Study On The Functionalization Of CNTs Via Plasma-Activiated Grafting And The CNTs/Epoxy Composites

Highly functionalized carbon nanotubes (CNTs) with good dispersion, good interface compatibility and high interface bonding strength were prepared in a simple, economical and environment-friendly way.Argon plasma treated CNTs were exposed in the air to form peroxides and hydroperoxides on the surface. Through thermal initiation, these peroxides and hydroperoxides reacted with maleic anhydride (MA) to functionalize CNTs. The functionalized CNTs were further modified with amino groups. The as-obtained functionalized CNTs then reacted with epoxy matrix to prepare the CNTs/Epoxy composites. The effect of the plasma discharge parameters (discharge time, plasma power, working pressure, plasma time etc.) on the content of the peroxides and hydroperoxides on the surface of CNTs was investigated, as well as the effect of thermal initiation temperature and time on the grafting ratio. In addition, thermal and mechanical properties of the CNT/Epoxy composites were evaluated in correlation to the content of CNTs. Structure, composition and morphology of the related products were characterized by Energy spectrometers (EDS), Scanning electron microscopy (SEM) , Transmission electron microscopy (TEM), X-ray photoelectron spectrometers (XPS), Thermogravimetric anylyzer (TGA)and Infrared spectrometer (IR). Dynamic mechanics analyses (DMA) and mechanical testing results show that the functionalized CNTs can significantly improve the mechanical strength and heat resistance of the epoxy matrix.The technique of sublimation plasma polymerization of MA was also developed. The effect of the plasma discharge parameters on the anhydride group reservation and the thickness of the film were studied. The optimal plasma discharge parameters were selected to functionalize CNTs. SEM,XPS, IR, TGA and other methods all verified CNTs were highly functionalized, thus improve the CNTs'dispersion in the epoxy matrix.