Fabrication And Property Study On Graphene/Cellulose Nanocomposite Material Based On Naoh/Urea System

With the concept of environmental,sustainable development enjoying supports of people,a wide range of research about natural cellulose processing and application is studied.In recent years,the discovery of sodium hydroxide/urea dissolution system has provided more possibilities for the development of various cellulosic materials.However,the imbalance of mechanical properties and limited functionality,to a certain extent,hindered the further development and application of regenerated cellulose materials.Therefore,this paper is forced on the preparation of high-performance regenerated cellulose film and graphene/cellulose composite films based on sodium hydroxide/urea system and characterization of its structure,exploring the relationship between structure and performance,the detailed works are as follows:The first part is that a green and environmental method was proposed to prepare graphene oxide/cellulose nanocomposite films with superior mechanical performances and excellent ultraviolet-shielding properties.Unexpectedly,it is found that more uniform dispersion of graphene oxide(GO)in cellulose/NaOH/urea aqueous solution could be realized by mixing them at low temperature rather than room temperature.Epichlorohydrin(ECH)was introduced as cross-linking agent to enhance the performance of GO/cellulose nanocomposite films.With the synergistic effect of chemical crosslinking and the strong hydrogen bonding interaction between GO and the cellulose matrix,the tensile strength,elongation at break and fracture energy of thus prepared composite film with 0.5 wt% GO loading were significantly improved by 78%,172% and 397%,respectively,compared with the pure cellulose film.Moreover,it is found that the crosslinked GO/cellulose composite film also possessed excellent ultraviolet-shielding properties.The cellulose based composite material has great potential for use as highperformance bioplastic film.In the second part,the graphene was exfoliated by simple and low-cost ball milling and surfactant and the graphene/cellulose composite film was prepared based on sodium hydroxide/urea solvent system.The structure of as-prepared graphene is complete,low-layer,and it can be stably dispersed in the aqueous solution in high concentration.Compared with pure cellulose film,the as-prepared graphene/cellulose composite film has high mechanical properties,thermal stability and conductivity.And the addition of a small amount of ionic liquid can greatly reduce the resistivity of the graphene / cellulose composite membrane and increase its conductivity.The third part of the work is mainly about the plasticization and stretching of the prepared cellulose hydrogel film based on sodium hydroxide/urea system,and finally producing high-orientation,porous cellulose film.The whole process is simple,economical and no addition of toxic substances,and as-prepared high-orientation cellulose film has excellent mechanical properties.The porous structure of the cellulose membrane surface makes it possible to be applied in the battery separator materials and filter materials.