Performance Characterization Of Epoxy Composites Reinforced With Magnetically Aligned MWCNTs And Research On Controllable Preparation Of Carbon Nanotube Films With Fluorescent Respsonsivenes

Due to unique one-dimensional structure, extraordinary mechanical and electromagnetic properties, carbon nanotubes are widely applied in various fields. However, carbon nanotubes have large aspect ratio and the van der Waals force between each other resluting in poor dispersion and poor interfacial bonding in matrix, especially in polymer matrix with disorderd arrangement, which makes it difficult to enhance the nanocomposites. By atom transfer radical method (ATRP), chemical co-precipitation method and fluorescence labeling method, carbon nanotubes were modified to be magnetic as MWCNTs-Fe3O4 in this paper, and different contents and alignment of carbon nanotubes reinforced nanocomposites were prepared. The influence of MWCNTs-Fe3O4 contents and orientation degree on nanocomposites mechanical and electrical properties was systematically studied. The alignment degree of MWCNTs-Fe3O4 was quantitatively analysised via matrix method. Using the vacuum filtration method, the aligned fluorescent and magnetic carbon nanotube films were prepared. The effects of concentration of F&M-MWCNTs suspension, the intensity of magnetic field and ultrasonication time on the orientation states of F&M-MWCNTs were studied and the details of film-forming mechanism and alignment of F&M-MWCNTs were analysised.MWCNTs-Fe3O4, prepared by ATRP method and chemical co-precipitation process, were used as the reinforcement of epoxy nanocomposites. By adding different content of MWCNTs-Fe3O4 (0.5 wt.%,1. Wt.%,1.5 wt.%,2.0 wt.%) into the eposy matrix with and without magnetic field to prepare nanocomposites samples, aligned and randomly arranged MWCNTs-Fe3O4/nanocomposites were obtained. Scanning electron microscope (SEM) and optical microscope (OM) were employed to characterize the orientation states of MWCNTs-Fe3O4 in resin matrix. The characterization through mechanical and electrical tests illustrated the orientation mechanism of MWCNTs-Fe3O4 in matrix and the reinforcing performance.Fluorescent labeling and magnetic modification was applied on MWCNTs-PGMA to obtain F&M-MWCNTs. By infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV-vis), fluorescence spectroscopy (FM), transmission electron microscope (TEM), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM), the structure performance and surface morphologies of F&M-MWCNTs were characterized. Aligned F&M-MWCNTs films were produced via a vacuum filtration process under application of an external magnetic field. By scanning electron microscope (SEM) and laser confocal scanning microscope (CLSM), the morphologies of films, orientation structures and fluorescence were characterized and analysised. The theoretical analysis on film-forming and orientation mechanism revealed that under the conditions of 1mg/ml suspension concentration,4 hours of ultrasonication and 45-50mT magnetic field, F&M-MWCNTs fimls with best alignment could be prepared under control.