Fabrication And Functionalization Of Vapor Grown Carbon Nanoifber/epoxy Resin Composites

Vapor grown carbon nanofibers (VGCNFs), with excellent performance, were used as fillerto improve the thermal stability and mechanical properties of epoxy resin (EP) matrix, and theVGCNF/EP composites with special function could be obtained via compound technology. Inthis paper, the VGCNF/EP composites which possess good mechanical properties, shapememory and magnetic properties were prepared by using surface functionalized VGCNFs asreinforcing materials. It can be provide the reference for the optimize performance of EPcomposites and broaden the range of applications.The agglomeration state of VGCNFs in EP and the poor interfacial adhesion between theVGCNFs and EP greatly affect the properties of VGCNF/EP composites, as raw-VGCNFs are aninherently inert material and easy to agglomerate and entangle. Therefore, with the aim ofimproving dispersion of VGCNFs and mechanical properties of VGCNF/EP composites, surfaceoxidation of VGCNFs was respectively performed with H2O2/HNO3. The microstructure,mechanical properties of the composites and the dispersion of VGCNFs in polymer matrix werecharacterized by Fourier transform infrared spectroscopy (FTIR), field emission scanningelectronic microscopy (FE-SEM). The results show that the containing oxygen functional groupsare grafted on the surface of VGCNFs after oxidation treatment.In order to give VGCNF/EP composites superior mechanical properties and versatility, firstlyCo3O4modifying VGCNFs was successfully achieved via Chemical-thermal treatment process.The composition and phase structure of Co3O4-VGCNFs hybrid materials were characterized byFT-IR and X-ray diffraction (XRD). The morphology of Co3O4was investigated using FE-SEM.It is found that the presence of Co3O4nanoparticles, and which are firmly immobilized onVGCNFs sidewalls. Secondly, Co3O4-VGCNFs hybrid nanofillers and oxidized-VGCNFs wererespectively compounded with epoxy resin to fabricate the oxidized-VGCNF/EP composites andCo3O4-VGCNF/EP composites. The dispersion of nanofiller in the epoxy resin, tensile strength,thermal stability, magnetic properties and the shape memory properties of composites weresystematically and explicitly investigated. The results indicate that the Co3O4-VGCNF/EPcomposites have excellent performances, and the mechanical properties of composites are validly improved by VGCNFs. Compared with raw-VGCNF/EP composites, the tensile strengthof Co3O4-VGCNF/EP and oxidized-VGCNF/EP are raised by44.6%and20.7%respectively,when the mass fraction of VGCNFs is0.5wt%. In addition, a dynamic mechanical analysis(DMA) shows that the storage modulus and tan delta of oxidized-VGCNF/EP and Co3O4VGCNF/EP composites increase as compared to raw-VGCNFs. Meanwhile, the thermal stabilityof oxidized-VGCNF/EP and Co3O4-VGCNF/EP has improved.The functional studies on the composites show that, the oxidized-VGCNF/EP composites andCo3O4-VGCNF/EP composites exhibit excellent shape memory performance. Magnetizationmeasurements reveal that Co3O4-VGCNF/EP composites exhibit ferromagnetic behavior, and thesaturation magnetization (Ms) and coercivity (Hc) of the composites with2wt%ofCo3O4-VGCNF is0.0429emu g-1and0.75kOe respectively. In summary, the modified VGCNFsreinforced epoxy resin composites not only exhibit the excellent thermal and mechanicalproperties, but also the versatility.