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  • 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

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    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.

  • 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

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  • 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

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    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.

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

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

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  • Hybrid polyurethane nanocomposite foams

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

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  • 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

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  • 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

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  • 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

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  • 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

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    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.

  • 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

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  • 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

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    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

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    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

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    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

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    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

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    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.

  • 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

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  • 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

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  • 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

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

     de Sousa Pais Antunes, Marcelo
    Award or recognition

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    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

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    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

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    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

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    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.

  • 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

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  • 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

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  • 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

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  • Polypropylene foams: production, structure and properties

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio; de Redondo Realinho, Vera Cristina
    Date of publication: 2011-11-01
    Book chapter

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    It is well known the relevance given to the study of heat transfer in polymer foams, as one of the main applications is as lightweight thermal insulating elements. Alongside some of the possible strategies for improving the thermal insulating characteristics of polymer foams, there is also a tremendous interest in further extending the applications of these materials, mainly focusing on improving their poor mechanical properties. Although there is a great deal of interest in preparing and studying polypropylene foams, largely due to their good balance of properties and reduced cost, there is still lack of information regarding their mechanical and thermal conduction characterizations. With that in mind, this chapter considers the preparation, structure and properties of different polypropylene and polypropylene-based nanocomposite foams, focusing on the importance of the foam’s cellular structure and microstructure characteristics and/or filler’s orientation and dispersion in the mechanical and mainly thermal conduction properties, with the main objective of developing new multifunctional thermal insulating lightweight materials for diverse applications. A great deal of importance is given to some of the different strategies used towards the development of rigid polypropylene-based foams to be used as structural elements with improved thermal insulation characteristics. Particularly, we have focused on reducing the value of thermal conductivity via cellular structure control, as it is known to strongly depend on cellular structure characteristics such as cell size, cell density and cell anisotropy. First of all we have addressed the importance of the foaming process and foaming parameters in establishing a certain cellular structure, and secondly in the possibilities of adding high aspect ratio nano-sized fillers, that act as cell nucleating sites, promoting the formation of finer closed-cell foams.

  • Preparación y caracterización termo-mecánica de espumas de polipropileno reciclado reforzado con fibras celulósicas

     de Sousa Pais Antunes, Marcelo; Ardanuy Raso, Monica; Martinez Benasat, Antonio; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales Compuestos
    p. 171-176
    Presentation's date: 2011-07-06
    Presentation of work at congresses

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    Determinación de KIC en compuestos de fibra corta a 1 m/s  Open access

     Martinez Benasat, Antonio; Arencón Osuna, David; Franco Urquiza, Edgar Adrian; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina
    Congreso Nacional de Materiales Compuestos
    p. 387-392
    Presentation's date: 2011-07-07
    Presentation of work at congresses

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    Caracterización mecánica de espumas rígidas multifuncionales de poliuretano  Open access

     de Sousa Pais Antunes, Marcelo; Cano, Álvaro; de Redondo Realinho, Vera Cristina; Arencón Osuna, David; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales Compuestos
    p. 77-82
    Presentation's date: 2011-07-06
    Presentation of work at congresses

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    En el presente trabajo se prepararon y caracterizaron espumas de poliuretano con refuerzo multi-escalar combinando concentraciones variables de arcilla organofílica (montmorillonita) y de lana de esparto, con el propósito de desarrollar espumas rígidas multifuncionales. La incorporación de montmorillonita contribuyó a favorecer la espumación y la formación de estructuras celulares más finas y homogéneas, resultando en espumas con esfuerzos de colapso a compresión inferiores a los obtenidos para las espumas de poliuretano. Sin embargo, un análisis comparativo frente a la densidad relativa, demuestra que las propiedades mecánicas de ambas series de espumas siguen una única tendencia común. La combinación de lana de esparto y montmorillonita contribuyó a reducir aún más el tamaño celular, promoviendo simultáneamente la apertura parcial de las celdas, lo que resulta es espumas con esfuerzos de colapso inferiores.

  • CO2 desorption behaviour in poly(methyl methacrylate)-organoclay nanocomposites during supercritical CO2 dissolution microcellular foaming

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Martinez Benasat, Antonio; Velasco Perero, Jose Ignacio
    International Conference on Diffusion in Solids and Liquids
    p. 147-148
    Presentation's date: 2011-06-29
    Presentation of work at congresses

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  • Composite and biocomposite foams based on polypropylene with reinforcements and functional fillers prepared by supercritical CO2 dissolution

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Ardanuy Raso, Monica; Maspoch Ruldua, Maria Lluïsa; Velasco Perero, Jose Ignacio
    International Conference Blowing Agents and Foaming Processes
    p. 1-10
    Presentation's date: 2011-05-10
    Presentation of work at congresses

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  • Fractura de espumas poliméricas multifuncionales

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio; de Redondo Realinho, Vera Cristina; Ardanuy Raso, Monica; Haurie Ibarra, Laia
    Competitive project

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  • The effects of combining nanoclay and steel wires multi-scalar reinforcements on the structure and properties of polyurethane foams

     Cano, Álvaro; de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Haurie Ibarra, Laia; Velasco Perero, Jose Ignacio
    SPE EUROTEC Plastics Technical Conference
    Presentation's date: 2011
    Presentation of work at congresses

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    In this paper we prepared and characterized several polyurethane composite foams by combining variable concentrations of organophilic clay (montmorillonite) and metal reinforcement, with the objective of developing novel multi-scalar multifunctional rigid foams. The addition of montmorillonite clay 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 polyurethane 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 montmorillonite and metal reinforcement further reduced the cell size of foams, ultimately resulting in foams with similar mechanical properties for considerably lower relative densities. Although no important differences in thermal conductivity were found for the polyurethane foams with adding montmorillonite, the incorporation of the metal reinforcement led to considerably higher thermal conductivities, its value increasing with increasing relative density.

  • Novel PC-graphene nanocomposite foams prepared by sc-CO2 dissolution

     de Sousa Pais Antunes, Marcelo; Gedler, Gabriel; de Redondo Realinho, Vera Cristina; Velasco Perero, Jose Ignacio
    EEIGM International Conference in Advanced Materials Research
    p. 64
    Presentation's date: 2011
    Presentation of work at congresses

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  • Heat transfer in polyolefin foams

     de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio; Solórzano Quijano, Eusebio; Rodríguez Pérez, Miguel Ángel
    DOI: 10.1007/978-3-642-04403-8
    Date of publication: 2011
    Book chapter

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    This chapter is dedicated to the study of heat transfer in polyolefin-based foams, particularly thermal conductivity, as a function of their structure and chemical composition. A small review of the main experimental techniques used to measure the thermal conductivity of these materials is also given, focusing on the transient plane source method (TPS), as well as different theoretical models commonly used for estimating its value. Alongside cellular structure (cell size, anisotropy, etc) and composition considerations, particular importance is given to the analysis of the presence of micrometric and nanometric-sized fillers in the resulting cellular composite thermal properties. This is a novel research field of particular interest, thought to extend the application range of these lightweight materials by tailoring their conductivity.

  • Essential work of fracture (EWF): a useful tool for the fracture toughness characterization of particulate polyolefin composites

     Arencón Osuna, David; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio
    Date of publication: 2011-01-03
    Book chapter

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    The characterization of the fracture toughness of polyolefin composites filled with inorganic particles is commonly solved by means of standardized testing procedures based wherther on the Linear Elastic Fracture Mechanics (LEFM) and the Elastic-Plastic Fracture Mechanics approaches. Fracture parameters as Kc, Gc and Jc are obtained and managed as "material" parameters in plain strain conditions. Nevertheless, particulate polyolefin composites are often in form of film or sheet, making difficult to achieve the specimen size criteria for fracture toughness characterization under plain strain conditions. In such cases, the concept os Essential Work of Fracture (EWF) is nowadays being increasingly applied and considered as a reliable way of fracture toughness determination for this kind of composites. The EWF has traditionally been used for fracture characterization of metals and ductile polymers under plain stress conditions, and most recently applied to ductile particulate composites. In the present chapter, the application of the EWF testing method to the particulate polyolefin composites is reviewed analyzed with regard to the variables of the testing method and the composite characteristics, such as the polyolefin nature and its ductility , the reinforcing particle characteristics and concentration, and the interfacial adhesion level, among others.

  • Preparación y caracterización de espumas multifuncionales a base de nanocompuestos de poliolefinas  Open access  awarded activity

     de Sousa Pais Antunes, Marcelo
    Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya
    Theses

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    En esta tesis doctoral se presenta la preparación y caracterización de espumas rígidas multifuncionales obtenidas a partir de compuestos y nanocompuestos en base polietileno (PE) y polipropileno (PP), indagando en la relación existente entre la espumación, la estructura y microestructura de las espumas y sus respectivas propiedades.En primer lugar se realizó un análisis de la influencia de la espumación en la estructura de las espumas y respectivas propiedades. Se consideraron dos procesos de espumación: espumación química por compresión y espumación física por disolución de gas. En un ámbito más específico, se establecieron las condiciones y metodología para la preparación de espumas microcelulares de PP por un proceso de disolución de gas a elevada presión y espumación por control de la caída de presión. Se obtuvo una relación prácticamente lineal para estas espumas entre el módulo de almacenamiento y el producto del módulo del sólido por la densidad relativa de la espuma, demostrando la eficacia del proceso de espumación.Se analizó la influencia de la densidad relativa y de la estructura celular y microestructura en las propiedades mecánicas y de transporte de las espumas. En ambos casos se consideraron modelos de predicción de las propiedades de las espumas, tratando de analizar la eficacia de la espumación en la mejora de las propiedades específicas. En lo que concierne a la conductividad térmica, se demostró que ésta resulta prácticamente independiente de la estructura celular de la espuma, siendo estimada como el producto de la conductividad del sólido por la densidad relativa.En una segunda etapa se incorporaron distintos tipos de refuerzos funcionales a la matriz polimérica, en particular nanopartículas laminares de montmorillonita (MMT), nanofibras de carbono (CNF) y elevados porcentajes de hidróxido de magnesio (Mg(OH)2), y se procedió a su espumación, con el objetivo de extender el rango de propiedades y por ende de aplicaciones de las espumas. Se observó que la incorporación de refuerzos nanométricos al PP y PE resulta en un incremento de las propiedades mecánicas específicas de las espumas, fruto de un efecto combinado de nucleación de celdas por parte de los mismos y refuerzo de las paredes celulares. Consecuencia directa de su estructura celular más fina e isotrópica, las espumas de estos nanocompuestos presentan un comportamiento mecánico más isotrópico que el observado en las espumas sin refuerzos.La incorporación de ambos refuerzos nanométricos no afectó considerablemente a la conductividad de los sólidos y de las espumas. En el caso particular de las nanofibras de carbono, y aunque los sólidos presenten un valor constante de la conductividad independientemente de la concentración de CNF, se observa un incremento lineal de la conductividad en las espumas al incrementar el porcentaje de CNF, demostrando que la espumación contribuye a mejorar el mecanismo de transferencia térmica.La espumación de compuestos muy cargados de PP con Mg(OH)2 posibilitó la obtención de espumas con una estructura celular tanto isotrópica y de reducido tamaño de celda, como espumas con celdas orientadas en la dirección del crecimiento, dependiendo de la composición y la densidad relativa. La anisotropía celular induce una orientación preferencial de las partículas de Mg(OH)2, que a su vez afecta a la microestructura del polímero y a la conductividad térmica de las espumas, ésta última incrementándose en la dirección de crecimiento de la espuma.Con las nanofibras de carbono se lograron importantes mejoras en la conductividad eléctrica, siendo que las espumas presentan valores inferiores de la concentración crítica de nanofibras para conducción comparativamente a los sólidos.Asimismo, se demostró que la estructura celular y microestructura del PP en las espumas con CNF afecta enormemente al comportamiento de conducción eléctrica. Así, una estructura celular altamente orientada en la dirección de crecimiento, conlleva a superiores valores de la conductividad eléctrica en esa dirección debido a una reorientación parcial de las nanofibras.La incorporación de elevados porcentajes de Mg(OH)2 y posterior espumación resultó en espumas con propiedades mejoradas de resistencia al fuego, indicativas de una mayor auto-extinguibilidad en las espumas.Por último, se ha tratado de aplicar una nueva técnica de expandometría óptica y respectiva metodología de análisis de imagen para el seguimiento del proceso de espumación química en compuestos poliolefínicos.

    The aim of this research work was to prepare and characterize rigid multifunctional foams obtained from polyethylene (PE) and polypropylene (PP)-based composites and nanocomposites, investigating on the relations between foaming, structure and microstructure of the foams and their final properties.First of all, we analyzed the influence of the foaming process on the foam structure and respective properties. Two foaming processes were considered: compression-moulding chemical foaming and gas dissolution physical foaming. More specifically, we established the conditions and methodology for preparing PP microcellular foams by means of a high-pressure gas dissolution process and later foaming by sudden pressure drop (pressure-quench method). We found an almost linear relation between the storage moduli of these foams and the product of the moduli of the solids and the relative density, demonstrating the effectiveness of this foaming process.Besides, we analyzed the influence of the relative density, cellular structure and microstructure on the mechanical and transport properties of the foams. On both cases, we considered different models for predicting the properties of the foams, with the objective of correlating the efficiency of foaming in improving the specific properties.Concerning thermal conductivity, its value was found to be almost independent of the foam's cellular structure, and could be estimated as the product of the conductivity of the solid and the relative density.In a second stage of the thesis, different types of functional fillers were added to the polymer matrix, particularly montmorillonite nanoparticles (MMT), carbon nanofibres (CNF) and high amounts of magnesium hydroxide (Mg(OH)2), and the materials were later foamed, with the objective of extending their range of properties and thus possible applications. The incorporation of nanometric-sized fillers to PP and PE resulted in an increase of the foams' specific mechanical properties, direct result of a combined effect of cell nucleation and cell wall reinforcement by the fillers. Due to their finer and more isotropic cellular structures, these nanocomposite foams displayed a more isotropic-like mechanical behaviour than their unfilled counterparts.The incorporation of both nano-sized fillers did not considerably alter the thermal conductivity of both solids and foams. In the particular case of carbon nanofibres, and although solids presented a value of conductivity that was found to be independent of the amount of nanofibres, we observed a linear increase in the foams with increasing the concentration of CNF, showing that foaming improves the efficiency of the thermal conduction mechanism.From highly-filled Mg(OH)2-PP composites it was possible to prepare foams with an isotropic cellular structure with small cell sizes, as well as foams with cells highly elongated in the growth direction, depending on the composition and relative density. This cellular anisotropy induced a preferential Mg(OH)2 orientation, that in turn affected the polymer's microstructure and thermal conductivity of the foams, with conductivity increasing in the cell growth direction with increasing cell orientation.Carbon nanofibres enabled to improve the electrical conductivity, with foams displaying lower CNF critical concentrations for electrical conduction than solids. Also, it was demonstrated that the cellular structure and microstructure of PP-CNF foams enormously affects their electrical conduction behaviour. A cellular structure highlyoriented in the direction of foam growth resulted in foams with higher electrical conductivities in said direction, due to a partial reorientation of the nanofibres perpendicular to the foam's surface.The incorporation of Mg(OH)2 to PP and later foaming improved the flame retardancy behaviour, with foams exhibiting a higher extinguishability than the respective solid composites.Last but not least, a novel optical expandometry technique and respective image analysis methodology was developed to follow-up the evolution of the chemical foaming of polyolefinic composites.

  • Preparación y caracterización de espumas microcelulares nanoreforzadas

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Santana Pérez, Orlando Onofre; Sanchez Soto, Miguel Angel; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales
    p. 252-255
    Presentation's date: 2010-06-24
    Presentation of work at congresses

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  • Preparación y caracterización de espumas multifuncionales de polipropileno

     de Sousa Pais Antunes, Marcelo; de Redondo Realinho, Vera Cristina; Martinez Benasat, Antonio; Maspoch Ruldua, Maria Lluïsa; Velasco Perero, Jose Ignacio
    Congreso Nacional de Materiales
    Presentation's date: 2010-06-24
    Presentation of work at congresses

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    La combinación de la espumación junto con refuerzos funcionales permite ampliar el rango de propiedades de los sólidos, añadiendo a una elevada rigidez específica la regulación de otras características como las propiedades de transporte. Aunque las espumas poliolefínicas se encuentren extendidas, las ventajas de emplear PP en lugar de PE sólo empiezan a ser importantes para densidades > 100 kg/m3. Por ello, en este trabajo se presenta el estudio de la influencia de la espumación e incorporación de varios refuerzos en las propiedades de espumas de PP de densidad media-alta. Se muestra que la presencia de nanopartículas de montmorillonita induce estructuras celulares más isotrópicas, mejorando su comportamiento mecánico, pero sin alterar la conductividad térmica [1-2]. La incorporación de elevados porcentajes de carga mineral resulta en espumas rígidas con marcadas anisotropías celulares y térmicas, e interesantes propiedades de resistencia al fuego. También pueden obtenerse espumas conductoras eléctricas por incorporación de nanofibras de carbono con posibilidades en aplicaciones como el pintado electrostático

  • Foaming of polypropylene by using both chemical and physical blowing agents. A comparative study of the structure and physical properties

     Saiz-Arroyo, Cristina; Rodríguez Pérez, Miguel Ángel; de Sousa Pais Antunes, Marcelo; Velasco Perero, Jose Ignacio; de Saja, José Antonio
    International Conference Blowing Agents and Foaming Processes
    Presentation's date: 2010-05-20
    Presentation of work at congresses

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  • Access to the full text
    Nanocomposites of in-situ polymerized cyclic butylene terephthalate and polyhedral oligomeric silsesquioaxanes  Open access

     Abt, Tobias Martin; Illescas Fernandez, Silvia; de Sousa Pais Antunes, Marcelo; Caceres Moreno, Maria Angelica; Sanchez Soto, Miguel Angel
    Congreso Nacional de Jóvenes Investigadores en Polímeros
    p. 1-2
    Presentation's date: 2010-05-03
    Presentation of work at congresses

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    Nanocomposites were prepared by in-situ polymerization of CBT®, a cyclic form of poly(butylene terephthalate) (PBT) and polyhedral oligomeric silsesquioxane (POSS®) with 2.5, 5 and 10 wt% POSS content. Three different types of POSS were used; two with reactive functional groups, Trisilanolphenyl POSS (TPOSS) and Glycidyl POSS (G-POSS) and one POSS type having non-reactive functionality, Isooctyl POSS (I-POSS). SEM analysis showed that I-POSS was finely dispersed at a nanoscale level within the CBT, whereas T-POSS and GPOSS formed agglomerates microscaled rather than nanoscaled. T-POSS hinders the polymerization reaction of the CBT, resulting in a poor consolidation of the composite. However, Glycidyl POSS was found to crosslink the CBT during polymerization, making it possible to alter the final material properties. All nanocomposites with 10 wt% POSS content showed a hindered cold crystallization and subsequently showed no melting peak of the formed polymer in a DSC scan.

    Postprint (author’s final draft)

  • Microestructura y comportamiento mecánico y a fractura de nanocompuestos anisotrópicos de PMMA con montmorillonita

     de Redondo Realinho, Vera Cristina; de Sousa Pais Antunes, Marcelo; Arencón Osuna, David; Franco Urquiza, Edgar Adrian; Velasco Perero, Jose Ignacio
    Congreso Nacional de Jóvenes Investigadores en Polímeros
    Presentation's date: 2010-05-05
    Presentation of work at congresses

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