Reinforcing effect of magnetically aligned multi walled carbon nanotube on epoxy-based composites

Multi walled carbon nanotubes decorated with ferriferrous oxide nanoparticle (MWCNTs-Fe3O4) complex was used as an effective reinforcement in the polymer composites. The MWCNTs-Fe3O4 with various grafting contents of Fe3O4 nanoparticles were successfully prepared by combining in situ atom transfer radical polymerization (ATRP) and coprecipitation process, which was characterized with Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). The MWCNTs-Fe3O4 complex showed the strong magnetic response behavior, which could be easily aligned in an external magnetic field. The alignment state of MWCNTs-Fe3O4 complex could be modulated by adjusting the intensity of external magnetic field, grafting content of Fe3O4 nanoparticles and viscosity of the solvent. Moreover, with the addition of MWCNTs-Fe3O4, tensile strength and modulus of epoxy composites were enhanced by 12.3 and 10.9 %, respectively, which was due to the reinforcing effect of the aligned MWCNTs-Fe3O4 within magnetic field. Furthermore, on the basis of the above investigation, a kind of fluorescent molecular, fluorescein isothiocyanate (FITC), was introduced into the MWCNTs-Fe3O4 to obtain the novel nanotubes with fluorescent imaging performance (F&M-MWCNTs). The F&M-MWCNTs showed excellent fluorescence and strong magnetic response behavior, which could be easily aligned in matrixes under an external magnetic field. The fluorescence intensity of F&M-MWCNTs could be modulated by adjusting the labeling content of FITC. The unique electromagnetic and fluorescent properties of F&M-MWCNTs made them excellent candidates and as reinforcement of composites or as tracer in various application fields.