GRAPHENE MICROSPHERES IN FORM OF PAPER LUMP, COMPOSITE MATERIAL OF SUCH MICROSPHERES AND METHOD OF MAKING SUCH MICROSPHERES

摘要

FIELD: technological processes.;SUBSTANCE: invention relates to production of graphene microspheres in the form of paper lumps, as well as composite materials from such microspheres for making reinforced ceramics, composite plastics and coatings. Proposed graphene microsphere in the form of lump of paper consists of single-layer graphene sheet and having diameter of 500 nm - 5 microns, density of 0.2–0.4 g/cm³, the ratio of carbon/oxygen of 20–60 and a surface area less than 200 m²/g. Such graphene microspheres in the form of paper lumps are obtained by chemical reduction of graphene oxide microspheres in order to slowly remove oxygen-containing functional groups from graphene oxide surface to prevent volumetric expansion caused by fast removal of groups, which enables to maintain strong bond between graphene sheets without separation; as well as by removing remaining small amount of oxygen-containing functional groups and recovering defect structures in graphene oxide sheets by high-temperature treatment, as a result of which the graphene structure becomes ideal at ultrahigh temperatures (from 2500 to 3000 °C), which further improves adhesion between graphene sheets in microsphere and compacts structure.;EFFECT: obtained graphene microspheres in the form of paper lumps have good mechanical properties and elasticity, can effectively damp impact load, have high stability and density.;18 cl, 7 tbl, 95 ex, 5 dwg