Browsing by Author "Antunes, F."
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- Optimization of a Wood Plastic Composite for Architectural ApplicationsPublication . Martins, G.; Antunes, F.; Mateus, A.; Malça, C.The actual demand for sustainable construction has fostered the research of alternative products made of new materials, such as composites based on renewable resources obtained directly from nature or, most importantly in this context, from the wastes of industries thus encouraging the implementation of recycling processes. This study reports the optimization of wood plastic composites (WPC) made of industrial residues of pine sawdust, high density polyethylene (HDPE) and maleic anhydride-grafted-polyethylene (PE-g-MA) as coupling agent. These composites were specifically designed for the production of an innovative shading system to apply in the forefront of buildings, thus requiring an adequate combination of material properties concerning resistance to weather conditions, with mechanical and functional performance of the final products. The composites were optimized to enable their production and the fabrication of the shutter units through sequential extrusion processing. The optimization of the composites started with a thorough characterization of the raw materials and the mixtures were prepared after analysing the effect of the concentration of pine sawdust in the polymeric matrix, with variable amounts of the coupling agent. Torque rheometry was used to determine the most adequate viscosities for extrusion processing. The composites with optimized contents of pine sawdust and additives were characterized using SEM, FTIR, DSC-TGA, tensile testing, measurements of water contact angle and water absorption capacity. This allowed determining the respective microstructure, chemical interactions, thermal stability, mechanical properties, surface wettability and swelling capacity.
- Optimization of a Wood Plastic Composite to Produce a New Dynamic Shading SystemPublication . Martins, G.; Antunes, F.; Mateus, Artur; S. Baptista; C. MalçaThe shading systems of the windows may play a protagonist role in the reduction of energy consumption in lighting, artificial ventilation and air conditioning, contributing to sustainable development regarding bioclimatic architecture and improvement of the energetic efficiency in buildings. This work, resulting from a partnership between architecture and materials science, reports the development of an innovative and dynamic shading system that simultaneously fulfils various aesthetic, functional and environmental requirements. The original design of the system, derived from this collaboration, enables an industrial low cost production in virtue of the selection of technologies and materials concurrently adequate to multiple objectives. This work also aims at contributing to a sustainable construction through the use of eco-friendly materials such as biocomposites produced from recyclable polymers and vegetable fibres, using extrusion as processing technology both for blending the raw materials and for the shutter units production. The optimization of materials for this specific application involved wood plastic composites (WPC) based on high density polyethylene (HDPE), industrial residues of pine sawdust and additives such as coupling agents, pigments and UV protectors. Results showed that the optimized WPC made from recycled industrial pine wood residues presents thermal stability, mechanical strength and water absorption appropriate to be applied in the production of the new architectural solutions such as the innovative shading system presented.