184 results about "Phase change enthalpy" patented technology

The present invention provides composite phase transition heat accumulation material used gel as carrier, and the preparation method and the application of the material. The material of the present invention is formed by compositing the phase transition heat accumulation material accounted for 60 percent to 80 percent of the total mass into a macromolecule gel carrier accounted for 20 percent to 40 percent of the total mass, the material has thermo-plasticity and better thermo stability, compared with the same kind of macromolecule heat accumulation material, the material has higher phase transition enthalpy. The material can be used in temperature control and energy saving for buildings, and can also be used in heat preservation and energy saving fields for daily articles, thereby the present invention has wide application prospect.

A process for preparing a form-fixed phase change material includes plasticizing olefine polymer (10-50 wt.%) to become chips, gradually adding paraffine until its content is 90-50 wt%, breaking, smelting-extruding out, water cooling and baking. The said polymer may be at least one of polyethene, polypropene, polybutene, etc. The resultant material features 25-70 deg.c for phase-changing temp, high phase-changing enthalpy up to 175 KJ/kg and no molecular leakage.

The present invention relates to a kind of high molecular solid/solid phase changing material with mixed net and comb structure, and features that polyglycol with two active end radical and polyglycol with one active end radical are fixed onto the high molecular skeleton material to form 3D mixed net and comb structure. The material of the present invention has relatively great phase change enthalpy up to 120 J/g, proper phase change temperature capable of being altered in 0-65 deg.c, stable solid state before and after phase change without supercooling, separating and other unstable phenomenon, high mechanical strength, high solvent resistance, good machining performance, no toxicity, no leakage, no corrosion, no pollution, long service life and other advantages. The present invention may be used widely in solar energy utilization, afterheat recovering, intelligent air conditioner and other fields.

A phase-changing material in the form of micro capsule is prepared from the phase-changing material (paraffin wax) and basic supporting material (polystyrene and polyethene) through heating for fusing, mixing for coating, and microcapsule packing by in-situ polymerizing by melamine modified urea-aldehyde resin. It has adjustable phase-changing temp (0-70 deg.C) and high phase-changing enthalpy (138 KJ/kg).

The present invention discloses nano thermal conductivity enhanced microcapsule composite phase change material and a preparation method thereof, nano thermal conductivity enhancing material is high thermal conductivity nanoparticles such as boron nitride (BN), carbon nanotubes (CNTs) or graphene oxide (GO), and a microcapsule core material is organic phase change material. The phase change material, an emulsifier and a solvent are mixed and prepared according the preparation method of the invention to obtain thermal conductivity enhanced microcapsule composite phase change material based on nanoparticles such as BN, CNTs and GO, wherein all the added BN, CNTs and GO are modified to comprise hydroxyl groups. In addition, it is possible to add the nano thermal conductivity enhancing particles such as BN, CTNs or GR into the core material of the microcapsule core material according to actual needs. The composite phase change material prepared herein has high phase change enthalpy, good thermal cycle stability, excellent thermal conductivity and the like, has a simple preparation process, stable structure and high encapsulation rate and is widely applicable.

The present invention features that the material has crosslinked crystalline polyolefin as base body and crystalline alkyl hydrocarbon dispersed inside the crosslinked net as the composite material for phase change energy accumulation. In the composite material, the phase change energy accumulating component accounting for 40-80 % has solid-solid phase conversion at phase change temperature of 20-80 deg.c and phase change enthalpy greater than 80 J/g. The composite phase change material has relatively high energy accumulating density and excellent heat stability, may be used as energy accumulating material for the accumulation of solar energy and industrial afterheat, constant temperature in building and energy saving in air conditioner and as temperature control material in electronic instrument, machinery, etc. widely.

The invention relates to a three-dimensional phase-change material based on graphene and a preparing method of the three-dimensional phase-change material. A graphene oxide aqueous solution with certain concentration is added into liquid nitrogen to be quickly frozen, then graphene oxide aerogel is obtained through freezing drying and is fed into a high-temperature furnace to be subjected to high-temperature heat treatment at 500-3000 DEG C in the inert atmosphere, the treated graphene oxide aerogel is then soaked in dichloromethane solutions with different paraffin concentrations, the product is put into a 30 DEG C vacuum oven to be dried after sufficient absorption, and then the three-dimensional phase-change material based on graphene is obtained. The three-dimensional phase-change material based on graphene is good in paraffin encapsulation effect, the filling amount of paraffin ranges from 0.1% to 99.9%, films and paraffin are uniformly compounded, the melt phase change enthalpy and the solidification phase change enthalpy of the material are basically maintained unchanged after multiple times of heating and cooling circulation, and thus efficient heat energy storage is achieved.

The invention discloses a phase-change energy-storing fiber. The phase-change energy-storing fiber is of a skin-core structure which comprises a skin layer and a core layer, wherein a skin layer raw material is a thermoplastic polymer; and a core layer raw material is a mixture of the thermoplastic polymer, clay mineral powder and a phase-change material. A preparation method of the phase-change energy-storing fiber comprises the following steps: (1) weighing 2-20 parts of the phase-change material and 5-20 parts of the clay mineral powder in parts by weight, uniformly mixing the weighed phase-change material and clay mineral powder by virtue of ultrasonic oscillation under a vacuum condition, putting the mixture into a vacuum oven so as to obtain a composite phase-change material, and uniformly mixing 60-90 parts of thermoplastic polymer with the prepared composite phase-change material, so as to obtain the core layer raw material; and (2) carrying out melt spinning on the thermoplastic polymer, as skin layer raw material, and the core layer raw material by virtue of a compound spinning machine, so as to obtain the phase-change energy-storing fiber being of the skin-core structure. The preparation method is simple and low in cost, and the prepared phase-change energy-storing fiber has large phase-change enthalpy and a uniform temperature regulation effect.

The invention provides a preparation method of a phase change monomer with double-bond end groups, which comprises the following steps of: in an ice water bath, dissolving PEG (Polyethane Glycol MW2000-10000) in dichloromethane, and then adding an acid binding agent (triethylamine or N,N-dimethylacetylamide) and acryloyl chloride; reacting at a temperature of 25-35 DEG C for 4-8h under the protection of nitrogen; adding a precipitant (n-hexane or diethyl ether) in reacting liquid in the ice water bath, settling for 10-15 minutes and leaching to obtain a finished product, wherein the molar ratio of the PEG to the acryloyl chloride is 1:(1-3), the molar ratio of the PEG to the acid binding agent is 1:(1-3), and the molar ratio of the PEG to the dichloromethane is 1:(0.312-0.546). The monomer has high activity and is easy to carry out copolymerization or grafting reaction with other monomers or polymers to prepare solid-solid phase change materials. The monomer has higher phase change enthalpy (163.21J/g), proper phase change temperature (46.53 DEG C) and higher thermal tolerance (320 DEG C). The preparation technology is simple, and the production cost is low.

The invention relates to a graphene-based composite phase-change membrane and a preparation method thereof. The preparation method comprises the following steps: continuously and uniformly extruding a graphene oxide water solution with a certain concentration out of a preparation device with a slotted opening into a solidification solution, and quickly refrigerating in liquid nitrogen; and carrying out freeze-drying to obtain a graphene oxide aerogel membrane, sending the graphene oxide aerogel membrane into a high-temperature furnace, carrying out high temperature 1300-3000-DEG C heat treatment in an inert atmosphere, immersing the graphene oxide aerogel membrane in paraffin dichloromethane solutions with different concentrations, and sufficiently absorbing, thereby obtaining the composite phase-change membrane material. The graphene composite phase-change membrane material has excellent packaging effect on paraffin, and the paraffin loadability is 0.1-99.9%; the membrane and paraffin are compounded uniformly; and after repeated heating-cooling circulations, the melt phase-change enthalpy and solidifying phase-change enthalpy of the material are basically kept unchanged, thereby implementing high-efficiency heat energy storage.

The invention relates to a microencapsulated multi-component inorganic phase-change material which comprises polymethyl methacrylate as a shell material and a multi-component crystalline sodium sulfate-based phase-change material as a core material. The material is prepared by the following steps: stirring the shell material at 0-4 DEG C to make a shell material solution; mixing the shell material solution with a core material solution composed of core material, deionized water and emulsifiers; emulsifying; adding dropwise deionized water into the resulting emulsion and mixing to form a white viscous emulsion; standing in an ice bath to allow complete volatilization of ethyl acetate; washing and separating the resulting microcapsule-containing emulsion with petroleum ether; and freeze-drying to obtain the microencapsulated multi-component inorganic phase-change material product. The product is innoxious and non-corrosive. The phase change temperature of the product is 11-20 DEG C and the phase change enthalpy is 62-65 kJ/kg. The product is good in heat stability and has the advantages and benefits of simple preparation method, easily-accessible raw material and low cost.

The invention relates to a preparation method of a solid-solid phase-change material immobilized by a chemical cross-linking method. The method comprises the following steps: dissolving polyethylene glycol acrylate into deionized water, adding a cross-linking agent and an initiator, increasing the temperature of a system to 70-80 DEG C, reacting for 2-5 hours to form hydrogel with a crosslinked network structure, and drying the hydrogel at the temperature of 35 DEG C for 24 hours to get the solid-solid phase-change material, namely polyethylene glycol acrylate gel, wherein the weight ratio ofthe cross-linking agent to the polyethylene glycol acrylate is 1:(200-7):20, the weight ratio of the initiator to the polyethylene glycol acrylate is 1:(200-1):50, and the volume ratio of the deionized water to the polyethylene glycol acrylate is 6:(1-10):1. In the preparation method, the original chemical structure of the polyethylene glycol acrylate is changed through chemical reaction, the solid-solid phase change at the different temperatures can be realized, the cross-linking degree of a product is changed by controlling the reaction conditions, and the phase change temperature and the phase change enthalpy are further regulated so as to meet the different actual requirements.

The embodiment of the invention discloses a preparation method of a phase-change energy-storage microcapsule, which comprises the following steps: providing a preemulsion, wherein the preemulsion uses paraffin as the dispersed phase and uses a chitosan water solution as the continuous phase; dispersing the preemulsion in an outer oil phase to obtain a compound emulsion, wherein the outer oil phase is liquid paraffin; and adding glutaric dialdehyde into the compound emulsion to carry out cross-linking reaction, thereby obtaining the phase-change energy-storage microcapsule. The invention uses paraffin as the core material, uses chitosan as the shell material, and enables the chitosan to be crosslinked by adding the cross-linking agent glutaric dialdehyde, thereby obtaining the microcapsule. The invention uses chitosan as the shell polymer material, which has the advantages of no toxicity and easy preparation, thereby being beneficial to industrial production. In addition, compared with the prior art, the invention does not need to add an initiator or a surfactant, thereby having the advantage of simple preparation method. The experimental result indicates that the microcapsule can remain the structure and high phase-change enthalpy value after repeated heating and cooling, thereby having the function of phase-change energy-storage.

The invention discloses a double-layer coating solid inorganic phase change material micro-capsule and a preparation method thereof. The double-layer coating solid inorganic phase change material micro-capsule is prepared from the following methods of: firstly, with polymethyl methacrylate as an inner layer wall material and the solid inorganic phase change material as a core material, preparing a single-layer coating solid inorganic phase change material micro-capsule by a phase separation method; and then with polystyrene as an outer layer wall material and the prepared single coating solid inorganic phase change material micro-capsule as the core material, preparing the double-layer coating solid inorganic phase change material micro-capsule by the phase separation or a solvent evaporation method. The double-layer coating solid inorganic phase change material micro-capsule is simple in preparation method, the phase change temperature can be adjusted between 30 DEG C and 60 DEG C, and the enthalpy of phase change is up to 150kJ/kg at the most; by the double-layer coating, the strength of the solid inorganic phase change material micro-capsule is effectively enhanced and the problems of percolation and corrosion of the core material solid inorganic phase change material are solved.

The invention provides a method for preparing a cross-linked solid-solid phase change energy storage material, which relates to a method for, after homogeneous preparing laurel acid cellulose ester with high substitution by using a cellulose/LiCl/DMAc solution system, synthesizing a cross-linked polyethylene glycol/laurel acid cellulose ester phase change energy storage material by using laurel acid cellulose ester and polyethylene glycol as main materials through solution grafted polymerization in the presence of cross-linking agent. Although both polyethylene glycol and laurel acid cellulose ester are solid-liquid phase change materials, polyethylene glycol and laurel acid cellulose ester are mutually dissolved and cross-linked in the process of grafted cross-linked polymerization to have typical polyether type segmented cross-linking network structures, thereby containing and restricting their respective microflow mutually. The phase change enthalpies of two components are overlapped mutually, thus final product has higher phase change enthalpy up to 194.7J/g. The obtained material has proper phase change temperature at 19 to 60 DEG C, stable heat performance, no liquid produced in phase change process and completely invertible phase change process, is a polymer solid-solid phase change energy storage material with bigger use valve and development prospect.

The invention relates to a novel shaped phase-change material and a preparation method thereof. The novel shaped phase-change material is prepared from the following raw materials in parts by weight: 1-10 parts of acrylic monomers, 1-10 parts of phosphate ester functional monomer, 0.005-0.03 parts of initiator, 10-40 parts of organic phase-change materials, 50-90 parts of deionized water and 0.1-1 part of emulsifier. The novel shaped phase-change material is excellent in performance, safe and environment-friendly, not only can play good fire retardation by modification on a capsule wall through phosphate, but also compensates the defects of inflammable performance of the organic phase-change material, as a phosphate ester group is led to the capsule wall, the flame retardant property of the phase-change material is greatly improved, application of the phase-change material in the energy-saving field is expanded, direct mixing of the fire retardant and a phase-change master batch also can be avoided, high phase-change enthalpy of the phase-change material is ensured, and negative effects caused by the heat storage performance of the phase-change material is avoided.

The invention discloses a preparation method of a paraffin-SEBS thermoplastic elastomer composite phase change material. The paraffin-SEBS thermoplastic elastomer composite phase change material comprises the following components in parts by weight: 30-80 parts of phase change paraffin and 20-70 parts of SEBS elastic plastic. The flexible composite phase-change material has the beneficial effectsthat the blank of the current flexible composite phase-change material in the market is solved, the adsorption capacity is high, and the phase-change enthalpy value is large. Besides, the phase-changematerial with controllable phase-change temperature can be obtained by adjusting the mass ratio of the phase-change materials with different marks, so that the application field of the paraffin-basedcomposite phase-change material is further widened, and good economic benefits are achieved.

The invention relates to a preparation method of a microencapsulated stabilized phase-change material and belongs to the technical field of phase-change materials. The preparation method comprises the following steps: firstly, taking soap stock as a raw material; carrying out saponification and acidolysis to obtain fatty acid; mixing the fatty acid with paraffin wax to obtain a phase-change material, wherein the fatty acid can be used for reducing the melting point of the paraffin wax; inserting an ethylene monomer into a graphite flake layer; polymerizing to separate the graphite flake layer; doping graphite into a polymer so as to increase the thermal conductivity of the polymer; carrying out emulsion reaction to coat the phase-change material with the polymer; taking tetraethyl orthosilicate as a raw material and depositing silicon dioxide on the surface of the polymer under the action of alkali to form a coating film; finally, drying to obtain the microencapsulated stabilized phase-change material. The microencapsulated stabilized phase-change material prepared by the preparation method has an excellent heat-conducting performance, the phase change enthalpy reaches 130.14kJ/kg to 135.25kJ/kg and the phase change temperature is 20 DEG C to 40 DEG C; the microencapsulated stabilized phase-change material has good compatibility with a building material and related mechanical properties of the building material are not influenced; the microencapsulated stabilized phase-change material has wide application prospect.

The invention relates to a urea resin paraffin microcapsule material with high thermal conductivity and high enthalpy value and a preparation method. The urea resin paraffin microcapsule material is covered by graphene oxide. Graphene oxide serves as a covering layer, thermal conductivity of microcapsules is improved, and the phase change enthalpy value of the microcapsules is not reduced. The material is of a double-layer core-shell structure, the outermost layer is graphene oxide, the inner layer is urea resin, and a core is paraffin. The preparation method includes the steps that firstly, urea resin paraffin microcapsules are prepared, and the obtained microcapsules are washed and dried; secondly, graphene oxide and positive ion surfactant are added into deionized water for ultrasonic dispersion, and graphene oxide dispersion liquid is obtained; thirdly, the microcapsules obtained in the first step and a negative ion surfactant are added into water for ultrasonic dispersion, the dispersion liquid obtained in the second step is added to be stirred, and a final product is obtained through filtering, washing and drying. The microcapsules prepared through the method are uniform in particle size distribution, and thermal performance of paraffin microcapsules can be effectively improved.

The invention discloses an inorganic hydrated salt porous carbon composite phase change material and a preparation method thereof, wherein the preparation method comprises the following steps: firstly, preparing biomass-based porous carbon subjected to activation treatment, and weighing an inorganic hydrated salt phase change material, the biomass-based porous carbon and a pore sealing agent in proportion; and then preparing a saturated solution from the inorganic hydrated salt phase change material, adding biomass-based porous carbon, impregnating, carrying out vacuum pressurization and adsorbing; and finally, adding the pore sealing agent, stirring, wind-drying, and grinding and pulverizing, to obtain the inorganic hydrated salt porous carbon composite phase change material. The composite phase change material prepared by the method has the advantages of difficult liquid leakage, no phase separation, small supercooling degree, high phase change enthalpy, no toxicity, no corrosion, good thermal stability, good durability, low preparation cost and the like, and has broad market prospects in the fields of building and energy-storage materials.

The invention provides a preparing method for a polyethylene glycol/nano-silicon dioxide composite phase change material. Firstly, polyethylene glycol and a silane coupling agent are subjected to the reaction, prepolymer with a siloxane end group is generated; after the prepolymer and ethyl orthosilicate are mixed uniformly, the PEG-SiO2 sol system is prepared through the acid catalysis hydrolysis-condensation reaction, gel is obtained through volatilization of a solvent, and the polyethylene glycol/nano-silicon dioxide composite phase change material is obtained through drying. By means of the polyethylene glycol/nano-silicon dioxide composite phase change material prepared through the method, the heat conductivity of a compound system can be greatly improved, and the phase change enthalpy and the phase change temperature are obviously reduced.

The invention relates to a compound phase-change cold accumulation material and a preparation method thereof and belongs to the technical field of novel materials. The compound phase-change cold accumulation material is characterized in that the material is prepared by compounding an organic three-dimensional network gel material with a low-temperature phase-change material through a solvent displacement method, wherein the mass ratio of the organic three-dimensional network gel material to the low-temperature phase-change material is 1 to (5 to 10); the organic three-dimensional network gel material is prepared by crossly linking and polymerizing polyisocyanate and a polybasic alcohol polymer; the low-temperature phase-change material is water, N,N-dimethyl sulfoxide, ethylene glycol or awater solution of inorganic salt; the mass concentration of the water solution of the inorganic salt is 0.1 percent to 10 percent. The compound phase-change cold accumulation material and the preparation method thereof have the advantages of simple synthesis technology and convenience for application; the material has great phase-change enthalpy and long cold-keeping time; no liquid is leaked ina working process and the material can be repeatedly used and has a wide application prospect in the aspect of cold accumulation and cooling.

The invention belongs to the field of phase change energy storage materials, and discloses a phase change energy storage material with a skin-core fiber structure and a preparation method thereof. Polyacrylonitrile is dissolved in an organic solvent, the phase change energy storage materials are added into the solvent and uniformly mixed, and an oil phase solution is obtained. Water-soluble phasechange materials are dissolved in deionized water or the deionized water is directly used as an aqueous phase solution; the aqueous phase solution is added into the oil phase solution, an emulsifyingagent is added for homogenization and dispersion, oil in water emulsion is obtained, and a composite fiber material with the skin-core structure is obtained through electrostatic spinning; a hollow fiber material is obtained through freeze-drying; finally pre-oxidation and carbonization treatment are performed in an inert atmosphere, and the phase change energy storage material with the skin-corefiber structure is obtained. The fiber preparation technology is combined with the high-performance phase change material, the phase change energy storage material has higher phase change enthalpy and reversible capacity, and multi-scene application of the phase change energy storage material is achieved.

The invention relates to a phase-change paraffin preparation method, and belongs to the technical field of pharmaceutical and chemical engineering. The phase-change paraffin preparation method is simple in technology; by means of the method, demand-based customized production can be achieved, waste can be reduced, cost can be lowered, and economic benefits can be effectively increased. According to the technical scheme, the phase-change paraffin preparation method includes the following steps that coal is subjected to gasification production to obtain synthesis feed gas, the feed gas is subjected to a Fischer-Tropsch synthesis reaction to obtain Fischer-Tropsch synthesis products, the Fischer-Tropsch synthesis products are subjected to a hydrogenation reaction to obtain a wide-fraction mixture, namely, Fischer-Tropsch synthesis paraffin, the Fischer-Tropsch synthesis paraffin is subjected to molecular short steaming and rectification to obtain refined paraffin products with different phase change enthalpy values, and NNO is added to obtain stable phase-change paraffin.