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Descripción
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| Bipolar plates (BPs) of fuel cells represent about 80% of the mass, 30% of the cost and all volume of the stacks. Typically, graphite or metals such as stainless steel, aluminium or titanium are used as materials for BPs. However, graphite is not used at industrial level due to its brittleness. Metallic materials are more used, but they have high degradation rates and densities. In some applications, as portable devices or in aeronautical and naval vehicles, mass is a key factor. For these reasons, different composite materials are being studied for use as bipolar plates materials. In this work, seven thermoplastic materials are tested in order to analyse their behaviour as matrix for composite bipolar plates of direct methanol fuel cells (DMFC). Thermoplastic materials have been selected because of the possibility to be recyclable in such a way that the environmental impact is reduced. The materials tested are PLA (polylactic acid); ABS (acrylonitrile butadiene styrene); PC (polycarbonate); NY (nylon); TPU (thermoplastic polyurethane) and CPE and CPE+ (copolyester). Seven samples have been prepared with a 3D printer. These samples were immersed in a solution that simulates the conditions in a DMFC and its temperature is kept constant at 60 °C and a long-term experiment has been undertaken to study the degradation of the different samples with time. To assess the degradation features, 4 techniques have been used: mass loss, dimensional stability, hardness and absorbed moisture. By mass loss measurements it is concluded that the classification of the polymers according to their degradation rate is: PLA > NY > TPU > CPE = CPE+ > ABS = PC. Regarding the dimensional stability, the change of the thickness and planar surface of the samples has been analysed. The thickness of PLA, CPE and NY samples increases with time. NY samples also increase their planar surface. However, PLA and CPE reduce their planar surface so that a remarkable deformation occurs. By contrast, TPU samples reduce their thickness throughout the experiment, but keep their planar surface constant. ABS, PC and CPE+ are the most stable polymers since they keep constant both thickness and planar surface. In all cases, a slight decrease of hardness takes place with time. This reduction of hardness is more marked in NY, CPE+ and TPU, while the hardness of CPE samples is practically constant. The absorbed moisture percentage during the first 24 h shows that NY is the material with the higher moisture percentage (5.87%), while PC presents the lower values (0.19%) (NY > ABS > TPU >PLA > CPE+ > CPE > PC). In accordance with the results, the best materials for use as BPs in DMFCs are ABS and PC due to their reduced degradation rate and excellent dimensional stability. | |
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Internacional
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Si |
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Nombre congreso
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XI Congreso Nacional y II Congreso Internacional de Ingeniería Termodinámica 11CNIT |
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Tipo de participación
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970 |
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Lugar del congreso
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Albacete (españa) |
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Revisores
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Si |
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ISBN o ISSN
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978-84-09-11635-5 |
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DOI
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Fecha inicio congreso
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12/06/2019 |
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Fecha fin congreso
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14/06/2019 |
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Desde la página
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1604 |
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Hasta la página
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1612 |
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Título de las actas
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11CNIT-Proceedings Book XI Congreso Nacional y II Internacional De Ingeniería Termodinámica |