MXPA05012342A - Method for producing a porous, carbon-based material - Google Patents

Abstract

The invention relates to a method for producing a porous, carbon-based material comprising the following steps:provision of a polymer film, selected from sheets or coatings;pyrolysis and/or carbonisation of the polymer film in an atmosphere that is essentially devoid of oxygen, at temperatures ranging from 80°C to 3500°C. The invention also relates to a carbon-based material that can be produced according to said method.

Description

METHOD TO PRODUCE A POROUS MATERIAL OF CARBON BASE The present invention relates to a method for producing a porous carbon-based material by pyrolysis and / or carbonization of polymer films, selected from films or lacquers, in an atmosphere that is essentially free of oxygen at temperatures in the range of 80 °. C at 3,500 ° C. Carbon porous materials have been used for a long time in the area of fluid separation. This type of material can be prepared and used appropriately as adsorbents, membranous layers or self-supporting membranes. The various possibilities for specifically changing both the porosity as well as the chemical properties of the porous carbon-based materials made from these materials are especially interesting in particular for the tasks of selective separation of fluids. In the prior art, a number of methods for the preparation of porous carbon-based materials that are in dimensional form, in particular in sheet form, are described. In WO 02/32558, for example, a method is described for the preparation of flexible and porous adsorbents in the carbonic base comprising the materials, wherein a matrix of dimensional base, whose P05 / 076-BMG components are linked together essentially by hydrogen bonds, is prepared in a paper producing machine and subsequently subjected to pyrolysis. The raw materials used in this international application are essentially fibrous substances of various types, since these are commonly used in paper producing machines and the individual fibers in the prepared paper are essentially bound by hydrogen bonds. Similar methods are described, for example, in Japanese patent application JP 5194056 A, as well as in Japanese patent application JP 61012918. In these documents, processes for the production of paper are also described, with the help of this type of Paper sheets are made from organic fibers or plastic fibers as well as pulp which are treated with phenol resin and subsequently dried, subjected to thermal compression and carbonized in an inert gas atmosphere. In this way, porous thin carbon sheets with resistance against chemical agents and electrical conductivity can be obtained. However, a disadvantage of the methods described in the above is that the fibrous materials used in the raw material largely predetermined, depending on their fiber thicknesses and lengths P05 / 076-BMG of fiber as well as its distribution in the sheet-like paper material, the density and thus also the porosity of the resulting carbonaceous material after pyrolysis, so that these oversized pores need additional and complex further stages to the treatment, as for example, the infiltration in vapor phase, in order to narrow the pores by the deposition of additional carbonaceous material. Furthermore, according to the methods of the prior art, only raw materials can be used that can be used in a necessarily aqueous process of paper processing, which severely limits the selection of possible raw materials, in particular in the area of hydrophobic plastics. However, often only such hydrophobic plastics, such as polyolefins, are considered preferred raw materials over natural fibers, due to their relatively high carbon content and constant quality of easy availability. Therefore, there is a need for a simple and cost-effective method for the preparation of porous carbon-based materials without the need for the use of sheet-like materials prepared from fibers. Accordingly, the object of the present invention is to provide a method for the preparation of P05 / 076-BMG porous materials essentially of carbonic base that allows the preparation of the respective materials from raw materials that are economical and, with respect to their properties, widely changing in a cost-effective manner and with few stages of process. A further object of the present invention is the provision of a method for the preparation of porous carbon-based materials that allows the preparation of stable self-supporting structures or membranes or membrane layers from porous carbon-based material. The solution of the objectives set forth above according to the present invention, consists of a method for the preparation of porous carbon-based material comprising the following steps: a) the supply of a polymeric film selected from films or coatings b) pyrolysis and / or carbonization of the polymer film in an atmosphere that is essentially free of oxygen at temperatures in the range of 80 ° C to 3,500 ° C. In the preferred embodiments of the present invention, the pyrolysis and / or carbonization of the polymeric film is carried out in an atmosphere that is essentially free of oxygen at temperatures in the P05 / 076-BMG range from 200 ° C to 2,500aC. According to the invention, it has been discovered that from the polymeric films of suitable polymeric materials and coatings, carbonaceous materials can be made by pyrolysis and / or carbonization at elevated temperatures, the porosities of which can be specifically adjusted in wide ranges depending on the material of the polymer film that was used, its thickness and structure. Polymeric films have the advantage that they are easily prepared or available in the market in almost any dimension. Polymeric films are easy to obtain and cost-effective. In contrast to paper as a raw material for pyrolysis and / or carbonization, polymeric films, particularly films and coatings, such as lacquers, have the advantage that they are hydrophobic materials that usually can not be used with pulps or hydrocompatible natural fibers used in papermaking, and can be used for the preparation of carbon-based materials. Polymeric films can be shaped easily and can, for example, be processed in assemblies and large structures before pyrolysis or carbonization, this type of structure is maintained essentially during P05 / 076-BMG the pyrolysis / carbonization of the polymer film material. In this way, by forming multiple layers on top of one another polymer films, it is possible to form a film or cover with a sheet packings and, after pyrolysis and / or carbonization according to the method of the present invention, generate packaging or modular structures from porous carbon-based material which, due to the mechanical strength of the resulting material, can be used as adsorbent gaskets or as mechanically stable self-supporting membranes in the separation of fluids. Prior to pyrolysis and / or carbonization, the polymeric films can be suitably structured by bending, stamping, blanking, printing, extrusion, spraying, injection molding, folding and the like and optionally, they can be joined together. For this purpose, conventional and known adhesives and other suitable adhesive materials may be used, such as, for example, sodium silicate, starch, acrylates, cyanoacrylates, hot-melt adhesives, rubber, or solvent-free adhesives as well as those containing solvents. , etc., whereby the method according to the present invention makes possible the preparation of specifically constructed three-dimensional structures P0S / 076-BMG with a planned accumulation of the desired carbon-based porous material. In this sense, the carbon-based material does not have to be prepared firstly afterwards, it is prepared in complex forming steps, the desired three-dimensional structure that is required, for example, for membrane packaging, etc., the method according to the invention it allows the supply of the finished structure or the shaping of the polymeric film just before the pyrolysis and / or carbonization. Accordingly, by means of the method according to the present invention, it is also possible to create difficult structures having small spaces that can not be processed or this is achieved only with difficulty, from the carbonaceous finishing material by means of the subsequent forming. In this aspect, for example, shrinkage that usually occurs during pyrolysis and / or carbonization can be used specifically. Polymeric films that can be used in accordance with the present invention can be provided in sheets or in two-dimensional continuous paper rolls, for example, as rolls of material or also in the form of a tube or in a tubular or capillary geometry. Polymeric films in the form of films or P05 / 076-BMG Capillaries can be prepared by, for example, phase inversion methods (asymmetric layer accumulation) from polymer emulsions or suspensions. Suitable polymer films in the method of the present invention are, for example, films, tubes or capillaries from plastics. Preferred plastics comprise homo and copolymers of aliphatic or aromatic polyolefins, such as, for example, polyethylene, polypropylene, polybutene, polyisobutene, polypentene; polybutadiene; polyvinyl, such as, for example, polyvinyl chloride or polyvinyl alcohol, poly (meth) acrylic acid, polyacrylonitrile, polyacrylocyanoacrylate; polyamide; polyester, polyurethane, polystyrene, polytetrafluoroethylene; polymers, for example, collagen, albumin, gelatin, hyaluronic acid, starch, celluloses, such as, for example, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, phthalate; waxes, paraffin waxes; Fischer-Tropsch waxes; casein, dextrans, polysaccharides, fibrinogen, poly (D, L-lactides), poly (D, L-lactides-co-glycolides), polyglucolides, polyhydroxybutylates, polyalkyl carbonates, polyorthoesters, polyhydroxyvaleric acid, polydioxanones, polyethylene terephthalate, polylactic acid, politartronic acid, polyanhydrides, polyphosphazenes, polyamino acids; polyethylene vinyl acetate, silicon; poly (ester urethanes), poly (ether) P05 / 076-BMG urethanes), poly (ester ureas), polyethers, such as, for example, polyethylene oxide, polypropylene oxide, pluronics, polytetramethylene, glycol; polyvinyl pyrrolidone, poly (vinyl acetate phthalate), mixtures of homo or copolymers of one or more of the aforementioned materials, as well as of additional polymeric materials known to those skilled in the art, which can also usually be processed into films, tubes or capillaries. Other preferred types of polymeric films are polymeric foam systems, for example, phenol foams, polyolefin foams, polystyrene foams, polyurethane foams, fluoropolymer foams which can be converted to porous carbonaceous materials in a later carbonisation or pyrolysis step. according to the invention. These materials have the advantage that in the carbonization stage, materials with a porous structure can be obtained, that is, they can be adjusted depending on the porosity of the foam. For the preparation of foamed polymers, all conventional foaming methods of the state of the art using conventional blowing agents, such as, for example, halogenated hydrocarbons, carbon dioxide, nitrogen, hydrogen and low-point hydrocarbons can be used. fusion. Loading agents can also be applied in or on the films P05 / 076-BMG polymeric, which are suitable to cause the formation of foam in or on the polymeric film. Still further, in the method according to the present invention, the polymeric film can be a coating, such as, for example, a lacquer film, which was produced from a lacquer with an alkyd resin binder base, chlorinated rubber, resin epoxy, formaldehyde resin, (meth) acrylate resin, phenol resin, alkylphenyl resin, amine resin, melamine resin, oily base, nitro base (cellulose nitrate), polyesters, polyurethane, rosin, Novolac-epoxy resins, resin of vinylester, tar and tar-like substances, such as tar pitch, bitumen, as well as starch, cellulose, shellac, waxes, modified binding agents of the aforementioned substances, or binders of renewable organic raw materials or combinations of the substances mentioned above. Those which are considered especially preferred are the lacquers on the base of phenol and / or melamine resins, which optionally can be completely or partially epoxidized, for example, commercial lacquers for packaging, such as, for example, lacquers of uni or bicomponents in the base of optionally epoxidized aromatic hydrocarbon resins. The coatings that can be used in P05 / 076-BMG According to the present invention, they can be applied to a suitable carrier material from a liquid, pulpy or paste-like state, for example, by coating, painting, lacquer application, phase inversion, atomization, dispersion or hot-applied coating. extrusion, melting, immersion or as hot applications starting from a solid state by means of powder coating, flame spraying, sintering or the like according to known methods. Lamination of the carrier materials with suitable polymers is also a method that can be used in accordance with the present invention for the delivery of the polymeric film in the form of a coating. The use of coatings in the method according to the present invention can be carried out, for example, such that a coating is applied to an internal carrier material, optionally it can be dried and subsequently subjected to pyrolysis and / or carbonization, the material carrier is essentially completely pyrolyzed or carbonized through the proper selection of the pyrolysis or carbonization conditions, so that the coating, in this case a lacquer, remains after the pyrolysis or carbonization in the form of a porous base material carbonic In the method according to the present invention, the use of coatings, P05 / 076-BMG particularly lacquers, finishes, laminates and the like, it makes possible the preparation of porous carbon-based materials especially thin in the form of a sheet. Still further, preferred polymeric films can also be obtained with transfer methods, wherein materials, lacquers, finishes, laminates of the aforementioned polymeric materials or materials are applied to transfer to the carrier material, for example, the aforementioned films, optionally they can be cured, and after that, they can be formed into strips from the carrier material so that they can subsequently be supplied to the carbonization. In this context, the coating of the carrier material can be carried out with suitable printing methods, such as, for example, printing with Anilox rolls, knife coating, spray coating or thermal laminations under pressure or wet wet and the like. Various thin and optionally desired layers can be obtained in order to ensure, for example, the accuracy of the polymer film. Furthermore, during the application of coatings on the transfer carrier material, various grids can optionally be used for a lacquer distribution that is as homogeneous as possible. With the transfer methods of the type before P05 / 076-BMG described, it is also possible to produce films classified as multilayers with different frequencies of layer materials, which after carbonization can be obtained materials classified as carbon based, where, for example, the density of the material can fluctuate depending on the location. In cases where very thin polymeric films are required for use in the method according to the present invention, these films can be produced in suitable films by the transfer method through, for example, powder coating or hot-applied coating. and then its configuration in strips and its carbonization. In case where the carrier film is completely volatilized under carbonization conditions, such as for example polyolefin films, it can be considered that a strip pattern of the carrier film is not necessary or on the contrary can be considered preferred. Furthermore, by means of the transfer method it is also possible to achieve a structuring or micro structuring of the polymer films produced by pre-structuring and appropriately transferring the carrier material, for example, through a previous plasma etching. With the thin coating, the structure of the carrier material in this way, P05 / 076-BMG transfers to the polymer film. In certain embodiments of the invention, the polymeric film is also applied as a coating to temperature-resistant substrates in order to obtain, after pyrolysis or carbonization, porous carbon-based layers which can be used as membrane or molecular layers. The substrates can be composed of, for example, glass, ceramic, metal, metal alloys, metal oxides, silicon oxides, aluminum oxides, zeolite, titanium oxide, zirconium oxide, as well as mixtures of these materials and can be preforming the way you want. A preferred use of this embodiment is the preparation of adsorbent beads with membranous coating of material that can be produced according to the invention. In certain preferred embodiments, the polymeric film used in the method of the present invention can be coated, impregnated or modified with organic and / or inorganic compounds prior to pyrolysis and / or carbonization. A coating applied to one or both sides of the polymeric film can be composed of, for example: epoxy resins, phenol resins, tar, tar pitch, bitumen, rubber, polychloroprene or poly (styrene-co-butadiene) latex materials , siloxanes, silicates, metal salts or solutions of metal salts, P05 / 076-BMG for example, transition metal salts, carbon black, fullerenes, activated carbon powder, carbon molecular sieve, perovs ita, aluminum oxides, silicon oxides, silicon carbide, boron nitride, silicon nitride, precious metals, such as Pt, Pd, Au or Ag; as well as the combinations of these. Preferred embodiments may be obtained, for example, by the paryleneization or impregnation of the polymeric films or the carbon-based materials obtained therefrom. In this context, first, the polymer films are treated at elevated temperatures, usually about 600 ° C, with paracyclofan, a layer of poly (p-xylylene) is formed superficially on the polymeric films or materials created therefrom . These materials can be converted, optionally, into carbon at a later stage of pyrolysis or carbonization. In especially preferred embodiments, the sequence of parillanization and carbonization steps is repeated several times. With the coating on one or both sides of the polymeric film with the aforementioned materials or also with the specific incorporation of these materials in the structure of the polymeric film, they can, in a specific way, influence and improve the P05 / 076-BMG properties of the carbon-based porous material after pyrolysis and / or carbonization. For example, with the incorporation of layered silicates in the polymeric film or with the coating of the polymeric film with layered silicates, the nanoparticles, inorganic metal nanocomposites, metal oxides and the like can be modified, the coefficient of thermal expansion of the resulting carbonaceous material as well as its mechanical properties or porosity properties. In particular during the preparation of coated substrates which are provided with a layer of the material prepared according to the invention, through the incorporation of the aforementioned additives in the polymeric film, the possibility of improving the adhesion of the layer applied to the polymer is created. substrate and, for example, the possibility of adjusting the coefficient of thermal expansion of the outer layer to that of the substrate, so that these coated substrates become more resistant to breaks in the membrane layer and to its delamination. Accordingly, these materials are considerably more durable and have superior long-term stability in some particular use as conventional products of this type. The application or incorporation of metals or metal salts, in particular also precious metals P05 / 07S-BMG and transmission metals, makes it possible to adjust the chemical properties and adsorbents of the resulting carbon-based porous material to meet each of the desired requirements, so that special applications of the resulting material can also be provided, for example with heterogeneous catalytic properties. . In preferred embodiments of the method according to the present invention, the physical and chemical properties of the porous carbon-based material are further modified after pyrolysis and / or carbonization with appropriate post-treatment steps and are adjusted for each of the applications desired. Suitable post-treatment steps are, for example, subsequent to the reduction treatment or oxidation steps, wherein the material is treated with reducing agents and / or suitable oxidizing agents, such as, for example, hydrogen, carbon dioxide, steam , oxygen, air, nitric acid and the like, as well as optionally with mixtures of these. The post-treatment stages can optionally be carried out at elevated temperatures, but at temperatures below the pyrolysis temperature, for example from 40 ° C to 1,000 ° C, preferably from 70 ° C to 900 ° C, with higher preference from 100 ° C to 850 ° C, even with higher P05 / 076-B G preference of 200 ° C to 800 ° C, and with a greater preference to 700 ° C. In especially preferred embodiments, the material prepared according to the present invention is modified reductively or oxidatively or with a combination of these steps subsequent to the treatment at room temperature. With the oxidative or reductive treatment or also with the incorporation of additives, bulking agents or functional materials, the surface properties of the materials prepared according to the present invention can be influenced or changed, optionally. For example, with the incorporation of nanocomposites or inorganic nanoparticles, such as, for example, stratified silicates, the surface properties of the material can be hydrophilized or hydrophobized. Suitable additives, fillers or functional materials are, for example, silicon or aluminum oxides, alu inosilicates, zirconium oxides, talc, graphite, carbon black, zeolites, clay materials, phyllosilicates and the like which are usually Common use for those skilled in the art. In preferred embodiments, the porosity adjustment can be performed through the washing of bulking agents, such as, for example, polyvinylpyrrolidone, polyethylene glycol, aluminum powder, fatty acids, P05 / 076-BMG Microcells or emulsions, paraffins, carbonates, dissolved gases or water-soluble salts with water, solvent, acids or bases or by oxidative or non-oxidative distillation or decomposition. The porosity can also be optionally generated by structuring the surface with powdered substances, such as, for example, powdered metals, carbon black, powdered phenol resin, fibers, in particular carbon and natural fibers. The addition of aluminum based fillers produces, for example, an increase in the coefficient of thermal expansion and the addition of glass, graphite or quartz base fillers, produces a decrease in the coefficient of thermal expansion, so that with mixing of the components in the polymer system, accordingly, the coefficient of thermal expansion of the materials according to the present invention can be adjusted individually. Another possible adjustment of the properties can be realized, for example and not exclusively, with the preparation of a fibrous complex by means of the addition of carbon, polymer, glass or other fibers in tissue and non-woven form, which produces a remarkable increase of the elasticity and other mechanical properties of the coating. The materials prepared according to the present invention can also be provided P05 / 076-BMG subsequently with biocompatible surfaces, with the incorporation of suitable additives and optionally, they can be used as bioreactors or excipients. For this purpose, drugs or enzymes can be introduced into the material, among others, the aforementioned can optionally be released in a controlled manner through suitable properties of delay and / or selective permeation of the membranes. Still further, in certain embodiments it is preferred to fluorinate the materials prepared according to the present invention. Depending on the degree of fluorination applied, the materials according to the present invention can be endowed with lipophobic properties with a high degree of fluorination and with lipophilic properties with low degree of fluorination. Moreover, it is optionally preferred to hydrophilize, at least superficially, the materials according to the present invention by treatment with water-soluble substances, such as, for example, polyvinylpyrrolidone or polyethylene glycols, polypropylene glycols. With these measurements, the wetting behavior of the materials can be modified as desired. Optionally, the carbonized material is also P05 / 076-BMG It can be subjected to processes called chemical vapor phase (CVD or Chemical Vapor Deposition), in an optional and additional process step in order to further modify the surfaces or porous structure and its properties. For this purpose, the carbonized material is treated with suitable precursor gases at elevated temperatures. This type of methods has been used for a long time in the state of the art. Almost all known saturated and unsaturated hydrocarbons with sufficient volatility under CVD conditions are considered as precursors to the carbon depuration. Some examples are: methane, ethane, ethylene, acetylene, linear or branched alkanes, alkenes and alkynes with a carbon number of C_ -C2o, aromatic hydrocarbons, such as benzene, naphthalene, etc., as well as alkyl, alkenyl and Alkynyl-substituted aromatics, such as toluene, xylene, cresol, styrene, etc. BC13, NH3, silanes, such as, for example, tetraethoxysilanes, can be used as ceramic precursors.

(TEOS), SiH_, dichlorodimethylsilane (DDS), methyltrichlorosilane (MTS), trichlorosilyldichloroborane (TDADB), hexadicloromethylsilyl oxide (HDMSO), A1C13, TiCl3 or mixtures of these. These precursors are mostly used in P0S / 076-BMG CVD methods in small concentrations of approximately 0.5 to 15 volume percent with an inert gas, such as nitrogen, argon or the like. It is also possible to add hydrogen for the adequate deposit of gas mixtures. At temperatures between 200 and 2,000 ° C, preferably 500 to 1,500 ° C, and more preferably 700 to 1,300 ° C, the aforementioned compounds depurate fragments of hydrocarbons or carbon or ceramic precursors which are deposited and distributed essentially in a manner uniform in the porous system of the pyrolyzed material, they modify the porous structure thereof and therefore, create an essentially homogeneous pore size and a pore distribution in the sense of improved optimization. For the control of the uniform distribution of the carbon or ceramic particles deposited in the porous system of the carbonized material, for example, during the deposition of the carbon precursors on a surface of the carbonized object, a pressure gradient may be applied, example, in the form of a negative pressure or continuous vacuum, whereby the deposited particles are sucked uniformly into the porous structure of the carbonized substance (so-called, forced flow CVI, Chemical Vapor Infiltration, chemical vapor phase infiltration; see, for example, P0S / 076-BMG W. Benzinger et. al Coal 1996, 34, page 1465). Even more, the homogenization of the porous structure achieved in this way, increases the mechanical resistance of materials prepared in this way. This method can also be used in an analogous manner, with ceramics, sintered metals, metal precursors or metal alloys such as those mentioned above. Still further, by means of ion implantation, the surface properties of the material according to the present invention can be modified. With the implementation of nitrogen, nitride, carbonitride or oxynitride, phases can be formed with included transition metals, which remarkably increase the chemical resistance and mechanical resistivity of the carbon-containing materials. The ionic carbon implantation can be used for increasing the mechanical strength of the materials according to the present invention as well as for the redensification of porous materials. In still more preferred embodiments, the material prepared according to the present invention is mechanically reduced to small pieces after pyrolysis and / or carbonization by means of suitable methods, for example, through a ball mill or roller mill. and the similar. The material prepared in this way, which P05 / 076-BMG reduced to small pieces can be used as powder, flakes, rods, spheres, hollow spheres of different granulation or can be processed to granules or extrudates in various ways by means of conventional methods of the state of the art. Hot press methods may also be used, optionally with the addition of suitable binding agents, in order to form the material according to the convention. All polymers that inherently possess membrane properties or are properly prepared in order to incorporate the materials mentioned in the foregoing are particularly suitable for this purpose. In addition, the small-sized powder material can also be prepared in accordance with the method according to the present invention by reducing the polymer film to small pieces in a suitable manner prior to pyrolysis and / or carbonization. However, in the embodiments of the method of the present invention that are considered especially preferred, the polymer films are suitably structured prior to pyrolysis and / or carbonization, for example, they are stamped or combined with each other in structural units, adhesively bonded or mechanically bond with each other, as this increases the chances that the pre-structured polymer film material P05 / 076-BMG suitably easily formed in a simple manner, the structure essentially remains unchanged during the pyrolysis stage. The step of pyrolysis or carbonization of the method according to the present invention is usually carried out at temperatures in the range of 80 ° C to 3,500 ° C, preferably of about 200 ° C to 2,500 ° C, more preferably about 200 ° C to 1,200 ° C. The preferred temperatures in some modes are at 250 ° C to 500 ° C. The temperature depending on the properties of the materials used is preferably chosen so that the polymer film is essentially completely transformed into a solid containing carbon with as low a temperature as possible. With proper selection or control of the pyrolysis temperature, the porosity, strength and stiffness of the material and other properties can be adjusted. The atmosphere during the pyrolysis or carbonization stage is found in the method according to the present invention, essentially free of oxygen. The use of inert gas atmospheres, for example of nitrogen, noble gases such as for example argon, neon, as well as all other inert gases, with gases or gaseous compounds not reactive to carbon, reactive gases such as for example dioxide, is preferred. carbon, hydrochloric acid, P05 / 076-BMG ammonia, hydrogen and mixtures of inert gases. In some cases, after carbonization, activation may occur with the reactive cases, which subsequently also comprises oxygen or water vapor, in order to achieve the desired properties. The step of pyrolysis and / or carbonization in the method according to the present invention is usually carried out at a normal pressure in the presence of inert gases mentioned in the above. However, optionally the use of high pressures of. Inert gas can also prove advantageous. In certain embodiments of the method according to the present invention, the pyrolysis and / or carbonization can also be carried out under negative pressure or in vacuum. The pyrolysis step is carried out, preferably, in a continuous incinerator process. Therefore, optionally structured, coated or pretreated polymer films are supplied in the oven on one side and exit the oven at the other end. In preferred embodiments, the polymeric film or the material formed from the polymeric films can lie on a perforated plate, a screen or the like so that a negative pressure can be applied through the polymeric film during pyrolysis and / or carbonization. This not only allows a simple fixation P05 / 076-BMG of the materials in the furnace, but also optimal depletion and fluence of the inert gas through the films or structural units during the pyrolysis and / or carbonization. By means of the appropriate isolation of the inert gas, the furnace can be subdivided into individual segments, where one or more stages of pyrolysis or carbonization can be carried out successively, optionally under different conditions of pyrolysis or carbonization, such as, for example, different temperature levels. , different inert or empty gases. Furthermore, in appropriate segments of the furnace, optionally also post-treatment steps can be carried out, such as, for example, reactivation to reduction or oxidation or impregnation with metals, solutions of metal salts or catalysts, etc. Alternatively to this, the pyrolysis and / or carbonization can also be carried out in a closed oven, which is considered particularly preferred, when the pyrolysis and / or carbonization is carried out under vacuum. During the pyrolysis and / or carbonization in the method according to the present invention, a decrease in weight of the polymer film of about 5% to 95%, preferably from about 40% to 90%, with higher 50% preference to P05 / 07S-BMG 70%, depending on the raw material and the pretreatment used. Still further, during the pyrolysis and / or carbonization in the method according to the present invention, shrinkage of the polymeric film or structure or structural unit created from the polymeric films usually occurs. The shrinkage may have a magnitude of 0% to about 95%, preferably 10% to 30%. The materials prepared according to the present invention are chemically stable, mechanically chargeable, electrically conductive and heat resistant. In the method according to the present invention, the electrical conductivity can be adjusted over wide ranges, depending on the pyrolysis or carbonization temperature used and on the nature and amount of the additive or filler used. Therefore, with temperatures in the range of 1,000 to 3,500 ° C, due to the grafitization that occurs from the material, a higher conductivity can be achieved than that achieved with lower temperatures. In addition, the electrical conductivity can also be increased, for example, by adding graphite to the polymeric film, which can then be pyrolyzed or carbonized at lower temperatures.

P0S / 07S-B G The materials prepared according to the present invention after heating in an inert atmosphere of 20 ° C to 600 ° C and of their subsequent cooling at 20 ° C exhibit a dimensional change not greater than +/- 10%, preferably not greater +/- 1%, with greater preference not greater than +/- 0.3%. The carbon-based porous material prepared according to the present invention exhibits, depending on the raw material, an amount and nature of the fillers, a carbon content of at least 1 weight percent, preferably at least 25 weight percent. percent by weight, optionally also at least 60 percent by weight and more preferably at least 75 percent by weight. The material that is considered especially preferred according to the present invention has a carbon content of at least 50 weight percent. The specific surface according to BET of materials prepared according to the present invention, is usually very small, since the porosity is smaller than that which can be detected with this method. However, by means of additives or appropriate methods (porosity or activation agent), BET surfaces greater than 2,000 m2 / g are achieved. The material prepared according to the method according to the present invention in the form of P05 / 076-BMG Sheet or powder can be used for the preparation of membranes, adsorbents and / or membranous modules or membranous packaging. The preparation of the membranous modules according to the method according to the present invention can be carried out for example, in the manner described in WO 02/32558, a polymeric film is used instead of the base matrix of paper described in that document. The disclosures of WO 02/32558 are incorporated herein by reference. Some examples for the use of the material prepared according to the present invention in the area of fluid separation are: the general separation of gases, as for example, the separation of oxygen and nitrogen for the accumulation of oxygen obtained from the air, the separation of hydrocarbon mixtures, the isolation of hydrogens from gaseous mixtures containing hydrogen, the filtration of gases, the isolation of C02 from ambient air, the isolation of volatile organic compounds from exhaust gases or from ambient air, purification, desalination, softening or recovery of drinking water, such as fuel cell electrode, in the form of Sulzer packets, Raschig rings and the like. In a special modality of this P05 / 07e-B G invention, the polymeric film is applied to conventional membranes or adsorbent materials, such as, for example, activated carbon, zeolite, ceramics, sintered metals, papers, woven materials, non-woven materials, metals or metal alloys and the like, preferably adsorbent materials in the form of beads or granules, for example, in the form of a surface coating prior to pyrolysis or carbonization. After pyrolysis or carbonization, adsorbent materials with a surface membranous layer can be prepared, thanks to which the selectivity of the absorbers can be determined by the selectivity of the membrane. In this way, for example, adsorbent granules can be prepared which selectively adsorb only those substances which are capable of penetrating through the membrane. With this, the rapid exhaustion of the adsorbent caused by a coating with undesirable accessory components is prolonged or avoided. Thanks to this, the interchange intervals of the adsorbent cartridges can be extended in appropriate applications, leading to an increased cost efficiency. Preferred applications of this type of membrane-coated adsorbents are, for example, in pressure swing adsorption systems (PSA or P05 / 07S-BMG Pressure Swing Adsorption), in cabins of cars or airplanes, respiratory protection systems, such as gas masks, etc.

EXAMPLES Example 1: The pyrolysis and carbonization of the cellulose acetate film thinly coated on both sides with nitrocellulose, manufacturer UCB Films, type Cellophane 'MS 500, total thickness 34.7 microns, 50 g / m2. The film was subjected to pyrolysis or carbonization at 830 ° C in a purified nitrogen atmosphere (flow rate of 10 liters / minute) for a period of 48 hours in a commercial high temperature furnace. Subsequently, the shrinkage that occurs as a result was determined by comparing the average measured values of each of the three rectangular pieces and the carbon sheets prepared from this. The results are presented in Table 1.

P05 / 07S-B G Table 1: Shrinkage of the film coated with nitrocellulose Subsequently, the nitrogen and hydrogen permeability of the carbon sheets prepared above were evaluated under different conditions. The conditions and results are listed below in Table 2. The permeability values are average values obtained from three measurements.

Table 2: Membrane data: P05 / 076-BMG Example 2: The pyrolysis and carbonization of cellulose acetate films thinly coated on both sides with polyvinylidene chloride (PVdC), manufacturer UCB Films, type Cellophane XS 500, total thickness 34.7 microns, 50 g / m2. The film was subjected to pyrolysis or carbonization at 830 ° C in a purified nitrogen atmosphere (flow rate of 10 liters / minute) for a period of 48 hours in a commercial high temperature furnace. Subsequently, the shrinkage that occurs as a result was determined by comparing the average measured values of each of the three rectangular pieces and the carbon sheets prepared from this. The results are presented in Table 3.

Example 3: Pyrolysis and carbonization of homogenous and defect-free epoxy resin films, total thickness of 7 microns before carbonization, 2.3 P0? / 076-BMG microns after carbonization. The film was prepared with a solvent evaporation method from 20 percent by weight of the solution. The carbonization was carried out at a temperature of 830 ° C in a purified nitrogen atmosphere (flow rate of 10 liters / minute) for a period of 48 hours in a commercial high temperature furnace. Subsequently, the shrinkage that occurs as a result was determined by comparing the average measured values of each of the three rectangular pieces and the carbon sheets prepared from this. The results are presented in Table 4.

The sheet material prepared in this manner was a) subjected, in a second activation step, to a second temperature treatment in air at 350 ° C for 2 hours. b) It was provided, in a second stage, with P05 / 076-B G a layer of CVD of hydrocarbons, carried out at 700 ° C in a second temperature treatment. Consequently, the water absorption capacity changed, which was quantified as follows: 1 ml of VE water was placed on the surface of the film with a pipette (with a diameter of 20 mm) and was allowed to act for 5 minutes. minutes After this, the difference in weights was determined.

Water absorption (g) Carbonized sample 0.0031 a) Activated sample 0.0072 b) Modified sample with CVD 0.0026 From this it can be observed that the modification with CVD reduces the porosity, at the same time that it increases the porosity of the sheet material.

Example 4: Pyrolysis and carbonization of homogenous and defect-free epoxy resin films, total thickness 3 g / m2. The film was prepared with a solvent evaporation method from 15 weight percent epoxy coating solution in which 50% of a polyethylene glycol (based on epoxy resin lacquer) was added.

P05 / 076-BMG Pm 1,000 g / mol) in a dip coating method on stainless steel substrates with a diameter of 25 mm. The carbonization occurred at 500 ° C in a purified nitrogen atmosphere (flow rate of 10 liters / minute) for a period of 8 hours in a commercial high temperature furnace. Subsequently, the coating was washed at 60 ° C for 30 minutes in an ultrasonic bath and weighed.

Weight of round plate without coating 1.2046 g Weight after coating 1.2066 g Weight after carbonization 1.2061 g Weight after the washing procedure 1.2054 g The porosity of the films can be increased with the washing procedure. -05 / 076-BMG

Claims (12)

1. CLAIMS: 1. A method for the preparation of a porous carbon-based material comprising the following steps: a) the supply of a polymeric film selected from films or coatings; b) pyrolysis and / or carbonization of the polymer film in an atmosphere that is essentially free of oxygen at temperatures in the range of 80 ° C to 3,500 ° C. The method according to claim 1, characterized in that the polymer film is structured before pyrolysis and / or carbonization by stamping, folding, punching, printing, extrusion and the like 3. The method according to claim 1 or claim 2, characterized because the polymeric film comprises homo and copolymer films of aliphatic or aromatic polyolefins, such as, for example, polyethylene, polypropylene, polybutene, polyisobutene, polypentene; polybutadiene; polyvinyl, such as, for example, polyvinyl chloride or polyvinyl alcohol, acid mixtures and combinations thereof. 4. The method according to claim 1 or claim 2, characterized in that the polymeric film is a selected coating of lacquer, P05 / 076-BMG laminate or finish. The method according to claim 4, characterized in that the polymeric film is a lacquer film prepared from a lacquer with an alkyd resin binder base, chlorinated rubber, epoxy resin, acrylate resin, phenol resin, amine resin, oily base, nitro base, polyester, polyurethane, phenol resin, tar, tar-like materials, tar pitch, bitumen, starch, cellulose, shellac, organic materials of renewable organic raw materials or combinations of these. The method according to any of the preceding claims, characterized in that the polymeric film comprises additives or inorganic fillers. The method according to claim 6, characterized in that the inorganic fillers or fillers are selected from silicon or aluminum oxides, aluminosilicates, zirconium oxides, talc, graphite, carbon black, zeolites, clay materials, phyllosilicates, wax, paraffin, salts, metals, metal compounds, soluble organic compounds, such as, for example, polyvinylpyrrolidone, polyethylene glycol and the like. The method according to claim 6 or claim 7, characterized in that the charging agents P05 / 07S-BMG they are removed from the matrix by washing with water, solvent, acids or bases, or by oxidative or non-oxidative decomposition. The method according to any of the preceding claims 6 to 8, characterized in that the bulking agents are present in the form of powders, fibers, woven materials and non-woven materials. The method according to any of the preceding claims 6 to 9, characterized in that the fillers are suitable to cause foaming in or on the polymeric film. The method according to any of the preceding claims, characterized in that the material is subjected to an oxidative and / or post-treatment reduction step after pyrolysis and / or carbonization. 12. A porous carbon-based material that can be reproduced according to the method according to any of the preceding claims. P05 / 076-BMG