Graphene Oxide Modified Carbon Fiber/Epoxy Resin Composites

Carbon fiber(CF)reinforced resin matrix composites have many advantages,including light weight,specific strength,high modulus and so on.It has been widely used in the fields of aeronautics and astronautics,upmarket sports equipment and other fields.However,the modification of carbon fiber reinforced resin matrix composites has never ceased with the continuous improvement of material performance requirements in different application situations.Graphene oxide(GO)is an oxide of graphene,not only with excellent mechanical and thermal properties,but also with hydroxyl group,carbonyl group,epoxy group and other oxygen-containing active groups,which make GO has a good compatibility with the organic resin matrix and has great potential in the modification of resin based composites.In this paper,GO was used to modify the carbon fiber/epoxy(CF/EP)matrix composites.(1)The GO/CF/EP hybrid composites were prepared.(2)Making use of GO and carbon nanotube(CNT)to prepare the 2D-films,and then prepared the GO/CNT/CF/EP interlayer modified composites by the method of inter-layer toughening.(3)With the good compatibility between GO and CF,EP,a preliminary study was made on the modification of high-performance T800 type and M40J type carbon fiber reinforced epoxy resin composites.Using wet prepreg technology and molding process,graphene oxide modified CCF300 carbon fiber/epoxy resin(CF/E54-DDS)hybrid composites were prepared,and the modification mechanism of GO to the composites was studied by thermal analysis,IR analysis and microscopic morphology.The compression strength(CAI)test after impact was used,combined with the ultrasonic C-scan method and damage/destruction characteristics to study the effect of GO on the impact resistance of CCF300 carbon fiber/epoxy resin composites.The results showed that the lower content of GO was beneficial to the cross-linking density of the resin system,and the glass transition temperature(Tg)of the composites increased.But the high content of GO maked the ratio of the curing agent DDS in the solidified network structure decrease greatly,it damaged the heat resistance of the composite instead.Adding 0.2 wt%of GO could increase the Tg of CF/E54-DDS from 196.3? to 201.5?.The maximum thermal decomposition temperature and residual char rate of GO/E54-DDS were both increased when the GO content was low,and decreased with the increase of the GO content.The CAI test and ultrasonic C-scan of GO/CF/E54-DDS hybrid composites show that addition of GO could inhibit the delamination and reduce the pits depth and damage area of CF/EP composites.The CAI of 0.2 wt%GO/CF/EP increased from 168 MPa of pure CF/EP to 180 MPa.By the micro-morphology,GO maked the CF/EP interface have a significant change.The graphite oxide/carbon nanotubes(GO/CNT)film interlayer toughened CF/EP composites were fabricated via molding process in this chapter.Model I interlaminar fracture toughness GIc of laminates and model II interlaminar fracture toughness GHc of laminates are used to characterize the fracture toughness of the laminates.Furthermore,the interlaminar toughening mechanism of GO/CNT film on composites was discussed through microstructure of the fracture surface combining mechanical properties.The results show that the GO/CNT films prepared by the 30 wt%content of graphene oxide and the carbon nanotubes,which with hydroxyl group and the tube diameter of 30-50 nm,had better film forming process and wettability.Though GO/CNT films had no obvious enhancement effect on the open-type model I interlaminar fracture toughness GIC of CF/EP composites,but has a better effect on the slip-type model II interlaminar fracture toughness GIc of CF/EP composites.The GHc of GO/CNT/CF/E54-DDS increased from 1855 J/m2 of CF/E54-DDS to 2720 J/m2,which increased by about 47%.The interpenetrating structure formed between the layers of the GO/CNT film and the resin suppresses the propagation of micro cracks between the layers.Three kinds of carbon fibers were chosen,including the Dongli medium model carbon fiber T700,the domestic high strength medium model carbon fiber CCF800,the domestic high strength high model carbon fiber CCM40J,and using GO to modify the three kinds of carbon fiber epoxy resin matrix composites.The modification effects of GO on these three kinds of carbon fiber/epoxy composites were studied by combining micro-topography and dynamic thermo-mechanical analysis.The results show that the addition of GO makes the interfacial properties of the three GO/CF/EP composites change significantly compared with the CF/EP,and the destruction of CF/EP composites mainly occurs on the surface of carbon fibers,while the damage of GO/CF/EP composites mainly occurs in the interlayer GO/EP region of the composites.With the addition of 0.2 wt%GO,the Tg of Dongli T700.domestic CCF800 and domestic CCM40J theses three kinds of carbon fiber epoxy resin matrix composites have different degrees of improvement,and the improvement of the high model of domestic CCM40J is the most obvious.