The Research On Functionalization And Epoxy Composite Of Multi-walled Carbon Nanotubes

As a new type of one-dimension function material, carbon nanotubes (CNTs) have a lot of potential applications in the future Hi-Tech field due to their excellent mechanical, electronic and other properties. However, ascribed to chemical inertia, CNTs'poor dispersion in the polymer matrix has become the impediment during developing their applications. In view of this, the functionalization to CNTs has become an effective way to improve their dispersibility in the polymer matrix and interfacial interaction between nanotubes and polymer, which is research focus in recent years. In this paper, multi-walled carbon nanotubes (MWCNTs) were oxidated by an acidic solution (H2SO4/HNO3, 3:1), then functionalization was carried out to MWCNTs to improve their chemical activity and dispersibility by using free radical from peroxysuccinic acid. On the basis of this, functionalized MWCNTs were used to modify epoxy resin (EP) and then the mechanical, thermal and electronic properties of modified composites were investigated.Firstly, functionalization was carried out to MWCNTs by using carboxylic free radical from thermal decomposition of peroxysuccinic acid via the approach of free radical addition reaction. The resulted product was characterized by FT-IR,XPS and Raman spectroscopy and the dispersibility of MWCNTs in organic solvent (ethanol) and the dispersion stability of MWCNTs suspension (solvent: H2O) were surveyed. The results show that a certain amount of carboxyl and acylamide groups have been introduced on to the surface of MWCNTs and the process of functionalization do not destroy the structure of MWCNTs. TEM results show that the degree of MWCNT twining is reduced after functionalization. Moreover, the active functional groups grafted on the surface of MWCNTs help to improve their dispersibility in organic solvent (ethanol). The dispersion stability of MWCNTs suspension analysis indicate that functionalized MWCNTs have the highest dispersion stability under the same circumstances compared to unfunctionalized MWCNTs.Secondly, MWCNTs/EP composites were made by solution blending and then the effects of MWCNTs before and after functionalization, different amounts of MWCNTs on the mechanical, thermal and electronic properties of the composites were surveyed. Furthermore, the dispersion of functionalized MWCNTs and unfunctionalized MWCNTs in EP was investigated. The results show the adding of MWCNTs, especially the functionalized MWCNTs, help to improve the mechanical, conductive properties and heat stability of the composites. SEM results show the funtionalized MWCNTs disperse evenly in EP matrix.