Graphenization of anthracite and nanocomposite with nature rubber through microwave irradiation-solid state mechanochemistry strategy

The anthracite and Lewis acid catalyst CuCl₂ were mixed evenly and placed under the alternating action of microwave field and solid state shear field for solid state reaction. The microwave field made the internal temperature of the coal reach the reaction temperature of the coal-based graphenization and the Lewis acid catalyst made the alkyl removal reaction of the coal molecules under high temperature environment. Direct graphenization of the Taixi anthracite was achieved by strong shear force field and repeated pulverizing and exfoliating provided by the solid state mechanochemical reactor, and then the nanocomposites of coal-based graphene (CB–GE) and natural rubber (NR) were realized in solid state shear milling, and the CB–GE/NR nanocomposites were successfully prepared. The structure and properties of the nanocomposites were characterized by proximate analysis, elemental analysis, scanning electron microscopy, transission electron microscopy, X-ray diffractometer, Raman spectroscopy and atomic force microscopy. The results show that under the combined action of copper chloride catalysis, solid state shear milling and microwave irradiation, the grinding, stripping, deoxidation, dehydrocarb, dehydrogenation and aromatic condensed rings of the Taixi anthracite can be realized and then developed to the direction of graphenization. Finally, the "coal base graphene (CB–GE)" with 2D morphology of 3.5 nm thickness can be obtained. When the mass fraction of CB–GE is 20%, the tensile strength, elongation at break and electrical conductivity of the CB–GE/NR nanocomposites respectively reach 22.36 MPa, 278.8% and 9.8×10⁻⁴ S/cm. Compared with the natural rubber material, they are increased by 314.1%, 40.52% and 9 orders of magnitude, respectively. When the mass fraction of CB–GE is 4%, the antistatic requirements can be reached. The results show that the prepared CB–GE can enhance the natural rubber and carry out electrostatic functionalization. There is almost no waste generated in the process of graphenization of anthracite by copper chloride catalyzation-solid state shear force-microwave field, which can improve the economy of preparing coal-based graphene composites. At the same time, the solid-state mechanochemical compounding technology can realize nano dispersion and direct composite of graphenized anthracite in different polymer matrix materials, and can obtain oriented CB–GE/polymer nanocomposites.