Preparation of amine-modified multiwalled carbon nanotubes and their use in composites

Multiwalled carbon nanotubes(MWCNTs) were modified by a graft reaction of diamines with different chain lengths,such as ethylenediamine(EDA),hexamethylene diamine(HMDA) and decamethylene diamine(DMDA).FTIR,Raman spectroscopy,XPS and TEM were used to characterize their chemical structure.XPS indicated that the molar content of N on the surface of MWCNTs-EDA,MWCNTs-HMDA and MWCNTs-DMDA reached 3.52%,4.18% and 2.88% respectively under the same reaction conditions.The dispersion of MWCNTs in organic solvents before and after the modification was measured semi-quantitatively using UV-Vis spectra and a Turbiscan analyzer.It was found that the amino-modified MWCNTs improved their dispersion in polar solvents and MWCNTs-HMDA had the best dispersion stability.MWCNTs-HMDA were introduced into a traditional carbon fiber reinforced epoxy system to prepare three phase composites which showed remarkably improved flexural and impact strengths.