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Advisor(s)
Abstract(s)
A crescente pressão nos ecossistemas pela exploração excessiva de recursos cria a necessidade de encontrar soluções para a falta de matérias-primas e para a indevida disposição de resíduos com potencialidade de serem reaproveitados. A introdução de termoplásticos reciclados em materiais compósitos é uma forma de fechar o ciclo de vida dos polímeros, permitindo que, matéria que de outra forma seria enviada para aterro, seja introduzida no fabrico de novos materiais de engenharia. Na presente dissertação é apresentado o trabalho experimental de integração de materiais reciclados na produção de novos materiais compósitos. São apresentados os conceitos base para a compreensão da produção de materiais compósitos de matriz termoplástica, os seus constituintes, os objetivos do material a ser produzido e, também, o processo de reciclagem de termoplásticos para a sua integração na produção de novos semi-produtos. No decurso desta dissertação, foram produzidos pré-impregnados de matriz termoplástica, utilizando o Polietileno Tereftalato (PET) tanto na forma de polímero virgem como reciclado. Após se obter os pré-impregnados, procedeu-se à sua transformação por compressão a quente, para o fabrico de laminados compósitos. Durante o processo realizou-se análise da consolidação, de forma a otimizar os tempos de processamento. De forma a avaliar a qualidade dos materiais produzidos, e permitir um comparativo eficaz entre os materiais produzidos a partir de PET virgem e reciclado, realizaram-se ensaios mecânicos de tração e de flexão, assim como ensaios de calcinação para avaliar os teores de fibra e polímero presentes no compósito. Foram também realizados ensaios óticos com vista a analisar a dispersão de fibras e polímero no pre-impregnado e nos compósitos finais.
The increasing pressure on ecosystems due to the overexploitation of resources creates the need to find solutions to the lack of raw materials and the improper disposal of waste with the potential to be reused. The introduction of recycled thermoplastics in composite materials is a way to close the life cycle of polymers, allowing material that would otherwise be sent to landfill to be introduced in the manufacture of new engineering materials. In this dissertation is presented the experimental work of integration of recycled materials in the production of new composite materials. The basic concepts for the understanding of the production of thermoplastic matrix composite materials, their constituents, the objectives of the material to be produced and the thermoplastic recycling process for its integration in the production of new semi-products are presented. During this dissertation, thermoplastic matrix prepregs were produced, using Polyethylene Terephthalate (PET) in both virgin and recycled polymer form. After obtaining the prepregs, they were processed by hot compression to produce composite laminates. During the process, consolidation analysis was performed to optimize the processing times. In order to evaluate the quality of the materials produced, and to allow an effective comparison between the materials produced from virgin and recycled PET, tensile and bending mechanical tests were performed, as well as calcination tests to assess the fibre and polymer contents in the composite. Optical tests were also performed to analyze the dispersion of fibres and polymers in the prepreg and in the final composites.
The increasing pressure on ecosystems due to the overexploitation of resources creates the need to find solutions to the lack of raw materials and the improper disposal of waste with the potential to be reused. The introduction of recycled thermoplastics in composite materials is a way to close the life cycle of polymers, allowing material that would otherwise be sent to landfill to be introduced in the manufacture of new engineering materials. In this dissertation is presented the experimental work of integration of recycled materials in the production of new composite materials. The basic concepts for the understanding of the production of thermoplastic matrix composite materials, their constituents, the objectives of the material to be produced and the thermoplastic recycling process for its integration in the production of new semi-products are presented. During this dissertation, thermoplastic matrix prepregs were produced, using Polyethylene Terephthalate (PET) in both virgin and recycled polymer form. After obtaining the prepregs, they were processed by hot compression to produce composite laminates. During the process, consolidation analysis was performed to optimize the processing times. In order to evaluate the quality of the materials produced, and to allow an effective comparison between the materials produced from virgin and recycled PET, tensile and bending mechanical tests were performed, as well as calcination tests to assess the fibre and polymer contents in the composite. Optical tests were also performed to analyze the dispersion of fibres and polymers in the prepreg and in the final composites.
Description
Keywords
Materiais compósitos Compósitos termoplásticos Reciclagem Fitas pré-impregnadas PET reciclado Composite materials Thermoplastic composites Recycling Pre-impregnated tapes Recycled PET