To study the mechanical performance of delamination and aggregation of graphite by mechanical delamination method for preparing graphene,taking ultrafine natural graphite powders as materials,graphene dispersion was prepared in surfactant-free de-ionized water by mechanical delamination method with high shear efficiency,in which there were graphite sheets with volume fraction of 18.5% and layers less than 5. The delaminated graphite sheets were characterized by AFM,SEM,and particle size analyzer to get the ...