Percorrer por autor "Nunes, J. P."
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- Compression molding of pultruded carbon reinforced thermoplastic compositesPublication . Novo, P.J.; Nunes, J. P.; Silva, J. F.; Marques, A. T.Historically, thermoset resins have dominated the composite industry but they start to be replaced by thermoplastics. In this study two different thermoplastic matrix carbon reinforced pre-impregnated materials were used, one produced in our laboratories (towpreg) and another obtained from co-extrusion process (PCT). Carbon fibre and two different thermoplastic matrices (polypropylene and PRIMOSPIRE®) were selected for the production of the pre-impregnated materials. Heated compression moulding and pultrusion were the two manufacturing technologies used to obtain composite plates and profiles for study. The optimization of those processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced carbon fibres thermoplastic matrix pre-impregnated materials and composites. The composite relevant mechanical properties were determined and the final composites were submitted to Dynamic Mechanical Analysis (DMA), Scanning Electron Microscope (SEM), optical microscopy and calcination tests. The determination of the fiber volume fraction of all studied composite was obtained comparing the results of thermogravimetric analysis (TGA), SEM and calcination tests.
- Optimizing the production and processing of fibre reinforced thermoplastic pre-impregnated materialsPublication . Novo, P.J.; Silva, J. F.; Nunes, J. P.; Marques, A. T.The aim of this work is to optimize the production of new continuous carbon fibres reinforced polypropylene matrix pre-impregnated materials (towpregs) continuously processed by dry deposition of polypropylene (PP) powder. The processing of the produced towpregs by pultrusion using a prototype equipment was also optimized. The method of Taguchi/DOE (Design of Experiments) was used to achieve this goal allowing improved choices of processing windows. Towpregs were characterized by scanning electron microscopy (SEM), visual analysis and their polymer mass contents were also determined. The final pultruded composite profiles were also submitted to tensile, interlaminar, flexural, calcination and optical microscopy tests.