Preparation And Characterization Of Graphene Oxide-polyacrylonitrile Composite Fibers

Graphene is a crystal of a honeycomb lattice structure composed of carbon atoms sp~2hybridized,and has only one atomic thickness,high strength,good modulus,nice thermal stability and excellent UV resistance.However,the dispersibility in the solvent is poor.Compared with graphene,Graphene oxide(GO)has better hydrophilicity than graphene,and has better dispersion stability in most polar organic solvents.The compounding of macromolecules and nanofillers usually used to improve the performance of traditional polymer materials.Nano-fillers can be zero-dimensional,one-dimensional,and two-dimensional nanomaterials.Because two-dimensional nano-fillers can achieve surface contact with macromolecules and high interfacial bonding force,they are very suitable for preparing high-performance composite materials.Due to its two-dimensional nanosheet structure,high strength,and versatility,GO is widely used as a nanofiller for polymer composites.By adding GO,the mechanical properties of polymer materials can be enhanced,and can be prepared multifunctionality polymer composites.Polyacrylonitrile(PAN)fibers are fibers made by spinning PAN polymers,which are soft and comfortable,but their strength limits their wide range of applications.With the idea of using complex composites to produce synthetically superior high-performance composites,this paper can effectively improve the tensile strength of PAN fibers by adding GO and polyvinyl alcohol(PVA)during polyacrylonitrile spinning,and at the same time give PAN composite fibers excellent thermal stability,UV resistance and other properties.In the research work of this paper,the preparation of graphene oxide by modified Hummers method.The spinning dope of GO/PAN,PVA/PAN,GO/PVA/PAN was obtained by the solution method.GO/PAN nanocomposite fibers were prepared by dry-wet spinning.Through the characterization of the composite fibers,the results show that there are hydrogen bonding interactions between GO sheet and PAN matrix.The addition of GO can improve the tensile strength,UV resistance,thermal stability,and crystallinity of the composite fibers.The tensile strength of GO/PAN fibers was the highest when adding 5 wt.%GO,which was 38.05%higher than the pure sample.When the addition of GO exceeds 5 wt.%,GO agglomerates and stacks in the PAN molecular chain,and result in decreasing of the tensile strength.The preparation of PVA/PAN,GO/PVA/PAN composite fibers by gel spinning.the results of the study show that PVA molecular chains are embedded into the PAN molecular chain,which significantly improves the tensile strength of the composite fiber.However,when the PVA addition amount exceeds the zero point of interpenetrating,the PVA/PAN system has an uneven density distribution,the tensile strength of the fiber decrease.and the introduction of PVA molecular chains reduces the UV resistance and thermal stability of the composite fibers.For GO/PVA/PAN composite fibers,GO is dispersed monolithically in PVA/PAN matrix.The interaction between GO and matrix not only improves the tensile strength of the fiber,but also enhances the UV resistance and thermal stability.When the amount of GO is 0.3 wt.%,The crystallinity of the GO/PVA/PAN composite fiber reaches the maximum and the tensile strength is the highest.