The Ball-milling Preparation?Functionalization Of Graphene/Chitin Nanofibers Hybrids And Their Application

Graphene has attracted tremendous attention in recent years due to its unique two-dimensional structure,large surface area and extraordinary mechanical,electrical and thermal properties.However,it's still a persistent challenge to realize its economical accessibility and easy processability.The aggregation and restacking of graphene sheets caused by the strong ?-? effects hinder its application as well.In the past decades,numerous studies found that liquid-phase exfoliation of graphite by sonication or high-speed shear mixing in different solvents is the most promising way to prepare high quality graphene in large quantities.To prohibit the irreversible reaggregation of graphene,stabilizers such as surfactants,organic salts and aromatic molecules are often required for liquid-phase exfoliation.Recently,hybridization of graphene with some nanoparticles provided a new way to avoid agglomeration of graphene sheets.Meanwhile,the latest studies also demonstrated that graphene-based hybrid nanobuilding blocks can broaden the application of graphene due to the synergetic effects resulting from the interaction between graphene and the nanoparticles decorated on it.We succeeded in on-step preparing stable graphene and chitin nanofibers hybrid nanomaterials.In addition,we added this hybrid nanomaterials into polyvinyl alcohol,remarkably improving the mechanical properties of poly(vinyl alcohol):(1)Through exploring on the effect of process conditions,such as time,speed ball mill,ball mill bead ratio and the dosage,on the result of ball milling for graphene,we determine the optimum process conditions of wet ball milling,which laid a foundation for follow-up study.(2)A green,simple and large-scale method to exfoliate graphite into waterdispersible graphene with the assistance of chitin nanofibers(Ch NFs)by ball milling and the concentration of graphene can reach up to 1.5 mg ml-1.Unexpectedly,the hybridization of exfoliated graphene and Ch NFs is realized simultaneously.And we used a series of characterization methods,such as the AFM,TEM,DLS,RAMAN,XRD and FI-IR,to prove that there is some interaction between graphene and chitin nanofibers and the successful hybridization of graphene and chitin nanofibers.(3)We also prepared the PVA/GECH nanocomposite films.The pronounced enhancing effect of the graphene/Ch NFs hybrids on the mechanical properties of PVA validated the synergistic effect of GECH hybrids on PVA..