Use of recovered carbon fibres for sustainable polymer composites
Carbon fibre recovery is a must since it has been forecasted that the demand will surpass the production rate of the industry. In addition, several directives regarding recycling are currently being rolled out, in which reinforced carbon fibre polymers are not exempt. One of the main challenges for...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:dnet:upcommonspor::38faec96afb14740dc6034ad1a9e3f66 |
| Acceso en línea: | https://hdl.handle.net/2117/461705 |
| Access Level: | acceso abierto |
| Palabra clave: | Composite materials polymeric composite fibre-reinforced polymer recycling carbon fibre random short fibre anisotropic Compostos de fibra de carboni Fibres de carboni — Reciclatge Materials compostos — Proves Àrees temàtiques de la UPC::Enginyeria dels materials |
| Sumario: | Carbon fibre recovery is a must since it has been forecasted that the demand will surpass the production rate of the industry. In addition, several directives regarding recycling are currently being rolled out, in which reinforced carbon fibre polymers are not exempt. One of the main challenges for recycled carbon fibre is overcoming the fact that they are shorter in length, compared to the virgin fibres, which can limit its suitability for determined applications. Given that, this project focuses on obtaining carbon fibre composites from both virgin and recycled fibres, as well as a mixture of these; followed by characterization and comparison to check if the recycled fibres are suitable for the manufactured products. Firstly, randomly aligned carbon fibre mats were manufactured as semi-products via wet lay-up. These mats were used for composite manufacturing via vacuum infusion and compression moulding. During the process all mistakes and improvements were noted to ensure the reproducibility of the obtained composites. Characterization of the composites includes visual inspection and checking thermal diffusivity with a thermal camera as techniques to find defects. On the other hand, mechanical characterization was performed via 3-point bending and tensile test. Moreover, some predictions on the mechanical properties of the composites can be obtained by micromechanics, using the Rule of Mixtures and Halpin-Tsai model, as well as their modifications for hybrid composites and Classical Laminate Theory. The results of the mechanical testing indicate that the compression moulding samples have an average bending modulus of 23 GPa and tensile modulus of 31 GPa, which were above the literature values found. Stress and strain at failure were found to be lower in the samples with only recycled fibres, which could be caused by the lack of sizing on these. This results in a poorer adhesion between matrix and fibre, creating an area where damage initiates early and cracks are easier to propagate. A rough estimation about void content could also be obtained thanks to the experimental and predicted values by micromechanics, and it resulted higher in the recycled samples. Nevertheless, hybrid samples are almost equal in mechanical properties compared to the samples with only virgin fibres. Overall, the incorporation of recycled fibres into carbon fibre recycled polymers does not heavily compromise their mechanical properties, so they are a suitable substitution for virgin fibres, especially in the case of the hybrid composites where properties are not significantly altered. |
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