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Abstract(s)
A pultrusão de compósitos termoplásticos com a utilização de pré-impregnados tape e towpreg
é uma técnica moderna de fabricação de materiais compósitos leves e resistentes. No processo
de pultrusão, as fibras de reforço são puxadas continuamente e são impregnadas com polimero
termoplástica, e por fim consolidadas em vários tipos de perfis com forma constante.
Os termoplásticos, quando usados como matriz, oferecem vantagens em relação aos materiais
termoendurecíveis, onde permitem a aquisição de maior resistência ao impacto, melhor
capacidade de reciclagem e tempos de processamento mais curtos, uma vez que a cura química
não é necessária. No entanto, o processo de pultrusão requer um controlo preciso da
temperatura, da velocidade de puxo durante a fusão, a consolidação e adesão entre a matriz
termoplástica e as fibras de reforço.
Nesta dissertação, foi realizado a produção de pré-impregnados de fibras com matriz
termoplástica, para serem transformados pelo processo de pultrusão. As fibras de carbono (FC)
e de vidro (FV) foram utilizadas como reforço, enquanto o polipropileno (PP) e o polietileno
tereftalato de etileno (rPET) foram as matrizes termoplásticas utilizadas, constituindo assim
compósitos híbridos
Durante a produção de perfis compósitos, as condições de processamento foram otimizadas
para estudar a influência da variação dos parâmetros nas propriedades finais dos compósitos.
Ensaios de flexão e tração foram realizados, juntamente com testes de calcinação para ser
possível a determinação de frações mássicas e volumétricas das fibras, permitindo a
comparação entre as propriedades esperadas teoricamente com as obtidas
experimentalmente.
Pultrusion of thermoplastic composites using tape and towpreg is a modern technique for manufacturing lightweight and resistant composite materials. In the pultrusion process, the reinforcing fibres are pulled continuously and are impregnated with thermoplastic polymer, and finally consolidated into various types of profiles with a constant shape. Thermoplastics, when used as a matrix, offer advantages over thermosetting materials, where they enable the acquisition of greater impact resistance, better recyclability and shorter processing times, since chemical curing is not necessary. However, the pultrusion process requires precise control of the temperature, the pulling speed during melting, consolidation and adhesion between the thermoplastic matrix and the reinforcing fibre, thus constituting hybrid compounds. In this dissertation, the production of fibre prepregs with a thermoplastic matrix was carried out, to be transformed by the pultrusion process. Carbon fibres (CF) and glass fibres (GF) were used as reinforcements, while polypropylene (PP) and polyethylene terephthalate (rPET) were the thermoplastic matrices used. During the production of composite profiles, processing conditions were optimised to study the influence of parameter variations on the final properties of the composites. Bending and tensile tests were carried out, along with calcination tests to determine the mass and volume fractions of the fibres, enabling a comparison between the properties expected theoretically and those obtained experimentally.
Pultrusion of thermoplastic composites using tape and towpreg is a modern technique for manufacturing lightweight and resistant composite materials. In the pultrusion process, the reinforcing fibres are pulled continuously and are impregnated with thermoplastic polymer, and finally consolidated into various types of profiles with a constant shape. Thermoplastics, when used as a matrix, offer advantages over thermosetting materials, where they enable the acquisition of greater impact resistance, better recyclability and shorter processing times, since chemical curing is not necessary. However, the pultrusion process requires precise control of the temperature, the pulling speed during melting, consolidation and adhesion between the thermoplastic matrix and the reinforcing fibre, thus constituting hybrid compounds. In this dissertation, the production of fibre prepregs with a thermoplastic matrix was carried out, to be transformed by the pultrusion process. Carbon fibres (CF) and glass fibres (GF) were used as reinforcements, while polypropylene (PP) and polyethylene terephthalate (rPET) were the thermoplastic matrices used. During the production of composite profiles, processing conditions were optimised to study the influence of parameter variations on the final properties of the composites. Bending and tensile tests were carried out, along with calcination tests to determine the mass and volume fractions of the fibres, enabling a comparison between the properties expected theoretically and those obtained experimentally.
Description
Keywords
Pultrusion Thermoplastic composites Prepregs Commingled fibres Polypropylene Recycled PET Pultrusão Compósitos termoplásticos Pré-impregnados Fibras towpreg Polipropileno PET reciclado