Mechanical characterization of cork-polymer composites through experimental tests

• Autor(a) principal: Carvalho, João Daniel Rodrigues
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/23876
• topic: Composites; Reinforced polymers; Cork; Mechanical tests; Charpy test; Tensile test

This document will review the mechanical tests that were conducted in order to evaluate and identify an optimization threshold for the relative mixtures between standardized polymers and cork. Polyethylene, Polycarbonate and ABS were mixed with varying percentages of cork grains to provide insight into the applicability of utilizing cork as a sustainable alternative in the helmet’s outer shell without statistically significant deterioration of mechanical resistance. This study was conducted to investigate the usage of a composite material composed by a mixture of polymer with cork, for helmets outer shell, such as cycling, motorcycle, alpinism, among others. The study was fulfilled by creating samples with different percentages of cork grains to evaluate the adhesive characteristics of the cork grains with the different polymers. Utilizing increasing percentages of cork grain from 10% to 50%. The addition of cork as a percentage of the total substance was increased in increments of 10 and the intermediate points are interpolated from the data collected. Even though the polyethylene is not a common material for the helmet outer shell, similar testing and evaluation was undertaken for purposes of scientific curiosity. Using the mixer available, the combination of both materials was conducted under heat. Finally, the laboratorial experiments of this dissertation can be divided in two distinct parts: 1) An impact test was implemented to observe the quantity of energy retained by each sample mixture. 2) A tensile test, where it is possible to observe characteristics such as yield stress, maximum elongation or the young modulus.