Synergistic improvement of epoxy composites with multi-walled carbon nanotubes and hyperbranched polymers

摘要

This paper presented the preparation of composites that consist of multi-walled carbon nanotubes (MWCNTs), hyperbranched polymers (HBPs), epoxy resins (EP) and curing agent. The influences of HBPs and MWCNTs content on the curing process of epoxy systems and mechanical performances of MWCNTs/HBPs/EP composites were discussed. Results from differential scanning calorimeter (DSC), tensile, impact and toughness tests are provided. The tensile and impact fracture surface were observed by field-emission scanning electron microscopy. The addition of HBPs resulted in accelerating the curing process of epoxy systems. MWCNTs/HBPs/EP composites were capable of increasing tensile strength by up to 38%, giving a tensile modulus of 25%, impact strength of 68%, fracture toughness of 66%, and a glass transition temperature (T-g) of 46% in comparison with unmodified epoxy thermosets. Field emission-scanning electron micrographs showed that these increases were associated with a synergistic effect of plastic deformation mechanism and crack pinning mechanism, which were induced by the present of HBPs and MWCNTs, respectively.