Papers by Author: Mário de Araújo

Abstract: This work reports on research being carried out in the area of functional knitted fabrics with a special structure incorporating hydrophobic fibres near to the skin and suction channels of hydrophilic fibres to suck moisture from the skin on the hydrophilic layer away from the skin; in this way, comfort is maximised in active wear as the fabric does not feel wet near to the skin.

Abstract: This work reports on research being carried out in the area of functional knitted fabrics with a special structure incorporating hydrophobic fibres near to the skin and suction channels of hydrophilic fibres to suck moisture from the skin on the hydrophilic layer away from the skin; in this way, comfort is maximised in active wear as the fabric does not feel wet near to the skin.

Abstract: This paper describes the work that is being done at the University of Minho concerning the development of braided rods for concrete reinforcement. A preliminary research study has been conducted to understand the mechanical behaviour of braided fabrics. Various samples have been produced varying the type of fiber (glass, polyester and aramid), the type of braided fabric (simple, hybrid and core reinforced) and in the latter case, the number of core reinforcing yarns. The tensile properties of these samples have been evaluated and the results presented. The influence of each factor on the tensile properties of braided fabrics has also been analysed and discussed. In order to produce braided reinforced composite rods to use as a concrete reinforcement, a special technique has been developed using a standard vertical braiding machine. The braided reinforced composite materials have been produced in rib structure to improve adhesion between them and the concrete. Special samples have been prepared and tested to evaluate the adherence between both materials involved. The tensile and bending properties of braided reinforced composite rods have been evaluated and the results obtained presented and discussed.

Abstract: In the present work, glass fibre polypropylene (GF/PP) woven fabrics were manufactured from cost-effective flexible thermoplastic towpregs produced by a developed dry coating process. The paper describes the modifications made on the developed coating line to allow producing thermoplastic towpregs able to be woven in textile equipments. The produced fabrics were observed under optical microscopy and submitted to tests in order to evaluate their textile-like properties, glass fibre content and flexibility. Composites processed from those fabrics by compression moulding were also submitted to mechanical testing in order to assess their performance. The obtained experimental results have shown that the woven fabrics produced are cost-effective and present properties good enough to be applied in large-scale commercial markets (e.g. automotive). Future research efforts will be carried to try decreasing the towpreg frictional properties and the amount of polymer lost during the textile processing and improving the feeding technology to warp yarns directly from a creel.