The Research On Surface Modification And Epoxy Nanocomposites Of Multi-walled Carbon Nanotubes

Multi-walled carbon nanotubes （MWCNTs） exhibit excellent performances due to their unique structures, which can be considered as an ideal reinforcement additive for advanced composites. However, unfunctionalized MWCNTs are chemical inertia and exhibit weak interfacial interactions with resin matrix, which become most serious impediments during developing its researches and applications. The functionalization of MWCNTs is an effective method to solve those problems, which has attracted more and more attentions in recent years. In this paper, MWCNTs were oxidated by acidic solution firstly, then treated by silane coupling agents in order to improve their chemical activity and solubility. Subsequently, the functionalized MWCNTs based on silanization reaction were added into Epoxy resin （Ep） using as the reinforcement. Finally, MWCNTs/Epoxy resin composites with different MWCNTs contents were prepared by solution blend. The mechanical, thermal and electronic properties of modified composites were investigated.Firstly, MWCNTs were functionalized using three kinds of oxidation system （H₂SO₄/H2O2, H₂SO₄/K2Cr2O7, H₂SO₄/HNO3）, respectively. Then, the best oxidation samples were treated by silane coupling agents. The functionalized samples were characterized by Fourier Transform Infrared spectroscopy （FT-IR）, Raman spectroscopy, thermogravimetry analysis （TGA）, Zeta potential measurement analyzer, Field emission scanning electron microscopy （FESEM）, Energy dispersive spectroscopy （EDS） and Transmission electron microscopy （TEM）. The research results indicate that the silane molecules are covalent attachment on the surface of MWCNTs, and the tubular structures of MWCNTs are not distinctly destroyed. Both functionalized samples and oxidized samples are dispersed in deionized water uniformly and stably.Secondly, nanocomposites based on Epoxy resin （AG80） and different weight percentages of silanized MWCNTs were prepared by solution blend. The effects of MWCNTs content on the mechanical, thermal and electronic properties of modified composites were studied. The research results show that the dispersion and interfacial adhesion of functionalized MWCNTs in AG80 Epoxy matrix are obviously improved, and the composites with good thermal stability exhibit better mechanical and electronic properties compared with pristine MWCNTs. When the MWCNTs content is 0.75 wt%, the MWCNTs/Epoxy resin composites exhibit the best mechanical property.