Facultad Regional San Francisco
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Item Síntesis de nuevas polibenzoxazinas termoestables para aplicaciones en la industria electrónica, aeronáutica y aeroespacial(CONGRESO INTERNACIONAL DE METALURGIA Y MATERIALES SAM-CONAMET/IBEROMAT/MATERIA 2014, 2014-10-20) Spontón, Marisa; Dieser, María Fernanda; Taverna, María E.; Estenoz, DianaPor la buena combinación de propiedades que presentan, las polibenzoxazinas están encontrando una creciente aplicación en las industrias química, eléctrica, aeronáutica y aeroespacial. Desde el punto de vista industrial, los monómeros de mayor interés son los polifuncionales porque permiten generar materiales entrecruzados en una posterior polimerización por apertura de anillo. Entre las numerosas resinas desarrolladas hasta el momento, se destacan las benzoxazinas derivadas del bisfenol-A (Sponton, et al; 2008, 2012). En este trabajo se desarrollaron dos nuevas benzoxazinas con funcionalidad ácida la Bz-FA y Bz-PFA a partir de fenol o bisfenol A, etanolamina, paraformaldehído y anhídrido maleico. Las estructuras químicas fueron caracterizadas por Resonancia Magnética Nuclear (RMN) y por Espectroscopía de Infrarrojo (FT-IR). Las reacciones de curado fueron estudiadas por Calorimetría Diferencial de Barrido (DSC) y por FT-IR. La benzoxazina convencional (Bz-BA) fue incluida en el estudio con fines comparativos. Los resultados del DSC y FT-IR mostraron que Bz-FA y Bz-PFA presentan más de un proceso químico de curado. El primer proceso químico se debe a la apertura del anillo de la oxazina, y el segundo podría ser debido a la esterificación por condensación entre grupos ácidos y entre los grupos ácidos y los grupos fenólicos. Se observó que, además de obtener una polibenzoxazina del tipo fenólica, se produjo una red entrecruzada de enlaces ésteres. Por otro lado, el grupo funcional ácido de la Bz-FA se comportó como iniciador catiónico de la apertura del anillo de la oxazina, exhibiendo una temperatura de curado menor que la de Bz-BA.Item Bio-composite Films Based on Alginate and Rice Husk Tar Microparticles Loaded with Eugenol for Active Packaging(2022-01-29) Taverna, María E.; Busatto, Carlos Alberto; Saires, Paula J.; Bertero, Melisa Paola; Sedran, Ulises A.; Estenoz, DianaThis work focused on the valorization of tar derived from rice husk pyrolysis as a precursor of matrices for the encapsulation of active principles. In this regard, the development of novel films based on alginate and eugenol-loaded tar microparticles with suitable mechanical properties and antibacterial activity was studied. Tar microparticles loaded with eugenol were incorporated into sodium alginate films and the effect on the mechanical, thermal and humidity resistance properties were determined, as well as the antimicrobial activity. Films with different crosslinking degrees were also prepared using CaCl2, and the eugenol controlled release profiles were evaluated. Crosslinked films exhibited improved mechanical and humidity resistance properties, as well as a lower release rate of eugenol in water. The antimicrobial studies showed that eugenol-loaded films present a higher antimicrobial activity against Staphylococcus aureus. Alginate/eugenol-loaded tar microparticles composites showed an enhancement of antibacterial properties and suitable physical characteristics to be used in active packaging applications.Item Morphology modulation of silica mesoporous nano- and microparticles for atrazine - controlled release(2022-06-09) Fookes, Federico A.; Busatto, Carlos Alberto; Taverna, María E.; Casis, Natalia; Lescano, Maia Raquel; Estenoz, DianaAtrazine is a moderately toxic triazine, used as a selective pre- and post-emergence herbicide. After application, it remains in the environment due to its low biodegradability causing severe environmental effects. Several controlled release systems have been proposed in order to minimize the negative impact of the herbicide on the environment. In particular, mesoporous silica nanoparticles have shown great potential in the agricultural area due to their controlled size and porosity, high surface area and non-toxicity. In this work, silica nano- and microparticles were synthesized and evaluated as atrazine delivery systems. The morphology and size distribution of the particles were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The release profiles were studied by in vitro assays in water. In addition, phytotoxicity tests were performed using Lactuca sativa seeds. The mesoporous nano- and microparticles exhibited sustained release for at least 24 h and reduced phytotoxicity compared to free atrazine.Item On the use of espina corona gum as a polymeric additive in water-based drilling fluid(2022-06-26) Villada, Yurany A.; Taverna, María E.; Maffi, Juan M.; Gilleta, Sebastián; Casis, Natalia; Estenoz, DianaThe aim of this work is to evaluate the espina corona gum (ECG) as a sustainable viscosifier or filtration reducer additive in water-based drilling fluids (WBMs) as a potential replacement of guar gum (GG). ECG is a galactomannan isolated from leguminous seeds of Gleditsia amorphoides, trees that grow in South America with viscosifier properties and applications in the food area. ECG was characterized by FTIR, Z potential, intrinsic viscometry, TGA, and steady and oscillatory shear rheological analysis. Moreover, its effect on the main functional properties of WBMs was studied. Fluids containing bentonite (BT), polyanionic cellulose (PAC), GG or ECG were prepared, and rheological, filtration, thermal and structural properties were determined. In order to study the theoretical rheological behavior, several models such as power law, Sisko and Herschel-Bulkley were evaluated. The rheological studies revealed that WBMs containing ECG exhibit higher viscosities in comparison with those with GG. Herschel-Bulkley parameters indicated that the WBMs with high ECG concentration showed higher yield stress. In addition, the presence of ECG improves the thermal stability and filtration properties. The results indicate that ECG can be considered as an innovative, renewable and non-toxic alternative to partially or totally replace GG in WBMs.Item Tailoring thermal and thermomechanical properties of biobased blends by hybridization of difuran benzoxazine with polysiloxane-based benzoxazine and epoxy monomers(2022-11-28) Forchetti Casarino, Agustín; Taverna, María E.; Candia, Adriana; Spontón, Marisa; Palmese, Giuseppe; La Scala, John; Estenoz, DianaA difuran bio-based benzoxazine (SA-dfda) was synthesized by a three-stage process from difurandiamine (DFDA) and 2-hydroxybenzaldehyde with a final yield of 90%. Three copolymer systems were prepared by blending the difuran bio-resin with epoxy resin (DGEBA), conventional benzoxazine (BA-a), and polysiloxane-based benzoxazine precursor [Pr(BA-3aptms)] at different ratios. In order to study the effect of the renewable content on the main characteristics of the materials, thermal, thermomechanical, and morphological analyses were performed. The bio-based benzoxazine/epoxy systems exhibited the lowest polymerization temperature with enhanced processability. However, the incorporation of epoxy slightly decreased the mechanical properties of materials. Bio-based copolymers containing 5 wt%. of polysilsesquioxane precursor showed the highest glass transition temperatures, thermal stability, and char yields. All the copolymers exhibited good flame retardant properties as it was observed by their limiting oxygen index values (>21) and UL-94 tests (V-0 or V-1). The copolymerization of bio-based benzoxazines with different thermoset resins such as epoxy or benzoxazines can be used as a strategy to develop novel materials with tailor-made properties.Item Supernucleation dominates lignin/poly(ethylene oxide) rystallization kinetics(2022-08) Taverna, María E.; Altorbaq, Abdullah S.; Kumar, Sanat K.; Olmedo-Martínez, Jorge L.; Busatto, Carlos Alberto; Zubitur, Manuela; Mugica, Agurtzane; Nicolau, Verónica V.; Estenoz, Diana; Müller, Alejandro J.The effect of lignin nanoparticles (LNPs) on the crystallization kinetics of poly(ethylene oxide) (PEO) is examined. Lignin from spruce and ionic isolation was used to prepare LNPs with a number-averaged diameter of 85 nm (with a relatively large polydispersity) by an ultrasonication method. PEO-based nanocomposites with four different LNP contents (5, 10, 15, and 20 wt %) were prepared and subject to isothermal and nonisothermal crystallization protocols in a series of experiments. Scanning electron microscopy (SEM) images showed welldispersed LNPs in the crystallized PEO matrix. The incorporation of LNPs exponentially increases nucleation density at moderate loadings, with this trend apparently saturating at higher loadings. However, the spherulitic growth rate decreases monotonically with LNP loading. This is attributed to the substantial PEO/LNP affinity, which impacts chain diffusion and induces supernucleation effect (with efficiencies in the order of 200%), but leads to slower growth rates. The overall crystallization kinetics, measured by the DSC, shows faster nanocomposite crystallization rates relative to the neat PEO at all LNP contents examined. This indicates that the supernucleation effect of LNPs dominates over the decrease in the growth rates, although its influence slightly decreases as the LNP content increases. The strong hydrogen-bonded interactions between the LNPs and the PEO are thus reminiscent of confinement effects found in polymer-grafted NP nanocomposites (e.g., PEO-g-SiO2/ PEO) in the brush-controlled regime.Item Additives based on vegetable biomass to improve the stabilisation of expansive clay soil(2021-05) Orlandi, Sandra; Taverna, María E.; Villada, Yurany A.; Pique, Teresa; Laskowski, Cecilia; Nicolau, Verónica V.; Estenoz, Diana; Manzanal, DiegoThis paper investigates the effect of different bio-based additives on the expansiveness of an Argentinian natural clayey soil (CR-clay). CR-clay was characterised to determine (a) the Atterberg parameters and other index properties, (b) the particle size distribution by laser diffraction, (c) the specific surface area (Se) and cationic exchange capacity by the methylene blue method, (d) the mineralogy by using X-ray diffraction, (e) the functional groups by Fourier transform infrared spectroscopy (FTIR) and (f) the free swelling and swelling pressure by using an odometer. Starches from potato, cassava, corn and rice flour; seeds and derivatives from flax, sunflower and quinoa; kraft lignin; and lignosulfonates were evaluated as soil stabilisation additives on the basis of measurements of Atterberg parameters. Reductions in the soil plasticity index (PI) between 10 and 60% were generally observed. Lignins exhibited a very good balance between the ability to improve soil stabilisation, low costs, environment-friendliness and availability. In particular, kraft lignin showed high performance as a CR-clay stabiliser with a PI reduction of 46%. The stabilisation mechanism of lignin and CR-clay blends was investigated using Z potential and FTIR. Based on the experimental results, lignins constitute promising alternatives to the additives used as stabilisers of expansive soils, particularly for reducing free-swell and swelling pressure.Item Efecto de la incorporación de nanopartículas de lignina iónica en la cristalización de polióxido de etileno(2020-04) Taverna, María E.; Olmedo, Jorge; Busatto, Carlos Alberto; Zubitur, Manoli; Nicolau, Verónica V.; Estenoz, Diana; Müller, Alejandro J.El polióxido de etileno (POE) es un poliéter semicristalino cuya cinética de cristalización ha sido ampliamente estudiada tanto en el componente puro como en sus mezclas con otros polímeros amorfos y semicristalinos. Se han investigado materiales compuestos basados en mezclas de POE y lignina (polímero natural, amorfo, abundante y de bajo costo). La mezcla eficiente de estos polímeros depende en gran medida de la compleja estructura de la lignina. Se ha reportado la cinética de cristalización de la mezcla de POE y lignina proveniente de procesos de aislamiento Alcell y/o Kraft.2 En este trabajo se estudia la síntesis de nanopartículas de lignina de origen iónico y su empleo en la obtención de mezclas con POE. Específicamente, se evalúa la influencia de nanopartículas en la cinética de cristalización del POE.Item Nuevos recubrimientos basados en residuos de poliestireno expandido y aceite esencial de naranja para su aplicación en la construcción.(Universidad de Mar del Plata-CONICET, 2023-12) Garnero, Paula Carolina; Boriglio, Rocío; Marchiaro, Giuliana; Raspo, Matías A.; Taverna, María E.; Andreatta, Alfonsina E.En este contexto, se llevó a cabo la elaboración de barnices a partir de la disolución de EPS en aceite esencial de naranja obtenido en el laboratorio mediante el uso de un equipo de arrastre con vapor de agua a partir de sus cáscaras. El EPS se caracterizó empleando técnicas cromatográficas (SEC) mientras que el aceite esencial se caracterizó mediante cromatografía gaseosa acoplada a un espectrómetro de masas (CG-MS).Item Los ODS como hoja de ruta de la Universidad: Caso de estudio de un grupo de investigación interdisciplinario(2024-02-23) Garnero, Paula Carolina; Taverna, María E.; Vázquez, ManuelaActualmente, las universidades están contribuyendo al logro de los Objetivos de Desarrollo Sostenible (ODS) a través de sus actividades diarias en formación, investigación y otras iniciativas. No obstante, para lograr los ODS a nivel mundial, es necesario que estas instituciones educativas se conviertan en promotoras del progreso sostenible y desempeñen un papel de liderazgo en la implementación de estos. Dicha tarea presenta importantes desafíos, entre los cuales se incluye trabajar en forma interdisciplinaria dentro y fuera de las organizaciones para impulsar y desarrollar un verdadero liderazgo interno de las acciones emprendidas. En función de ello, en este trabajo se presenta un mapeo de múltiples acciones realizadas por integrantes de un grupo de investigación interdisciplinario universitario teniendo en cuenta el marco de los ODS. El objetivo es evidenciar la importancia de que todos los actores de la universidad en todas sus funciones adopten una postura participativa para actuar en términos de impacto social y ambiental.