KR20190042686A - Corrosive acid-induced conductive foam and devices - Google Patents

Abstract

A humic acid-derived foam comprising a plurality of pores and pore walls, wherein the pore walls contain a single layer or a few-layer corrosion acid-derived hexagonal carbon atom plane or sheet, The layered hexagonal carbon atom plane or sheet has from 2 to 10 layers of stacked hexagonal carbon atom planes with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.40 nm as measured by X-ray diffraction, The multiple layered hexagonal carbon atom planes contain from 0.01% to 25% by weight of non-carbon atoms and the corrosion acid is selected from the group consisting of oxidized corrosion acids, reduced corrosion acids, fluorinated corrosion acids, chlorinated corrosion acids, brominated corrosion acids, Wherein the corrosion acid is selected from the group consisting of a hydrogenated acid, a hydrogenated acid, a nitrated acid, a doped acid, a chemically functionalized acid, or a combination thereof.

Description

Corrosive acid-induced conductive foam and devices

Cross-reference to related application

This application claims priority to U.S. Patent Application No. 15 / 251,841 (Aug. 30, 2016) and U.S. Patent Application No. 15 / 251,849 (Aug. 30, 2016), which are incorporated herein by reference. do.

Technical field

The present invention relates generally to the field of carbon / graphite foams, more particularly to new types of conductive foams derived from corrosive acids, devices incorporating such humic acid-derived foams, , And a production process thereof.

Carbon can be used as a material of diamond, fullerene (0-D nano graphite material), carbon nanotube or carbon nanofiber (1-D nano graphite material), graphene (2-D nano graphite material) , Which are known to have five unique crystalline structures. In addition to fullerene, all of these materials can be made in a foamed structure.

Carbon nanotubes (CNTs) refer to tubular structures grown as a single wall or multiple walls. Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) have diameters ranging from several nanometers to several hundred nanometers. Its longitudinal hollow structure imparts unique mechanical, electrical, and chemical properties to the material. CNT or CNF is a one-dimensional nano-carbon or 1-D nano-graphite material. However, CNTs are difficult to produce and are very expensive. It is also known that CNTs are difficult to disperse in solvents or water and difficult to mix with other materials. These characteristics have seriously limited their application category.

A single layer graphene sheet consists of carbon atoms occupying a two-dimensional hexagonal lattice. Multilayer graphene is a platelet composed of more than one graphene plane. Individual single layer graphene sheets and multilayer graphene platelets are collectively referred to herein as nanographene platelets (NGPs) or graphen materials. NGPs include pristine graphene (essentially 99% carbon atoms), slightly oxidized graphene (less than 5% oxygen), and oxidized graphene (greater than 5% oxygen).

NGPs have been found to have a wide range of non-conventional physical, chemical, and mechanical properties. Our study group was the first to discover graphene (BZ Jang and WC Huang, " Nano-scaled Graphene Plates, " U.S. Patent Application No. 10 / 274,473 (Oct. 21, 2002) No. 7,071,258 (April 7, 2006)). Processes for producing NGPs and NGP nanocomposites have been previously reviewed by the present inventor (Bor Z. Jang and A Zhamu, " Processing of Nano Graphene Platelets (NGPs) and NGP Nanocomposites: A Review, 43 (2008) 5092-5101). NGP has been created in accordance with four major prior art approaches. The advantages and disadvantages of these are briefly summarized as follows:

Approach 1: Chemical formation and reduction of oxidized graphene (GO)

The first approach (Figure 1) is to treat natural graphite powder with an intercalating agent and an oxidizing agent (e.g., respectively concentrated sulfuric acid and nitric acid) to obtain graphite intercalation compound (GIC) or, in fact, graphite oxide (GO) (William S. Hummers, Jr., et al., Preparation of Graphitic Oxide, Journal of the American Chemical Society, 1958, p. 1339). Before insertion or oxidation, the graphite has an approximate spacing of 0.335 nm ( L _d = 1/2 d ₀₀₂ = 0.335 nm) between graphene planes. By intercalation and oxidation, the intergrain spacing is typically increased to a value greater than 0.6 nm. This is the first expansion step experienced by the graphite material during this chemical pathway. Then, the obtained GIC or GO will go through an additional expansion (which is often referred to as delamination (exfoliation)) in which thermal shock exposure or solution-is conducted using the auxiliary graphene layer stripping approach-based ultrasound.

In the thermal shock exposure approach, the GIC or GO is exposed to high temperatures (typically 800-1050 DEG C) for a short period of time (typically 15 to 60 seconds) to peel off the GIC or GO for the formation of exfoliated or further expanded graphite Graphite worm " composed of graphite flakes which are still interconnected with one another. The graphite worms are typically " graphite worms " This thermal shock procedure can produce some separated graphite flakes or graphene sheets, but usually most of the graphite flakes remain interconnected. Typically, the peeled graphite or graphite worm then undergoes flake separation treatment using air milling, mechanical shearing, or ultrasonic in water. Thus, Approach 1 basically involves three separate procedures: a first expansion (oxidation or insertion), a further expansion (or "exfoliation"), and a separation .

In the solution-based separation approach, the expanded or exfoliated GO powder is dispersed in water or an aqueous alcohol solution, which is sonicated. It is important to note that in these processes, ultrasonic waves are used after insertion of graphite and after oxidation (i.e. after the first expansion) and typically after the thermal shock exposure of the resulting GIC or GO (after the second expansion). Alternatively, the GO powder dispersed in water may be subjected to an ion exchange or prolonged purification procedure in such a way that the repulsion between the ions present in the interplanar space overcomes the graphene van der Waals forces resulting in the separation of the graphene layer It goes through.

There are several major problems associated with such conventional chemical production processes.

(1) This process requires the use of large amounts of some undesirable chemicals (such as sulfuric acid, nitric acid, and potassium permanganate or sodium chlorate).

(2) Chemical treatment processes typically require prolonged insertion and oxidation times ranging from 5 hours to 5 days.

(3) Strong acids consume significant amounts of graphite by "corroding graphite" (converting graphite to carbon dioxide, which is lost in this process) during this long-time insertion or oxidation process. It is common that 20 to 50% by weight of the graphite material immersed in strong acid and oxidizer is lost.

(4) Heat peeling requires a high temperature (typically 800 to 1,200 ° C) and is therefore a highly energy-intensive process.

(5) Both the heat-induced detachment approach and the solution-induced detachment approach require a very cumbersome cleaning and purification step. For example, typically 2.5 kg of water is used to flush and recover 1 g of GIC, producing an enormous amount of wastewater, which needs to be treated appropriately.

(6) In both the heat-induced stripping approach and the solution-induced stripping approach, the resulting product is GO platelets, which must undergo further chemical reduction treatment to reduce the oxygen content. Typically after the reduction, the electrical conductivity of the GO platelets remains much lower than that of pristin graphene. In addition, the reduction procedure often involves the use of toxic chemicals, such as hydrazine.

(7) Also, the amount of interstitial solution retained on the flakes after draining may range from 20 to 150 parts by weight (pph), more typically from about 50 to 120 pph, per 100 parts by weight of graphite flake. During hot stripping, the residual insert species retained by the flakes are degraded to produce sulfuric acid and nitrite compounds (e.g., NO _x and SO _x ) of various species, which are undesirable. The effluent requires an expensive purification procedure to avoid harmful environmental impacts.

Approach 2: Direct formation of pristine nano-graphene platelets

In 2002, our team of researchers succeeded in isolating single and multi-layer graphene sheets from partially carbonized or graphitized polymeric carbons obtained from polymers or pitch precursors (BZ Jang and WC Huang, " Nano- scaled Graphene Plates, " U.S. Patent Application No. 10 / 274,473 (October 21, 2002), now U.S. Patent No. 7,071,258 (April 7, 2006)). Mack et al. (&Quot; Chemical manufacture of nanostructured materials " U.S. Patent No. 6,872,330, Mar. 29, 2005) discloses a process for producing a graphite sheet comprising the steps of inserting a potassium melt into graphite and contacting the obtained K- Lt; RTI ID = 0.0 > NGPs < / RTI > This process must be carried out carefully in a vacuum or in a pole-drying glovebox environment, since pure alkali metals such as potassium and sodium are very sensitive to moisture and pose an explosion hazard. This process is not suitable for mass production of NGPs.

Approach 3: Epitaxial growth of nano-graphene sheet on inorganic crystal surface and chemical vapor deposition

Small-scale production of ultra-thin graphene sheets on a substrate can be achieved by thermal decomposition-based epitaxial growth and laser desorption-ionization techniques (Walt A. DeHeer, Claire Berger, Phillip N. First, film graphite devices and method for making same "US Patent No. 7,327,000 B2 (June 12, 2003)). Epitaxial films of graphite with only one or several atomic layers have technical and scientific significance due to their unique properties and great potential as device substrates. However, these processes are not suitable for mass production of isolated graphene sheets for composite materials and energy storage applications.

Another process for producing graphene in thin film form (typically to a thickness of less than 2 nm) is the catalytic chemical vapor deposition process. Such catalytic CVD involves catalytic cracking of hydrocarbon gases (e.g., C ₂ H ₄ ) on the Ni or Cu surface to form a single layer or few-layer graphene. The carbon atoms obtained through the decomposition of hydrocarbon gas molecules at a temperature of 800 to 1,000 DEG C using Ni or Cu as a catalyst are directly deposited on the surface of the Cu foil or precipitated on the surface of the Ni foil from the Ni- Layer or several layers of graphene (less than five layers). The Ni- or Cu-catalyzed CVD process itself does not provide deposition of more than 5 graphene planes (typically less than 2 nm), and if exceeded, the underlying Ni or Cu layer no longer has any catalyst The effect can not be provided. CVD graphene films are very expensive.

Approach 4: Bottom-Up Approach (Synthesis of Graphene from Small Molecule)

Yang et al., &Quot; Two-dimensional Graphene Nano-ribbons, " J. Am. Chem. Soc. 130 (2008) 4216-17) A nanograffin sheet with a maximum length of 12 nm was synthesized using a method starting with Suzuki-Miyaura coupling of phenyl-benzene and 4-bromophenylboronic acid. The resulting hexaphenylbenzene derivative was further derivatized and ring-fused to form a small graphene sheet. This is a slow process that has produced very small graphene sheets so far.

Thus, in terms of properties, it has a new class of carbon nanomaterials that are comparable to or better than graphene, but that can be produced more cost-effectively, faster, more scalable, and more environmentally harmless There is an urgent need for something. The production process for such new carbon nanomaterials can be used to reduce the amount of undesirable chemicals (or removal of all of these chemicals), shortened process times, less energy consumption, undesirable chemistry into the drainage species (e. g., sulfuric acid) or undesirable species of the air into require a reduction or removal of leakage (e.g., SO ₂ and nO _2). In addition, such new nanomaterials must be readily manufacturable into thermally and electrically comparatively conductive foam structures.

Generally speaking, the foam or foamed material consists of pores (or cells) and pore walls (solid material). The pores may be interconnected to form an open cell foam. As an example, graphene foam is composed of pore walls and pores containing graphene material. There are three main ways of creating graphene foam, all of which are time-consuming, energy-consuming, and slow:

The first method typically involves sealing the aqueous graphene graphene (GO) suspension in a high pressure autoclave and heating at a high pressure (tens or hundreds of atm) for a prolonged period of time (typically 12 to 36 hours) Lt; RTI ID = 0.0 > of GO < / RTI > A useful reference to this method is provided below: Y. Xu, et al., &Quot; Self-Assembled Graphene Hydrogel via a One-Step Hydrothermal Process, " ACS Nano 2010, 4, 4324-4330. There are several major problems associated with this method: (a) High pressure requirements create impractical methods for industrial scale production. For one thing, this process can not be carried out continuously. (b) it is difficult, but not impossible, to control the pore size and porosity level of the resulting porous structure. (c) there is no flexibility (e.g., it can not be made into a film shape) that can vary the shape and size of the resulting reduced oxidized graphene (RGO) material. (d) The method involves the use of very low concentrations of GO suspended in water (for example, 2 mg / mL = 2 g / L = 2 kg / kL). Removing non-carbon elements (up to 50%) can produce less than 2 kg of graphene material (RGO) per 1000 liters suspension. In addition, it is practically impossible to operate a 1000 liter reactor which must withstand high temperature and high pressure conditions. Clearly, this is not a scalable process for mass production of porous graphene structures.

A second method is based on a template-assisted catalytic CVD process, which involves CVD deposition of a graphene on a sacrificial mold (e.g., Ni foam). The graphene material depends on the shape and dimensions of the Ni foam structure. The Ni foams are then etched using an etchant to leave a monolith of the graphene framework, which is essentially an open cell foam. Useful reference literature on such methods is provided in: Zongping Chen, et al., &Quot; Three-dimensional flexible and conductive interconnected graphene networks grown by chemical vapor deposition, " Nature Materials, 10 (June 2011) 424-428. There are a number of problems associated with this process: (a) catalytic CVD is inherently very slow, highly energy-intensive, and expensive; (b) The etchant is typically a chemical that is not very desired, and the resulting Ni-containing etch solution is a source of contaminants. It is very difficult and expensive to recover or recycle the dissolved Ni metal from the etchant solution. (c) When Ni foams are etched, it is difficult to maintain the shape and dimensions of the graphene foam without damaging the cell walls. The resulting graphene foam is typically very brittle and fragile. (d) transport of CVD precursor gas (e. g., hydrocarbons) into the interior of the metal foam can result in non-uniform structure because a particular spot inside the sacrificial metal foams can be transferred to the CVD precursor gas Because it can not be accessed.

The third method of producing graphene foam also uses a sacrificial material (e.g., colloidal polystyrene particles, PS) coated with oxidized graphene sheets using a self-assembly method. For example, Choi et al. Prepared chemically modified graphene (CMG) paper in two steps: a stand-alone PS / PS gel by vacuum filtration of a mixed aqueous colloidal suspension of CMG and PS (2.0 쨉 m PS spheres) (BG Choi, et al., &Quot; 3D Macroporous Graphene Frameworks for Supercapacitors with High Energy and Power Densities, " ACS Nano, 6 (2012) 4020- 4028]). Choi et al. Prepared a stand-alone PS / CMG paper that was well aligned by filtration, which is disclosed by separately preparing a negatively charged CMG colloidal and positively charged PS suspension. A mixture of CMG colloidal and PS suspensions was dispersed in solution at a controlled pH (= 2), where the two compounds had the same surface charge (+13 ± 2.4 mV for CMG and +68 ± 5.6 mV < / RTI > When the pH was raised to 6, CMGs (zeta potential = -29 ± 3.7 mV) and PS spheres (zeta potential = +51 ± 2.5 mV) were assembled due to electrostatic interactions and hydrophobic characteristics between them, And incorporated into the PS / CMG composite paper through the filtration process. This method also has several disadvantages: (a) this method requires a very tedious chemical treatment of both the graphene grains and the PS particles. (b) Removal of PS by toluene also weakens the macroporous structure. (c) Toluene is a highly regulated chemical and should be handled with extreme caution. (d) pore size is typically excessively large (e.g., a few microns) and too large for many useful applications.

The above discussion clearly shows that all prior art methods or processes for producing graphene and graphene foams have significant defects. It is therefore an object of the present invention to provide a new class of foam materials which are thermally and electrically conductive and mechanically robust and to provide a cost-effective way of producing this class of foam.

Corrosive acids (HA) are organic materials commonly found in soils and can be extracted from the soil using bases (e.g., KOH). HA can also be extracted in high yield from coal types called leonardite, a highly oxidized form of lignite. The HA extracted from the soft lignite contains a plurality of oxygenated groups (e.g., carboxyl groups) located around the edges of the graphene-like molecule center (SP ² core of hexagonal carbon structure). This material is somewhat similar to oxidized graphene (GO) produced by strong acid oxidation of natural graphite. HA has a typical oxygen content of 5 wt% to 42 wt% (the other major elements being carbon and hydrogen). The HA after chemical or thermal reduction has an oxygen content of 0.01 wt% to 5 wt%. For the purpose of defining the claims in this application, the corrosion acid (HA) refers to a total oxygen content ranging from 0.01% to 42% by weight. The reduced corrosion acid (RHA) is a special type of HA with an oxygen content of 0.01% to 5% by weight.

The present invention is directed to a new class of graphene-like 2D materials (i.e., corrosion acids) that can be converted into a foamed structure having surprisingly high structural integrity. Thus, another object is to provide a cost-effective process for producing such nanocarbon foam (specifically, a corrosion acid-derived foam) in large quantities. This process does not involve the use of chemicals that are not environmentally friendly. The method enables flexible design and control of porosity level and pore size.

Another object of the present invention is to provide a corrosion acid-derived foam that exhibits thermal conductivity, electrical conductivity, elastic modulus, and / or strength comparable to or greater than conventional graphite foam, carbon foam, or graphene foam. It is a further object of the present invention to provide a corrosion acid-derivatized foam, preferably having a mesoporous pore size range (2 to 50 nm).

It is a further object of the present invention to provide a product (e.g., a device) that accommodates the corrosion acid-derived foam of the present invention and a method of operation of these products.

The present invention provides a corrosion acid-induced foam comprising a plurality of pores and pore walls, wherein the pore walls contain a single layer or multiple layers of corrosion acid-induced hexagonal carbon sheets, Has a stacked hexagonal carbon atom plane of 2 to 10 layers with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.60 nm (preferably 0.40 nm or less) The single layer or multi-layer hexagonal carbon sheet contains from 0.01% to 25% by weight of the non-carbon element. Corrosive acids (HA) are formed from oxidized corrosion acids, reduced corrosion acids, fluorinated corrosion acids, chlorinated corrosion acids, brominated corrosion acids, iodinated corrosion acids, hydrogenated corrosion acids, nitrided corrosion acids, An acid, a chemically functionalized acid, or a combination thereof.

The corrosion acid-derived foam of the present invention is divided into three types: (a) at least 10 wt% (typically 10 wt% to 42 wt%, most typically 10 wt% to 25 wt% (In this case, some of the chemical bonds between the HA molecules occur, although the original corrosion acid molecules remain in substantially the same state); (b) chemically coalesced and reduced corrosion-resistant foams, where extensive connections and merging occur between the original HA molecules to form an initial graphene-like hexagonal carbon sheet that constitutes the pore wall, (Thus, the non-carbon element content is generally reduced to 2 wt% to 10 wt%); And (c) a caustic acid-derived graphite foam (essentially less than 2% by weight, preferably less than 1% by weight, more preferably less than 0.1% by weight of non-carbon content) , A single layer or multiple layers (2 to 10) graphene-like sheets that are hexagonal carbon atom planes.

Preferably and typically, the HA-derived foam has a density of 0.005 to 1.7 g / cm ³ and / or a specific surface area of 50 to 3,200 m ² / g and / or a thermal conductivity per unit of specific gravity of at least 100 W / mK and / or the electrical conductivity per unit of specific gravity is 500 S / cm or more. More typically, the corrosion acid-derived foam has a density of 0.01 to 1.5 g / cm ^3, or an average pore size of 2 nm to 50 nm. In one embodiment, the foam has a specific surface area of 200 to 2,000 m ² / g or a density of 0.1 to 1.3 g / cm ³ .

Typically, when the HA-derived foam is produced from a process that does not include a heat treatment temperature (HTT) higher than 300 ° C, the foam has a non-carbon element content in the range of 10 wt% to 42 wt%. The pore wall may still contain an identifiable corrosion acid molecule that is a sheet-like hexagonal carbon atom structure. The non-carbon element may comprise an element selected from oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, or boron. In a specific embodiment, the pore wall contains a fluorinated corrosion acid, and the foam has a fluorine content of from 0.01 wt% to 25 wt%. In another embodiment, the foam has an oxygen content of from 0.01 wt% to 25 wt%.

For HTTs higher than 300 ° C, closely packed and well aligned neighboring HA molecules may be chemically linked together to form a multi-ring aromatic structure similar to the initial graphene-like hexagonal carbon atom structure. As the heat treatment continues, these highly aromatic molecules are merged together in an edge-to-edge fashion to increase the length and width of the graphene-like hexagonal plane, and at the same time, some hexagonal carbon planes are stacked together to form a multi- Lt; RTI ID = 0.0 > carbon-atom < / RTI > The spacing between planes is typically reduced to < 0.60 nm, and more typically to less than 0.40 nm. When the HTT is between 300 ° C and a maximum of 1,500 ° C, typically a chemically combined and reduced caustic-phase foam is produced, where extensive connections and merging occur between the original HA molecules and the initial graphene- Like hexagonal carbon sheet. The non-carbon content in the foam is typically reduced to 2% to 10%.

When the HTT is between 1,500 ° C. and 3,200 ° C., the foam can be essentially a graphite foam, wherein the pore wall contains a single layer or multiple layers of graphene-like hexagonal carbon planes and the non-carbon content is less than 2% .

In a preferred embodiment, the foam is in the form of a continuous-length roll sheet having a thickness of 200 [mu] m or less and a length of at least 1 meter, preferably at least 2 meters, more preferably at least 10 meters, and most preferably at least 100 meters (Rolls of continuous foam sheet). Such sheet rolls are produced by a roll-to-roll process. There is no prior art HA-induced graphene-like foam made in sheet roll form.

In a preferred embodiment, the HA-derived foam has an oxygen content or a non-carbon content of less than 1% by weight and the pore wall has a planar spacing of less than 0.35 nm and / or a thermal conductivity per unit of specific gravity of at least 200 W / / Or has a stacked graphene-like plane with an electrical conductivity per unit of specific gravity of at least 1,000 S / cm.

In a further preferred embodiment, the HA-derived foam has an oxygen content or a non-carbon content of less than 0.1% by weight and the pore wall has an interplanar spacing of less than 0.34 nm and / or a thermal conductivity per unit of specific gravity of at least 250 W / mK and / or a stacked graphene-like hexagonal carbon atom plane having an electrical conductivity per unit of specific gravity of 1,500 S / cm or more.

In another preferred embodiment, the graphene foam has an oxygen content or a non-carbon content of 0.01 wt% or less and the pore wall has a graphene spacing of less than 0.336 nm and / or a mosaic dispersion value of 0.7 or less , A thermal conductivity per unit of specific gravity of at least 300 W / mK and / or an electrical conductivity per unit of specific gravity of 2,000 S / cm or more.

In another preferred embodiment, the graphene foam has a planar spacing of less than 0.336 nm and / or a mosaic dispersion value of less than or equal to 0.4, or a thermal conductivity per unit of specific gravity of greater than 400 W / mK and / Has pore walls containing stacked graphene-like atomic planes with an electrical conductivity greater than 3,000 S / cm.

In a preferred embodiment, the pore walls contain laminated graphene-like hexagonal carbon atom planes with an interplanar spacing of less than 0.337 nm and a mosaic dispersion value of less than 1.0. In a preferred embodiment, the foam exhibits a degree of graphitization of at least 80% (preferably at least 90%) and / or a mosaic dispersion value of less than 0.4. In a preferred embodiment, the pore walls contain a 3D network of interconnected graphene-like hexagonal carbon atom planes.

In a preferred embodiment, the solid foam contains a mesopore pore having a pore size of 2 nm to 50 nm. The solid foams can also be prepared to contain micro-scale pores (1 to 500 mu m).

The HA-derived foam of the present invention can be produced by a process comprising the steps of: (a) preparing a corrosion acid dispersion having a plurality of corrosion acid molecules or sheets dispersed in a liquid medium, the corrosion acid The method of any one of claims 1 to 3, wherein the oxidized acid, the reduced acid, the fluorinated acid, the chlorinated acid, the brominated acid, the iodinated acid, the hydrogenated acid, the nitrated acid, Wherein the dispersion contains an optional blowing agent and wherein the weight ratio of blowing agent to the corrosion acid is from 0 / 1.0 to 1.0 / 1.0; (b) distributing and depositing a graphene dispersion onto the surface of a support substrate (e.g., a plastic film, a rubber sheet, a metal foil, a glass sheet, a paper sheet, etc.) to form a wetting layer of a corrosive acid; (c) partially or completely removing the liquid medium from the wetting layer of the corrosive acid to form a dry layer of the corrosive acid; And (d) inducing the formation and release of volatile gas molecules from non-carbon elements (e.g., O, H, N, B, F, Cl, Br, I, etc.) Lt; RTI ID = 0.0 > 80 C < / RTI > to < RTI ID = 0.0 > 3,200 C < / RTI > Preferably, the dispensing and deposition procedure comprises placing the corrosive acid dispersion under orientation-induced stress.

Such a selective blowing agent may be selected from the group consisting of a non-carbon element (for example, O, O, S, O, H, N, B, F, Cl, Br, I, etc.). Subsequent high temperature treatment serves to remove most of these non-carbon elements from the edges of the HA molecules to generate volatile gas species that produce pores or cells in the solid foam structure. In other words, very surprisingly, this non-carbon element serves as a blowing agent. Accordingly, the externally added blowing agent is optional (not necessarily). However, the use of blowing agents can additionally provide flexibility to adjust or adjust the porosity level and pore size for the desired application. Foaming agents are typically required when the content of non-carbon elements in the caustic acid is less than 5%.

The foaming agent may be a physical foaming agent, a chemical foaming agent, a mixture thereof, a dissolution-and-leaching agent, or a mechanically introduced foaming agent.

The process may further comprise the step of heat treating the solid foam at a second heat treatment temperature greater than the first heat treatment temperature for a period of time sufficient to obtain a graphene-like foam, wherein the pore wall has a pore size ranging from 0.3354 nm to Plane spacing d ₀₀₂ of 0.40 nm and a layered hexagonal carbon atom plane having a content of less than 5 wt% (typically 0.001 wt% to 2 wt%) of non-carbon elements. When the obtained non-carbon element content is 0.1% to 2.0%, the interplanar spacing d ₀₀₂ is typically 0.337 nm to 0.40 nm.

When the original HA molecules in the dispersion contain a non-carbon element content of greater than 5 wt%, the hexagonal carbon atom plane (after heat treatment) in the solid foam contains structural defects induced during the heat treatment step (d). The liquid medium may simply be water and / or alcohol, which is environmentally friendly.

In a preferred embodiment, the process is characterized in that steps (b) and (c) comprise feeding the support substrate from the feed roller to the deposition zone and continuously feeding the HA dispersion onto the surface of the support substrate to form a wet layer of HA material thereon Drying the wet layer of HA material to form a dried layer of HA material and collecting a dried layer of HA material deposited on the support substrate on a collector roller, To-roll process. This roll-to-roll or reel-to-reel process is a mass-production process on a real industrial scale that can be automated.

In one embodiment, the first heat treatment temperature is from 100 占 폚 to 1,500 占 폚. In another embodiment, the second heat treatment temperature comprises a temperature selected from at least (A) 300 to 1,500 占 폚, (B) 1,500 to 2,100 占 폚, and / or (C) 2,100 to 3,200 占 폚. In certain embodiments, the second heat treatment temperature comprises a temperature in the range of 300 to 1,500 DEG C for at least one hour, and then a temperature in the range of 1,500 to 3,200 DEG C for at least one hour.

The results of performing the first and / or second heat treatment on the dried HA layer have some surprising results, and different heat treatment temperature ranges allow to achieve the following different objectives: (a) (E. G., Yielding a reduced acid by thermal reduction of the fluorinated acid), which generates volatile gases to produce pores or cells in the HA foam, (b) activating the chemical or physical blowing agent (C) chemical coupling or incorporation of the corrosive acid molecules into the highly aromatic molecules, and (e) (c) chemical bonding or merging of the corrosion acid molecules in the foam wall (Length and width) of the graphene-like hexagonal carbon sheet of the present invention, (d) it may be present naturally in the HA or during fluorination, oxidation, or nitrification of the corrosive acid molecule. The recovery of the fault, and (e) re-organization and integrity of the graphite or graphite crystal domain (perfection). These different purposes or functions are achieved to different degrees within different temperature ranges. The non-carbon element typically comprises an element selected from oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, or boron. Surprisingly, even under low temperature foaming conditions, the heat treatment is often carried out in an edge-to-edge manner (partly, face-to-face manner) Or chemical bonds.

In one embodiment, the HA-derived foam has a specific surface area of 200 to 2,000 m < 2 > / g. In one embodiment, the solid foam has a density of 0.1 to 1.5 g / cm < 3 >. In one embodiment, step (d) of heat treating the HA material layer at a first heat treatment temperature is performed under compressive stress. In another embodiment, the process includes a compression step to reduce the thickness, pore size, or porosity level of the film of the HA-derived foam. In some applications, the foam has a thickness of 200 [mu] m or less.

In one embodiment, the HA dispersion has at least 5% by weight of HA dispersed in the liquid medium to form a liquid crystal phase. In one embodiment, the first heat treatment temperature contains a temperature in the range of 80 ° C to 300 ° C, and consequently, the HA foam has an oxygen content or a non-carbon element content of less than 5%, and the pore wall has a porosity of less than 0.40 nm Plane spacing, thermal conductivity of at least 150 W / mK (more typically, at least 200 W / mk) per unit of specific gravity, and / or electrical conductivity of at least 1,000 S / cm per unit of specific gravity.

In a preferred embodiment, the first heat treatment temperature and / or the second heat treatment temperature contain a temperature in the range of 300 ° C to 1,500 ° C and consequently the HA-derived foam has an oxygen content or a non-carbon content of less than 2% And the pore wall has an interplanar spacing of less than 0.35 nm, a thermal conductivity of at least 250 W / mK per unit of specific gravity, and / or an electrical conductivity of at least 1,500 S / cm per unit of specific gravity.

The HA-derived foam has an oxygen content or a non-carbon content of less than 1% when the first heat treatment temperature and / or the second heat treatment temperature contains a temperature in the range of 1,500 ° C to 2,100 ° C, A thermal conductivity of at least 300 W / mK per unit of specific gravity, and / or an electrical conductivity of at least 3,000 S / cm per unit of specific gravity.

The HA-derived foam has an oxygen content or a non-carbon content of 0.1% or less when the first heat treatment temperature and / or the second heat treatment temperature contain a temperature higher than 2,100 ° C, A mosaic dispersion value of 0.7 or less, a thermal conductivity of at least 350 W / mK per unit of specific gravity, and / or an electrical conductivity of 3,500 S / cm or more per unit of specific gravity.

When the first heat treatment temperature and / or the second heat treatment temperature contain a temperature of 2,500 캜 or more, the HA-derived foam has an interplanar spacing of less than 0.336 nm, a mosaic dispersion value of 0.4 or less, and a specific gravity of 400 W / Has a pore wall containing a stacked graphene-like hexagonal carbon plane having a high thermal conductivity, and / or an electrical conductivity greater than 4,000 S / cm per unit of specific gravity.

In one embodiment, the pore wall contains a stacked graphene-like hexagonal carbon plane having an interplanar spacing of less than 0.337 nm and a mosaic dispersion value of less than 1.0. In another embodiment, the solid wall portion of the HA-derived foam exhibits a degree of graphitization of at least 80% and / or a mosaic dispersion value of less than 0.4. In yet another embodiment, the solid wall portion of the HA-derived foam exhibits a degree of graphitization of 90% or higher and / or a mosaic dispersion value of 0.4 or lower.

Typically, after heat treatment at HTT higher than 2,500 ° C, the pore walls in the HA-induced graphite foam contain a 3D network of interconnected hexagonal carbon atom planes that are electron-conducting paths. The cell wall is preferably at least 20 nm, more typically and preferably at least 40 nm, more typically and preferably at least 100 nm, more typically and preferably at least 500 nm, often more than 1 탆, and sometimes at least 10 탆 (L _a , length or width) of the graphite domain or graphite crystal. The graphite domain typically has a thickness of from 1 nm to 20 nm, more typically from 1 nm to 10 nm, and even more typically from 1 nm to 4 nm.

Preferably, the HA-derived foam contains a mesopore pore having a pore size between 2 nm and 50 nm (preferably between 2 nm and 25 nm).

In a preferred embodiment, the present invention provides a roll-to-roll process for producing a solid HA foam or HA-derived foam composed of a plurality of pores and pore walls. The process comprises the steps of: (a) preparing a corrosion acid dispersion having a plurality of corrosion acid molecules or sheets dispersed in a liquid medium, wherein the corrosion acid is selected from the group consisting of oxidized corrosion acids, reduced corrosion acids, Wherein the acid is selected from a group consisting of a hydrochloric acid, a hydrochloric acid, a chlorinated acid, a brominated acid, an iodinated acid, a hydrogenated acid, a nitrated acid, a doped acid, a chemically functionalized acid, Wherein the dispersion contains an optional foaming agent, wherein the blowing agent to corrosion acid weight ratio is from 0 / 1.0 to 1.0 / 1.0; (b) continuously or intermittently dispensing and depositing the HA dispersion onto the surface of the support substrate to form a wetting layer of the HA material, wherein the support substrate comprises a continuous thin film In step; (c) partially or completely removing the liquid medium from the wetting layer of the corrosive acid in one heating zone or in a plurality of heating zones to form a dry layer of the corrosive acid; And (d) at a desired heating rate sufficient to activate the foaming agent to produce a corrosion acid-derived foam having a density of from 0.01 to 1.7 g / cm ³ or a specific surface area of from 50 to 3,000 m ² / g. Heat treating the dry layer of the corrosive acid in one of the heating zones including the heating temperature. In this process, the heat treatment takes place in situ during the roll-to-roll process. This is a very cost-effective process suitable for mass production of HA-induced graphite foam sheets rolled on rollers for ease of transport and handling, and subsequently for ease of cutting and slitting.

The orientation-induced stress can be shear stress. As an example, shear stress can be encountered in a simple situation such as a " doctor blade " where the doctor blade guides the spreading of the HA dispersion onto the plastic or glass surface with a sufficiently high shear rate during the passive casting process. As another example, an effective orientation-induced stress may be obtained by an automated roll-to-roll process in which a "knife-on-roll" configuration distributes the graphene dispersion onto a moving solid substrate such as a plastic film to-roll coating process. The relative movement between the moving film and the coating knife serves to achieve the orientation of the graphene sheet along the shear stress direction. Comma coating and slot-die coating are particularly effective methods for this function.

This orientation-induced stress is a function of shear stress to cause the HA molecule or sheet to be oriented in a particular direction (e.g., in the X-direction or in the length-wise direction) to produce the desired orientation and to facilitate contact between the HA molecules or sheets along the foam wall. ), Which is an important step in the production of the HA-derived foam of the present invention. Surprisingly, this preferred orientation and improved HA-to-HA contact also facilitates chemical incorporation or linkage between HA molecules or sheets during subsequent heat treatment of the dried HA layer. These preferred orientations and improved contact are essential to ultimately achieve the exceptionally high thermal conductivity, electrical conductivity, modulus of elasticity, and mechanical strength of the resulting HA-derived foam. In general, such excellent properties could not be obtained without such shear stress-induced orientation control.

The present invention also provides an oil-removing device or an oil-separating device that contains a caustic acid-derived foam as the oil-absorbing element. Also provided is a solvent-removing device or solvent-separating device containing a caustic acid-derived foam as the solvent-absorbing or solvent-separating element.

The present invention also provides a method for separating oil from water. The method comprises the steps of: (a) providing an oil-absorbing element comprising an integral corrosion acid-derived foam; (b) contacting the oil-water mixture with an element to absorb oil from the mixture; (c) reprocessing the element from the mixture and extracting oil from the element; And (d) reusing the element.

In addition, the present invention provides a process for separating an organic solvent from a solvent-water mixture or from a multi-solvent mixture. The method comprises the steps of: (a) providing an organic solvent-containing or solvent-detachment element comprising an integral corrosion acid-derived foam; (b) contacting the urea with an organic solvent-water mixture or a multi-solvent mixture containing a first solvent and at least a second solvent; (c) allowing the urea to absorb the organic solvent from the mixture or at least separating the first solvent from the second solvent; (d) reprocessing the element from the mixture and extracting an organic solvent or a first solvent from the element; And (e) reusing the element.

A thermal management device is also provided that accommodates a corrosive acid-derived foam as a thermal diffusion or heat dissipating element. The thermal management device may include a heat exchanger, a heat sink, a heat pipe, a high conductivity insert, a conductive plate between the heat sink and the heat source, a heat-diffusing component, a heat-dissipating component, a thermal interface medium, or a thermoelectric or peltier And a Peltier cooling device.

Corrosive acids (HA) are organic materials commonly found in soils and can be extracted from the soil using bases (e.g., KOH). HA can also be extracted from a coal type, called kirka, which is a highly oxidized form of lignite. The HA extracted from the soft lignite contains a plurality of oxygenated groups (e.g., carboxyl groups) located around the edges of the graphene-like molecule center (SP ² core of hexagonal carbon structure). This material is somewhat similar to oxidized graphene (GO) produced by strong acid oxidation of natural graphite. HA has a typical oxygen content of 5 wt% to 42 wt% (the other major elements being carbon, hydrogen, and nitrogen). An example of the molecular structure of a corrosive acid with various components including quinones, phenols, caffeols and sugar moieties is provided in Scheme 1 below (Source: Stevenson FJ " Humus Chemistry: Genesis, Composition, Reactions , &Quot; John Wiley & Sons, New York 1994 ).

[Scheme 1]

Non-aqueous solvents for the acidic acids include polyethylene glycol, ethylene glycol, propylene glycol, alcohols, sugar alcohols, polyglycerols, glycol ethers, amine-based solvents, amide-based solvents, alkylene carbonates, organic acids or inorganic acids.

The present invention provides a corrosion acid-derived foam comprising a plurality of pores and pore walls and a process for the production thereof. The pores in the foams are such that the sheet-like corrosion acid molecules are (1) chemically linked / combined together (edge-to-edge and / or face-to-face) at a temperature typically between 100 and 1500 占 폚, and / (Referred to herein as graphitization) to a larger graphite crystal or domain along the pore wall at a high temperature (typically greater than 2,100 DEG C, and more typically greater than 2,500 DEG C) or (2) at a high temperature

The present invention also provides a production process comprising the steps of: (a) preparing a corrosion acid dispersion having a plurality of corrosion acid molecules or sheets dispersed in a liquid medium, wherein the corrosion acid is selected from the group consisting of oxidized acid, A chlorinated acid, a chlorinated acid, a brominated acid, a iodinated acid, a hydrogenated acid, a nitrated acid, a doped acid, a chemically functionalized acid, Wherein the dispersion contains a selective foaming agent, wherein the blowing agent to corrosion acid weight ratio is from 0 / 1.0 to 1.0 / 1.0; (b) distributing and depositing a graphene dispersion onto the surface of a support substrate (e.g., a plastic film, a rubber sheet, a metal foil, a glass sheet, a paper sheet, etc.) to form a wetting layer of a corrosive acid; (c) partially or completely removing the liquid medium from the wetting layer of the corrosive acid to form a dry layer of the corrosive acid; And (d) to induce volatile gas molecules from non-carbon elements (e.g., O, H, N, B, F, Cl, Br, I etc.) or to activate the blowing agent to produce a corrosion acid- Heat treating the dried layer of the corrosion acid at a first heat treatment temperature of from 80 캜 to 3,200 캜 at a sufficient desired heating rate. Preferably, the dispensing and deposition procedure comprises placing the corrosive acid dispersion under orientation-induced stress. These non-carbon elements produce volatile gases that act as foaming agents or blowing agents when removed through heat-induced cracking.

The resulting corrosion acid-derived foam typically has a density of 0.005 to 1.7 g / cm ³ (more typically 0.01 to 1.5 g / cm ³ , even more typically 0.1 to 1.0 g / cm ³ , 0.75 g / cm ³ ) or a specific surface area of 50 to 3,000 m ² / g (more typically 200 to 2,000 m ² / g, most typically 500 to 1,500 m ² / g).

Blowing agents or foaming agents are substances that can generate a cell or foamed structure through a foaming process in a variety of materials that cause cure or phase transition, such as polymers (plastics and rubbers), glass, and metals. This is typically applied when the foamed material is in a liquid state. Previously, it was not known that foaming agents could be used to produce foamed material while in a solid state. More significantly, it has not been previously taught or implied that an aggregate of acidic acid molecules can be converted to a graphene-like foam through a blowing agent. The cell structure in the matrix is typically created for the purpose of reducing density and increasing heat resistance and sound insulation while increasing the thickness and relative stiffness of the original polymer.

Blowing agents or related blowing mechanisms that produce pores or cells (bubbles) in the matrix for producing foamed or cell material can be classified into the following groups:

(a) Physical blowing agents: for example, hydrocarbons (e.g., pentane, isopentane, cyclopentane), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and liquid CO ₂ . The bubble / foam-forming process is an endothermic process, i. E. It requires heat to volatilize the liquid foaming agent (e. G., From a chemical exotherm due to a melting process or crosslinking).

(b) Chemical blowing agents: for example, isocyanates, azo, hydrazine, and other nitrogen-based materials (for thermoplastic and elastomeric foams), sodium bicarbonates (e.g. used in baking soda, thermoplastic foams) . Here, gaseous products and other by-products are formed by chemical reactions, which are promoted by the exothermic heat of the process and the reacting polymer. Since the foaming reaction involves forming a low molecular weight compound that acts as a foaming gas, additional pyrogenic heat is also released. The titanium hydride powder is used as a foaming agent in the production of metal foams because it decomposes to form titanium and hydrogen gases at elevated temperatures. Zirconium (II) hydride is used for the same purpose. Immediately after formation, the low molecular weight compound will never return to the original foaming agent (s), i.e., the reaction is irreversible.

(c) Mixed physical / chemical blowing agents: Used to produce, for example, flexible polyurethane (PU) foams with very low densities. Both chemical and physical foaming can be used together to balance each other with respect to the emitted / absorbed thermal energy. As a result, temperature rise is minimized. For example, a diisocyanate and water (the reaction to form a CO ₂₎ is a mattress (mattresse) extremely with a lower density (the boiling to provide a gaseous form) of the liquid CO ₂ in the production of flexible PU foam for Is used.

(d) Mechanically injected agents: The mechanically prepared foam includes a method of introducing the bubble into a liquid polymerizable matrix (e.g., a non-vulcanizable elastomer in the form of a liquid latex). This method is advantageous for whisking-in air or other gas or low-boiling volatile liquid to the low-viscosity grating, injecting the gas into an extruder barrel or die, or into an injection-molded barrel or nozzle and providing a very fine bubble or gas Lt; RTI ID = 0.0 > shear / mix < / RTI > When the melt is molded or extruded and the part is at atmospheric pressure, the gas exits the solution just prior to solidification and expands the polymer melt.

(e) Soluble and leachable agents: soluble solid fillers, for example solid sodium chloride crystals which are mixed in a liquid urethane system and then shaped into solid polymer parts, Impregnated to form small interconnected holes in the relatively high density polymer product.

(f) The present inventors have discovered that all of the above five mechanisms can be used to generate pores in HA-derived materials while in a solid state. Another mechanism for producing pores in the HA material is through the generation and vaporization of volatile gases by removing such non-carbon elements in a high temperature environment. This is a unique self-foaming process that has never been taught or presented before.

In the foam of the present invention, the pore walls (cell walls) contain chemically bonded and merged graphene-like hexagonal carbon atom planes. These planar aromatic molecules or hexagonal carbon atoms are physically and chemically well interconnected. The lateral dimensions (length or width) of such planes are enormous (greater than 20 nm to greater than 10 microns), typically several times or even tens times greater than the maximum length / width of the starting corrosion acid molecule. The hexagonal carbon atom planes are essentially interconnected to form a long electron-conducting path with low resistance. It is a unique and novel class of material that has not been previously identified, developed, or likely to be present.

In step (b), the HA suspension is preferably formed into a wetting layer on the solid substrate surface (e. G., PET film or glass) under the influence of shear stress. One example of such a shear procedure is casting or coating a thin film of the HA suspension using a coating machine. This procedure is analogous to the layer of varnish, paint, coating, or ink coated on a solid substrate. Rollers, "doctor's blades," or wipers can be used to generate shear stress at a sufficiently high kinetic rate when the film is shaped, or when there is relative movement between the roller / blade / wiper and the support substrate . Very unexpectedly and remarkably, such shear action causes the planar HA molecules to be well aligned along the shear direction, for example. More surprisingly, such molecular alignment or preferred orientation is not destroyed when the liquid component in the HA suspension is subsequently removed to form a well-packed layer of highly aligned sheet-like HA molecules at least partially dried. The dried HA film has a high birefringence coefficient between the in-plane direction and the normal direction to the plane.

In one embodiment, this HA layer is then thermally-induced to remove non-carbon elements (e.g., F, O, etc.) from HA molecules to generate volatile gases as byproducts and / or Treated with a heat treatment to activate the blowing agent. These volatile gases generate pores or bubbles inside the solid HA material and push the sheet-like HA molecules into the wall structure to form the HA foam. If no blowing agent is added, the non-carbon element in the HA material preferably occupies at least 10 wt% (preferably at least 20 wt%, and more preferably at least 30 wt%) of the HA material. The first (initial) heat treatment temperature is typically above 80 ° C, preferably above 100 ° C, more preferably above 300 ° C, even more preferably above 500 ° C and as high as 1,500 ° C. The blowing agent is typically activated at a temperature of from 80 캜 to 300 캜, but may be higher. The foaming process (formation of pores, cells or bubbles) is typically completed within a temperature range of 80 to 1,500 占 폚. Surprisingly, the chemical linkage or incorporation between the hexagonal carbon atom planes in the edge-to-edge and in the face-to-face manner (Figure 2) can occur at relatively low heat treatment temperatures (e.g. as low as 150 to 300 ° C) have.

The HA-derived foam may be treated with at least a further heat treatment comprising a second temperature which is significantly higher than the first heat treatment temperature.

A suitably programmed heat treatment procedure may be carried out at only a single heat treatment temperature (e.g., only a first heat treatment temperature), at least two heat treatment temperatures (a first temperature for a predetermined time, (Or maintained at this second temperature), or any other combination of heat treatment temperatures (HTT) comprising an initial treatment temperature (first temperature) and a final heat treatment temperature (HTT) (second) . The highest or final HTT from which the dried HA layer is formed can be divided into four distinct HTT regimes:

Method 1 (80 ° C to 300 ° C): In this temperature range (chemical coupling and thermal reduction, and also, if present, the activation method for the blowing agent), the HA layer provides heat- Which is roughly exemplified in the upper part of Fig. This also results in the reduction of the oxygen content typically from 20 to 42% to about 10 to 25% (of O in HA), accompanied by the removal of some non-carbon atoms such as O and H. This treatment may be achieved by reducing the interplanar spacing in the foam wall from approximately 0.6 to 1.2 nm (at dry) to approximately 0.4 to 0.6 nm and increasing the thermal conductivity to 100 W / mK per unit of specific gravity and / / cm. < / RTI > (Since the degree of porosity of the graphene foam material, and thus the level of specific gravity, can vary, and both the thermal and electrical conductivities vary with specific gravity when providing the same graphene material, These property values should be divided by weight to facilitate a fair comparison). Even at these low temperature ranges, some chemical linkage occurs between the HA molecules. The interplanar spacing is kept relatively large (0.4 nm or greater). There are a number of O-containing functional groups (e.g., -OH and -COOH).

Method 2 (300 ° C to 1,500 ° C): In such chemical coupling and merging schemes, a wide range of chemical combinations, polymerization, and crosslinking occur between adjacent HA molecules or linked HA molecules, resulting in the initial graphene- Forming an atomic plane, as illustrated in the lower portion of FIG. The oxygen content is typically reduced to 2% to 10% (e.g., after chemical bonding and incorporation), resulting in a reduction in planar spacing of approximately 0.345 nm. This is in sharp contrast to conventional graphitizable materials (e.g., carbonized polyimide films) that typically require temperatures as high as 2,500 ° C to initiate graphite, suggesting that some initial graphitization has already been initiated at these low temperatures it means. This is another distinctive feature of the graphene foam of the present invention and its production process. This chemical coupling reaction results in an increase in thermal conductivity up to 250 W / mK per unit of specific gravity, and / or an increase in electrical conductivity up to 2,500-4,000 S / cm per unit of specific gravity.

Method 3 (1,500 to 2,500 ° C): In this sorting and graphitizing mode, extensive graphitization or merging of graphene-like planes occurs, which significantly improves the degree of structural alignment in the foam wall. As a result, the oxygen content is typically reduced by 0.1% to 2%, and the intergranular spacing is reduced to approximately 0.337 nm (achieving a graphitization degree of 1% to about 80%, depending on the actual HTT and time length). The improved degree of alignment is also reflected by an increase in thermal conductivity up to 350 W / mK per unit of specific gravity, and / or an increase in electrical conductivity up to more than 3,500 S / cm per unit of specific gravity.

Method 4 (higher than 2,500 ° C): In such recrystallization and finishing schemes, extensive migration and removal of grain boundaries and other defects takes place, resulting in the formation of nearly perfect single crystalline or polycrystalline graphene-like crystals with large grains in the foam walls , Which may be tens of times larger than the original size of the HA molecule. The oxygen content is essentially eliminated, typically from 0% to 0.01%. The interplanar spacing is reduced to approximately 0.3354 nm (from 80% to nearly 100% graphitization), corresponding to the intergraphic spacing of the complete graphite single crystals. The foamed structure thus obtained exhibits a thermal conductivity of greater than 400 W / mK per unit of specific gravity and an electrical conductivity of greater than 4,000 S / cm per unit of specific gravity.

The HA-derived foam structure of the present invention is characterized in that the dried HA is subjected to a temperature program comprising at least a first mode (typically requiring from 1 to 4 hours in this temperature range if the temperature does not exceed < RTI ID = 0.0 > 500 C) , More typically, the first two modes (preferably one to two hours), and more typically the first three modes (preferably 0.5 to 2.0 hours in mode 3) (Including Method 4 for 0.2 to 1 hour, which may be performed to achieve the highest conductivity).

The X-ray diffraction pattern was obtained with an X-ray diffractometer equipped with CuKcv radiation. The shift and broadening of the diffraction peaks were corrected using silicon powder standards. The degree of graphitization (g) is calculated using the equation of Mering, d ₀₀₂ = 0.3354 g + 0.344 (1-g), where d ₀₀₂ is the interlayer spacing of graphite- or graphene- Lt; / RTI > pattern. This equation is valid only when d ₀₀₂ is approximately 0.3440 nm or less. An HA-derived foam wall having a d ₀₀₂ higher than 0.3440 nm may have an oxygen-containing functional group (e. G., A-OH on the graphene-like molecular plane surface or edge,> 0, And -COOH).

Another structural index that can be used to characterize the degree of alignment of the hexagonal carbon atom planes stacked and bonded in the foam wall of HA-induced graphene-like and conventional graphite crystals is " mosaic spread & Is expressed by the maximum half width of the rocking curve (X-ray diffraction intensity) of the (002) or (004) reflection. This degree of alignment characterizes the graphite or graphene crystal size (or grain size), the grain size and the amount of other defects, and the desired degree of grain orientation. Almost complete single crystals of graphite are characterized by having a mosaic dispersion value of 0.2 to 0.4. Most of the inventive graphene walls have a mosaic dispersion value in this range of 0.2 to 0.4 (when produced at a heat treatment temperature (HTT) of 2,500 占 폚 or higher). However, some values are in the range of 0.4 to 0.7 for the HTT of 1,500 to 2,500 占 폚 and in the range of 0.7 to 1.0 for the HTT of 300 to 1,500 占 폚.

The most likely chemical linking and merge mechanism is illustrated in FIG. 2, where only two aligned HA molecular segments are shown as an example, but multiple HA molecules may be chemically linked together and multiple " linked " HA molecule " can chemically combine to form a foam wall. In addition, the chemical linkage can occur not only on the edge-to-edge but also on the face-to-face for HA molecules or sheets. These linking and merging reactions proceed in such a way that molecules are chemically merged, linked, and integrated into a single entity. The resulting product is not a simple aggregate of individual HA sheets but essentially a single entity that is a network of interconnected macromolecules with essentially infinite molecular weights. All of the hexagonal carbon planes that make up are very large in lateral dimension (length and width), and if the HTT is high enough (e.g., above 1,500 ° C or much higher), these planes are essentially bonded together.

In an in-depth study using a combination of SEM, TEM, selected area diffraction, X-ray diffraction, AFM, Raman spectroscopy and FTIR, it is stated that the HA-derived foam wall consists of several large hexagonal carbon atom planes (typically >> 20 nm, more typically >> 100 nm, often >> 1 μm, and in many cases, >> 10 μm, or even >> 100 μm). These giant graphene-like planes are often formed in the thickness direction (crystallographic c-axis direction) through van der Waals forces (as in conventional graphite crystallizers) as well as covalent bonds, when the final heat treatment temperature is lower than 2,500 ° C. Are stacked and joined together. In this case, while not wishing to be bound by theory, Raman and FTIR spectroscopy studies indicate that co-existence of sp ² (dominant) and sp ³ (present but weak) electron configurations, rather than the usual sp ^2, is indicated in graphite .

(1) Such HA-induced graphite foam walls are not made by bonding or bonding separate flakes / plates together with resin binders, linkers, or adhesives. Instead, HA molecules are incorporated into integrated graphene-like crystal entities through linkage or formation of covalent bonds to each other, without using any externally added linker or binder molecules or polymers.

(2) Foam walls are typically polycrystals composed of large particles with incomplete grain boundaries. This entity is derived from multiple HA molecules, and these aromatic HA molecules lost their original identity. Upon removal of the liquid component from the suspension, the resulting HA molecules essentially form an amorphous structure. Upon heat treatment, these HA molecules are chemically combined and connected to form a single or integral graphite entity that constitutes the foam wall. The foam wall is highly ordered.

And (3) their specific chemical composition (including oxygen or non-carbon content), morphology, crystal structure (including interplanar spacing), and structural features (e.g., high degree of orientation, very few defects, The HA-derived foam has significant thermal conductivity, electrical conductivity, mechanical strength, and rigidity (elasticity) due to the absence of chemical bonds, the absence of gaps between graphene sheets, and substantially no interruption in the hexagonal carbon plane Modulus). ≪ / RTI >

It can further be mentioned that when the non-carbon element content (H and O) is 2 to 20% by weight, the desired desired hydrophilicity can be imparted to the pore walls of the corrosion acid-derived foam. These features enable the separation of oil from water by selectively absorbing oil from the oil-water mixture. In other words, such HA-derived foam materials can recover oil from water, which helps to clean oil-spilled rivers, lakes, or oceans. The oil absorption capacity is typically 50% to 500% of the foam's own weight. This is a very useful material for environmental protection purposes.

If high electrical conductivity or thermal conductivity is required, the HA-carbon foam may undergo a graphitization treatment at temperatures higher than 2,500 ° C. The resulting material is particularly useful for thermal management applications (e.g., for use in manufacturing finned heat sinks, heat exchangers, or heat spreaders).

The HA-carbon foam may be referred to as being able to undergo compression during and / or after the graphitization treatment. This operation makes it possible to adjust the graphene sheet orientation and porosity.

In order to characterize the structure of the resulting graphite material, an X-ray diffraction pattern was obtained using an X-ray diffractometer equipped with CuKcv radiation. Silicon powder standards were used to compensate for shift and broadening of the diffraction peaks. Mering equation _{(Mering's Eq), d 002} = 0.3354 g + 0.344 (1 - g) ( wherein, d ₀₀₂ is graphite or Yes The interlayer spacing of the pins determined (unit: nm)) by using the degree of graphitization from the X- ray pattern, g . This equation is valid only when d ₀₀₂ is approximately 0.3440 nm or less. In this study, graphene-like (HA or RHA) foam walls with d ₀₀₂ of greater than 0.3440 nm are present in the presence of oxygen-containing functionalities such as -OH, > O, and -COOH on the graphene molecular plane surface or edge , Which acts as a spacer to increase spacing between graphenes.

Another structural index that can be used to characterize the orderliness of stacked and bonded RHA planes in the foam wall of graphene and conventional graphite crystals is " mosaic spread ", which is either (002) ) Is represented by the half-width of the rocking curve of the reflection (X-ray diffraction intensity). This orderliness characterizes graphite or graphene crystal size (or grain size), grain size and other defects, and the degree of desired grain orientation. Almost complete single crystals of graphite are characterized by a mosaic dispersion value of 0.2 to 0.4. Most of the RHA walls of the present invention (when produced with a heat treatment temperature (HTT) of 2,500 占 폚 or more) have a mosaic dispersion value within the range of 0.2 to 0.4. However, some values are in the range of 0.4 to 0.7 for the HTT of 1,500 to 2,500 占 폚 and in the range of 0.7 to 1.0 for the HTT of 300 to 1,500 占 폚.

Thorough research using a combination of SEM, TEM, selected area diffraction, X-ray diffraction, AFM, Raman spectroscopy, and FTIR has shown that the corrosion acid-carbon foam wall has some large graphic planes >> 20 nm, more typically >> 100 nm, often >> 1 μm, in many cases >> 10 μm). This is a very unexpected thing because the lateral dimensions (length and width) of the original cored sheets or molecules before heat treatment are typically less than 20 nm, and more typically less than 10 nm. This implies that a plurality of HA sheets or molecules can be merged to one another edge-to-edge through covalent bonds to form a larger (longer or wider) sheet.

These large graphene-like planes can also be laminated and bonded along the thickness direction (crystallographic c- axis direction), which is often due to the van der Waals forces (as in conventional graphite microcrystals) Lt; RTI ID = 0.0 > 2500 C < / RTI > In these cases, although not wishing to be bound by theory, Raman and FTIR spectroscopy studies show the coexistence of sp ² (predominant) and sp ³ (weakly present) electron configurations as well as conventional sp ² in graphite see.

The integral HA-derived foam is comprised of a plurality of pore and pore walls, and the pore walls contain a chemically bonded single layer or multiple layer HA sheet, wherein the multiple layer HA sheet is measured by X-ray diffraction , Wherein the single-layer or multi-layer graphene-like HA sheet has 2 to 10 layers of laminated graphene-like merged HA planes with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.36 nm, 25% by weight of non-carbon elements (more typically less than 15%).

Typically, the integral HA-derived foam has a density of 0.001 to 1.7 g / cm ³ and / or a specific surface area of 50 to 3,000 m ² / g and / or a thermal conductivity per unit of specific gravity of at least 200 W / mK and / , The electric conductivity per unit of specific gravity is 2,000 S / cm or more. In a preferred embodiment, the pore walls contain a laminated graphene-like RHA plane with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.40 nm when measured by X-ray diffraction.

Most of the HA sheets can be merged to form edge-to-edge through covalent bonding to form an integrated reduced HA (RHA) entity. (E. G., Degree of orientation, very few defects, chemical bonds, and graphene-like structures), and the like, as well as their specific chemical composition (including oxygen or hydrogen content), morphology, crystal structure The absence of a gap between similar sheets, and virtually no interruption along the hexagonal plane direction), the HA-derived foam has a unique combination of outstanding thermal conductivity, electrical conductivity, mechanical strength, and stiffness (elastic modulus) .

Thermal management application

The above-mentioned features and characteristics make the integral HA-derived foam an ideal element for a wide range of engineering and biomedical applications. For example, if only for thermal management purposes, the form can be used in the following applications:

a) Compressible, HA-derived foam with high thermal conductivity is ideally suited for use as a thermal interface material (TIM) that can be implemented between a heat source and a heat spreader or between a heat source and a heat sink.

b) HA-derived foams can be used as heat spreaders themselves due to their high thermal conductivity.

c) The HA-derived foam has a high heat-diffusing ability (high thermal conductivity) and a high heat-dissipating ability (many surface pores induce large air-convection micro- or nano channels) as a heat sink or heat dissipating material Can be used.

d) light weight (low density adjustable between 0.001 and 1.8 g / cm ³ ), high thermal conductivity per unit of specific gravity or per unit of physical density, and high structural integrity (HA sheets are merged together to form long electron- Makes this HA-derived foam an ideal material for durable heat exchangers.

The HA-derived foam-based heat management or heat dissipating device may include a heat exchanger, a heat sink (e.g., a pinned heat sink), a heat pipe, a high conductivity insert, a thin or thick conductive plate , Thermal interface media (or thermal interface materials, TIM), thermoelectric or Peltier cooling plates, and the like.

A heat exchanger is a device used to transfer heat between one or more fluids; For example, gas and liquid flow separately in different channels. The fluids are typically separated by a solid wall to prevent mixing. The HA-derived foam material of the present invention is an ideal material for such walls, unless the foam is a fully open cell foam that allows mixing of fluids. The method of the present invention enables the generation of both an open cell foam structure and a closed cell foam structure. A high surface pore area allows for very rapid heat exchange between two or more fluids.

Heat exchangers are widely used in refrigeration systems, air conditioning units, heaters, power plants, chemical plants, petrochemical plants, petroleum refining, natural gas processing, and sewage treatment. A well known example of a heat exchanger is found in an internal combustion engine where circulating engine coolant flows through a radiator coil during which air flows past the coil, which cools the coolant and heats the incoming air. Solid walls (e.g., those that constitute radiator coils) are typically made of high thermal conductivity materials, such as Cu and Al. The HA-derived foams of the present invention with higher thermal conductivity or higher specific surface area are, for example, superior substitutes for Cu and Al.

There are many types of heat exchangers that can be purchased: shell and tube heat exchangers, plate heat exchangers, plate and shell heat exchangers, adiabatic wheel heat exchanger, plate fin heat exchanger, pillow plate heat exchanger, fluid heat exchanger, waste heat recovery unit, dynamic scraped surface heat exchanger, Phase change heat exchanger, direct contact heat exchanger, and microchannel heat exchanger. Both of these types of heat exchangers can utilize the exceptional high thermal conductivity and specific surface area of the foam material of the present invention.

The solid HA-derived foam of the present invention can also be used in a heat sink. Heat sinks are widely used in electronic devices for heat dissipation purposes. Central processing units (CPUs) and batteries in portable microelectronic devices (e.g., notebook computers, tablets, and smart phones) are well known heat sources. Typically, a metal or graphite object (e.g., a Cu foil or a graphite foil) is brought into contact with a hot surface and the object is exposed to heat (mainly by conduction and convection and to a lesser extent by radiation) Helping to diffuse into the outside air. In most cases, a thin thermal interface material (TIM) mediates between the hot surface of the heat source and the heat spreader or the heat-diffusing surface of the heat sink. (The HA-derived foam of the present invention can also be used as a TIM.)

The heat sink includes a high conductivity material structure having one or more flat surfaces to ensure good thermal contact with the components to be cooled and a high conductivity material structure having a surface contact with air, typically arrays of comb or fin-like protrusions. A heat sink can be used with the fan to increase the speed of airflow over the heatsink. The heat sink may have multiple pins (an extended or protruding surface) to improve heat transfer. In an electronic device having a limited amount of space, the shape / arrangement of the fins must be optimized to maximize the heat transfer density. Alternatively or additionally, a cavity (inverted pin) may be embedded in the region formed between adjacent fins. These cavities are effective in extracting heat from the various heat generating bodies to the heat sink.

Typically, the integrated heat sink includes at least one heat dissipating member (e.g., a fin or multiple pins) integral with a heat collecting member (core or base) and a heat collecting member (base) . Without the use of externally applied adhesives or mechanical fastening means to connect the pin to the core, the pin and core are naturally connected or integrated together to form an integrated body. The heat collection base has a surface in thermal contact with a heat source (e.g., an LED), collects heat from such heat sources, and dissipates heat through the fins into the air.

As an illustrative example, FIG. 10 provides a schematic view of two heat sinks 300, 302 . The first contains a plurality of fins or heat dissipating members (e.g., pins 306 ) connected to a heat collecting member (or base member) 304 and a base member 304 . The base member 304 is shown having a heat collecting surface 314 intended to be in thermal contact with a heat source. The heat-dissipating member or fin ( 306 ) is shown having at least a heat dissipating surface ( 320 ).

A particularly useful embodiment is an integral radial heat sink 302 that includes a radially finned heat sink assembly comprising: (a) a base 308 including a heat collection surface 318 ; And (b) or supported by a base 308. In the integral of a plurality of spaced parallel flat pin member (for example, as two examples 310 and 312) (where, flat pin member (e.g., 310) Includes at least one heat dissipating surface 322 ). The plurality of parallel flat fin members are preferably equally spaced.

The HA-derived foam of the present invention, which is highly elastic and resilient, is itself a good thermal interface material and likewise a highly effective heat diffusing element. In addition, these high conductivity foams can also be used as inserts for electronic cooling and to improve heat removal from a small chip to a heat sink. Since space occupied by high conductivity materials is a major concern, it is more efficient to use a high conductivity path that can be embedded into the heat generating body. The elastic and highly conductive solid graphene foams disclosed herein fully satisfy these requirements.

The high resilience and high thermal conductivity are obtained when the solid HA-derived foam of the present invention is placed as a heat transfer interface between a heat source and a low temperature fluid (or any other heat sink) to improve cooling performance, Plate it. In such an arrangement, the heat source is cooled under a subsequent HA-induced foam plate instead of being cooled in direct contact with the cooling fluid. The HA-derived foam backplane plate can significantly improve the heat transfer between the heat source and the cooling fluid by conducting the heat current in an optimal manner. No additional pumping power and extra heat transfer surface area are required.

HA-derived foam is also an excellent material for constructing heat pipes. A heat pipe is a heat transfer device that transports a large amount of heat with a very small difference in temperature between the high temperature interface and the low temperature interface, using evaporation and condensation of the two-phase working fluid or coolant. A typical heat pipe consists of a sealed hollow tube made of a thermally conductive metal, such as Cu or Al, and a wick to return the working fluid from the evaporator to the condenser. The pipe contains both saturated liquid and vapor of the working fluid (e.g. water, methanol or ammonia) and all other gases are excluded. However, both Cu and Al are prone to oxidation or corrosion, and their performance deteriorates relatively quickly over time. In contrast, HA-derived foams are chemically inert and have no such oxidation or corrosion problems. A heat pipe for thermal management of an electronic device may have a foam envelope and a wick, wherein water is used as the working fluid. HA-derived foam / methanol may be used when the heat pipe needs to be operated at a temperature lower than the freezing point of water, and HA-derived foam / ammonia heat pipes may be used for cooling the electronic device in space.

The Peltier cooling plate is operated in a Peltier effect to generate a heat flux between the junctions of two different electrical conductors by applying current. These effects are commonly used to cool electronic components and small appliances. Indeed, many such junctions can be arranged in series to increase the effect on the amount of heating or cooling required. HA-derived foams can be used to improve heat transfer efficiency.

Filtration and fluid absorption applications

The HA-derived foam may be prepared to contain microscopic pores (less than 2 nm) or mesoporous pores with pore sizes between 2 nm and 50 nm. The HA-derived foam may also be prepared to contain micro-scale pores (1 to 500 [mu] m). Based on well-controlled pore size only, the present HA-derived foam can be an exceptional filter material for air or water filtration.

In addition, the corrosive acid (HA) pore wall chemistry can be controlled to impart different amounts and / or types of functional groups to the pore walls (as reflected, for example, by percentages of O, F, N, . In other words, concurrent or independent control of both the pore size and the chemical functional group at different sites of the internal structure may result in many unexpected properties, synergistic effects, and any unique combination of properties typically considered to be mutually exclusive (e.g., , A portion of the structure is hydrophobic and the other portion is hydrophilic; or the foam structure is both hydrophobic and lipophilic). ≪ RTI ID = 0.0 > A surface or material is said to be hydrophobic if water is repelled from such a material or surface and a droplet placed on the hydrophobic surface or material forms a large contact angle. The surface or material is said to have a strong affinity for oil and a lipophilicity for water. The method allows precise control over hydrophobicity, hydrophilicity, and lipophilicity.

The present invention also provides an oil-removing, oil-separating, or oil-recovering device containing the HA-derived foam of the present invention as an oil-absorbing or oil-separating element. Also provided is a solvent-removing or solvent-separating device which contains HA-derived foam as the solvent-absorbing element.

The main advantage of using this HA-derived foam as an oil-absorbing element is its structural integrity. Due to the concept that HA sheets are chemically incorporated and thus have a high structural integrity, the resulting foam will not disintegrate during repeated oil absorption operations. In contrast, it has been found that the graphene-based oil-absorbing element prepared by hydrothermal reduction, vacuum-assisted filtration, or freeze-drying disintegrates after absorbing oil two or three times. There is nothing to keep these separate graphene sheets together (other than the weak van der Waals forces that existed before the first contact with the oil). Once these graphene sheets are wetted by the oil, they can no longer be returned to the original shape of the oil-absorbing element.

Another major advantage of the present technology is the ability to absorb the oil to an amount as high as 400 times its own weight while still maintaining its structural shape (without substantial expansion) in designing and manufacturing the oil- to be. This amount is dependent on the specific pore volume of the foam, which can be controlled primarily by the ratio between the amount of original carrier polymer particles and the amount of HA molecules or sheet before heat treatment.

The present invention also provides a method for separating / recovering oil from an oil-water mixture (e.g., oil-effluent water or wastewater from an oil sand). The method comprises the steps of: (a) providing an oil-absorbing element comprising an integral HA-derived foam; (b) contacting the oil-water mixture with an element to absorb oil from the mixture; And (c) reprocessing the oil-absorbing element from the mixture and extracting the oil from the element. Advantageously, the method comprises the further step of (d) reusing the element.

In addition, the present invention provides a process for separating an organic solvent from a solvent-water mixture or from a multi-solvent mixture. The method comprises the steps of: (a) providing an organic solvent-absorbing element comprising an integral HA-derived foam; (b) contacting the urea with an organic solvent-water mixture or a multi-solvent mixture containing a first solvent and at least a second solvent; (c) allowing the element to absorb the organic solvent from the mixture or at least absorb the first solvent from the second solvent; And (d) reprocessing the element from the mixture and extracting the organic solvent or first solvent from the element. Preferably, the method comprises (e) an additional step of reusing the solvent-absorbing element.

1 is a schematic diagram illustrating a process for producing a graphene sheet from natural graphite particles.
Figure 2 is a possible mechanism for the chemical linkage and coalescence between the acidic acid molecules and the " connected HA molecules ". Two or three original HA molecules can be chemically linked together to form longer or wider HA molecules called " connected HA molecules ". A number of " connected HA molecules " can be merged to form a graphene-like hexagonal carbon atom plane.
Figure 3a is a thermal conductivity value for specific gravity of HA-derived foam, mesophase pitch-induced graphite foam, and Ni foam-mold assisted CVD graphene foam produced by the process of the present invention.
Figure 3b is the thermal conductivity values of the HA-derived foam, the sacrificial plastic bead-cast GO foam, and the hydrothermally reduced GO graphene foam.
Figure 4 is electrical conductivity data of HA-derived foam and hot-reduced GO slipform foam produced by the process of the present invention.
Figure 5 is a graphical representation of the thermal conductivity values of a foam sample derived from HA and fluorinated HA as a function of specific gravity.
Figure 6 is a thermal conductivity value of a foam sample derived from HA and pristine graphene as a function of final (maximum) heat treatment temperature.
Figure 7 is a graphical representation of the amount of oil absorbed per gram of HA-derived foam as a function of the oxygen content in the foam with a porosity level of approximately 98% (oil separation from the oil-water mixture).
Figure 8 is a plot of the amount of oil absorbed per gram of integral HA-derived foam as a function of porosity level (assuming the same oxygen content).
Figure 9 is a plot of the amount of chloroform absorbed from the chloroform-water mixture as a function of degree of fluorination.
10 is a schematic view of a heat sink structure (two embodiments).

The following examples are used to illustrate some specific details of the best modes of carrying out the invention and are not to be construed as limiting the scope of the invention.

Example 1: Corrosive acid from reduced lignite and reduced corrosive acid

By dispersing the friable lignite in a basic aqueous solution (pH 10), the caustic acid can be extracted from the friable lignite at a very high yield (in the range of 75%). Subsequent acidification of this solution leads to precipitation of the corrosive acid powder. In the experiment, 3 g of brown coal was dissolved in 300 ml of a double deionized water solution containing 1 M KOH (or NH ₄ OH) under magnetic stirring. The pH value was adjusted to 10. The solution was then filtered to remove any large particles or any residual impurities. The resulting corrosion acid dispersion, containing HC alone or in the presence of a blowing agent, was cast on a glass substrate to form a series of films for subsequent heat treatment.

In some samples, a chemical blowing agent (hydrazodicarbonamide) was added to the suspension just prior to casting. Then, the obtained suspension was cast on a glass surface using a doctor blade to exert shear stress to induce HA molecular orientation. The HA coating film obtained after removal of the liquid has a thickness that can vary from approximately 10 nm to 500 μm (preferably and typically from 1 μm to 50 μm).

To prepare HA foam specimens, the HA coating film was then heat treated such that the heat treatment is typically carried out for 1 to 8 hours at an initial heat reduction temperature of 80 to 350 占 폚, for a period of 0.5 to 5 hours at 1,500 to 2,850 占 폚 Followed by a heat-treatment at a second temperature. It has been noticed that it is necessary to apply compressive stress to the coating film sample during the first heat treatment. This compressive stress is believed to be responsible for maintaining good contact between the HA molecules or sheets, allowing for chemical coalescence and linkage between the HA molecules or sheets while the pores are being formed. Without such compressive stresses, the heat-treated film is typically excessively porous, and the constituent hexagonal carbon atom planes in the pore walls are very poorly oriented / positioned and may not be chemically coupled and connected to one another. As a result, the thermal conductivity, electrical conductivity, and mechanical strength of the graphene foam are severely impaired.

Example 2: Various blowing agents and pore-forming (bubble-forming) processes

In the field of plastics processing, chemical blowing agents are mixed in plastic pellets in powder or pellet form and dissolved at higher temperatures. Above a specific specific temperature for blowing agent dissolution, a gaseous reaction product (usually nitrogen or CO ₂ ) is generated, which acts as a blowing agent. However, a chemical blowing agent that is solid rather than liquid can not be dissolved in the graphene material. This presents a problem in using chemical blowing agents to generate pores or cells in the graphene material.

After extensive experimentation, the inventors have found that practically any chemical foaming agent (e.g., powder or pellet form) can be used to produce pores or bubbles in the dried layer of graphene when the first heat treatment temperature is sufficient to activate the foaming reaction ≪ / RTI > The chemical blowing agent (powder or pellets) may be dispersed in the liquid medium to become a second component in the suspension, which may be deposited on a solid support substrate to form a wetting layer. The wet layer of such HA material can then be dried and heat treated to activate the chemical blowing agent. After the chemical blowing agent is activated and the bubble is generated, the resulting foamed HA structure is subsequently substantially retained when a higher heat treatment temperature is applied to the structure. This is actually very unexpected.

Chemical foaming agents (CFAs) may be organic or inorganic compounds that release gases upon thermal decomposition. CFAs are typically used to obtain medium- to high-density foams and are often used with physical blowing agents to obtain low-density foams. CFAs can be categorized as either endothermic or exothermic, which refers to the type of decomposition that takes place in this. The endothermic type absorbs energy, typically releases carbon dioxide and water during decomposition, and the exothermic type emits energy and usually produces nitrogen when decomposed. The total gas yield by the exothermic foaming agent and the pressure of the released gas are often higher than the endothermic type. Endothermic CFAs are generally known to decompose in the range of 130 to 230 ° C (266 to 446 ° F), and some of the more common exothermic foaming agents decompose at approximately 200 ° C (392 ° F). However, the decomposition range of most pyrogenic CFAs can be reduced by the addition of certain compounds. The activation (decomposition) temperature of CFAs is within these heat treatment temperature ranges. Examples of suitable chemical blowing agents are sodium bicarbonate (baking soda), hydrazine, hydrazide, azodicarbonamide (pyrogenic chemical blowing agent), nitroso compounds (such as N, N-dinitrosopentamethylene Tetramine), hydrazine derivatives (for example, 4,4'-oxybis (benzenesulfonylhydrazide) and hydrazodicarbonamide), and hydrogen carbonate (for example, sodium hydrogen carbonate). All of which are commercially available in the plastics industry.

In the production of foamed plastics, the physical blowing agent is metered into the plastic melt during foam extrusion or injection molding foaming, or is fed to one of the precursor materials during polyurethane foaming. Previously it was not known that the physical blowing agent could be used to produce pores in the HA material in solid state (but not in the melt). The inventors have surprisingly observed that a physical blowing agent (e.g., CO ₂ or N ₂ ) can be injected into the stream of HA suspension before being coated or cast on a support substrate. This will also cause a foamed structure when the liquid medium (e.g., water and / or alcohol) is removed. The dried layer of graphene material can maintain a controlled amount of pores or bubbles during liquid removal and subsequent heat treatment.

Technologically feasible foaming agents include carbon dioxide (CO ₂ ), nitrogen (N ₂ ), isobutane (C ₄ H ₁₀ ), cyclopentane (C ₅ H ₁₀ ), isopentane (C ₅ H ₁₂ ), CFC- ₃ ), HCFC-22 (CHF ₂ CI), HCFC-142b (CF ₂ CICH ₃ ), and HCFC-134a (CH ₂ FCF ₃ ). However, in selecting foaming agents, environmental safety is an important factor to consider. Its impact on the Montreal Protocol and its significant agreements is a major challenge for Forms producers. Despite the effective nature and ease of handling of previously applied chlorofluorocarbons, there has been a worldwide consensus that their ozone depletion potential (ODP) prohibits this. Some halogenated chlorofluorocarbons are also environmentally unsafe and, therefore, already prohibited in many countries. Alternatives are hydrocarbons, such as isobutane and pentane, and gases such as CO ₂ and nitrogen.

Except for such regulated substances, all blowing agents recited above were tested in this experiment. For both physical blowing agents and chemical blowing agents, the amount of blowing agent introduced into the suspension is typically defined as the blowing agent-to-HA material weight ratio from 0 / 1.0 to 1.0 / 1.0.

Example 3: Preparation of corrosion acid from coal

In a typical procedure, 300 mg of coal was suspended in concentrated sulfuric acid (60 ml) and nitric acid (20 ml), followed by cup sonication for 2 hours. The reaction was then stirred and heated in an oil bath at 100 or 120 < 0 > C for 24 hours. The solution was cooled to room temperature, poured into a beaker containing 100 ml of ice, and then NaOH (3M) was added until the pH reached 7.

In one experiment, the neutral mixture was then filtered through a 0.45 mm polytetrafluoroethylene membrane and the filtrate was dialyzed for 5 days in a 1000 Da dialysis bag. For larger corrosion acid sheets, the time may be shortened by 1 to 2 hours using cross-flow ultrafiltration. After purification, the solution was concentrated using rotary evaporation to give a solid corrosion acid sheet. These corrosive acid sheets alone and their mixtures with blowing agents were redispersed in solvents (ethylene glycol and alcohols separately) to obtain some dispersion samples for subsequent casting or coating.

A chemical foaming agent (N, N-dinitrosopentamethylenetetramine or 4,4'-oxybis (benzenesulfonylhydrazide)) in various amounts (1% to 30% by weight for HA material) ≪ / RTI > The suspension was then cast on a glass surface using a doctor blade to exert shear stress to induce orientation and proper positioning of the HA molecules or sheets. Several samples were cast, including those prepared using CO ₂ as the physical blowing agent introduced into the suspension just prior to casting. The resulting HA film has a thickness that can vary from approximately 1 to 100 mu m after removal of the liquid.

The HA film was then treated with a heat treatment comprising an initial (first) thermal reduction temperature of 80 to 1,500 占 폚 for 1 to 5 hours. This first heat treatment generated HA foam (when the HTT was less than 300 占 폚) and foam of a large sheet-like HA molecule or domain of the hexagonal carbon atom plane at the pore wall (when the HTT was between 300 and 1,500 占 폚). Subsequently, some of the foam samples are exposed to a second temperature of 1,500 to 2,850 ° C, so that the graphene-like domain of the hexagonal carbon atom plane in the foam wall can be further completed (graphitized to be more orderly or more ordered Can have a high degree of crystallinity).

Comparative Example 3-a : CVD graphene foam on a Ni foam mold

The procedure was constructed from those disclosed in the following published literature: Chen, Z., et al. "Three-dimensional flexible and conductive interconnected graphene networks grown by chemical vapor deposition," Nat. Mater. 10, 424-428 (2011). A porous structure with nickel in a nickel foam, i.e., a nickel in an interconnected 3D scaffold, was selected as the template for growth of the graphene foam. Briefly, the CH ₄ carbon by decomposition at ambient pressure and, after 1,000 ℃, and introduced into a nickel foam, a pin Yes film was deposited on the surface of the nickel foam. Due to the difference in the thermal expansion coefficient between nickel and graphene, ripples and wrinkles were formed on the graphene film. To recover the (separate) graphene foam, the Ni frame should be etched. A thin layer of poly (methyl methacrylate) (PMMA) was coated on the surface of the graphene film as a support to protect the graphene network from collapse during nickel etching, prior to etching the nickel skeleton with a hot HCl (or FeCl ₃ ) solution. Lt; / RTI > After the PMMA layer was carefully removed by hot acetone, a fragile graphene foam sample was obtained. The use of a PMMA backing layer is important for making a stand-alone film of graphene foam, and only a seriously distorted and deformed graphene foam sample was obtained without the PMMA backing layer. This is a tedious process that is not environmentally friendly and scalable.

Comparative Example 3-b : Conventional graphite foam from pitch-based carbon foam

Pitch powder, granules, or pellets were placed into aluminum molds having the desired final foam shape. Mitsubishi ARA-24 meso phase pitch was used. The sample was evacuated to less than 1 torr and then heated to a temperature of approximately 300 캜. At this point, the vacuum was released to a nitrogen blanket and then a pressure of 1,000 psi or less was applied. Thereafter, the temperature of the system was raised to 800 ° C. This was carried out at a rate of 2 [deg.] C / min. The temperature was maintained for at least 15 minutes to achieve immersion and then cooled to room temperature at a rate of approximately 1.5 [deg.] C / min with the furnace power turned off and the pressure evacuated at a rate of approximately 2 psi / min. The final foam temperature was 630 캜 and 800 캜. During the cooling cycle, the pressure is gradually released to atmospheric conditions. The foam was then heat treated to 1050 占 폚 under a nitrogen blanket and subsequently heat treated separately in graphite crucibles to 2500 占 폚 and 2800 占 폚 in argon.

Samples from the foam were machined into specimens to measure the thermal conductivity. The bulk thermal conductivity ranged from 67 W / mK to 151 W / mK. The density of the sample was 0.31 to 0.61 g / cm3. When the weight is taken into account, the non-thermal conductivity of the pitch-induced foam is approximately 67 / 0.31 = 216 and 151 / 0.61 = 247.5 W / mK per specific gravity (or physical density).

The compressive strength of the sample with an average density of 0.51 g / cm3 was measured to be 3.6 MPa and the compressibility was measured to be 74 MPa. In contrast, the compressive strength and compressive modulus of HA-derived graphite foams with similar physical densities are 5.7 MPa and 103 MPa, respectively.

FIG. 3A is a thermal conductivity value for specific gravity of HA-derived foam, mesophase pitch-induced graphite foam, and Ni foam mold-assisted CVD graphene foam. These data clearly demonstrate unexpected results:

1) HA-derived foams produced by the process of the present invention are significantly higher in comparison to both mesophase pitch-induced graphite foams and Ni foam mold-assisted CVD grains, when providing the same physical density Thermal conductivity.

2) This is quite surprising in view of the notion of CVD graphene as essentially pristine graphene, which, in the case of pristine graphene, has never been exposed to oxidation, so that oxygen-containing functional groups can be removed by conventional thermal or chemical reduction methods Should have exhibited much higher thermal conductivity as compared to the HA-induced hexagonal carbon atom plane (which has a high defect group and hence a low conductivity) that exhibits a high degree of defectivity after removal through the substrate. The unusually high thermal conductivity values observed for the HA-derived graphite foams produced here are very surprising.

3) Considering the same amount of solid material, the HA-derived foam of the present invention after heat treatment in HTT where the HTT is greater than 1,500 ° C exhibits essentially the highest conductivity, which results in a high level of graphite crystal integrity Dimensions, less grain boundaries and other defects, better crystal orientation, etc.). This is also unexpected.

4) The specific conductivity values (FIG. 5) of the HA-derived foam and the fluorinated HA-derived foam of the present invention show values of 250 to 490 W / mK per unit of specific gravity; Those of the other two foam materials are typically less than 250 W / mK per unit of specific gravity.

Comparative Example 3-c : Preparation of pristine graphene foam (0% oxygen)

Recognizing the potential for high defect populations in the HA sheet to serve to reduce the conductivity of individual graphene planes, the use of pristine graphene sheets (non-oxidizing and anoxic, non-halogenated, and halogen free) To lead to a graphene foam that has been found. Pristine graphene sheets were produced by direct sonication (also known in the art as liquid phase exfoliation).

In a typical procedure, to give the suspension was dispersed in the deionized water of 1,000 mL (containing Zonyl ^® FSO of DuPont dispersing agent 0.1% by weight) of graphite flakes in a 5 g grinding to a size of less than approximately 20 μm. An ultrasonic energy level of 85 W (Branson S450 Ultrasonic) was used for stripping, separation and size reduction of the graphene sheets for 15 minutes to 2 hours. The resulting graphene sheet is pristine graphene, which has never been oxidized and is anoxic and relatively defect free. There are no other non-carbon elements.

(N, N-dinitrosopentamethylenetetramine or 4,4'-oxybis (benzenesulfonylhydrazide)) in various amounts (1% to 30% by weight with respect to the graphene material) And then added to the suspension containing the graphene sheet and the surfactant. The suspension was then cast on a glass surface. Several samples were cast, including those made using CO ₂ as the physical blowing agent introduced into the suspension just prior to casting. The graphene film obtained after removal of the liquid has a thickness that can vary from approximately 10 to 100 mu m. The graphene film was then subjected to a heat treatment at a temperature of 80 to 1,500 DEG C for 1 to 5 hours, which produced a graphene foam.

6 summarizes the thermal conductivity data for a series of HA-derived foams and a series of initial graphene-derived foams, both plotted for the same final (maximum) heat treatment temperature. This data indicates that the thermal conductivity of the HA-derived foam is very sensitive to the final heat treatment temperature (HTT). Even when the HTT is very low, clearly some types of HA molecule linking and merge or crystal cleavage reactions have already been activated. Thermal conductivity increases monolithically with the final HTT. In contrast, the thermal conductivity of the initial graphene foam remains relatively constant until reaching a final HTT of approximately 2,500 ° C, suggesting the onset of recrystallization and completeization of the graphite crystal. Pristine graphene has no functional group that allows the chemical linkage of molecules at relatively low HTTs, such as -COOH and -OH at HA. For HTT as low as 1,250 캜, the HA molecules and the resulting hexagonal carbon atom planes can be merged to form a significantly larger graphene-like hexagonal carbon sheet with reduced grain boundaries and fewer electron transport path breaks. Although the HA-derivatized sheet inherently exhibits more defects than pristin graphene, the process of the present invention allows HA molecules to form graphite foams that exceed the pristine graphene foam. This is another unexpected result.

Comparative Example 3-d : Preparation of graphene foam from oxidized graphene (GO) suspension from natural graphite and hydrolyzed oxidized graphene

Graphite oxide was prepared by oxidizing graphite flakes at a ratio of 4: 1: 0.05 at 30 DEG C to an oxidant liquid consisting of sulfuric acid, sodium nitrate, and potassium permanganate. When the natural graphite flakes (particle size of 14 mu m) are immersed and dispersed in the oxidant mixture liquid for 48 hours, the suspension or slurry appears optically opaque and dark and remains. After 48 hours, the reacting mass was washed three times with water to adjust the pH value to at least 3.0. A series of GO-water suspensions was then prepared by adding a final amount of water. The present inventors have observed that a GO sheet forms a liquid crystal phase when the GO sheet occupies a weight fraction of more than 3%, and typically 5% to 15%.

A self-assembled graphene hydrogel (SGH) sample was then prepared by the hydrothermal method. In a conventional procedure, SGH can be easily prepared by heating a homogeneous aqueous graphene (GO) dispersion of 2 mg / mL sealed in a Teflon-lined autoclave at 180 ° C for 12 hours. SGH containing about 2.6% (by weight) graphene sheet and 97.4% water has an electrical conductivity of about 5 Х 10 ^-3 S / cm. Upon drying and heat treatment at 1,500 ° C., the resulting graphene foam exhibits an electrical conductivity of approximately 1.5 × 10 ^-1 S / cm, which is twice the electrical conductivity of the HA-derived foam of the present invention produced by the heat treatment at the same temperature It is low.

Comparative Example 3-e : Plastic Bead Molding of Reduced Oxidized Graphene Foam-Auxiliary Formation

A rigid mold-oriented aligned assembly for porous bubbled graphene film (MGF) was prepared. A mono-dispersed polymethyl methacrylate (PMMA) latex spheres were used as the hard mold. The GO liquid crystal prepared in Comparative Example 3-d was mixed with PMMA spherical suspension. Subsequent vacuum filtration was subsequently carried out to prepare an assembly of PMMA spheres and GO sheets, and the GO sheet was wrapped around the PMMA beads. The composite film was peeled from the filter, air dried, calcined at 800 DEG C to remove the PMMA template, and the GO was thermally reduced simultaneously with RGO. The gray independent PMMA / GO film turned black after firing and the graphene film retained its porosity.

FIG. 3B shows the thermal conductivity values of the HA-derived foam of the present invention, the GO foam produced through the sacrificial plastic bead template-assisted process, and the hot-reduced GO graphene foam. Most surprisingly, when providing the same HTT, the HA-derived foam exhibits the highest thermal conductivity. The electrical conductivity data summarized in Figure 4 also coincides with these results. When this data provides the same amount of solid material, the HA suspension of the present invention (with stress-induced orientation) and the subsequent heat treatment produce essentially the most conductive HA-derived foam to yield the highest levels of graphite But further reflects the quality crystal completeness (larger crystal dimensions, less grain boundaries and other defects, better crystal orientation along the pore wall, etc.).

All prior art processes for producing graphite foams or graphene foams have a physical density in the range of approximately 0.2 to 0.6 g / cm < 3 > with pore sizes typically too large (e.g., 20 to 300 mu m) for most intended applications Lt; RTI ID = 0.0 > macroporous < / RTI > In contrast, the present invention provides a process for producing an HA-derived foam having a density as low as 0.01 g / cm 3 and as high as 1.7 g / cm 3. The pore size may vary from a small scale (2 to 50 nm) to a maximum macro scale (1 to 500 탆) depending on the content of the non-carbon element and the amount / type of blowing agent used. The level of flexibility and variety that can be used to design various types of graphite foams is unprecedented and is not matched by any prior art process.

Example 4: Preparation of fluorinated HA foam

In a typical procedure, a sheet of HA-derived foam was fluorinated by vapor of chlorine trifluoride in a sealed autoclave reactor to obtain a fluorinated HA-carbon hybrid film. Different durations of fluorination time allowed different degrees of fluorination to be achieved. The sheets of fluorinated HA-derived foam were then separately immersed in the respective containers containing the chloroform-water mixture. These foam sheets selectively absorbed chloroform from water, and the amount of chloroform absorbed was observed to increase with the degree of fluorination until the fluorine content reached 7.2% by weight, as shown in FIG.

Example 5: Preparation of nitrated HA foams

Several pieces of the HA-derived foam prepared in Example 3 were immersed in a 30% H ₂ O ₂ -water solution for a period of 2 to 48 hours to obtain an oxidized HA- An inductive foam was obtained.

Some of the oxidized HA-derived foam samples were mixed with different proportions of urea and the mixture was heated in a microwave reactor (900 W) for 0.5 to 5 minutes. The product was washed several times with deionized water and vacuum dried. The product obtained was a nitrated HA foam. The nitrogen content was from 3 wt% to 17.5 wt% as determined by elemental analysis.

It can be mentioned that the different functionalization treatments of HA-derived foams are for different purposes. For example, an oxidized HA foam structure is particularly effective as an absorbent of oil from an oil-water mixture (i.e., the oil leaches into the water and is subsequently mixed together) (FIGS. 7 and 8). In this case, an integral HA-derived foam structure (with 0 to 15 wt% oxygen) exhibits both hydrophobic and lipophilic properties (Fig. 7). A surface or material is said to be hydrophobic if water is repelled from such a material or surface and a droplet placed on the hydrophobic surface or material forms a large contact angle. The surface or material is said to have a strong affinity for oil and a lipophilicity for water.

The different contents of O, F, and / or N also allow the HA-derived foam of the present invention to absorb different organic solvents from water or to separate one organic solvent from a mixture of multiple solvents.

Example 6 : Characterization of various HA-derived foams and conventional graphite foams

The internal structures (crystal structure and orientation) of several series of HA-carbon foam materials were investigated using X-ray diffraction. The X-ray diffraction curves of natural graphite typically show peaks at approximately 2 [Theta] = 26 [deg.], Corresponding to a graphene spacing (d ₀₀₂ ) of approximately 0.3345 nm. The RHA wall of the hybrid foam material typically exhibits a d ₀₀₂ spacing of 0.3345 nm to 0.40 nm, but more typically a maximum of 0.34 nm.

For a heat treatment temperature of 2,750 ° C for a foam structure under 1 hour of compression, the d ₀₀₂ spacing is reduced to approximately 0.3354 nm, which is the same value as the d ₀₀₂ spacing of graphite single crystals. Also, the second diffraction peak with high intensity appears at 2? = 55 °, which corresponds to X-ray diffraction from the (004) plane. The (004) peak intensity, or the I (004) / I (002) ratio for the (002) intensity on the same diffraction curve is a good indicator of the degree of crystalline completeness and the preferred orientation of the graphene-like plane. (004) peak is absent or relatively weak, with an I (004) / I (002) ratio of less than 0.1, for all graphite materials heat treated at a temperature of less than 2,800 ° C. I (004) / I (002) ratios for graphite materials (e.g., highly oriented pyrolytic graphite, HOPG) heat treated at 3,000 to 3,250 ° C range from 0.2 to 0.5. In contrast, graphene foam produced with a final HTT of 2,750 占 폚 for one hour exhibited an I (004) / I (002) ratio of 0.78 and a mosaic dispersion value of 0.21 indicating that the pore walls And is a substantially complete graphite single crystal having excellent preferable orientation degree.

The " mosaic dispersion " value is obtained from the maximum half width of the (002) reflection in the X-ray diffraction intensity curve. This index for the degree of alignment is characterized by the amount of graphite or graphene crystal size (or grain size), grain size and other defects, and the degree of desired grain orientation. Almost complete single crystals of graphite are characterized by having a mosaic dispersion value of 0.2 to 0.4. A portion of the HA-derived foam of the present invention has a mosaic dispersion value in this range of from 0.3 to 0.6 when produced using a final heat treatment temperature of at least 2,500 占 폚.

It is important to note that a heat treatment temperature as low as 500 ° C is sufficient to bring the average interplanar spacing between hexagonal carbon atom planes along the pore walls to less than 0.4 nm, closer to natural graphite or graphite single crystals. The great thing about this approach is that this HA suspension coating and heat treatment strategy has allowed the formation, alignment / alignment, and chemical incorporation of planar HA molecules to form an integrated structure, The pseudo-hexagonal carbon atom plane now has a larger lateral dimension (considerably larger than the length and width of the original HA molecule). Potential chemical connections and merging mechanisms are illustrated in FIG. This has resulted in exceptional thermal and electrical conductivity values.

In conclusion, the inventors have successfully developed an absolutely new, novel, unexpected, clearly distinct class of HA foam or HA-derived graphite foam materials and related production processes. The chemical composition (oxygen, fluorine, and% of other non-carbon elements), structure (crystal complete, grain size, defect group, etc.), crystal orientation, morphology, production process and properties of this new class of foam materials Are fundamentally different and distinctly distinguished from mesophase pitch-induced graphite foams, CVD graphene-derived foams, and graphene foams from GO hot reduction, and sacrificial bead template-assisted RGO foams. The thermal conductivity, electrical conductivity, modulus of elasticity, and flexural strength exhibited by the foam material of the present invention are much higher than prior art foam materials.

Claims (40)

A humic acid-derived foam comprising a plurality of pores and pore walls,
Wherein the pore wall contains a single layer or a few-layer corrosion acid-derived hexagonal carbon atom plane or sheet, wherein the multiple layer hexagonal carbon atom plane or sheet has a plane Layer planar hexagonal carbon atom planes with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.60 nm, said single layer or multi-layer planar hexagonal carbon atom planes comprising from 0.01% to 25% by weight of a non-carbon element Wherein the acid is selected from the group consisting of an oxidized acid, a reduced acid, a fluorinated acid, a chlorinated acid, a brominated acid, an iodinated acid, a hydrogenated acid, a nitrated acid, a doped acid , A chemically-functionalized acid, and combinations thereof. The method of claim 1, wherein the foam has a density of 0.005 to 1.7 g / cm ³ and / or a specific surface area of 50 to 3,200 m ² / g and / or a thermal conductivity per unit of specific gravity of at least 100 W / mK and / , A corrosion acid-derived foam having an electrical conductivity of 500 S / cm or more per unit of specific gravity. The corrosion acid-derived foam of claim 1, wherein the foam has a density of from 0.01 to 1.5 g / cm ^3, or an average pore size of from 2 nm to 50 nm. The method of claim 1, wherein the foam has a content of non-carbon elements in the range of from 0.01 wt% to 20 wt% and the non-carbon element is selected from oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, or boron ≪ / RTI > wherein the acid comprises an acid. The corrosion acid-derived foam of claim 1, wherein the pore wall contains a fluorinated acid and the foam has a fluorine content of from 0.01% to 25% by weight. The corrosion acid-derived foam of claim 1, wherein the pore wall contains oxidized acidic acid, and the foam has an oxygen content of from about 0.01% to about 25% by weight. The corrosion acid-derived foam of claim 1, wherein the foam has a specific surface area of 200 to 3,000 m ² / g or a density of 0.1 to 1.2 g / cm ³ . 2. The method of claim 1, wherein the sheet is in the form of a continuous-length roll sheet having a thickness of 100 nm to 10 cm and a length of at least 2 meters and is formed from a roll- Form. The foam of claim 1, wherein the foam has an oxygen content or a non-carbon content of less than 1 wt% and the pore wall has a planar spacing of less than 0.35 nm and / or a thermal conductivity per unit of specific gravity of at least 200 W / mK / ≪ / RTI > or a corrosion acid-derived foam having a stacked hexagonal carbon atom plane with an electrical conductivity per unit of specific gravity of at least 1,000 S / cm. The foam of claim 1, wherein the foam has an oxygen content or a non-carbon content of less than 0.01 wt% and the pore wall has a planar spacing of less than 0.34 nm and / or a thermal conductivity per unit of specific gravity of at least 300 W / / ≪ / RTI > or a stacked hexagonal carbon atom plane with an electrical conductivity per unit of specific gravity of at least 1,500 S / cm. The foam of claim 1, wherein the foam has an oxygen content or a non-carbon content of 0.01 wt% or less and the pore wall has a planar spacing of less than 0.336 nm and / or a thermal conductivity per unit of specific gravity of at least 350 W / / ≪ / RTI > or containing a layered hexagonal carbon atom plane with an electrical conductivity per unit of specific gravity of at least 2,000 S / cm. The foam according to claim 1, wherein the foam is a laminated sheet having a planar spacing of less than 0.336 nm and / or a thermal conductivity per unit of specific gravity of greater than 400 W / mK and / or an electrical conductivity per unit of specific gravity of greater than 3,000 S / cm A corrosion acid-derived foam having pore walls containing hexagonal carbon atom planes. The corrosion acid-derived foam of claim 1, wherein the pore wall contains a stacked hexagonal carbon atom plane with an interplanar spacing of less than 0.337 nm and a mosaic spread value of less than 1.0. The corrosion acid-induced foam of claim 1, wherein the pore walls contain a 3D network of interconnected hexagonal carbon atom planes. The corrosion acid-derived foam of claim 1, wherein the foam contains a mesopore pore having a pore size between 2 nm and 50 nm. An oil-removing device or oil-separating device containing the corrosive acid-derived foam of claim 1 as an oil-absorbing element.  A solvent-removing device or solvent-separating device containing the corrosive acid-derived foam of claim 1 as a solvent-absorbing or solvent-separating element. A method for separating oil from water,
a. Providing an oil-absorbing element comprising a corrosion acid-derived foam of claim 1;
b. Contacting the oil-water mixture with the element to absorb oil from the mixture;
c. Reprocessing the element from the mixture and extracting oil from the element; And
d. Steps to reuse elements
/ RTI > A method for separating an organic solvent from a solvent-water mixture or from a multi-solvent mixture,
a. Providing an organic solvent-absorbing or solvent-separating element comprising a corrosion acid-derived foam of claim 1;
b. Contacting said element with an organic solvent-water mixture or a multi-solvent mixture containing a first solvent and at least a second solvent;
c. Allowing the element to absorb an organic solvent from the mixture or to separate the first solvent from the at least second solvent;
d. Reprocessing the element from the mixture and extracting an organic solvent or a first solvent from the element; And
e. Steps to reuse elements
/ RTI > A thermal management device incorporating the corrosive acid-derived foam of claim 1 as a thermal diffusion or heat dissipating element. 21. The method of claim 20, further comprising the steps of: providing a heat exchanger, a heat sink, a heat pipe, a high conductivity insert, a conductive plate between the heat sink and the heat source, a heat spreader component, Or a Peltier cooling device. ≪ Desc / Clms Page number 14 > As a process for producing a caustic acid-derived foam,
(a) preparing a corrosion acid dispersion having a plurality of corrosion acid molecules or sheets dispersed in a liquid medium, wherein the corrosion acid is selected from the group consisting of an oxidized acid, a reduced acid, a fluorinated acid, a chlorinated acid, Wherein the dispersion is selected from the group consisting of a brominated acid, a brominated acid, an iodinated acid, a hydrogenated acid, a nitrated acid, a doped acid, a chemically functionalized acid, and combinations thereof, A blowing agent and a blowing agent to corrosion acid weight ratio of from 0 / 1.0 to 1.0 / 1.0;
(b) distributing and depositing the corrosion acid dispersion on the surface of the support substrate to form a wetting layer of a corrosive acid;
(c) partially or completely removing the liquid medium from the wetting layer of the corrosive acid to form a dry layer of the corrosive acid; And
(d) drying the caustic acid at a first heat treatment temperature of from 80 캜 to 3,200 캜 at a desired heating rate sufficient to induce volatile gas molecules from the non-carbon element or to activate the blowing agent to produce the corrosion acid- Wherein the porous acid-conducting foam comprises a plurality of pores and pore walls, the pore walls containing a single layer or multiple layers of a corrosion acid-derived hexagonal carbon atom plane or sheet, The multi-layer hexagonal carbon atom planes or sheets have from 2 to 10 layers of stacked hexagonal carbon atom planes with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.60 nm, as measured by X-ray diffraction, Or multi-layered hexagonal carbon atom planes contain from 0.01% to 25% by weight of non-carbon elements. 23. The process of claim 22, wherein the dispensing and deposition procedure comprises placing the corrosion acid dispersion under orientation-induced stress. 23. The method of claim 22, further comprising: thermally treating the corrosion acid-derived foam at a second heat treatment temperature that is greater than the first heat treatment temperature for a period of time sufficient to obtain a graphite foam, Wherein the planar spacing d ₀₀₂ is between 0.3354 nm and 0.36 nm and the content of non-carbon elements is less than 2% by weight. 23. The process according to claim 22, wherein the blowing agent is a physical blowing agent, a chemical blowing agent, a mixture thereof, a dissolution-and-exuding agent, or a mechanically introduced blowing agent. 23. The process of claim 22, wherein the step (b) and step (c) comprise the steps of feeding the support substrate from a feed roller to a deposition zone, Continuously or intermittently depositing on the surface of the support substrate to form a wetting layer of the wetting acid, drying the wetting layer of the wetting acid to form a dry layer of the wetting acid, ≪ / RTI > and collecting the dried layer of said corrosive acid on a collection roller. 23. The process of claim 22, wherein the first heat treatment temperature is between 100 DEG C and 1,500 DEG C. The process according to claim 24, wherein the second heat treatment temperature comprises at least a temperature selected from the group consisting of (A) 300 to 1,500 ° C, (B) 1,500 to 2,100 ° C, and (C) 2,100 to 3,200 ° C. 25. The process of claim 24, wherein the second heat treatment temperature comprises a temperature in the range of 300 to 1,500 DEG C for at least one hour and then a temperature in the range of 1,500 to 3,200 DEG C for at least one hour. 25. The process of claim 24, wherein the non-carbon element comprises an element selected from the group consisting of oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, and boron. The process according to claim 24, wherein the step (d) of heat treating the dry layer of the corrosion acid at the first heat treatment temperature is performed under compressive stress. 23. The process of claim 22, further comprising a compressing step to reduce the thickness, pore size, or porosity level of the foam. 26. The method of claim 24, wherein the first and / or second heat treatment temperature comprises a temperature in the range of 300 < 0 > C to 1,500 C, the foam has an oxygen content or non-carbon content of less than 1% Is less than 0.35 nm and / or the thermal conductivity per unit of specific gravity is at least 250 W / mK and / or the electrical conductivity per unit of specific gravity is at least 2,500 S / cm. 26. The method of claim 24, wherein the first and / or second heat treatment temperature comprises a temperature in the range of 1,500 DEG C to 2,100 DEG C, the foam has an oxygen content or a non-carbon content of less than 0.01% Is less than 0.34 nm and / or the thermal conductivity per unit of specific gravity is at least 300 W / mK and / or the electrical conductivity per unit of specific gravity is at least 3,000 S / cm. The method of claim 24, wherein the first and / or second heat treatment temperature comprises a temperature greater than 2,100 ° C, the foam has an oxygen content or a non-carbon content of less than 0.001%, the pore wall has a planar spacing of 0.336 nm Or wherein the mosaic dispersion value is less than or equal to 0.7 and / or the thermal conductivity per unit of specific gravity is at least 350 W / mK and / or the electrical conductivity per unit of specific gravity is at least 3,500 S / cm. The method of claim 24, wherein the first and / or second heat treatment temperature comprises a temperature of at least 2,500 ° C, the foam has a planar spacing of less than 0.336 nm and / or a mosaic dispersion value of less than or equal to 0.4, Having a pore wall containing a laminated hexagonal carbon plane with a thermal conductivity per unit of more than 400 W / mK and / or an electrical conductivity per unit of specific gravity of more than 4,000 S / cm. A roll-to-roll process for producing a continuous-length sheet of corrosion acid-derived foam,
(a) preparing a corrosion acid dispersion in which the corrosion acid molecules are dispersed in a liquid medium and contains a foaming agent;
(b) continuously or intermittently dispensing and depositing said corrosive acid dispersion onto the surface of a support substrate to form a wetting layer of a corrosive acid, said support substrate being fed from a feed roller and being collected on a collection roller Continuous thin film;
(c) partially or completely removing the liquid medium from the wetting layer of the corrosive acid in one heating zone or a plurality of heating zones to form a dry layer of a corrosive acid; And
(d) drying the corrosive acid in a heating zone of one of the heating zones, wherein the heating zone comprises a heating temperature of from 80 DEG C to 500 DEG C at a desired heating rate sufficient to activate the foaming agent to produce the corrosion acid- Wherein the porous acid-conducting foam comprises a plurality of pores and pore walls, the pore walls containing a single layer or multiple layers of a corrosion acid-derived hexagonal carbon atom plane or sheet, The multi-layer hexagonal carbon atom planes or sheets have from 2 to 10 layers of stacked hexagonal carbon atom planes with an interplanar spacing d ₀₀₂ of 0.3354 nm to 0.60 nm, as measured by X-ray diffraction, Or multi-layered hexagonal carbon atom planes contain from 0.01% to 25% by weight of non-carbon elements. The method of claim 22, wherein the humic acid-derived foam density of from 0.005 to 1.7 g / cm ^3, and / or a specific surface area of 50 to 3,200 m ² / g, and / or, a per unit of heat conductivity of the portion of at least 100 W / mK and / or the electrical conductivity per unit of specific gravity is at least 500 S / cm. The method of claim 24, wherein the humic acid-derived foam density of from 0.005 to 1.7 g / cm ^3, and / or a specific surface area of 50 to 3,200 m ² / g, and / or, a per unit of heat conductivity of the portion of at least 100 W / mK and / or the electrical conductivity per unit of specific gravity is at least 500 S / cm. The method of claim 37, wherein the humic acid-derived foam density of from 0.005 to 1.7 g / cm ^3, and / or a specific surface area of 50 to 3,200 m ² / g, and / or, a per unit of heat conductivity of the portion of at least 100 W / mK and / or the electrical conductivity per unit of specific gravity is at least 500 S / cm.

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