Fabrication Of Graphene/Carbon Nanotubes Nanohybrids And Performances Of Their Composites

Carbon nanomaterials and their composites have outstanding mechanical,thermal,electrical and optical properties,which leads to great potential applications in many fields.Graphene（G）and carbon nanotubes（CNTs）have received significant attention in recent years.However,the stacking of G sheets and the aggregation of CNTs are the main factors which result in inferior properties of the nanomaterials and their composites.Nevertheless,assembling two-dimensional G sheets and one-dimensional CNTs into three-dimensional G/CNTs nanohybrids has overcome the mentioned-above defects.CNTs adsorbed onto the surface of G sheets serve as the spacer that effectively avoids the aggregation of the G sheets.Meanwhile,the synergic effects of G and CNTs could endow the co-organized nanohybrids and their composites with excellent properties.In this paper,the in-situ reduction method is used to prepare reduced graphene oxide（RGO）/CNTs nanohybrids with the FeSO₄ or2-ethyl-4-methyl imidazole（2,4-EMI）as reducing agents,respectively.Then numerous characterization and measurement are performed to evaluate their structure and properties.Subsequently,the RGO/CNTs composites are fabricated by solution mixing method and vacuum-assisted impregnation method.The RGO/CNTs nanohybrids reduced by 2.4-EMI are selected as the reinforcement,while the styrene and epoxy resin（EP）are selected as matrix resins,respectively.Electrical,thermal and mechanical properties of the resulting composites are measured.The results show that a three dimensional carbon nanohybrids with certain amphiphilicity and hierarchically porous structure are constructed by RGO and CNTs.The composites fabricated by vacuum-assisted impregnation method own more excellent properties.Compared with RGO/CNTs/polystyrene（PS）composites,RGO/CNTs/EP composites demonstrate higher electrical,thermal and mechanical performance,which make them promising candidate for a wide range of application.In addition,compared with neat EP,the electrical conductivity,thermal conductivity,flexural strength and compressive strength of RGO/CNTs/EP composites are enhanced by 11 orders of magnitude,2.2 times,18% and 37%,respectively.