Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 113 results
  • Compression properties and cellular structure of polyurethane composite foams combining nanoclay and different reinforcements

     de Sousa Pais Antunes, Marcelo; Cano, Álvaro; de Redondo Realinho, Vera Cristina; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    International Journal of Composite Materials
    Vol. 4, num. 5A, p. 27-34
    DOI: 10.5923/j.materials.201401.04
    Date of publication: 2014-11
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In the present work we prepared and characterized several polyurethane (PU) composite foams by combining variable concentrations of nanoclay (montmorillonite, MMT) with metal wires or low cost cellulosic-based reinforcements, with the objective of developing multi-scalar rigid foams for structural applications. The addition of MMT promoted foaming and the formation of finer and more homogeneous cellular structures, resulting in foams with compressive elastic moduli and collapse stresses lower than that of the unfilled PU foams. However, a comparative analysis versus the foams’ relative density demonstrated that both mechanical properties follow one single trend for the two materials. The combination of MMT and the macroscopic metal wires or cellulosic-based reinforcements further reduced the cell size of foams and resulted in foams with similar compressive collapse strengths as the unfilled ones for considerably lower relative densities, hence demonstrating their effectiveness as mechanical reinforcements of rigid PU foams and opening up new possibilities in terms of developing low cost lightweight materials.

  • Microstructural characteristics of graphene/polycarbonate nanocomposite foams

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Rende, Deniz; Schadler, Linda; Velasco Perero, Jose Ignacio; Ozisik, Rahmi
    International Conference on Foam Materials & Technology
    Presentation's date: 2014-09-11
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The microstructural characteristics of polycarbonate-graphene nanocomposite foams prepared using supercritical CO2 foaming are investigated using small and wide angle X-ray diffraction to understand the effect of graphene, cellular microstructure and polymer morphology on electromagnetic interference shielding effectiveness. The observed microstructural changes suggest a preferential orientation of polycarbonate chains and graphene nanoplatelets induced by foaming, which could explain the enhancement observed in electromagnetic interference shielding effectiveness of up to five times when compared to the unfoamed material, therefore, opening up the possibility of using polycarbonate-graphene foams in electronic applications.

  • Graphene nanoplatelets as a multifunctional filler for polymer foams

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    International Conference on Diamond and Carbon Materials
    Presentation's date: 2014-09-09
    Presentation of work at congresses

    Read the abstract Read the abstract  Share Reference managers Reference managers Open in new window

    The increasingly demanding industrial requirements for polymers with enhanced specific properties and functional characteristics have aroused a great interest in the development of lightweight nanocomposites by combining foaming with the addition of functional nanosized fillers. In midst of these, graphene-based materials have recently generated a great attention as a way to extend the range of applications of polymers due to their combination of high mechanical and transport properties, enabling to overcome some of the limitations of common conducting polymers, such as high cost, low thermal stability and poor mechanical performance. Among currently available graphene-based materials scalable to mass production, graphene nanoplatelets have emerged as an interesting multifunctional filler for polymer foams. Nevertheless, there is still a considerable lack of information regarding the influence that these nanoparticles have on the microstructure and cellular structure and thus on the final properties of the resulting foams. With the goal of analyzing the effects of graphene nanoplatelets (GnP) on the structure and mechanical and transport properties of polymer foams, polycarbonate (PC) nanocomposites containing graphene nanoplatelets prepared by melt compounding were foamed using a supercritical CO2 (scCO2) dissolution process. While an ordered non-crystalline PC phase was observed when dissolving scCO2 in PC (PC-CO2), it was only when combining the nanoplatelets and scCO2 (PC-GnP-CO2) that it was possible to promote PC’s crystallization. This induced crystallization led to foams with improved thermal stabilities and specific moduli when compared to the unfilled PC. Foams resulted electrically conductive, with their electrical conductivity increasing with increasing the expansion ratio, which was related to a reduction of the critical distance between the conductive nanoplatelets due to foaming. Additionally, controlled deformation of the foams induced even higher electrical conductivities, suggesting their possible use for piezoelectric, EMI shielding and ESD applications.

  • Polymer-carbon nanotube nanocomposite foams

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    DOI: 10.1002/9781118945964
    Date of publication: 2014-09
    Book chapter

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Since the publication of the successful first edition of the book in 2010, the field has matured and a large number of advancements have been made to the science of polymer nanotube nanocomposites (PNT) in terms of synthesis, filler surface modification, as well as properties. Moreover, a number of commercial applications have been realized. The aim of this second volume of the book is, thus, to update the information presented in the first volume as well as to incorporate the recent research and industrial developments. This edited volume brings together contributions from a variety of senior scientists in the field of polymer nanotube composites technology to shed light on the recent advances in these commercially important areas of polymer technology. The book provides the following features: -Reviews the various synthesis techniques, properties and applications of the polymer nanocomposite systems - Describes the functionalization strategies for single walled nanotubes in order to achieve their nanoscale dispersion in epoxy matrices - Provides insights into the multiscale modeling of the properties of PNT Provides perspectives on the electron microscopy characterization of PNT - Presents an overview of the different methodologies to achieve micro-patterning of PNT - Describes the recent progress on hybridization modifications of CNTs with carbon nanomaterials and their further applications in polymer nanocomposites - Provides details on the foams generates with PNT - Provides information on synthesis and properties of polycarbonate nanocomposite. - Describes the advanced microscopy techniques for understanding of the polymer/nanotube composite interfaces and properties.

  • Preparación y caracterización de membranas a base de nanocompuestos de polieterimida (PEI)

     Abbasi, Hooman; Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales
    p. 126-127
    Presentation's date: 2014-06-19
    Presentation of work at congresses

    Read the abstract Read the abstract  Share Reference managers Reference managers Open in new window

    La polieterimida (PEI) es un termoplástico de altas prestaciones (Tg = 215 ºC), que presenta elevadas propiedades mecánicas y resistencia térmica debido a su estructura de imida aromática, buena procesabilidad por la flexibilidad del enlace éter presente, y elevada selectividad frente a ciertos gases. Por todo ello, en la actualidad se emplea en la fabricación de membranas asimétricas para nanofiltración de solventes orgánicos, absorción de gases y otros procesos de separación. El método más común de preparación es el proceso de inversión de fases, en el que la disolución del polímero, una vez vertida, es puesta en contacto con un no-solvente. El intercambio entre ambos solventes induce la separación de fases, dando lugar a la estructura porosa de la membrana. La estructura es responsable de las propiedades, y depende en gran medida de su composición y condiciones de preparación. En particular, una de las estrategias que se siguen para la regulación de la morfología de estas membranas y, en consecuencia de sus propiedades, es incorporar aditivos y nanocargas inorgánicas. Con el fin de regular las características morfológicas y estructurales de membranas de PEI, y de determinar la influencia sobre sus propiedades, en el presente trabajo se prepararon membranas a base de nanocompuestos de PEI (Ultem 1000, Sabic) con diferentes porcentajes de nanopartículas de grafeno (GnP, XGSciences), y se caracterizaron a nivel morfológico y estructural, térmico y mecánico, principalmente, empleando para ello técnicas de microscopía electrónica de barrido (SEM), difracción de rayos-X (WAXS), calorimetría diferencial de barrido (DSC), análisis termogravimétrico (TGA) y análisis térmico mecánico dinámico (DMTA). Asimismo, debido a las propiedades conductoras de las nanopartículas de grafeno, las membranas presentan conductividad eléctrica, lo que permite extender su campo de aplicación.

  • Comportamiento mecánico dinámico de espumas de policarbonato

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    Encuentro del Grupo Español de Fractura
    p. 403-408
    Presentation's date: 2014-04-04
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Se caracterizan por DMTA espumas de policarbonato (PC) y de policarbonato con nanopartículas de grafeno, producidas mediante dos procesos diferentes de disolución de CO2 supercrítico con posterior expansión en una o en dos etapas. Se analizan los efectos derivados de la presencia del grafeno en el PC, así como la influencia de la densidad relativa de la espuma y de sus características morfológicas y microestructurales sobre su respuesta elástica y viscosa. De modo general, el módulo de almacenamiento específico se ve mejorado en las espumas de PC con la incorporación del grafeno. Por lo que respecta a la componente de disipación viscosa, existen sendas relaciones entre la posición e intensidad del pico de tand, asociado a la transición vítrea del polímero, con la densidad relativa. No obstante, estas relaciones se ven modificadas al cristalizar el PC durante la espumación, ya que la presencia combinada de grafeno y CO2 induce la cristalización del polímero.

  • Polycarbonate foams with tailor-made cellular structures by controlling the dissolution temperature in a two-step supercritical carbon dioxide foaming process

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Journal of supercritical fluids
    Vol. 88, p. 66-73
    DOI: 10.1016/j.supflu.2014.01.013
    Date of publication: 2014-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Closed-cell polycarbonate foams were prepared using a two-step foaming process, which consisted of the initial dissolution of supercritical CO2(scCO2) into PC foaming precursors and their later expansion by heating using a double contact restriction method. The effects of the parameters of both CO2 dissolution and heating stages on the cellular structure characteristics as well as on the physical aging of PC in the obtained foams were investigated. A higher amount of CO2 was dissolved in PC with increasing the dissolution temperature from 80 to 100 ºC, with similar CO2 desorption trends and diffusion coefficients being found for both conditions. PC foams displayed an isotropic-like microcellular structure at a dissolution temperature of 80 ºC. It was shown that it is possible to reduce their density while keeping their microcellular structure with increasing the heating time. On contrary, when dissolving CO2 at 100 ºC and later expanding, PC foams presented a cellular morphology with bigger cells and with an increasingly higher cell elongation in the vertical growth direction with increasing the heating time. Comparatively, PC foams obtained by dissolving CO2 at 100 ºC presented a more marked physical aging after CO2 dissolution and foaming, although this effect could be reduced and ultimately suppressed with increasing the heating time.

  • Thermal stability and fire behaviour of flame retardant high density rigid foams based on hydromagnesite-filled polypropylene composites

     de Redondo Realinho, Vera Cristina; Haurie Ibarra, Laia; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Composites Part B: Engineering
    Vol. 58, p. 553-558
    DOI: 10.1016/j.compositesb.2013.11.015
    Date of publication: 2014-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The present work deals with the development of new rigid polypropylene composite foams filled with high amounts of flame-retardant systems based on synthetic hydromagnesite, a basic magnesium carbonate obtained from an industrial by-product. A partially-interconnected cellular structure with a cell size around 100 micrometers was obtained for the hydromagnesite-filled PP foams. A 40% reduction of this cell size was observed when a small amount of a combination of montmorillonite and graphene layered nanoparticles was added to the hydromagnesite. The combination of hydromagnesite with an intumescent additive (ammonium polyphosphate) and layered nanoparticles led to improved thermal stability. In particular, the intumescent additive delayed the beginning of the thermal decomposition temperature and the layered nanoparticles split the second step of thermal decomposition in a third peak observed at higher temperatures. Improved flame retardancy, measured by means of cone calorimetry, was observed in the samples containing the intumescent additive. A novel normalized parameter, called foam efficiency ratio (FER), which takes into account the expansion ratio of the foam and the relation of its fire properties with that of the base solid, was also analyzed.

  • Multifunctional polymer foams with carbon nanoparticles

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Progress in polymer science
    Vol. 39, num. 3, p. 486-509
    DOI: 10.1016/j.progpolymsci.2013.11.002
    Date of publication: 2014-03
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Increasingly demanding industry requirements in terms of developing polymer-based components with higher specific properties have recently aroused a great interest around the possibility of combining density reduction through foaming with the addition of small amounts of functional nanosized particles. Particular interest has been given to the creation of lightweight conductive polymers by incorporating conductive carbon-based nanoparticles, related to processing improvements in attaining homogeneous nanoparticle dispersion and distribution throughout the polymer as well as new processes that enable a higher control and throughput of highly pure carbon nanoparticles, which could overcome some of the common problems of conductive polymers, such as high cost and poor mechanical properties. This review article considers the use of carbon nanoparticles in polymer foams, initially focusing on the important aspects of foam preparation, the main results found in the literature about conductive polymer composites containing carbon nanoparticles, as well as the main polymer foaming processes and types of foams. The main section is dedicated to the properties of multifunctional polymer foams with carbon nanoparticles, with special focus being given to the electrical and transport properties of these materials.

  • Polyfunctional polymeric materials (POLY2)

     Martinez Benasat, Antonio; Maspoch Ruldua, Maria Lluïsa; Sanchez Soto, Miguel Angel; Santana Pérez, Orlando Onofre; Arencón Osuna, David; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Franco Urquiza, Edgar Adrian; Abt, Tobias Martin; Gedler, Gabriel; Cailloux, Jonathan; Gómez Monterde, Javier; Wang, Liang; Bin Raja-Nazri, Raja Nazrul Hakim; Velasco Perero, Jose Ignacio
    Competitive project

     Share

  • Diffusion of CO2 in polymer nanocomposites containing different types of carbon nanoparticles and nanoclays for solid-state microcellular foaming applications

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Gedler, Gabriel; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    Journal of nano research
    Vol. 26, p. 63-74
    DOI: 10.4028/www.scientific.net/JNanoR.26.63
    Date of publication: 2014-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This work considers the study of the diffusion of carbon dioxide in polypropylene and amorphous polymers containing carbon nanoparticles, particularly carbon nanofibres and graphene, as well as nanoclays, to be used in microcellular foaming. The diffusion of CO2 out and into the nanocomposites was studied during high pressure CO2 dissolution, as the amount of CO2 dissolved into the nanocomposite and CO2 desorption rate are crucial in order to have a proper control of foaming. Comparatively, platelet-like nanoparticles slowed down the desorption of CO2 out of the nanocomposites by means of a physical barrier effect, enabling a higher concentration of CO2 to remain in the polymer and be used in foaming. As a consequence of the higher amount of CO2 retained in the polymer and the cell nucleation effect promoted by the nanoparticles, polymer nanocomposite foams presented finer microcellular structures, in the case of PMMA even submicrocellular, and higher specific moduli and electrical conductivities when compared to their pure counterparts.

  • Graphene in multifunctional polymeric materials

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Gedler, Gabriel; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    Jornada Internacional de Innovaciones Técnicas en Plástico
    Presentation's date: 2013-11
    Presentation of work at congresses

    Read the abstract Read the abstract  Share Reference managers Reference managers Open in new window

    A highly topical subject in Materials Science considers the development of multifunctional materials with improved specific properties by combining the low density of polymers with the incorporation of functional nanofillers. This is the case of graphene, a two-dimensional nanosized material that has recently attracted a great interest due to its unique combination of properties and that has been shown to result in significant property enhancements when added into polymers even at extremely low concentrations. This presentation covers the most recent applications of graphene in polymer-based materials with the goal of developing multifunctional lightweight materials with a vast range of applications.

  • Graphene-induced crystallinity of bisphenol A polycarbonate in the presence of supercritical carbon dioxide

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Polymer
    Vol. 54, num. 23, p. 6389-6398
    DOI: 10.1016/j.polymer.2013.09.050
    Date of publication: 2013-11-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Changes in the crystallinity of polycarbonate (PC) induced by the simultaneous presence of 0.5 wt% graphene nanoplatelets (GnP) and supercritical carbon dioxide (sc-CO2) were examined by means of Raman spectroscopy, WAXS, SAXS and DSC. Composites were prepared by melt-mixing, compression-molding and dissolving sc-CO2 at high pressure and temperature. It was found that dissolved CO2 induced the formation of an ordered non-crystalline phase in PC during slow cooling under pressure. A fast depressurization and cooling did not cause such an effect in the resultant foams. GnP induced a higher crystallinity in PC, especially when combined with sc-CO2, even during fast depressurization and cooling. Raman spectroscopy enabled to correlate changes in the PC vibration modes with the presence of ordered phases, as well as to detect interactions between GnP and PC. Additionally, evidence of GnP exfoliation in the composites could be explained by the intensity reduction of the (002) graphite diffraction peak.

  • Estudio comparativo por FT-IR de dos muestras de un material CR

     de Sousa Pais Antunes, Marcelo
    Date: 2013-10-30
    Report

     Share Reference managers Reference managers Open in new window

  • Hybrid polyurethane nanocomposite foams

     de Sousa Pais Antunes, Marcelo
    DOI: 10.1201/b15572-7
    Date of publication: 2013-10-18
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Diffusion of CO2 in polymer nanocomposites containing different types of carbon nanoparticles and nanoclays for solid-state microcellular foaming applications

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Gedler, Gabriel; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    International Conference on Diffusion in Solids and Liquids
    p. 189-
    Presentation's date: 2013-06-25
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Two-step supercritical carbon dioxide dissolution foaming of Bisphenol A polycarbonate: effects of the heating stage parameters on foam characteristics

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; Sanchez Soto, Miguel Angel; Maspoch Ruldua, Maria Lluïsa; Velasco Perero, Jose Ignacio
    International Conference on Diffusion in Solids and Liquids
    p. 222-
    Presentation's date: 2013-06-25
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Mechanical–viscoelastic characterization in nanocomposites

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    DOI: 10.1002/9783527652372.ch5
    Date of publication: 2013-06
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Combined effects of sc-CO2 and graphene nanoparticles on the crystallinity of bisphenol A polycarbonate

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Martinez Benasat, Antonio; Velasco Perero, Jose Ignacio
    International Symposium Frontiers in Polymer Science
    p. P3.103
    Presentation's date: 2013-05-23
    Presentation of work at congresses

    Read the abstract Read the abstract  Share Reference managers Reference managers Open in new window

    There is still lack of information regarding changes in the microstructure of polycarbonate (PC) due to the addition of secondary phases and processing. In this work, PC composites with graphene were expanded using supercritical CO2 (sc-CO2). Raman spectroscopy, XRD and DSC demonstrated that the presence of graphene and CO2 induced PC’s crystallization during saturation. Double melting behavior indicated the presence of crystals with different thermal stabilities. Saturation temperature, time and CO2 pressure had a direct effect on PC's melting temperature, indicating that processing parameters may be regulated to achieve different crystalline microstructures. Raman spectroscopy enabled to correlate changes in PC’s crystallinity with processing conditions, showing that graphene and sc-CO2 favored the formation of an ordered non-crystalline phase. This induced crystallization, combined with graphene, led to composites with specific moduli that were up to 15% higher than that of unfilled PC.

  • Multifunctional nanocomposite foams based on polypropylene with carbon nanofillers

     de Sousa Pais Antunes, Marcelo; Gedler, Gabriel; Velasco Perero, Jose Ignacio
    Journal of cellular plastics
    Vol. 49, num. 3, p. 259-279
    DOI: 10.1177/0021955X13477433
    Date of publication: 2013-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This work considers the preparation and characterization of polypropylene foams with variable concentrations of graphene and carbon nanofibres, focussing on the influence of the foaming process and the nanofillers on the microstructural and dynamic-mechanical- thermal properties of the foams. Great differences were found in terms of foam morphology depending on the type of foaming process, with foams prepared by physical foaming showing a vertically deformed cell structure, while chemical foams presented an isotropic-like cellular structure. The addition of graphene resulted in foams with higher cell densities and more uniform cellular structures when compared to the ones with nanofibres. All these considerations are of extreme importance, as some of the most promising applications of these polymer foams require a good electromagnetic interference shielding efficiency, which greatly depends on the developed foam morphology.

  • Determinación de las curvas tensión-deformación verdaderas en polímeros

     Maspoch Ruldua, Maria Lluïsa; Loaeza, David; Martinez Benasat, Antonio; Arencón Osuna, David; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Encuentro del Grupo Español de Fractura
    p. 495-500
    Presentation's date: 2013-03-14
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Application of layered nanoparticles in the micromechanical reinforcement and flame retardancy of polymer foams

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Date of publication: 2013
    Book chapter

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    One of the key objectives of nanotechnology is to develop our knowledge to manipulate matters at nanoscale level to create novel, smart, cost effective and eco-friendly macrostructures to improve quality of human life. Recent advancement in development of nano-materials and structures motivate engineers to design nano-modified smart, effective, high performance and sustainable macro-units. This volume contains recent research progresses on development and application on construction based nanomaterials, market potential, problems regarding conventional building system and nanostructures characterized by higher potency, greater robustness and resilience, increased speed of construction, and lessened environmental impact. It contains vivid discussion on methods, mechanical properties, electrical and resistive properties, thermal conductive and damping properties of nanomaterials like titanium dioxide and carbon nanotubes, ultra high pressure –sensitive cement based composites and their potential applications. Authors lucidly and ornately discussed about self cleaning rods, fabrics, electricity generating coatings, heating/ cooling installation systems, micro-electromechanical systems (MEMS) in automobiles, development of nano based structures for disaster protection, waste and pollutant treatment, aviation and land transportation systems, and their applications. Nanotechnology not only finds its use in building highways, dams, bridges and flyovers, but also in making eco-friendly and smart nano-surfaces in ceramics and glasses which currently holds a very potential market globally. This volume will not only expand the knowledge and enhance the analytical ability of the students and researchers, but also help the industrial scientists, engineers, constructors and developers, to address many unsolved problems regarding production and characterisation of construction materials and their prospective applications.

    A great deal of attention has been given in the last years to the study of the influence of incorporating nanosized particles and particularly nanoparticles with a flat-like morphology such as nanoclays or layered double hydroxides, in the properties of polymer nanocomposites. The high aspect ratio of these nanofillers could result in improved interactions with polymer molecules at low filler concentrations, maintaining some of the main advantages of polymer composites such as reduced density. These improved interactions could lead to mechanical improvements or enable to regulate polymer nanocomposites' properties such as transport properties or even improve their intrinsically low flame retardancy. Recently, polymer foam preparation and characterization has gained a lot of attention, as foams have been shown to extend the range of properties and thus possible applications of polymers. The combination of foaming with the incorporation of nanosized particles (polymer nanocomposite foams) could further extend the material's properties, as nanoparticles could have a direct effect in the cellular structure of the foamed material and thus in its final properties. This chapter pretends to give a review of the most recent studies carried out on the influence of layered nanoparticles, focusing on silicate nanoclays and layered double hydroxides, on the mechanical and flame retardancy properties of polymer foams, with the final goal of developing multifunctional lightweight materials with improved properties for applications in sectors such as construction or automotive.

  • Foamed polypropylene for industrial applications

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Date of publication: 2013
    Book chapter

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    There is a great deal of industrial interest in the development of increasingly lighter materials based on polymer foams with improved specific properties for the most varied purposes, from flexible foams for packaging to rigid ones for structural applications. Due to its good combination of properties and reduced cost, foamed polypropylene (PP) could come as a good option. Depending on the base material, foam density and developed cellular structure and microstructure, PP foams may cover a wide range of characteristics and properties which, combined with the incorporation of functional fillers, could ultimately result in the development of multifunctional lightweight materials. This chapter presents a review of the most recent developments in polypropylene foams, starting out by the commercially available PP grades thought out for foaming applications, the different types of PP-based foams depending on their characteristics and final uses, from low-density flexible foams for cushioning and packaging to medium-high density foams for structural purposes, and the main industrial foaming processes, going from melt-like foaming to solid-state chemical and physical foaming. Recent developments in the field of PP foams are also considered, focusing on the combination of cellular structure control via foaming and the incorporation of micro and nanosized functional fillers, with the ultimate objective of developing PP-based foams with a wide range of properties and unique characteristics, from electrically conductive foams through the incorporation of conductive carbon-based nanofillers to foams with direction-dependent transport properties.

    There is a great deal of industrial interest in the development of increasingly lighter materials based on polymer foams with improved specific properties for the most varied purposes, from flexible foams for packaging to rigid ones for structural applications. Due to its good combination of properties and reduced cost, foamed polypropylene (PP) could come as a good option. Depending on the base material, foam density and developed cellular structure and microstructure, PP foams may cover a wide range of characteristics and properties wich, combined with the incorporation of functional fillers, could ultimately result in the development of multifunctional lightweight materials. This chapter presents a review of the most recent developments in polypropylene foams, starting out by the commercially available PP grades thought out for foaming applications, the different types of PP-based foams depending on their characteristics and final uses, from low-density flexible foams for cushioning and packaging to medium-high density foams for structural purposes, and the main industrial foaming processes, going from melt-like foaming to solid state chemical and physical foaming. Recent developments in the field of PP foams are also considered, focusing on the combination of cellular structure control via foaming and the incorporation of micro and nanosized functional fillers, with the ultimate objective of developing PP-based foams with a wide range of properties and unique characteristics, from electrically conductive foams through the incorporation of conductive carbon-based nanofillers to foams with direction-dependent transport properties.

  • Layered double hydroxides (LDHs) as functional fillers in polymer composites

     Velasco Perero, Jose Ignacio; Ardanuy Raso, Monica; de Sousa Pais Antunes, Marcelo
    Date of publication: 2012-10-31
    Book chapter

     Share Reference managers Reference managers Open in new window

  • The multi-scalar effect of incorporating nanofillers and cellulosic-based reinforcements into polyurethane foams: towards the development of low cost structural lightweight materials

     de Sousa Pais Antunes, Marcelo; Maspoch Ruldua, Maria Lluïsa; Velasco Perero, Jose Ignacio
    International Conference on Foam Materials & Technology
    Presentation's date: 2012-09-13
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Characterization of polycarbonate foam structures prepared by one-step SC-CO2 dissolution process  Open access

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    International Conference on Foam Materials & Technology
    Presentation's date: 2012-09-12
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this communication polycarbonate foams were prepared by a supercritical CO2 dissolution one-step batch foaming process. Firstly, CO2 diffusion behavior in polycarbonate was studied by means of desorption experiments. The cellular structure of foams prepared under different foaming conditions was characterized through scanning electron microscopy. Different foaming temperatures as well as CO2 saturation pressures and times were applied. The foams displayed typical closed-cell structures with cell densities ranging from 3x10⁵ to 3x10⁶ cells/m³ and cell average sizes from around 70 to 150μm. Analysis by X-ray diffraction and differential scanning calorimetry seemed to suggest that slight crystallization took place because of the plasticizing effect of CO2 during saturation and foaming. Thermogravimetric analysis showed a higher thermal stability of the foams when compared to the compact polymer. The preliminary results shown in this work suggest the possibility of developing lightweight polycarbonate components with improved specific thermal properties through carefully controlling the foaming parameters.

    Electronic version of an article published as "FOAMS 2012: 10th International Conference on Foam Materials & Technology : Barcelona, Spain, September 12 - September 13, 2012". Society of Plastics Engineers.

  • Nucleation efficiency of talc in the foaming behavior and cellular structure of polyolefin-based foams: new perspectives for optimized lightweight materials

     Meli, Gilles; Abler, Caroline; Jouffret, Frédéric; de Sousa Pais Antunes, Marcelo; Gedler, Gabriel; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    International Conference on Foam Materials & Technology
    Presentation's date: 2012-09-12
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The research consisted in evaluating the nucleation efficiency of different types of talc (with different particle size distributions, morphologies and even surface modifications) in the foaming behaviour and cellular structure os polypropylene-based materials, with the objective of developing lightweight materials with improved stiffness and lower densities. Nucleation efficiency was first evaluated in talc filled PP foamed with a physical blowing agent inside a high pressure vessel. Depending on different talc characteristics, such a particle size distribution, surface area and morphology, cell density as much as doubled. Optimized foamed PP-talc composites prepared by injection-moulding using the MuCell process displayed further weight reductions for similar stiffness values.

  • Halogen-free flame retardant polyolefin foams

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Santana Pérez, Orlando Onofre; Velasco Perero, Jose Ignacio
    International Conference on Foam Materials & Technology
    Presentation's date: 2012-09-12
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Influence of graphene nanoparticles on the thermal stability of polycarbonate nanocomposite foams

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    International Conference on Modification, Degradation and Stabilization of Polymers
    p. 397-398
    Presentation's date: 2012-09-05
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Thermal conductivity anisotropy in polypropylene foams prepared by supercritical CO2 dissolution

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio; Solórzano Quijano, Eusebio; Rodríguez Pérez, Miguel Ángel; de Saja, José Antonio
    Materials chemistry and physics
    Vol. 136, num. 1, p. 268-276
    DOI: 10.1016/j.matchemphys.2012.07.001
    Date of publication: 2012-09
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Different relative density polypropylene foams were prepared by means of two foaming processes: chemical foaming by compression moulding and physical foaming by high pressure CO2 dissolution. By controlling the foaming parameters, such as blowing agent concentration, foaming temperature, pressure drop and pressure drop rate, it was possible to regulate the cellular structure, foams showing from markedly isotropic-like cellular structures to ones with highly-elongated cells in the vertical foam growth direction (honeycomb-like cell orientation). The thermal conductivity was measured using the transient plane source method. Using this technique, it was possible to measure the global conductivity and the thermal conductivity in both the axial and radial directions of a given sample. Results show that the global thermal conductivity of foams was mainly regulated by their relative density. In addition, the honeycomb-like cell orientation of the CO2 dissolution foams resulted in considerably higher values in axial direction when compared to radial, demonstrating that there was a direct influence of cellular structure on the thermal conduction behaviour of these foams, enabling the development of new polypropylene foams with direction-dependent thermal properties.

  • Premi extraordinari de doctorat de la UPC - Àmbit d’Enginyeria Industrial

     de Sousa Pais Antunes, Marcelo
    Award or recognition

     Share

  • Optical expandometry: a technique to analyze the expansion kinetics of chemically blown thermoplastic foams

     Solórzano Quijano, Eusebio; de Sousa Pais Antunes, Marcelo; Saiz-Arroyo, Cristina; Velasco Perero, Jose Ignacio; Rodríguez Pérez, Miguel Ángel; de Saja, José Antonio
    Journal of applied polymer science
    Vol. 125, num. 2, p. 1059-1067
    DOI: 10.1002/app.34306
    Date of publication: 2012-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A novel technique to determine in situ the free expansion kinetics of chemically foamed thermoplastic foams, so-called optical expandometry, is presented in this work. This technique is based on the camera monitoring of a free-foaming material placed inside a furnace. Images are acquired under special illumination conditions to facilitate the later image processing. The present article explains the experimental set-up and the image processing methods used to determine the free volumetric expansion of different polyolefinbased foams. The results are compared with those obtained using thermo-mechanical analysis. In addition, several possible applications of this method are detailed, such as studying the effect of polymer rheology, foaming temperature, blowing agent content and the anisotropy of the expansion.

  • Access to the full text
    Espumas ignífugas de poliolefina libres de halógenos  Open access

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Haurie Ibarra, Laia; Maspoch Ruldua, Maria Lluïsa; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales
    Presentation's date: 2012-06-01
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    En el presente trabajo se han preparado y caracterizado espumas ignífugas de poliolefinas libres de halógenos. Se ha utilizado para ello una formulación comercial, empleada típicamente en la industria de cables, y se le ha añadido pequeños porcentajes másicos (entre 2 y 4%) de dos sistemas retardantes de llama: "sílice-borato de zinc" y manolaminillas de "montmorillonita y grafeno expandible". Durante la caracterización celular de las espumas, preparadas por espumación química utilizando como agente espumante azodicarbonamida, se ha constatado que la presencia de las nanopartículas promovía una estructura celular con tamaño de celda más pequeño. Mediante un análisis termogravimétrico, se ha observado un aumento del residuo inorgánico de la formulación base a temperaturas superiores a 500ºC. Esta observación puede ser debida, en cierta medida, a un efecto sinérgico entre ambos sistemas retardantes de llama, el cual promueve una mayor estabilidad térmica de la formulación base. Durante la caracterización del comportamiento frente al fuego mediante ensayos de cono calorimétrico, se ha constatado que el sistema "síliceborato de zinc" retarda en tiempo hasta ignición de la llama (mayores valores de TTI) y que la presencia de las nanopartículas disminuye el valor del PHRR (máxima tasa de liberación de calor).

  • Multifunctional nanocomposite foams based on polypropylene with carbon nanofillers

     de Sousa Pais Antunes, Marcelo; Gedler, Gabriel; Mudarra Lopez, Miguel; Velasco Perero, Jose Ignacio
    International Conference on Blowing Agents and Foaming Processes
    Presentation's date: 2012-05-09
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Study of the fracture behaviour of flexible polypropylene foams using the Essential Work of Fracture (EWF)

     Arencón Osuna, David; de Sousa Pais Antunes, Marcelo; Martinez Benasat, Antonio; Velasco Perero, Jose Ignacio
    Polymer testing
    Vol. 31, num. 2, p. 217-225
    DOI: 10.1016/j.polymertesting.2011.10.013
    Date of publication: 2012-04-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Comportamiento a fractura de láminas de espuma de polipropileno producidas mediante dos métodos diferentes de espumación

     Arencón Osuna, David; de Sousa Pais Antunes, Marcelo; Martinez Benasat, Antonio; Velasco Perero, Jose Ignacio
    Encuentro del Grupo Español de Fractura
    p. 265-272
    Presentation's date: 2012-03-22
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Influencia de las nanocargas en las propiedades termomecánicas de espumas poliméricas  Open access

     de Sousa Pais Antunes, Marcelo; Gedler, Gabriel; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    Encuentro del Grupo Español de Fractura
    p. 273-280
    Presentation's date: 2012-03-22
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Se presenta la influencia de nanopartículas y nanofibras sobre las propiedades termomecánicas de espumas poliméricas. A una formulación base polipropileno especial para espumación se le incorporaron nanocargas (silicatos laminares) y nanofibras de carbono al objeto de aportar a los materiales celulares resultantes características de multifuncionalidad (rigidezm retardancia a la llama y conductividad). En el presente trabajo se analizan los efectos que introducen las partículas incorporadas sobre las características termodinámicas de las espumas, a través de análisis térmico mecánico dinámico (DMTA), en relación con la composición de las espumas, con su densidad relativa y con su estructura celular. Los resultados han demostrado que la influencia de las nanopartículas y nanofibras añadidas al polímero base de la espuma alcanza, no sólo a su cristalidad, temperaturas de transición características o propiedades mecánicas, sino también a la generación de estructuras celulares más finas y homogéneas que las de sus homónimos de referencia sin partículas.

  • Vegetable fibres from agricultural residues as reinforcement in recycled polyolefin-based green foams

     Ardanuy Raso, Monica; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Waste management
    Vol. 32, num. 2, p. 256-263
    DOI: 10.1016/j.wasman.2011.09.022
    Date of publication: 2012-02
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Thermal stability of polycarbonate-graphene nanocomposite foams

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    Polymer degradation and stability
    Vol. 97, num. 8, p. 1297-1304
    DOI: 10.1016/j.polymdegradstab.2012.05.027
    Date of publication: 2012
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Novel polycarbonate-graphene nanocomposite foams prepared by CO2 dissolution  Open access

     Gedler, Gabriel; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    IOP Conference Series: Materials Science and Engineering
    Vol. 31, num. 1
    DOI: 10.1088/1757-899X/31/1/012008
    Date of publication: 2012
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Polycarbonate foams reinforced with 0,5 wt% of graphene were obtained by firstly melt-mixing the polycarbonate and graphene in an internal mixer, compression-moulding the melt-compounded grinded material and lastly dissolving CO2 inside a high pressure vessel. The CO2 desorption behaviour in the unfilled polycarbonate and nanocomposite was studied in terms of the CO2 saturation concentration and desorption diffusion coefficient, with the graphene-filled nanocomposite displaying a higher CO2 loss rate when compared to the neat polycarbonate. The cellular structure of the foams was found to be highly dependent on the saturation/foaming temperature, with smaller cell sizes being obtained with decreasing the temperature. Another parameter that had an important influence was the residual pressure, with higher residual pressure values resulting in foams with more uniform and regular cells.

    Originally published as "IOP Conference Series: Materials Science and Engineering", vol. 31, no 1, 2012. DOI:10.1088/1757-899X/31/1/012008. .

  • Fire behaviour of flame-retardant rigid polypropylene foams

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    EUROTEC
    Presentation's date: 2011-11-15
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • The Effects of nanofillers and reinforcements on the properties of multi-scalar multifunctional rigid polyurethane foams

     Cano, Álvaro; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    EUROTEC
    p. 8
    Presentation's date: 2011-11-14
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window