A Novel Route for the Amidation of Carbon Nanotubes and their Use as Rein-forcement in Epoxy Matrix Composites

One of the most frequent questions in the manufacture of composites with carbon nanotubes (CNT) is the interfacial interaction between the CNT and the matrix. In order to improve this interaction, multi-wall carbon nanotubes (MWCNT), after prior oxidation, were functionalized with amine groups by a novel route for CNT, using hexabromoacetone (HBA). MWCNT were characterized, before and after functionalization procedures, by elemental analysis, high resolution electron scanning microscopy (FEG) and TGA. Epoxy (DGEBA) matrix composites were manufactured with pristine, oxidized and amino-MWCNT, in concentrations of MWCNT ranging from 0.042 to 0.083 wt%. The composites were characterized by mechanical tests in flexural mode, differential scanning calorimetry (DSC) and thermogravimetry (TGA). Elemental analyses confirmed the increases in the contents of oxygen, after the oxidation procedure, and nitrogen, after amination using HBA, proving the efficiency of both methods for the functionalization of MWCNT. Flexural tests show there were no changes in moduli and maximum flexural strength for the composites with functionalized MWCNT when compared to the pure resin. The glass transition temperature (Tg) of composites with 0.1 wt% of aminated- MWCNT increased 18°C when compared with the Tg of the neat resin.