Examinando por Materia "Electrospinning"
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Ítem Biodegradable nanofiber membranes produced by green electrospinning for air filtration applications(Universidad EAFIT, 2023) Ángel Gómez, Sara; Álvarez Láinez, Mónica LucíaÍtem Experimental design as a tool for the manufacturing of filtering media based on electrospun polyacrylonitrile/-cyclodextrin fibers(Springer-Verlag France, 2016-05-01) Noreña-Caro, D.; Alvarez-Láinez, M.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)The aim of this work is the manufacturing of non-woven fabrics to be used as Filtering media. These fabrics were produced from polyacrilonitrile (PAN) and -cyclodextrin (-CD) solutions in dimethylsulfoxide using a horizontal electrospinning system with a flat collecting screen. The information from the experiments was statistically analyzed in order to define the process parameters (PAN concentration in solution, volumetric flow and applied voltage) needed for obtaining fibers with the smallest average diameters. First, PAN fibers were produced following a full factorial experimental design and this information was used for preparing the corresponding Response Surfaces needed to define the best conditions for the production of PAN/-CD nonwoven fabrics. The viscosity of the polymer solutions was analyzed using a rotational rheometer and a pseudoplastic behavior was observed, the diameter of the obtained nanofibers was determined using scanning electron microscopy. At the end, the polymer concentration (viscosity) and the volumetric flow rate were selected as the most statistically significant factors affecting the fiber diameter. Besides, uniform PAN and PAN/-CD nanofibers with average fiber diameters between 200 and 500 nm were obtained.Ítem The influence of electrospinning parameters and solvent selection on the morphology and diameter of polyimide nanofibers(Elsevier Ltd, 2018-03-01) Lasprilla-Botero; J.; Álvarez-Láinez; M.; Lagaron; J.M.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)Polyimide (PI) fibers display excellent thermal and mechanical performance; they have been recently investigated to fabricate hydrophobic membranes (mats) for high-performance applications. We studied the effect of electrospinning processing parameters and solvent selection on the morphology and the diameter of PI fibers. 11 different solvents and 22 solvent systems able to dissolve PI were located in a Teas graph with the aim of building the solubility-electrospinnability map for this material. PI solutions prepared with various solvents were electrospun at different electrospinning process parameters according to a 34–1 fractional factorial design of experiments. Polymer concentration and applied voltage were the most significant factors to create thin and uniform fibers. More homogeneous fibers and reproducible electrospinning process were obtained by using polymer concentrations above 15 wt%. However, all solutions showed different morphological evolution according to the solvents used. Based on the solubility–spinnability region settled for this PI, non-woven mats were obtained with rough surface fiber morphology and high water contact angle, suitable for applications such as hydrophobic membranes for oil-water separation. © 2017 Elsevier LtdÍtem Superhydrophobic bilayer coating based on annealed electrospun ultrathin poly("-caprolactone) fibers and electrosprayed nanostructured silica microparticles for easy emptying packaging applications(MDPI AG, 2018-05-01) Lasprilla-Botero, J.; Torres-Giner, S.; Pardo-Figuerez, M.; álvarez-Láinez, M.; Lagaron, J.M.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)A coating rendering superhydrophobic properties to low-density polyethylene (LDPE) films used in packaging applications was herein generated by means of the electrohydrodynamic processing (EHDP) technique. To this end, electrospun ultrathin poly("-caprolactone) (PCL) fibers, followed by electrosprayed nanostructured silica (SiO2) microparticles, were deposited on top of the LDPE film. Various electrospinning and electrospraying times were tested and optimized followed by a thermal post-treatment to provide physical adhesion between the bilayer coating and the LDPE substrate. The morphology, hydrophobicity, permeance to limonene, and thermal stability of the resultant nanostructured coatings were characterized. It was observed that by controlling both the deposition time of the electrospun ultrathin PCL fibers and the electrosprayed SiO2 microparticles, as well as the conditions of the thermal post-treatment, effective superhydrophobic coatings were developed onto the LDPE films. The resultant multilayer presented a hierarchical micro/nanostructured surface with an apparent contact angle of 157° and a sliding angle of 8°. The addition of silica reduced, to some extent, the limonene (aroma) barrier, likely due to the increased surface-to-volume ratio, which allowed permeant sorption to occur but improved the thermal stability of the LDPE/PCL film. As a result, the developed multilayer system of LDPE/PCL/SiO2 has significant potential for use in easy-to-empty packaging applications of high water activity products. © 2018 by the authors.Ítem Towards an understanding of particulate matter adhesion on electrospun nanofiber membranes to obtain high filtration performance(Universidad EAFIT, 2024) Valencia Osorio, Laura Margarita; Álvarez Láinez, Mónica Lucía