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• Fiber reclamation from composite materials by thermal treatment: experimental and mathematical optimization of operating parameters

  A. Lopez-Urionabarrenechea, I. Marco, B. Caballero

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 125

  
  

  Abstract

  Las fibras de carbono y de vidrio que se encuentran en los residuos que se generan en los sectores industriales que fabrican o utilizan materiales compuestos reforzados con fibra pueden recuperarse a través del tratamiento térmico. Este tratamiento consiste en el calentamiento del material en atmósfera inerte (pirólisis) hasta la temperatura suficiente para que se descomponga la resina polimérica y la posterior oxidación de los productos carbonosos generados en esta descomposición en presencia de aire. El resultado de este tratamiento es la eliminación completa de la resina y la recuperación de las fibras, que mantienen buenas propiedades físico-químicas. En este trabajo se ha utilizado el diseño estadístico de experimentos para determinar la influencia que tienen las tres variables de operación principales involucradas en la recuperación de fibras por tratamiento térmico (temperatura de pirólisis, temperatura de oxidación y tiempo de oxidación) sobre el rendimiento de eliminación de resina polimérica. La estrategia experimental utilizada ha sido el diseño factorial completo 2k, donde k=3, las variables de operación estudiadas. El método se ha aplicado a residuos procedentes del sector eólico y del sector aeronáutico, tanto de piezas curadas como pre-pregs caducados, y reforzadas con fibra de carbono y fibra de vidrio. Con los resultados obtenidos en la experimentación con termobalanza se ha determinado la importancia relativa de las variables estudiadas para cada una de las muestras y se han definido las ecuaciones matemáticas que permiten predecir el rendimiento de eliminación de resina en función del valor que tomen estas variables.

  Abstract
  Las fibras de carbono y de vidrio que se encuentran en los residuos que se generan en los sectores industriales que fabrican o utilizan materiales compuestos reforzados con [...]

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• Study of the rheological behavior of polymer-modified asphalts

  I. Feijoó, C. Abreu, S. Gómez-Barreiro, M. Echeverría, C. Echeverría

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 124

  
  

  Abstract

  Nowadays asphalts modified with polymers (PMA) are used in a wide range of applications, for example, as waterproofing, pavements and membranes, and are being object of a great amount of publications and patents. The processes of modification of asphalt with polymers are widely used to achieve the use of asphalts for some applications where the use of non-modified asphalt is not suitable due to their high thermal susceptibility, their tendency to oxidize or their high content of saturated and aromatic compounds. In this work, milled rubber has been used as an asphalt modifier for the manufacture of waterproofing covers. The use of milled rubber makes it possible to find a viable outlet for the large quantities of discarded tires that accumulate in the tanks and achieve an ecological benefit. Therefore, the rheological study of new compositions with different percentages of polymer addition have been carried out. As main results, it is observed that the asphalt without polymer (MA) at 30º C behaves practically like a Newtonian liquid, while the PMA samples behave as non-Newtonian fluids. On the other hand, the addition of rubber leads to an increase in two orders of magnitude of the elastic and viscous modulus, as does the complex viscosity. The yield stress is greater in the PMA samples, and both the maximum force and the adhesion work increase. The addition of elastomer increases the viscosity of the product, but further increases its elastic component. In MA, the viscous component is greater than the elastic component whereas in the PMAs this behavior is reversed.

  Abstract
  Nowadays asphalts modified with polymers (PMA) are used in a wide range of applications, for example, as waterproofing, pavements and membranes, and are being object of a [...]

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• Cell geopolymers: development of ecological light concrete without cement (GEOCEL project)

  S. Pintos, L. Freire, P. Rodríguez, . G.J.Guzmán, . J.Fernández, . J.M.Lago, . C.Trancón

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 123

  
  

  Abstract

  Cement is the most used construction material in the world (3670 MT/year are generated), being highly polluting, emitting aproximately one ton of CO2 per ton of cement. In this sector, in which the search for more sustainable materials becomes essential, the geopolymers or alkaline cements are introduced as an ecological alternative, resulting in 80% less polluting and requiring 50% less of energy comsumption in the manufacturing process. In this context, GeoCel project is oriented to the developing of ecological construction materials to get concretes and mortars (without Portland cement) of cellular structure. Different constructive solutions were proposed for these inovative materials as wall cladding and insulation panels and  continous and draining  pavements.The caracterization of the different solutions was carried out bymechanical resistance, fire resistance and thermal conductivity tests, among others, based on the requiremens imposed at the industrial level, in order to evaluate the technical viability of the new materials. The results obtained have been promising, getting mechanical strengths superior to conventional materials  in case of mortars , as well as classification of reaction to fire A1.

  Abstract
  Cement is the most used construction material in the world (3670 MT/year are generated), being highly polluting, emitting aproximately one ton of CO2 per ton of cement. [...]

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• Softwood kraft lignin characterization and melt extrusion of blends with two bioderived polyesters

  M. Guerreiro, J. Goncalves, E. Oliveira, B. Silva, M. Paivab

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 122

  
  

  Abstract

  Lignin is one of the three major polymeric constituents of wood. It is a natural and renewable resource, and due to its structure it is the most abundant aromatic polymer on Earth. The present work reports the thermal and chemical characterization of a kraft lignin and the study of it’s mixing ability with two bioderived polyesters, namely PLA and PHB, to test their suitability for the production of green fibre.

  Abstract
  Lignin is one of the three major polymeric constituents of wood. It is a natural and renewable resource, and due to its structure it is the most abundant aromatic polymer [...]

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• Surface modification of carbon fibres for its use as supercapacitors in electric vehicles

  M. Utrilla, A. Ureña, J. Artigas, B. Muñoz, M. Sanchez, J. Prado

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 121

  
  

  Abstract

  Carbon fibre reinforced composite materials show potential as energy storage components, due to the high electric conductivity of the carbon fibre. Supercapacitors store electrostatic energy over the electrode surface. Increasing the surface area of electrodes based on carbon fibre could lead to an increase in storage capacitance. Different methods to increase surface area of carbon fibre are studied with the aim of increasing energy storage capacitance of the fibres working as electrodes for structural electrochemical capacitors. Surface modification was carried out by the deposition of carbon nanoparticles (GNP) and porous carbon (CAG). Effectiveness of the different methods was analysed by measurements of BET surface area and microscopy characterisation. The effect on mechanical properties of individual fibres was analysed and storage capacitance was measured by electrochemical characterisation.

  Abstract
  Carbon fibre reinforced composite materials show potential as energy storage components, due to the high electric conductivity of the carbon fibre. Supercapacitors store electrostatic [...]

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• Comparative of mechanical properties of tensile, compression and in plane shear strength of natural composite materials

  A. Pozo, A. Fernández-López, A. Güemes

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 120

  
  

  Abstract

  Developing a sustainable industry based on respectable materials with the environment, through optimal processes with low impact is a fundamental aim, but it remains a considerable challenge to achieve. Despite the large amount of research on composite materials in natural fibers, the limitations in the results have been obtained, being usual to find mechanical results with a wide coefficient of variation and values ​​much lower than expected. The industry of products with bamboo fiber has increased in decorative applications because it is one of the lowest cost raw materials. However, there are limited structural applications, due to the low mechanical properties. A study of the methodology and the extraction area has been carried out in order to maximize the Young's modulus, doubling the value with respect to the E-type and epoxy glass material. Once, continuous networks such as linen, sisal, silk and cotton have been reduced, to develop a unidirectional tape semi-impregnated by a winding process, which allows the fabrication of structures with curvature, with comparable shear values ​​in the plane with the reference material. Finally, in addition to the extensive campaign of mechanical tests, three demonstrators have been manufactured with their respective respect to show the capacity of use and the limitations of the materials. Environmental terms, industrial sectors such as wind or automotive.

  Abstract
  Developing a sustainable industry based on respectable materials with the environment, through optimal processes with low impact is a fundamental aim, but it remains a considerable [...]

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• Vol4 num3-15 Two-component epoxy sel-healing adhesive throught the incorporation of smart microcapsules

  R. Rodriguez, H. Villaverde, S. Flórez

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 118

  
  

  Abstract

  In this work, the effect of the localization of the catalyst in a self-repairing system based on the microencapsulation technology in a bi-component epoxy adhesive has been studied. The efficiency of a conventional self-healing system (microcapsules + catalyst) has been compared with a system in which the curing agent and the catalyst are in the same microcapsule but isolated from each other. This system has been called "All in one" and has shown to be more efficient than the conventional one, achieving efficiencies of up to 116%.

  Abstract
  In this work, the effect of the localization of the catalyst in a self-repairing system based on the microencapsulation technology in a bi-component epoxy adhesive has been [...]

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• Prediction of fiber orientation in thermoplastic composites

  F. Garitaonandia, . A.Arriaga, ,. K.Zulueta, I. López, . J.Ibarretxe, . M.Iturrondobeitia

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 116

  
  

  Abstract

  The prediction of the fiber orientation in thermoplastic composites, manufactured by the injection moulding process, allows the determination of the mechanical behaviour with greater precision. In the present work, the prediction of the fibre orientation made by the Autodesk Moldflow Insight program has been analysed through the ARD-RSC model. This model presents six coefficients that can be modified and according to which values take the result of the prediction of the orientation of the fiber will be different. That is why the response surface method has been applied to know the relationship between the coefficients of the ARD-RSC model and its prediction of fibre orientation. The precision and correlation of this calculated fiber orientation has been analysed in two ways. The first of them using tomographic analysis with which you can visualize and compare with the actual arrangement of the fibre in the thermoplastic composite and the second moving the orientation calculated by Autodesk Moldflow Insight to the Digimat program and comparing its prediction of mechanical properties with the real properties that the thermoplastic composite presents in the mechanical tests carried out. Taking into account the modification of the coefficients, the improvement of the correlation between the experimental test and the structural simulation has been observed in the analyzed component.

  Abstract
  The prediction of the fiber orientation in thermoplastic composites, manufactured by the injection moulding process, allows the determination of the mechanical behaviour with [...]

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• Fabricación mediante laminación automática en un paso con materiales termoplásticos de una estructura altamente integrada

  M. Zuazo, F. Chamorro, . V.García-Martínez, . S.Calvo, . E.Lorenzo-Villafranca

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 115

  
  

  Abstract

  During the last years, the benefits of using carbon reinforced thermoplastic composite materials (CRTP) have been questioned and defended (higher fatigue resistance, greater toughness, better durability, reprocesability, recyclability and so on), they are considered as a future innovative technology allowing  highly integrated structures, impacting in weight reduction and reducing energetic costs by using out of autoclave processes. Therefore, (CRTP) could be considered as a future substitute of metallic materials and composite materials with thermoset matrices for aerospace applications, automotive and other industries. Under the frame of the OUTCOME project (Clean Sky II), the design and analysis of the Upper Skin (upper coverage of a stiffened wing) for the militar aircraft C295 is developed, a medium tactical transport aircraft of ADS. The selected material for the work is the unidirectional composite material APC2/AS4, supplied by Solvay, with PEEK as the thermoplastic matrix and carbon fibre as the reinforcement. Flat panels, detailed elementals and subelementals have been manufactured, all of them have been widely characterized attempting to obtain the required design allowables.  Moreover, with the goal of cost reduction, productivity increases and environmental impact control, the manufacturing selected processes have been: a)  Hot-forming in oven and/or self heated toolings for stringers manufacturing and b) Automatic lamination in one step for the co-consolidation (full-integration) of the skin with the stringers. The main goal of this review is showing the different steps in the manufacturing of a detailed element for a later structural test. 

  Abstract
  During the last years, the benefits of using carbon reinforced thermoplastic composite materials (CRTP) have been questioned and defended (higher fatigue resistance, greater [...]

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• Development and characterization of polypropylene nano-composites

  S. Pintos, E. Rodriguez, A. Gonzalez

  Materiales Compuestos (2022). Vol. 04 - Comunicaciones Matcomp19 (2020), (Núm. 3 - Materiales bioinsipirados), 114

  
  

  Abstract

  Modification of polymer matrices has a great insterest in the field of new materials, based on the possibilities offered by the additivation, being able to modulate the properties of the base material depending on the incorporated aggregates. Among the improvements searched include the increase in the mechanical strength of the material or the improvement in the interaction with other materials (adhesion), in addition to providing multifunctionality, combining properties of materials separately in order to obtain a composite with improved properties. This study focuses on the modification of a polypropylene-ethylene co-polymer by the incorporation of nanoclays and carbon nanotubes (MWCNTs) in low concentrations (0.1% by weight). In order to facilitate the dispersion of the nanomaterials in the matrix by mixing and extrusion, maleic anhydride was used as a compatibilizer. The behavior of these composites was characterized by studying the variation of torque during the compounding, in addition to analize the melt flow index (MFI) and perform an analysis by DSC, TGA and TEM of the composites obtained. Based on the low polarity of polypropylene, the introduction into the matrix of maleic anhydride provides a certain polarity in the composite, so the increase in the surface energy of the different formulations is studied by contact angle measurements (using the OWRK/Fowkes method). The increase in surface energy involves a greater affinity for polar materials, such as polyurethane (PU) or other foams.

  Abstract
  Modification of polymer matrices has a great insterest in the field of new materials, based on the possibilities offered by the additivation, being able to modulate the properties [...]

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