Nanocompósitos de resina epóxi/nanotubos de carbono de paredes múltiplas: preparação, estudo da estrutura, propriedades físico-químicas e mecânicas

Abstract

The influence of chemical modification by acid treatment followed by thefunctionalization with triethylenetetramine (TETA) on the surface of multi-walled carbon nanotubes (MWNT) was studied qualitatively and quantitatively. Thermogravimetric analysis (TGA) showed that, in the case of amine-functionalized MWNT, 16% of mass loss could be attributed to the COTETA and residual oxygencontaining functional groups. X-ray photoelectron spectroscopy (XPS) was used to evaluate the aminated and oxygenated functions covalently linked to the MWNTsurface. The functionalization not caused significant changes in the data obtained from the Raman spectra. With the aid of a three roll mill, nanocomposites with 0.1, 0.5 and 1.0% in mass of oxidized MWNT (MWNT-COOH) and aminated MWNT (MWNTCOTETA) with 0 and 5% of reactive diluent were prepared. The glass transition temperature (Tg) was investigated and mechanical tests in the tensile strength, compression strength and impact strength were conducted to evaluate the influence of chemical modifications on the physicochemical and mechanical properties of the nanocomposites. A reproducible increase of approximately 20 ° C was obtained for the nanocomposite with 0.5 wt% MWNT-COTETA and gains between 17 and 358% in impact strength were obtained for nanocomposites containing low concentrations of MWNT, MWNT-COOH and MWNT-COTETA. The images of transmission electron microscopy (TEM), optical microscopy (OM) and scanning electron microscopy (SEM) showed that the process used in the dispersion of the tubes reduces the size of aggregate, that the fracture surfaces roughness and the density of tubes in the aggregatesgrow with the increase in the wt% of MWNT.