| Carbon nanotubes (CNTs) have attracted increasing attentions because oftheir outstanding electronic, mechanical, chemical properties and significantpotential applications in nanoscience and nanotechnology. Similarly with othernanoparticles such as carbon black, clay and silica, CNTs can improve bothmechanical and functional properties of resin matrix. While the processing andapplication of CNTs are always limited to the aggregation, the poor dispersion,the disturbance of the arrangements in matrix. Hence how to achieve highlyordered alignment of CNTs has been a hot field of nanocomposite research.To achieve the alignment of CNTs in polymer composites, the surface ofCNTs was modified with Fe3O4nanoparticles, so that the magnetic CNTs(m-CNTs) were prepared. Then, the m-CNTs are introduced into EP resin andaligned under a low magnetic field to achieve highly orientation.Finally themechanical properties of m-CNTs/EP nanocomposites were measured. Theexperiment results showed that the m-CNTs could be aligned in the EP resin by alow magnetic field and improved the mechanical properties of nanocompositessignificantly.1.In this paper, we propose a mild, effective method for preparing m-CNTsby a novel water-in-oil (W/O) emulsion technique. The CNTs and Fe3O4nanoparticles were self-assembly in castor oil without heating at hightemperatures or the protection of inert gas compared to the traditional methods.2.The size and coverage of magnetite nanoparticles are both effectivelycontrolled along the surface of CNTs. Both the structure and the magneticproperties of m-CNTs with various C-Fe atomic ratios were compared. Finallythe m-CNTs with C-Fe atomic ratio5:1was selected as a candidate to beintroduced into epoxy resin. The average size of Fe3O4nanoparticles was20-30nm diameter.3.The size and direction are key factors in the arrangement of m-CNTs.Based on the magnetic properties of the m-CNTs gain from the experiment, thelow magnetic field used here are theoretically calculated and designed, which isabout100mT.4.In order to improve the dispersibility of m-MWCNTs in EP resin,m-MWCNTs were modified with the surfactant polyvinylpyrrolidone (PVP).Then, the m-MWCNTs were introduced into EP resin and aligned under a lowmagnetic field to achieve highly orientation. The experiment results showed thatthe m-MWCNTs could be aligned in the EP resin by a low magnetic field and improved the mechanical properties of nanocomposites significantly. The tensileand flexural strength of the ordered nanocomposites were improved by15.36%and82.88%than epoxy resin which was much higher than those randomarrangement ones. |
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