Estrategia aplicada para focalizar conceptos importantes en cursos cortos multidisciplinares: encuesta didáctica previa y posterior

La formación complementaria a la enseñanza universitaria permite a los estudiantes aumentar y ampliar el conocimiento en un determinado campo profesional. La formación complementaria se basa en la generación del conocimiento de un tema específico en un entorno multidisciplinar donde participan estudiantes de diversas carreras. La estrategia docente para estimular el interés de todo el alumnado de carácter multidisciplinar resulta de especial interés para poder alcanzar la generación de conocimiento durante el proceso de enseñanza-aprendizaje. En el curso de formación complementaria de “Ecoefficients Materials” llevado a cabo en el marco del curso de primavera “What are you made of? Board of European Students of Technology (BEST)- 2014” se realizó una encuesta breve antes de comenzar el curso para evaluar el conocimiento del alumnado sobre los conceptos principales a desarrollar en el curso. Una vez acabado el curso se completó nuevamente la misma encuesta comprobando que los conocimientos de los conceptos principales incrementaron en todos los casos (entre un 4,5% a un 18,2%). La estrategia docente de utilizar una breve encuesta previa y posteriormente al dictado del curso permitió focalizar la atención del alumnado de áreas multidisciplinares en los conceptos principales, mejorando así la eficacia del proceso enseñanza-aprendizaje

Formación académica, movilidad geográfica y colaboración científica pluridisciplinar

La colaboración entre grupos de investigación de diversas áreas de la ciencia y tecnología, la movilidad geográfica y la formación académica representan los pilares del desarrollo de un buen trabajo de investigación durante la formación doctoral. La colaboración entre distintos grupos de investigación pluridisciplinares permite abordar un mismo tema de investigación desde diversos enfoques, resultando más innovadores y completos. Durante el desarrollo de una tesis doctoral del programa de Doctorado en Ciencia, Tecnología y Gestión Alimentaria de la Universitat Politècnica de València (UPV), cuyo trabajo experimental fue desarrollado principalmente en el Instituto de Tecnología de Materiales (ITM) de la Escuela Politécnica Superior de Alcoy de la UPV (EPSA-UPV) se planteó como objetivo principal el desarrollo de envases alimentarios plásticos a partir de materiales biobasados y biodegradables. Teniendo en cuenta las numerosas disciplinas involucradas en el campo de los biomateriales para envasado de alimentos (Ciencia y Tecnología de Polímeros y Alimentos; Química Analítica y Orgánica, Nanotecnología, etc.), se realizaron colaboraciones con diversos grupos de investigación localizados dentro y fuera de la comunidad autónoma así como también en el extranjero con la finalidad de aprender de científicos expertos en técnicas y tecnologías específicas y mejorar la calidad del trabajo de investigación

ADDITIVE MANUFACTURING OF SURLYN SPECIMENS WITH A NANO-REINFORCEMENT OF CARBON NANOTUBES.

This paper explores the self-healing abilty of the ionomer called Surlyn® 8940 (manufactured by DuPont), a partially neutralised poly(ethylene-co-methacrylic acid) (EMAA) ionomer copolymer, and the improvement of the mechanical properties after adding a nano-reinforcement of multiwall carbon nanotubes (MWCNTs) to the structure of the polymer. It begins with the manufacture the nanocomposite material, based on Surlyn® 8940 as raw material, and the mixture process with MWCNTs. Afterwards, an extrusion process was optimized to obtain a homogeneous reinforced filament, which was subsequently used to manufacture the final test samples by means of a 3D printing machine. Specimens with different concentrations of MWCNTs (0.0, 0.1, 0.5, 1.0 % wt.) were manufactured, in order to test the mechanical properties and self-healing ability of unreinforced and nano-reinforced samples. The results show that nano-reinforced samples had an increase of their self-healing ability (increase for 0.5 y el 1% wt. of MWCNTs) and mechanical properties (σTS 18.35, 25.91, 26.92, 28.02 MPa to 0, 0.1, 0.5 y 1 % wt. de MWCNTs respectively). Specimens of 5% of MWCNTs have also been manufactured with different mixing times in the extrusion chamber to study the conductivity of the polymer. Electrical conductivity values ​​for 8 and 10 minutes of mixing times reached S/m units order have been obtained

Biodegradable electrospun bionanocomposite fibers based on plasticized PLA-PHB blends reinforced with cellulose nanocrystals

[EN] Electrospun biobased and biodegradable nanocomposites for sustainable flexible films were developed. Poly(lactic acid) (PLA) was blended with 25 wt% of poly(hydroxybutyrate) (PHB) to produce bead-less fibers and plasticized with 15 wt% of acetyl(tributyl citrate) (ATBC) to obtain flexible materials. The system was further loaded with cellulose nanocrystals (CNC) in 1 wt% and 5 wt% to obtain bionanocomposites with improved thermal and mechanical resistance. The morphological, structural, thermal and mechanical performance of electrospun bionanocomposites was investigated. The effect of ATBC was characterized by a decrease of the glasstransition temperature and an increase in the elongation at break. Meanwhile, CNC improved the thermal and mechanical resistance of mats. Thus, good performance for the intended use was achieved for the bionanocomposite loaded with 1 wt% of CNC (PLA-PHB-ATBC-CNC1), which also showed appropriate surface water resistance. All electrospun bionanocomposites were fully disintegrated under composting conditions showing their possible applications as compostable flexible film materials. (C) 2015 Elsevier B.V. All rights reserved.Authors thank Spanish Ministry of Science and Innovation (MAT2013-48059-C2-1-R and MAT2014-55778-REDT) and Regional Government of Madrid (S2013/MIT-2862). L.P. and M.P.A. acknowledge the “Ramon y Cajal” and the “Juan de la Cierva” contracts from the MINECO, respectively.Arrieta, MP.; López-Martínez, J.; López, D.; Kenny, J.; Peponi, L. (2016). Biodegradable electrospun bionanocomposite fibers based on plasticized PLA-PHB blends reinforced with cellulose nanocrystals. Industrial Crops and Products. 93:290-301. https://doi.org/10.1016/j.indcrop.2015.12.058S2903019

Development of flexible materials based on plasticized electrospun PLA PHB blends: Structural, thermal, mechanical and disintegration properties

In this work flexible PLA-PHB electrospun materials were developed by means of electrospinning technique. The processing parameters to obtain PLA-PHB electrospun fibers in different proportions (100:0; 75:25; 50:50, 25:75 and 0:100) were conditioned. A complete morphological, structural, thermal and mechanical characterization of the developed materials was conducted. The addition of PHB to PLA matrix, reduced considerably the formation of beads. PHB acts as nucleating agent for PLA in PLA-PHB blends. FTIR and Raman studies have showed interactions between PLA-PHB, mainly at proportion 75:25. The influence of the presence of plasticizer was also studied to obtain information on the possibility to use these thin mats as flexible films. Thus, PLA and PLA75-PHB25 electrospun mats were further plasticized with acetyl tri-n-butyl citrate (ATBC), which provoked an increase in elongation at break, achieving the ductility required for flexible films. The ternary system, PLA75-PHB25/ATBC, showed improved thermal stability due to the good interaction among three components. Disintegrability tests under composting conditions confirmed the biodegradable character of all electrospun mat formulations. Also, it was found that PHB slowed down the disintegration, while ATBC speeded it up. (C) 2015 Elsevier Ltd. All rights reserved.We are intended to the Spanish Ministry of Economy and Competitiveness (MAT2013-48059-C2-1-R and MAT2014-55778-REDT) and to the Regional Government of Madrid (S2013/MIT-2862) for their economic support. LP acknowledges also, the support of JAEDoc grant from CSIC cofinanced by FSE.Arrieta, MP.; López-Martínez, J.; López. D.; Kenny, JM.; Peponi, L. (2015). Development of flexible materials based on plasticized electrospun PLA PHB blends: Structural, thermal, mechanical and disintegration properties. European Polymer Journal. 73:433-446. https://doi.org/10.1016/j.eurpolymj.2015.10.036S4334467

3D-printing self-healing composite polymer reinforced with carbon nanotubes

EMAA copolymer neutralized with sodium salt is a type of ionomer with self-healing abilities. This polymer has been used as raw material for the manufacturing of nanocomposite material by the addition of multiwall carbon nanotubes (MWCNTs). The optimization of the extrusion process, as well as the mixing and dispersion of the nano-reinforcement in the polymeric matrix during extrusion, deals with the manufacturing of a homogeneous reinforced filament. The obtained filaments were used afterwards as feeding materials of a 3D polymer printing machine and tensile test samples were manufactured. Mechanical properties of both unreinforced and reinforced samples were tested. The MWCNTs-reinforced samples exhibited higher mechanical properties without affecting its self-healing ability

Effect of chitosan and catechin addition on the structural, thermal, mechanical and disintegration properties of plasticized electrospun PLA-PHB biocomposites

In this paper the processing and properties of flexible electrospun biocomposites based on poly(lactic acid) (PLA) blended with 25 wt% of poly(hydroxybutyrate) (PHB), plasticized with 15 wt% of acetyl(tributyl citrate) (ATBC) and further loaded with 1 wt% and 5 wt% of chitosan (Ch) or catechin (Cat) microparticles are reported. Both fillers present a high content of hydroxyl groups on their surfaces. The morphological, structural, thermal and mechanical performance of electrospun biocomposites was investigated. The lowest amounts of Ch or Cat added (1 wt%) produced better interactions among PLA, PHB and plasticizer. Chitosan produced some bead defects in the fibers, which leads to a reduction of the mechanical performance on biocomposites. Catechin antioxidant effect improved the thermal stability of biocomposites and produced beads-free fibers with better mechanical performance. All biocomposites were disintegrated in composting conditions showing their possible applications as biodegradable films. (C) 2016 Elsevier Ltd. All rights reserved.Authors thank Spanish Ministry of Science and Innovation (MAT2013-48059-C2-1-R and MAT2014-55778-REDT) and Regional Government of Madrid (52013/MIT-2862). M. P. Arrieta and L. Peponi are recipients of a "Juan de la Cierva" contract (FJCI-2014-20630) and "Ramon y Cajal" contract (RYC-2014-15595) from the Spanish Ministry of Economy and Competitiveness, respectively.Arrieta, MP.; López-Martínez, J.; López, D.; Kenny, JM.; Peponi. L. (2016). Effect of chitosan and catechin addition on the structural, thermal, mechanical and disintegration properties of plasticized electrospun PLA-PHB biocomposites. Polymer Degradation and Stability. 132:145-156. https://doi.org/10.1016/j.polymdegradstab.2016.02.027S14515613