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Publication
Estudo das propriedades mecânicas de compósitos verdes reforçados com lã de ovelha e pêlo de cão da Serra da Estrela
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Authors
Abstract(s)
A consciencialização ambiental levou as indústrias a substituir os produtos derivados de
recursos petrolíferos por produtos de origem natural. No setor dos materiais compósitos,
a substituição das fibras sintéticas (carbono, vidro, aramida) por fibras naturais, como
material de reforço, tem aumentado nos últimos anos.
As fibras naturais são biodegradáveis, têm um custo menos elevado que as fibras
sintéticas, possuem uma elevada disponibilidade e apresentam boas propriedades
mecânicas que podem ser equiparadas às apresentadas pelas fibras sintéticas.
No presente trabalho produziram-se vários compósitos verdes reforçados com diferentes
fibras naturais animais (lã de ovelha e pêlo de cão). Como reforço foram produzidos e
utilizados vários tecidos têxteis com diferentes arquiteturas.
Os compósitos produzidos foram sujeitos a ensaios de flexão e de tração de modo a
estudar e analisar as suas propriedades mecânicas.
Para além disso, as fibras da lã de ovelha e do pêlo de cão utilizadas foram caracterizadas
por Difração de Raios-X (DR-X), e os fios produzidos a partir dessas fibras foram
também sujeitos a ensaios de tração de modo a avaliar as suas características físicomecânicas.
Por fim, foi realizada uma análise crítica dos resultados obtidos nos vários ensaios
mecânicos realizados. Com base nos resultados obtidos, pode-se concluir que o número
de fios e o diâmetro das agulhas utilizadas durante a produção do reforço têm um
impacto significativo nas propriedades mecânicas dos compósitos. Os compósitos
reforçados com lã de ovelha apresentam valores mais elevados para a resistência à tração,
resistência à flexão e módulo de Young do que os reforçados com pêlo de cão (aumento
médio de 45,16%, 36,97% e 72,99%, respetivamente). Além disso, foi possível observar
que os compósitos reforçados com tecidos feitos por tecelagem e por crochê possuem os
valores de resistência à tração, resistência à flexão e módulo de Young mais elevados. Os
compósitos reforçados com tecidos feitos por tecelagem apresentam os valores mais
elevados de deformação à rutura/1ª falha e de tenacidade.
Environmental awareness has led industries to replace products derived from oil resources with products of natural origin. In the composites materials sector, the replacement of synthetic fibres (e.g.: carbon, glass, and aramid) with natural fibres as a reinforcement material has increased in recent years. Natural fibres are biodegradable, cost less than synthetic fibers, are highly available and have good mechanical properties than can be compared to those of synthetic fibers. In this study, several green composites reinforced with different animal fibres (sheep´s and dog wool) were produced. As reinforcement, various textile fabrics with different architectures were produced and used. The composites produced were subjected to bending and tensile tests to study and analyze their mechanical properties. In addition, the sheep´s wool and dog hair fibres used were characterized by X-Ray Diffraction (X-RD), and the yarns produced from these fibres were also subjected to tensile tests to assess their physical and mechanical characteristics. At the end, a critical analysis of the results obtained in the various mechanical tests was carried out. From the results obtained, we can conclude that the number of yarns and the diameter of the needles used during the production of the reinforcement have a significant impact on the mechanical properties of the composites. The composites reinforced with sheep´s wool exhibit higher values of tensile strength, flexural strength and Young´s modulus than those reinforced with dog wool (average increases of 45,16%, 36,97% and 72,99%, respectively). It was also possible to observe that the composites reinforced with fabrics made by weaving and crochet exhibit the highest values of tensile strength, flexural strength and Young´s modulus. The composites reinforced with fabrics made by weaving exhibit the highest values for deformation at the break/first failure and toughness.
Environmental awareness has led industries to replace products derived from oil resources with products of natural origin. In the composites materials sector, the replacement of synthetic fibres (e.g.: carbon, glass, and aramid) with natural fibres as a reinforcement material has increased in recent years. Natural fibres are biodegradable, cost less than synthetic fibers, are highly available and have good mechanical properties than can be compared to those of synthetic fibers. In this study, several green composites reinforced with different animal fibres (sheep´s and dog wool) were produced. As reinforcement, various textile fabrics with different architectures were produced and used. The composites produced were subjected to bending and tensile tests to study and analyze their mechanical properties. In addition, the sheep´s wool and dog hair fibres used were characterized by X-Ray Diffraction (X-RD), and the yarns produced from these fibres were also subjected to tensile tests to assess their physical and mechanical characteristics. At the end, a critical analysis of the results obtained in the various mechanical tests was carried out. From the results obtained, we can conclude that the number of yarns and the diameter of the needles used during the production of the reinforcement have a significant impact on the mechanical properties of the composites. The composites reinforced with sheep´s wool exhibit higher values of tensile strength, flexural strength and Young´s modulus than those reinforced with dog wool (average increases of 45,16%, 36,97% and 72,99%, respectively). It was also possible to observe that the composites reinforced with fabrics made by weaving and crochet exhibit the highest values of tensile strength, flexural strength and Young´s modulus. The composites reinforced with fabrics made by weaving exhibit the highest values for deformation at the break/first failure and toughness.
Description
Keywords
Propriedades Mecânicas Compósitos Verdes Fibras Animais Lã de Ovelha Lã de Pêlo de Cão