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Tensile deformation and failure of thin films of aging laponite suspension / Asima Shaukat in Industrial & engineering chemistry research, Vol. 48 N° 17 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 8211–8218 Titre : Tensile deformation and failure of thin films of aging laponite suspension Type de document : texte imprimé Auteurs : Asima Shaukat, Auteur ; Yogesh M. Joshi, Auteur ; Ashutosh Sharma, Auteur Année de publication : 2009 Article en page(s) : pp. 8211–8218 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Tensile  deformation  Failure  Visco-elastic  thin  films Résumé : In this paper, we study deformation, failure, and breakage of visco-elastic thin films of aging laponite suspension under a tensile deformation field. Aqueous suspension of laponite is known to undergo waiting time dependent evolution of its microstructure, also known as aging, which is accompanied by an increase in the elastic modulus and relaxation time. In the velocity controlled tensile deformation experiments, we observed that the dependence of force and dissipated energy on velocity and initial thickness of the film is intermediate to a Newtonian fluid and a yield stress fluid. For a fixed waiting time, strain at break and dissipated energy increased with velocity but decreased with initial thickness. With an increase in age, the strain at break and dissipated energy showed a decrease suggesting enhanced brittle behavior with an increase in waiting time, which may be caused by restricted relaxation modes due to aging. In a force controlled mode, decrease in strain at failure at higher age also suggested enhanced brittleness with an increase in waiting time. Remarkably, the constant force tensile deformation data up to the point of failure showed experimental time−aging time superposition that gave an independent estimation of relaxation time and elastic modulus dependence on age. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006326 [article] Tensile deformation and failure of thin films of aging laponite suspension [texte imprimé] / Asima Shaukat, Auteur ; Yogesh M. Joshi, Auteur ; Ashutosh Sharma, Auteur . - 2009 . - pp. 8211–8218. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 8211–8218 Mots-clés : Tensile  deformation  Failure  Visco-elastic  thin  films Résumé : In this paper, we study deformation, failure, and breakage of visco-elastic thin films of aging laponite suspension under a tensile deformation field. Aqueous suspension of laponite is known to undergo waiting time dependent evolution of its microstructure, also known as aging, which is accompanied by an increase in the elastic modulus and relaxation time. In the velocity controlled tensile deformation experiments, we observed that the dependence of force and dissipated energy on velocity and initial thickness of the film is intermediate to a Newtonian fluid and a yield stress fluid. For a fixed waiting time, strain at break and dissipated energy increased with velocity but decreased with initial thickness. With an increase in age, the strain at break and dissipated energy showed a decrease suggesting enhanced brittle behavior with an increase in waiting time, which may be caused by restricted relaxation modes due to aging. In a force controlled mode, decrease in strain at failure at higher age also suggested enhanced brittleness with an increase in waiting time. Remarkably, the constant force tensile deformation data up to the point of failure showed experimental time−aging time superposition that gave an independent estimation of relaxation time and elastic modulus dependence on age. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006326