Abstract: By the reaction of epoxy ring and the amino group on the surface of amine functionalized multiwalled carbon nanotube (MWCNTs-NH₂),monofunctional epoxy compound benzyl ether (EP 692) and twelve-fourteen alkyl ether (EPAGE) were grafted onto the surface of MWCNTs using ball milling techndogy,known as sizing treatment.As a result,the MWCNTs-692 and MWCNTs-AGE with different molecular structure of sizing were prepared.On this basis,1wt% of MWCNTs-NH₂,MWCNTs-692 and MWCNTs-AGE were added into diaminodiphenylmethane (DDM) cured bisphenol a diglycidyl ether (DGEBA) system,respectively,and the effects of these MWCNTs on the viscosity-temperature relationships,cure kinetics,thermal-mechanical and flexural properties of the resulting epoxy composites were investigated.The results of FT-IR,TGA and XPS show that EP 692 and EP AGE can be successfully grafted onto the surface of MWCNTs via covalent bond.Comparing with MWCNTs-NH₂,MWCNTs-AGE and MWCNTs-692 can effectively improve the dispersion states and compatibility of MWCNTs in epoxy resin,reduce the influence of nanoparticles on the viscosity and curing kinetics of epoxy resin.Moreover,these MWCNTs can improve the storage modulus and flexural properties of epoxy resin,especially for the MWCNTs-692 reinforced ones due to the existence of rigid functional groups.Comparing with the neat epoxy,the storage modulusof MWCNTs-692/epoxy composite increases by 30.6% after being added 1wt% MWCNTs-692,and the flexural strength and modulus of epoxy resin exhibit enhancement of 18.8% and 22.5%,respectively.