RESUMEN Se estudió el comportamiento mecánico dinámico, a temperaturas por debajo de 0 C, de pelí... more RESUMEN Se estudió el comportamiento mecánico dinámico, a temperaturas por debajo de 0 C, de películas alimenticias de distinto pH, conformadas por almidón de mandioca, glicerol (plastificante), agua y diferentes porcentajes de sorbato (agente antimicrobiano). ...
Biofilms based on cassava starch and containing glycerol as a plasticizer were characterized with... more Biofilms based on cassava starch and containing glycerol as a plasticizer were characterized with respect to the effect of potassium sorbate concentration and pH on color, crystallinity and mechanical performance al low temperature.It could be observed that a lower pH resulted in lower values of yellow index and tanδ and higher crystallinities.Crystallinity decreased with sorbate addition, which also resulted, in
We report the investigation of high energy ion beam irradiation on titanium (Ti) substrates at ro... more We report the investigation of high energy ion beam irradiation on titanium (Ti) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The surface modifications induced by the ion beam using two different anode materials, graphite and copper, are characterized using standard surface science diagnostic tools, such as x-ray diffraction, scanning electron microscopy,
Se presentan resultados acerca de la influencia del contenido de carga sobre la tension de fluenc... more Se presentan resultados acerca de la influencia del contenido de carga sobre la tension de fluencia en muestras de un compuesto particulado de matriz epoxi y aluminio. Para ello, se realizaron ensayos de compresion a temperatura ambiente y para distintas velocidades de deformacion, las mismas muestras se estudiaron mediante espectrometria temporal positronica. Se presentan resultados de la dependencia con la carga del volumen libre, obtenidos con positrones, y de las tensiones de fluencia, obtenidas mediante ensayos mecanicos. Dichos resultados se comparan con informacion previa obtenida en materiales compuestos de identica matriz pero con carga de cuarzo y se discuten analizando el rol del tipo de carga sobre la respuesta del material.
ABSTRACT Preformed polystyrene-co-butylacrylate (PScoBu) core-shell particles and polystyrene mic... more ABSTRACT Preformed polystyrene-co-butylacrylate (PScoBu) core-shell particles and polystyrene microspheres as well as amine-terminated butadiene nitrile (ATBN) rubber have been used for modification of both rigid and more flexible crosslinked DGEBA-based epoxy networks having significantly different crosslink densities. Some variations in cure kinetics have been shown by both thermal and rheological measurements. Independently of the crosslink density of the neat epoxy matrix, function of the cycloaliphatic or aliphatic hardener used, the toughening effect via core-shell modification has been found as good as that for rubber modification but with a better retention of thermal properties. Results are investigated as a function of the morphologies obtained by scanning electron microscopy (SEM) but also by atomic force microscopy (AFM). Larger fracture toughness was obtained for every-unmodified and modified- epoxy matrices cured with the aliphatic hardener as a consequence of the lower crosslink density of the corresponding mixtures.
We study experimentally and theoretically the critical pressure needed to move a liquid through a... more We study experimentally and theoretically the critical pressure needed to move a liquid through a network of pores and show that, for small aperture size, wetting and leaking are typical first-order transitions, with a singular behavior at the omniphobic/omniphilic limit.
Fil: Garate, Hernan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coord... more Fil: Garate, Hernan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina
A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with... more A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with selected aminic hardeners at different pre-cure temperatures is presented. Free- and macroscopic specific-volumes were measured by PALS and pressure–volume-temperature techniques, respectively. An analysis of the relation existing between macro- and nano-scales of the thermosetting networks developed by the different chemical structures is shown.
RESUMEN Se estudió el comportamiento mecánico dinámico, a temperaturas por debajo de 0 C, de pelí... more RESUMEN Se estudió el comportamiento mecánico dinámico, a temperaturas por debajo de 0 C, de películas alimenticias de distinto pH, conformadas por almidón de mandioca, glicerol (plastificante), agua y diferentes porcentajes de sorbato (agente antimicrobiano). ...
Biofilms based on cassava starch and containing glycerol as a plasticizer were characterized with... more Biofilms based on cassava starch and containing glycerol as a plasticizer were characterized with respect to the effect of potassium sorbate concentration and pH on color, crystallinity and mechanical performance al low temperature.It could be observed that a lower pH resulted in lower values of yellow index and tanδ and higher crystallinities.Crystallinity decreased with sorbate addition, which also resulted, in
We report the investigation of high energy ion beam irradiation on titanium (Ti) substrates at ro... more We report the investigation of high energy ion beam irradiation on titanium (Ti) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The surface modifications induced by the ion beam using two different anode materials, graphite and copper, are characterized using standard surface science diagnostic tools, such as x-ray diffraction, scanning electron microscopy,
Se presentan resultados acerca de la influencia del contenido de carga sobre la tension de fluenc... more Se presentan resultados acerca de la influencia del contenido de carga sobre la tension de fluencia en muestras de un compuesto particulado de matriz epoxi y aluminio. Para ello, se realizaron ensayos de compresion a temperatura ambiente y para distintas velocidades de deformacion, las mismas muestras se estudiaron mediante espectrometria temporal positronica. Se presentan resultados de la dependencia con la carga del volumen libre, obtenidos con positrones, y de las tensiones de fluencia, obtenidas mediante ensayos mecanicos. Dichos resultados se comparan con informacion previa obtenida en materiales compuestos de identica matriz pero con carga de cuarzo y se discuten analizando el rol del tipo de carga sobre la respuesta del material.
ABSTRACT Preformed polystyrene-co-butylacrylate (PScoBu) core-shell particles and polystyrene mic... more ABSTRACT Preformed polystyrene-co-butylacrylate (PScoBu) core-shell particles and polystyrene microspheres as well as amine-terminated butadiene nitrile (ATBN) rubber have been used for modification of both rigid and more flexible crosslinked DGEBA-based epoxy networks having significantly different crosslink densities. Some variations in cure kinetics have been shown by both thermal and rheological measurements. Independently of the crosslink density of the neat epoxy matrix, function of the cycloaliphatic or aliphatic hardener used, the toughening effect via core-shell modification has been found as good as that for rubber modification but with a better retention of thermal properties. Results are investigated as a function of the morphologies obtained by scanning electron microscopy (SEM) but also by atomic force microscopy (AFM). Larger fracture toughness was obtained for every-unmodified and modified- epoxy matrices cured with the aliphatic hardener as a consequence of the lower crosslink density of the corresponding mixtures.
We study experimentally and theoretically the critical pressure needed to move a liquid through a... more We study experimentally and theoretically the critical pressure needed to move a liquid through a network of pores and show that, for small aperture size, wetting and leaking are typical first-order transitions, with a singular behavior at the omniphobic/omniphilic limit.
Fil: Garate, Hernan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coord... more Fil: Garate, Hernan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina
A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with... more A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with selected aminic hardeners at different pre-cure temperatures is presented. Free- and macroscopic specific-volumes were measured by PALS and pressure–volume-temperature techniques, respectively. An analysis of the relation existing between macro- and nano-scales of the thermosetting networks developed by the different chemical structures is shown.
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Papers by S. Goyanes