Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/02—Materials undergoing a change of physical state when used
  • C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
  • C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials

Definitions

• the present invention belongs to the technical field of phase change materials (PCM) and, in particular, composites comprising such PCMs.
• PCM phase change materials
• the present invention provides a composite material comprising at least one organic PCM, distributed, coated, encapsulated or microencapsulated in a geopolymer matrix.
• the present invention also relates to various processes for preparing such com posite materials and their uses in particular as thermoregulatory materials.
• phase change materials or “Phase Change
• PCM Materials "or PCM) are used. These materials are substances having a high heat of fusion which, when the temperature passes from one side to the other of their melting point, makes it possible to store or to release a large volume quantity of thermal energy. Thus, the temperature is stabilized around the melting temperature of the compound. These systems are a major scientific issue and advances in this area are presented in recent work [1-5]. The main problem with the PCM operating principle is that when the temperature is above the melting point, the material is liquid and thus does not retain the desired shape. It is therefore necessary for many applications to format the PCM or to create a composite.
• PCM PCM
• inorganic PCMs such as hydrates
• organic PCMs such as paraffins, organic acids, chlorates, esters, etc.
• PCM has advantages and disadvantages.
• the inorganic PCMs have a relatively high latent heat but they are not chemically stable. They are frequently supercooled and are very corrosive to certain building materials. Inorganic PCMs are therefore shaped into hermetic capsules and used for so-called active thermal systems, with large temperature variations during a cycle.
• organic PCMs do not a priori have the disadvantages of inorganic PCM.
• they can interact with the matrix during the formation of a composite, which poses lixiviation problems and greatly reduces the mechanical properties of the material.
• microencapsulation must be used for the system to be effective. Indeed, since heat transfer is slow for organic PCMs, the exchange surface must be as large as possible.
• the inventors have therefore set themselves the goal of developing a method for preparing a composite material comprising at least one PCM, said process making it possible to obtain composite materials with thermoregulatory properties of interest while being easy to implement and inexpensive.
• the present invention overcomes, at least in part, the disadvantages and technical problems related to composite materials comprising phase change materials (PCM) and processes for preparing such composite materials.
• PCM phase change materials
• the present invention provides a composite material comprising at least one organic phase change material (organic PCM) in a geopolymer matrix, provided that when the composite material comprises only one organic phase change material, this the latter is neither dodecane nor eicosanone.
• organic PCM organic phase change material
• said at least one organic PCM advantageously has not undergone any pretreatment or (micro) pre-encapsulation.
• prior is meant no pretreatment or (micro) encapsulation prior to its incorporation into the composite material according to the invention ie prior to its introduction into the activation solution (step (a) below) or prior to its introduction into the cement mixture (step (b ') below).
• the organic PCM in the composite material according to the invention is neither surrounded by a shell of a polymer or plastic, nor in the form of porous aggregates impregnated with said PCM.
• composite material is meant, in the context of the present invention, an assembly of a geopolymer matrix and an organic PCM. This assembly can be in the form of an intimate mixture between the organic PCM and the geopolymer matrix, encapsulation of the organic PCM by the geopolymer matrix, micro-encapsulation of the organic PCM by the geopolymer matrix and / or coating the organic PCM with the geopolymer matrix.
• the composite material according to the invention is in the form of a geopolymer (or geopolymer matrix) in which microbeads and / or nanobeads of organic phase change material are coated.
• microbead means a droplet of organic liquid whose average diameter is between 1 and 1000 ⁇ , in particular between 5 and 500 ⁇ and, in particular between 10 and 100 ⁇ .
• Nanobead means a droplet of organic phase change material whose average diameter is between 1 and 1000 nm, especially between 10 and 900 nm and, in particular between 20 and 800 nm.
• the microbeads and nanobeads of material with organic phase change present in the composite material according to the invention may have various forms such as oval, spheroidal or polyhedral shapes.
• the composite material according to the present invention contains only microbeads and / or nanoshells of organic PCM and a geopolymer matrix.
• the composite material according to the present invention additionally has microbeads and / or nanobeads of organic PCM and geopolymer matrix, fines and / or fibers. These are added to enhance or further optimize the physical and mechanical properties of the resulting composite material.
• Fine also known as “fillers” or “addition fines” are a dry, finely divided product derived from cutting, sawing or working with natural rocks, aggregates and ornamental stones.
• granulate is meant a granular material, natural, artificial or recycled, the average grain size is advantageously between 10 and 125 mm.
• the fines have an average grain size of between 5 and 200 ⁇ .
• the fibers that can be used in the context of the present invention are fibers, natural or artificial, typically used in the reinforcement of materials such as, for example, in concretes.
• the fibers used in the context of the present invention may be either organic or inorganic.
• Natural fibers means fibrous organic materials derived from materials of plant or animal origin.
• these natural fibers are chosen from among the fibers of cotton, linen, hemp, banana, jute, ramie, raffia, sisal, wool, alpaca, mohair, cashmere, angora, silk, bamboo, miscanthus, coconut, agave, sorghum, switchgrass, wood and keratin fibers.
• the fibers used in the context of the present invention are chosen from polypropylene fibers, a blend of polypropylene / polyethylene, polyamide, acrylic, kevlar, aramid, carbon, basalt, mica, steel, stainless steel or cast iron.
• phase change material or PCM is generally meant a material having the ability to absorb and retain heat energy in the form of latent heat and then restore it during a phase change.
• the thermal energy is stored in the PCM during a melting process while it is restored during solidification processes.
• the ambient temperature of a liquid-solid PCM exceeds the melting temperature of the PCM, the latter absorbs heat in an endothermic process (molten state).
• the ambient temperature falls below the melting temperature of the PCM, the PCM releases the latent heat via an exothermic process and returns to the solid state.
• the composite material comprises a single organic PCM or a mixture of at least two different organic PCMs.
• the PCMs used alone or as a mixture are organic PCMs and in particular organic liquid-solid PCMs. Those skilled in the art know different types of organic liquid-solid PCMs that can be used in the context of the present invention.
• the organic PCMs used in the composite material according to the invention are advantageously insoluble in the activation solution.
• not soluble in the activation solution is meant that the organic PCMs used are completely soluble in the activation solution at a concentration of less than or equal to 2% by weight and at 25 ° C. and at atmospheric pressure.
• the at least one organic PCM has a melting enthalpy greater than or equal to 140 J / g.
• the composite material according to the invention comprises only one organic PCM, the latter has a melting enthalpy greater than or equal to 140 J / g.
• the composite material according to the invention comprises a mixture of at least two different organic PCMs, the mixture has a melting enthalpy greater than or equal to 140 J / g. Therefore, this mixture may comprise one or more organic PCM (s) having a melting enthalpy of less than 140 J / g.
• the organic PCM (s) is (are) chosen from the group consisting of paraffins, fatty alcohols, fatty acid esters, polyethers and polyalcohols.
• fatty alcohol is meant a compound of formula C m H2m + 2-2vO in which m represents an integer between 10 and 40 and v corresponds to the number of unsaturation (s) in the carbon chain represents 0 or a integer between 1 and 20.
• fatty acid ester is meant a compound of formula C x H 2 x + 1-2wC (O) OCyH 2 y + 1-2z in which x represents an integer between 9 and 39, y represents an integer between 1 and 20, w corresponding to the number of unsaturation (s) in the carbon chain to x carbons represents 0 or an integer between 1 and 20 and z corresponding to the number of unsaturation (s) in the carbon carbon chain. (s) represents 0 or an integer between 1 and 10.
• polyether is meant a polymer whose macromolecular backbone contains repeat units containing the ether group.
• a polyether is selected from the group consisting of poly (tetrahydrofuran), poly (ethylene glycol), poly (propylene glycol), poly (butylene glycol), block copolymers of ethylene oxide and propylene oxide, copolymers thereof and combinations thereof.
• polyalcohol an organic compound comprising at least two hydroxyl groups (-OH).
• the basic structure of the polyhydric alcohol can be an alkane, an alkene, an alkyne, a cycloalkane, a cycloalkene, an aryl or a heteroaryl, this structure being able to be substituted by other functional groups such as a carbonyl, a carboxyl, a primary, secondary or tertiary amine, a sulfonyl or a phosphonyl.
• organic PCM in the composite material according to the invention a compound selected from the group consisting of decane, undecane, a mixture comprising dodecane and at least one other organic PCM, tridecane, tetradecane pentadecane, hexadecane, heptadecane, octadecane, nonadecane, a mixture comprising eicosane and at least one other organic PCM, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, 1-undecanol, docadecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol
• the at least one organic PCM has a melting point of between 10 ° C. and 30 ° C.
• the composite material according to the invention comprises only one organic PCM, the latter has a melting point of between 10 ° C. and 30 ° C.
• the composite material according to the invention comprises a mixture of at least two different organic PCMs, the mixture has a melting point of between 10 ° C. and 30 ° C. Therefore, this mixture may comprise one or more organic PCM (s) having either a melting temperature below 10 ° C or a melting temperature above 30 ° C.
• the at least one organic PCM implemented in the context of the present invention is not an engine oil.
• glycopolymer or “geopolymer matrix” is meant in the context of the present invention a solid and porous material in the dry state, obtained following the hardening of a mixture containing finely ground materials (ie the alumino-silicate source ) and a saline solution (ie the activating solution), said mixture being able to set and harden over time.
• This mixture may also be referred to as “geopolymeric mixture”, “geopolymeric mixture”, “Geopolymeric composition” or “geopolymer composition”.
• this mixture may be referred to as "geopolymeric grout", “geopolymeric grout”, “geopolymeric paste” or “geopolymeric paste”.
• the hardening of the geopolymer is the result of the dissolution / polycondensation of the finely ground materials of the geopolymeric mixture in a saline solution such as a high pH salt solution (ie the activation solution).
• a geopolymer or geopolymer matrix is an amorphous aluminosilicate inorganic polymer.
• Said polymer is obtained from a reactive material essentially containing silica and aluminum (ie the aluminosilicate source), activated by a strongly alkaline solution, the solid / solution weight ratio in the formulation being low.
• the structure of a geopolymer is composed of an Si-O-Al lattice formed of silicate (SiO 4 ) and aluminate (AlO 4 ) tetrahedra bound at their vertices by oxygen atom sharing.
• cation (s) of compensation is (are) advantageously chosen from the group consisting of alkali metals such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb ) and cesium (Cs); alkaline earth metals such as magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba); and their mixtures.
• reactive material containing essentially silica and aluminum and “aluminosilicate source” are, in the present invention, similar and usable interchangeably.
• the reactive material containing essentially silica and aluminum that can be used to prepare the geopolymer matrix used in the context of the invention is advantageously a solid source containing amorphous aluminosilicates.
• amorphous alumino-silicates are chosen in particular from natural alumino-silicate minerals such as illite, stilbite, kaolinite, pyrophyllite, andalusite, bentonite, kyanite, milanite, grovenite, amesite, cordierite, feldspar, allophane, etc .; calcined natural aluminosilicate minerals such as metakaolin; synthetic glasses based on pure aluminosilicates; aluminous cement; pumice; sub- calcined products or industrial mining residues such as fly ash and blast furnace slags respectively obtained from the burning of coal and during the processing of cast iron ore in a blast furnace; and mixtures thereof.
• activation solution is a strongly alkaline aqueous solution which may optionally contain silicate components, especially chosen from the group consisting of silica, colloidal silica and vitreous silica.
• activation solution high pH saline solution
• strongly alkaline solution are, in the present invention, similar and interchangeably usable.
• strongly alkaline or “high pH” means a solution whose pH is greater than 9, especially greater than 10, in particular greater than 11 and more particularly greater than 12.
• the Activation solution has a concentration of OH " greater than 0.01 M, in particular greater than 0.1 M, in particular greater than 1 M and, more particularly, between 5 and 20 M. It should be noted that the pH of the activation solution after the addition of the at least one organic PCM as defined above must remain greater than 9, especially greater than 10, in particular greater than 11 and more particularly greater than 12.
• the activating solution comprises the compensation cation or the compensation cation mixture in the form of an ionic solution or a salt.
• the activating solution is chosen in particular from an aqueous solution of sodium silicate (Na 2 SiO 3), potassium silicate (K 2 SiO 2 ), sodium hydroxide (NaOH), potassium hydroxide ( KOH), calcium hydroxide (Ca (OH) 2 ), cesium hydroxide (CsOH) and their derivatives, etc.
• the present invention also relates to a process for preparing such a composite material.
• the method according to the present invention comprises the following steps: a) preparing an activation solution comprising at least one organic phase change material (organic PCM) in particular as previously defined,
• step (b) adding to the solution obtained in step (a) at least one alumino-silicate source,
• step (c) subjecting the mixture obtained in step (b) to conditions allowing the hardening of the geopolymer.
• Step (a) of the process according to the present invention consists in adding, to an activating solution as defined previously, the organic PCM.
• Prior preparation of the activation solution is a standard step in the field of geopolymers.
• the activation solution which is a high-pH saline solution comprising the compensation cation or the compensation cation mixture, may optionally contain one or more silicated component (s), in particular chosen from the group consisting of silica, colloidal silica and vitreous silica.
• silicated component s
• this or these latter (s) is (are) present in an amount of between 100 mM and 10 M, in particular between 500 mM and 8 M and, in particular, between 1 and 6 M in the activation solution.
• the organic PCM is added to the activation solution at once or in several times and even drop by drop. Once the organic PCM has been added to the activating solution, the resulting solution is mixed using a kneader, stirrer, magnetic bar, ultrasonic bath or homogenizer.
• the mixture / kneading in step (a) of the process according to the invention is carried out at a speed such that the mixture has a Reynolds number greater than 1, especially greater than 10, advantageously greater than 100, in particular greater than at 1000 and, more particularly, above 3000. Such agitation makes it possible to obtain an emulsion-type solution or a solution of the microemulsion type.
• Step (a) of the process according to the invention is carried out at a temperature of between 10 ° C.
• ° C. and 40 ° C. advantageously between 15 ° C. and 30 ° C. and, more particularly, at room temperature (ie 23 ° C. ⁇ 5 ° C) for a duration greater than 2 min, especially between 4 min and 1 h and, in particular between 5 min and 30 min.
• step (a) it may be necessary, during step (a), to use at least one surfactant, ie a molecule comprising a lipophilic portion (apolar) and a hydrophilic portion (polar), so as to obtain a uniform solution following step (a) of the process according to the invention.
• one or more surfactant (s) may need to be added to increase the stability of the emulsion or the dispersion of the organic PCM in the activating solution.
• the surfactant (s) may be added (i) to the activating solution prior to the addition of the organic PCM, (ii) to the organic PCM prior to its addition to the solution. activation or (iii) to the activation solution in which the organic PCM has already been added.
• the surfactant (s) is (are) added (s) either (i) to the activation solution prior to the addition of the organic PCM, or (ii) to the organic PCM prior to its addition to the solution. activation.
• anionic surfactants whose hydrophilic part is negatively charged such as alkyl or aryl sulfonates, sulfates, phosphates, or sulfosuccinates associated with a counterion such as an ammonium ion (NH 4+ ), a quaternary ammonium such as tetrabutylammonium, and the alkaline cations such as Na + , Li + and K + .
• anionic surfactants it is possible, for example, to use tetraethylammonium paratoluenesulphonate, sodium dodecyl sulphate, sodium palmitate, sodium stearate, sodium myristate, di (2-ethylhexyl) sulphosuccinate, sodium, methylbenzene sulfonate and ethylbenzene sulfonate.
• cationic surfactants whose hydrophilic part is positively charged, in particular chosen from quaternary ammoniums having at least less a C4-C22 aliphatic chain associated with an anionic counterion chosen in particular from boron derivatives such as tetrafluoroborate or halide ions such as F “ , Br, I " or Cl "
• anionic counterion chosen in particular from boron derivatives such as tetrafluoroborate or halide ions such as F " , Br, I " or Cl
• cationic surfactants it is for example, tetrabutylammonium chloride, tetradecylammonium chloride, tetradecyltrimethylammonium bromide (TTAB), cetrimonium bromide (CTAB), alkylpyridinium halides carrying an aliphatic chain and alkylammonium halides can be used.
• zwitterionic surfactants which are neutral compounds having formal electric charges of one unit and of opposite sign, chosen especially from compounds having a C 5 -C 20 alkyl chain generally substituted with a negatively charged function such as a sulfate or a carboxylate and a positively charged function such as ammonium.
• zwitterionic surfactants mention may be made of sodium N, N dimethyldodecylammoniumbutanate, sodium dimethyldodecylammoniumpropanate and amino acids.
• amphoteric surfactants which are compounds acting as both an acid or a base depending on the medium in which they are placed.
• amphoteric surfactants it is possible to use disodium lauroamphodiacetate, betaines such as alkylamidopropylbetaine or laurylhydroxysulfobetaine.
• neutral surfactants or nonionic surfactants whose surfactant properties, especially hydrophilicity, are provided by unfilled functional groups such as an alcohol, an ether, an ester or an amide, containing heteroatoms such as as nitrogen or oxygen; because of the low hydrophilic contribution of these functions, the nonionic surfactant compounds are most often polyfunctional.
• nonionic surfactants it is possible to employ polyethers such as polyethoxylated surfactants such as, for example, polyethylene glycol lauryl ether (Brij ® 35 or POE23), copolymers of ethylene oxide block and oxide propylene such as, e.g., Pluronic ® L35, polyols (sugar-derived surfactants), in particular glucose alkylates such as, for example glucose hexanate.
• the latter is chosen from cationic surfactants and nonionic surfactants.
• the amount of surfactant (s) used in the context of the present invention will greatly depend on the organic PCM and activating solution used in the process. Those skilled in the art will be able to determine the appropriate amount by means of routine tests.
• the surfactant is present in a proportion of between 0.001 and 20%, especially between 0.01 and 10% and, in particular, between 0.05 and 5%. % by volume relative to the total volume of said solution.
• Step (b) of the process according to the invention consists in bringing into contact the activation solution comprising the organic PCM and optionally a surfactant and the aluminosilicate source as defined above.
• the alumino-silicate source can be poured in one or more times on the activation solution containing the organic PCM and optionally a surfactant.
• the alumino-silicate source may be sprinkled onto the activating solution containing the organic PCM and optionally a surfactant.
• step (b) of the process according to the invention is carried out in a kneader in which the activation solution containing the organic PCM and optionally a surfactant has been introduced beforehand.
• a kneader known to those skilled in the art can be used in the context of the present invention.
• Step (b) of the process according to the invention therefore comprises a mixing or kneading of the activation solution containing the organic PCM and optionally a surfactant with the aluminosilicate source.
• the mixing / kneading in step (b) of the process according to the invention is carried out at a speed such that the mixture has a number of Reynolds greater than 0.01, in particular greater than 0.1, advantageously greater than 1, in particular greater than 10 and, more particularly, greater than 100.
• Step (b) of the process according to the invention is carried out at a temperature of between 10 ° C. and 40 ° C., advantageously between 15 ° C. and 30 ° C. and, more particularly, at room temperature (ie 23 ° C. ⁇ 5 ° C) for a duration greater than 2 min, especially between 4 min and 3 h and, in particular between 5 min and 30 min.
• alumino-silicate source to be used in the context of the present invention based on their knowledge in the field of geopolymerization as well as the nature of the organic PCM implemented and the amount of Organic PCM and activation solution implemented.
• the mass ratio activation solution / MK with activation solution representing the mass of activating solution containing the organic PCM and optionally a surfactant (expressed in g) and MK representing the mass alumino-silicate source (expressed in g) used is advantageously between 0.6 and 2 and in particular between 1 and 1.5.
• An activation solution / MK ratio between 1.2 and 1.4 makes it possible to guarantee a quantity and a size of the pores in the geopolymer that are suitable for encapsulation and in particular for the microencapsulation of organic PCM.
• fines and / or fibers as defined above can be used to prepare the composite material according to the invention.
• the fines and / or fibers can be added during the step
• step (at) following step (a) and prior to step (b); during step (b) and / or following the step
• Step (c) of the process according to the invention consists in subjecting the mixture obtained in step (b) to conditions allowing the geopolymeric mixture to harden. Any technique known to those skilled in the art for curing a geopolymeric mixture in which an organic PCM is present can be used during the curing step of the process.
• the conditions for curing during step (c) advantageously comprise a curing step optionally followed by a drying step.
• the curing step can be done in the open air, under water, in various hermetic molds, by humidifying the atmosphere surrounding the geopolymeric mixture or by applying an impervious coating on said mixture.
• This curing step can be carried out under a temperature of between 10 and 80 ° C., in particular between 20 and 60 ° C. and in particular between 30 and 40 ° C. and can last between 1 and 40 days, or even longer. . It is obvious that the duration of the cure depends on the conditions implemented during the latter and the skilled person will be able to determine the most suitable duration, once the conditions defined and possibly by routine tests.
• the curing step comprises a drying step
• this drying can be carried out at a temperature of between 30 and 90 ° C, in particular between 40 and 80 ° C and, in particular, between 50 and 70 ° C and can last between 6 hours and 10 days, especially between 12 pm and 5 days and, in particular, between 24 and 60 hours.
• the latter prior to the hardening of the geopolymeric mixture in which the organic PCM is present, the latter can be placed in molds so as to give it a predetermined shape following this hardening.
• the method according to the present invention comprises the following steps:
• step (b ) adding to the mixture obtained in step (a') at least one organic phase change material (organic PCM) in particular as previously defined,
• Step (a ') of the process according to the present invention consists in preparing an activation solution as defined above in which at least one aluminosilicate source as defined above is added. Such a step is conventional in the field of geopolymers.
• step (a) All that has been previously described as to the activation solution in step (a) also applies to the activation solution implemented in step (b ').
• step (b) all that has been previously described for step (b) and in particular the type of kneader, the temperature, the amount of alumino-silicate source and the mass ratio of activation solution / MK applies, mutatis mutandis in step (a ').
• Step (b ') of the process consists in introducing, into the mixture (activation solution + alumino-silicate source), the organic PCM. It is obvious that this step must be implemented relatively quickly after the preparation of the aforementioned mixture and this, prior to any hardening of this mixture which could prevent the production of a homogeneous mixture following step (b ').
• the organic PCM is added to the mixture (activation solution + alumino-silicate source) at once or in several times and even drop by drop.
• the preparation obtained is mixed using a kneader, a stirrer, a magnetic bar, an ultrasonic bath or a homogenizer.
• the mixing / kneading in step (b ') of the process according to the invention is carried out at a speed such that the mixture has a Reynolds number greater than 1, in particular greater than 10, advantageously greater than 100, in particular greater than 1000 and, more particularly, greater than 3000 and this, to obtain a homogeneous mixture following step (b ').
• Step (b ') of the process according to the invention is carried out at a temperature of between 10 ° C. and 40 ° C., advantageously between 15 ° C. and 30 ° C. and, more particularly, at room temperature (ie 23 ° C. ⁇ 5 ° C) for a longer period at 2 min, especially between 4 min and 3 h and, in particular between 5 min and 30 min.
• step (a ') or during step (b') it may be necessary, during step (a ') or during step (b'), to use at least one surfactant as defined above, so as to obtain a homogeneous mixture following step (b ') of the method according to the invention.
• one or more surfactant (s) may need to be added to increase the miscibility or dispersion of the organic PCM in the mixture (activation solution + alumino-silicate source).
• the surfactant (s) may be added (i ') to the activating solution prior to the addition of the aluminosilicate source, ( ⁇ ') to the aluminosilicate source beforehand. to its addition in the activation solution, (iii ') to the activation solution in which the alumino-silicate source has already been added, (iv') to the organic PCM prior to its addition to the mixture (solution of activation + alumino-silicate source) or ( ⁇ ') to the mixture (activation solution + alumino-silicate source) in which the organic PCM has already been added.
• Embodiment (i ') is preferable to the desired purpose. All that has been indicated for the surfactant in the context of step (a) and in particular the amount of surfactant also applies to step (b ').
• fines and / or fibers as defined above can be used to prepare the composite material according to the invention.
• the fines and / or the fibers may be added during step (a '); following step (a ') and prior to step (b'); during step (b ') and / or following step (b') and prior to step (c ').
• step (c) also applies to step (c ').
• the organic PCM (s) is (are) incorporated into the geopolymer matrix at an incorporation rate of less than or equal to 90% by volume relative to the total volume of said composite material. , in particular at an incorporation rate of less than or equal to 80% by volume with respect to total volume of said composite material and typically at a rate of incorporation of between 0.5 and 70% by volume relative to the total volume of said composite material.
• the organic PCM (s) represent (s) between 0.5 and 70% by volume relative to the total volume of the composite material according to the invention or composite material prepared according to the process object of the invention. 'invention.
• this degree of incorporation is between 1 and 65%, especially between 5 and 60% and, in particular, between 10 and 55% by volume relative to the total volume of said composite material.
• this incorporation rate can be of the order of 20% (ie 20% ⁇ 5%), of the order of 30% (ie 30% ⁇ 5%), of the order of 40% (ie 40% ⁇ 5%) or of the order of 50% (ie 50% ⁇ 5%) by volume relative to the total volume of said composite material.
• the material which is the subject of the present invention may be in various forms, of small or large size, depending on the desired application and in particular structures of predetermined shape in the context of 3D printing.
• the material which is the subject of the present invention may be in the form of a fine powder, a coarse powder, grains, granules, pellets, balls, balls, blocks, rods, cylinders, plates, panels or mixtures thereof.
• the present invention also relates to the use of a composite material as defined above or capable of being prepared by a preparation process as previously defined as a thermoregulating material and especially as a thermoregulating material in the construction.
• the composite material as previously defined or capable of being prepared by a preparation method as defined above can be used in the insulation of buildings and / or in the passive air conditioning and heating of buildings.
• the organic PCM or the mixture of organic PCMs to be used for this purpose.
• the melting temperature of the organic PCM or organic PCM mixture must be 3 ° C higher than that which it is desired to keep inside the building provided that the outside temperature the night goes down below the crystallization temperature of the organic PCM or organic PCM mixture and passes over in the day.
• Figure 1 is a photograph of test specimens of a composite material according to the invention hexadecane / geopolymer at 20% by volume.
• Figure 2 shows the thermal flux as a function of temperature for geopolymers with different levels of hexadecane incorporated namely 3.5%, 7.53% and 17.8% by mass respectively corresponding to 10, 20 and 40% by volume.
• the energy absorbed during the melting of the oil in Jg 1 is indicated for each composite.
• Table 1 Chemical composition of metakaolin used.
• the compensating cations and digestion agents selected are alkali hydroxides, introduced in the form of NaOH granules (Prolabo, Rectapur, 98%).
• a sodium silicate such as Betol 52T (Woellner) is also used in all of the following examples.
• Surfactants are also used in the examples hereinafter. It is either Pluronic L35 (Sigma Aldrich) i.e. a nonionic surfactant or cetrimonium bromide (CTAB, Sigma Aldrich) i.e. a cationic surfactant.
• Pluronic L35 Sigma Aldrich
• CTAB cetrimonium bromide
• phase-change material used is hexadecane used in an amount such that the volume fraction in the composite material (geopolymer + hexadecane) is equal to 10%, 20% and 40% by volume.
• the hexadecane used for this composite melts at 17.3 ° C, in the composite or for pure hexadecane. Under the same measurement conditions, the oil has a 46.4 kJ mol 1 fusion enthalpy is 205.1 Jg -1. The percentage of this energy corresponds to the mass percentage of hexadecane introduced into the geopolymer.
• hexadecane does not lose its thermal properties following insertion into the geopolymer.
• the plate Considering a slab of 2 cm thickness of a composite material to 40% by volume of hexadecane, the composite material having a density equal to 1.26 kg.l _1, the plate has a mass of 25, 36 kg and delivers an energy of 879 kJ during the phase change of the hexadecane contained in the plate. This represents a latent energy of 244 Wh.nr 2 .

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Thermal Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Glass Compositions (AREA)
• Inorganic Insulating Materials (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=58213199

Family Applications (1)

Country Status (4)

Families Citing this family (4)

Family Cites Families (2)

• 2016
  • 2016-11-03 FR FR1660644A patent/FR3058154B1/fr active Active
• 2017
  • 2017-10-31 MA MA046468A patent/MA46468A/fr unknown
  • 2017-10-31 WO PCT/FR2017/052990 patent/WO2018083411A1/fr not_active Ceased
  • 2017-10-31 EP EP17808534.6A patent/EP3523391A1/de not_active Withdrawn

Also Published As

Similar Documents

Legal Events