in paints / Tharwat F. Tadros / Weinheim [Germany] : Wiley-VCH (2010)

Titre : Colloids in paints Type de document : texte imprimé Auteurs : Tharwat F. Tadros, Auteur Editeur : Weinheim [Germany] : Wiley-VCH Année de publication : 2010 Collection : Colloids and interface science series num. 6 Importance : XVI-254 p. Présentation : ill. Format : 25 cm ISBN/ISSN/EAN : 978-3-527-31466-9 Prix : 164 E Note générale : Index - Bibliogr. Langues : Anglais (eng) Catégories : Colloides Revêtements:Peinture Index. décimale : 667.9 Revêtements et enduits Note de contenu : 1. Colloids in paints 2. Emulsion, dispersion and suspension polymerization : preparation of polymer colloids and their stabilization 3. Pigment dispersion 4. Colloids stabilization of paint dispersions 5. Particle deposition and adhesion 6. Basic principles of rheology 7. Rheology of suspensions, emulsions and their mixtures (suspoemulsions) 8. Rheology modifiers, thickeners and gels 9. Rheology in paints Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=25210

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Future developments in cosmetic formulations / Tharwat F. Tadros in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 14, N° 3 (06/1992)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 14, N° 3 (06/1992) . - p. 93-111 Titre : Future developments in cosmetic formulations Type de document : texte imprimé Auteurs : Tharwat F. Tadros, Auteur Année de publication : 1992 Article en page(s) : p. 93-111 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cosmétiques Emulsions multiples Formulation (Génie chimique) Liposomes Nanoparticules Surfactants Index. décimale : 668.5 Parfums et cosmétiques Résumé : In recent years, there have been a great deal of interest in applications of microemulsions, liposomes (vesicles) and multiple emulsions in cosmetic formulations. These systems will provide the cosmetic industry with new types of formulations which are easier to apply, better functional benefit and potentially safer formulations. Microemulsions are thermodynamically stable systems and hence shelf life is no problem. Many cosmetic ingredients can be adequately solubilized in the swollen micelles of the microemulsions. Such solubilized systems may enhance transport and diffusion through various barriers, eg., the skin, thus enhancing the efficacy of the formulations. However, microemulsions may cause skin irritation by disrupting the liquid crystalline structure of the stratum corneum. This problem may be overcome by formulating microemulsions, which on evaporation produce lamellar liquid crystalline structures. The problem of skin irritation is certainly reduced or eliminated using liposomes or vesicles, which offer an alternative to microemulsions. The principles for formation and stabilization of vesicles are discussed in this paper and research work is needed to produce nanocapsules from liposomes, using polymerizable surfactants. Multiple emulsions of the water/oil/water (w/o/w) or oil/water/oil (o/w/o) types are also valuable systems for formulating cosmetics. In the first place, they offer a means of sustained release of the various ingredients. Secondly, they allow one to separate the various ingredients in the formulation, thus preventing their possible interaction. The basic principles required for preparation of stable multiple emulsions are summarised. Developments of polymeric surfactants led to the formulation of stable multiple emulsions. An example of a recently formulated stable w/o/w multiple emulsion is given in this paper The stability of the system was investigated using optical microscopy. Creaming occurred on storage, particularly at high temperature (40°C) and this was significantly reduced by addition of Kelzan (a polysaccharide with high molecular weight). The final formulation was studied rheological techniques. DOI : 10.1111/j.1467-2494.1992.tb00045.x En ligne : https://onlinelibrary.wiley.com/doi/10.1111/j.1467-2494.1992.tb00045.x Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26588 [article]

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Science and technology of emulsions - From nanoemulsions to multiple emulsions / Tharwat F. Tadros in IFSCC MAGAZINE, Vol. 3, N° 4 (10-11-12/2000)

[article]  inIFSCC MAGAZINE > Vol. 3, N° 4 (10-11-12/2000) . - p. 31-38 Titre : Science and technology of emulsions - From nanoemulsions to multiple emulsions Type de document : texte imprimé Auteurs : Tharwat F. Tadros, Auteur Année de publication : 2000 Article en page(s) : p. 31-38 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.5 Parfums et cosmétiques Résumé : This overview deals with the important aspects of emulsion science and technology. It starts with a section on the basic principles of emulsion formation and stability. The thermodynamics of emulsion formation and breakdown are briefly described to illustrate the kinetic stability of emulsions which requires the presence of an energy barrier (repulsive energy) to reduce flocculation and coalescence. The basic stabilization mechanisms that can be applied to produce such repulsion are briefly described. This is followed by a section o the main breakdown processes of emulsions, namely creaming and sedimentation, flocculation, Ostwald ripening, coalescence and phase inversion. The various methods that can be applied to control such processes are briefly described. The second section deals with the subject of nanoemulsions (with size range in the region of 100-200 nm) which attracted considerable attention in recent years for application in personal and health care. The problem of formation of small droplets is described in terms of the high Laplace pressure produced on deformation of small drops. This requires the application of high energy (e.g by application of high pressure homogenisers) and high surfactant concentration. The high stability of nanoemulsions stems from their small size which reduces an creaming or sedimentation as well as the lack of flocculation and/or coalescence. The latter is prevented as a result of the lack of fluctuation of the interface and the high steric repulsion between the droplets. However, nanoemulsions suffer from the problem of Ostwald ripening that arises from the difference in solubility between small and large droplets. The higher the oil solubility the the higher the rate of Ostwald ripening. The procedures that may be applied to reduce Ostwald ripening are briefly described. One of these methods is to incorporate a second highly insoluble oil component. Alternatively, one may incorporate a polymeric surfactant that is strongly adsorbed at the 0/W interface and which does not desorb during the process of ripening. Such polymeric surfactant should be highly insoluble in the continuous phase. The last section of this overview deals with multiple emulsions which offer some advantages for application in personal care. The main criteria for production of stable W/0/W multiple emulsions are briefly described. These are: two polymeric surfactants with low and high HLB numbers and optimum osmotic balance between the internal water droplets and the external continuous phase. Examples of such polymeric surfactants are given. This is followed by a brief description of the method of preparation of multiple emulsions (a two or one-stage process could be applied). Finally a description of the multiple emulsion drop is given and a brief account of the use of gelling agents to reduce creaming or sedimentation. The methods that can be applied to follow the stability of multiple emulsion are briefly described. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10798 [article]

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Surfactants / Tharwat F. Tadros / New York [Etats-Unis] : Academic Press inc. (1984)

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The role of fungi isolated from historical vegetable-tanned leather on the degradation of peptides and amino acids / Gomaa Abdel-Maksoud in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

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