▎ 摘　　要

NOVELTY - Producing unitary graphene material, comprises: preparing a graphene oxide gel having graphene oxide molecules containing an oxygen content higher than 20 wt.%, dissolved in a fluid medium; dispensing and depositing a layer of graphene oxide gel onto a surface of a supporting substrate, where dispensing and depositing procedure includes shear-induced thinning of graphene oxide gel; partially or completely removing fluid medium from deposited graphene oxide gel to form a graphene oxide mass having an oxygen content no less than 20 wt.%; and heat treating the graphene oxide mass. USE - The process is useful for producing unitary graphene material, which is useful for heat dissipation applications. ADVANTAGE - The process: provides the unitary graphene material, which exhibits an inter-graphene spacing less than 0.337 nm and a mosaic spread value less than 1, a degree of graphitization no less than 40% and/or mosaic spread value less than 0.7, a degree of graphitization no less than 80% and/or mosaic spread value no greater than 0.4, and has an electrical conductivity greater than 3000 S/cm, preferably greater than 15000 S/cm, thermal conductivity greater than 600 W/mK, preferably greater than 1500 W/mK, physical density greater than 1.8 g/cm3, preferably greater than 2 g/cm3 and/or tensile strength greater than 40 MPa, preferably greater than 80 MPa; provides unitary graphene matrix composite, which has a physical density of at least 1.8 g/cm3 or a porosity level lower than 5% (all claimed), high mechanical strength, good surface scratch resistance, good hardness and elimination of possibility of having surface graphite flakes or particles to flake off; provides cost effective production of thermally and electrically conductive graphene monolith or graphene matrix composite, which can be used to produce finned heat sinks cost effectively in large quantities, using commonly used, less complex, and easier to control processes with readily available, inexpensive equipment; requires low heat treatment temperatures as compared with processes for producing pyrolytic graphite (including highly ordered pyrolytic graphite) from either carbonized polymers (e.g. polyimide) or the chemical vapor deposition graphite; is simpler, hence more reliable, less energy-intensive and highly scalable; and provides unitary graphene material, which itself is an integrated graphene object, which is not an aggregate or stack of multiple discrete graphite flakes or discrete platelets of graphene, is a single graphene entity or monolith, not a simple aggregate of multiple graphite flakes and does not contain discrete graphite flakes or discrete graphene platelets dispersed in it that are derived from the graphene oxide gel, and is not made by gluing or bonding discrete flakes/platelets together with binder, linker or adhesive. DETAILED DESCRIPTION - Producing unitary graphene material, comprises: preparing a graphene oxide gel having graphene oxide molecules containing an oxygen content higher than 20 wt.%, dissolved in a fluid medium; dispensing and depositing a layer of the graphene oxide gel onto a surface of a supporting substrate to form a deposited graphene oxide gel on it, where dispensing and depositing procedure includes shear-induced thinning of the graphene oxide gel; partially or completely removing the fluid medium from the deposited graphene oxide gel to form a graphene oxide mass having an inter-plane spacing d002 of 0.4 nm to 1.2 nm as determined by X-ray diffraction and an oxygen content no less than 20 wt.%; and heat treating the graphene oxide mass to form the unitary graphene material at a heat treatment temperature higher than 100 degrees C to an extent that an inter-plane spacing d002 is decreased to a value of 0.3354-0.4 nm and the oxygen content is decreased to less than 5 wt.%. INDEPENDENT CLAIMS are also included for producing unitary graphene matrix composite, comprising either preparing a graphene oxide gel having graphene oxide molecules dissolved in a fluid medium to form a homogeneous solution, mixing a carbon or graphite filler phase in the graphene oxide gel to form a slurry, dispensing the slurry into a cavity of a molding tool or forming the slurry into a desired shape under the influence of a shear stress to create shear-induced thinning and molecular orientation, partially or completely removing the fluid medium from the slurry to form a composite precursor and heat treating the composite precursor to form the unitary graphene composite at a temperature higher than 100 degrees C or preparing graphene oxide gel having graphene oxide molecules dissolved in fluid medium to form homogeneous solution, combining carbon or graphite filler phase with the graphene oxide gel to form impregnated filler shape under the influence of shear stress that induces viscosity thinning, partially or completely removing the fluid medium from the impregnated filler shape to form composite precursor and heat treating the composite precursor to form the unitary graphene composite at higher than 100 degrees C.