Encontrados 18 documentos, a visualizar página 1 de 2
Monofilament composites of Co-continuous Polyamide12/Poly (Methyl Methacrylate)...
Covas, J. A.; Oliveira, Bruno; Barbosa, M. F.; Paiva, M. C.Polymer-polymer/carbon nanotube (CNT) composite fibres with a co-continuous morphology were developed, aiming at structural and functional applications. The objective was to produce fibres with electrical conductivity, provided by the incorporation of CNT, maintaining the mechanical properties at a level that allowed typical textile processing. If this goal is achieved, then the fibres may be incorporated into ...
Dispersion of carbon nanotubes in polyamide 6 for microinjection moulding
Ferreira, Tânia; Paiva, M. C.; Pontes, A. J.The focus of this study was to investigate the dispersion state of pure and functionalized carbon nanotubes in polyamide 6, on composites prepared by twin-screw extrusion and then processed by microinjection moulding. Nanocomposites were prepared with different carbonvnanotube compositions, with and without functionalization. The nanotubes were functionalized by the 1,3-dipolar cycloaddition reaction. The dispe...
Graphene nanoribbons from carbon nanotubes
Cunha, Eunice Paula Freitas; Paiva, M. C.; Proença, M. Fernanda R. P.; Melle-Franco, M.; Costa, Florinda; Fernandes, António J.; Torres, VítorChemical functionalization of the outer graphene layer of carbon nanotubes (CNT) has been increasingly studied, aiming at the application of CNT in different areas. The functionalization of CNT using the 1,3-dipolar cycloaddition reaction, leading to the formation of cyclic amine groups on the CNT surface [1], was observed to induce the unzipping of the CNT under specific conditions. The CNTs thus functionalize...
Formation of graphene nanoribbons in solution
Paiva, M. C.; Cunha, Eunice Paula Freitas; Proença, M. Fernanda R. P.; Araújo, Rui Filipe; Costa, Florinda; Fernandes, António J.; Ferro, Marta A.Recently, the formation of graphene by exfoliation of carbon nanotubes (CNT) has shown increasing interest. This process originates graphene nanoribbons (GNR) that are expected to present excellent electrical properties, depending on their width and on their edge shape [1]. Several methods for the unzipping of graphene from CNT were proposed along the past few years [2-6]. These methods often present some limit...
Functionalization of CNTS with maleic anhydride
Araújo, Rui Filipe; Paiva, M. C.; Proença, M. Fernanda R. P.; Silva, C. J. R.The outstanding properties of carbon nanotubes (CNTs) [1] are mainly related with their unique structural features. However, the high π-π staking between the tubes is a major drawback for their manipulation and interaction with other materials. Chemical functionalization has been used as a convenient tool to improve their performance in various applications [2]. The work reports the functionalization of multi-...
Characterization of microinjection moulded composites of polyamide 6 and carbon...
Ferreira, Tânia; Lopes, P. E.; Pontes, A. J.; Paiva, M. C.Microinjection molding is a powerful technology in micro-manufacture, providing millimeter scale parts at large scale production rate. In order to produce homogeneous composite parts, good dispersion of the nanoreinforcement in the polymer matrix is required. In the present work the carbon nanotube (CNT) reinforcement was dispersed in polyamide 6 (PA6) using a mini twin-screw extruder. Nanocomposites were prepa...
Dispersion of carbon nanotubes in poly(lactic acid)
Covas, J. A.; Novais, R. M.; Paiva, M. C.Carbon nanotubes (CNT) grow as entangled bundles that are difficult to disperse in polymer matrices, or even in solvents. However, their dispersion level in the polymer matrix strongly affects the final nanocomposite properties1. Previous studies have shown that filler dispersion can be assisted by the functionalization of the CNTs2. In the present work, CNTs were chemically functionalized to bond pyrrolidine g...
Graphene nanoribbons from carbon nanotubes
Paiva, M. C.Apresentação efectuada nas Jornadas do Centro de Física "Graphene and other bi-dimensional materials".
A comparative study of the dispersion of carbon nanofibres in polymer melts
Covas, J. A.; Novais, R. M.; Paiva, M. C.The dispersion of carbon nanofibres (CNF) in a polymer matrix using two melt mixing methods is studied. Distributive and dispersive mixing were evaluated by optical and electron microscopy. The CNF were chemically modified to improve the interface with the matrix. The results showed that the two methods produced good distribution of the filler, but extensional stresses induced higher dispersion. The latter corr...
Production of graphene in solution by unzipping of carbon nanotubes
Cunha, E. M.; Oliveira, Elisabete; Paiva, M. C.; Costa, Florinda; Fernandes, António J.Chemical modification of the outer graphene layer of carbon nanotubes is an approach increasingly used, mainly to overcome the problem of interfacial bonding with different materials. The effect of functionalization of CNT under different conditions, using the 1,3-dipolar cycloaddition reaction [1], was studied by Scanning Tunneling Microscopy (STM). STM demonstrated the potential for unzipping of the outer gra...
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