CN110628393A

CN110628393A - Method for preparing phase change latent heat material from crosslinking polyoxyethylene ether

Info

Publication number: CN110628393A
Application number: CN201910974137.XA
Authority: CN
Inventors: 刘晓; 白夏冰; 宋晓飞; 王子明; 许谦; 卢磊; 赖光洪; 管佳男
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2019-12-31
Anticipated expiration: 2039-10-14
Also published as: CN110628393B

Abstract

A method for preparing a phase change latent heat material from cross-linked polyoxyethylene ether relates to the technical field of phase change latent heat materials for cement concrete. The invention adopts acrylic ester, unsaturated carboxylic acid and polyoxyethylene ether as main reaction raw materials, and prepares a phase-change latent heat material by synthesizing cross-linked polyoxyethylene ether, namely, the acrylic ester and the polyoxyethylene ether are used as reaction monomers, and are copolymerized under the action of an initiator and a molecular weight regulator, and then are cross-linked and polymerized with the unsaturated carboxylic acid and the polyoxyethylene ether to obtain the product. The ceramsite material is selected as a storage carrier of the phase change latent heat material, and a layer of polymer film with excellent waterproof performance is covered on the surface of the ceramsite, so that the integrity in the stirring and construction processes is ensured. The material prepared by the invention has the advantages of obvious temperature control effect, excellent stability, low cost and simple and controllable preparation process, solves the problems of complex process, low energy efficiency, long time consumption and the like of the traditional phase change latent heat material, enriches the material types, and has wide market prospect and popularization and application potential.

Description

Method for preparing phase change latent heat material from crosslinking polyoxyethylene ether

Technical Field

The invention relates to the technical field of phase change latent heat materials for cement concrete, in particular to a specific preparation method for obtaining a phase change latent heat material by firstly polymerizing and then crosslinking to synthesize cross-linked polyoxyethylene ether and then adsorbing and filling ceramsite.

Background

The concrete material is the biggest building material such as building at present, road surface bridge engineering and water conservancy dam, in the middle of the work progress, cement hydration can release a large amount of heat, and concrete single pouring quantity is big, the structure section is thick and the cooling surface is little, make the heat that hydration produced can not distribute fast and gather inside concrete structure, form great inside and outside difference in temperature and then produce temperature stress, the change of external environment temperature also can make the inside temperature stress increase of concrete simultaneously, will appear temperature crack or even destroy when the temperature reaches concrete tensile strength limit, not only influence the outward appearance and the quality of concrete, and make the intensity and the durability of concrete greatly reduced. Therefore, in practical engineering, how to simply and effectively avoid the concrete from generating temperature cracks due to overhigh hydration heat in construction becomes a problem which needs to be solved at present.

The control measures for concrete temperature cracks include: the method is characterized in that a cementing material with lower hydration heat is selected to control the cast-in-place temperature of concrete, or strictly control the temperature and humidity in the later maintenance of the concrete, and the like, but the measures have complex process and high cost and can not effectively reduce the temperature difference and the temperature stress inside and outside the concrete for a long time. Therefore, more economic and effective temperature control measures are fundamentally selected to prevent temperature cracks, and the method has important research significance and engineering value.

The phase-change material can regulate and control the temperature through self heat absorption and release, and as an important member in the phase-change material, the solid-liquid phase-change material has the characteristics of large latent heat, narrow phase transition temperature, small volume change in the phase-change process and the like, and the material has low supercooling degree, higher thermal stability and chemical stability, but has the problems of small electric conductivity coefficient, small density, poor heat storage capacity per unit volume, phase-change leakage and the like. Therefore, the organic phase change material is subjected to molecular structure design modification, and is contained in a container, so that the organic phase change material not only has higher latent heat of phase change and proper phase change temperature of the traditional organic phase change material, but also can be prevented from leaking, corroding or polluting the environment, has good thermal stability and chemical stability, is finally applied to concrete to exert latent heat performance advantages, achieves the purposes of crack inhibition and the like, and has wide application value.

Patent CN1844269A (published: 2006, 05, 08) discloses a preparation method of a phase-change microcapsule, which comprises the steps of firstly preparing a relatively stable emulsion, then preparing a capsule wall top polymer, wherein the capsule wall is a silicon dioxide deposit, and finally coating with water glass as a phase-change material.

Patent CN104152115A (published: 2014, 11, 19) discloses a paraffin-SiO₂-TiO₂Phase-change micro-gelThe capsule is prepared by preparing phase-change microcapsule with oil phase paraffin as core and composite titania-silica material as shell by sol-gel method, and finally preparing phase-change microcapsule with paraffin-SiO₂-TiO₂The phase-change microcapsule, titanium dioxide, calcium carbonate, styrene-acrylic emulsion and various auxiliaries are used for preparing the heat storage and insulation coating. However, the shell of the microcapsule has high brittleness, is easy to crack and leak, has high heat conductivity coefficient and phase change temperature fluctuation, and has poor scrubbing resistance and coating appearance stability.

Patent CN101495223A (published: 2011, 9/21) discloses a composite phase change energy storage building coating and a preparation method thereof, wherein expanded perlite is used as a base material, and the base material and a room temperature ionic liquid, a straight chain fatty acid, alkane and other phase change materials form a composite phase change energy storage material, and then the composite phase change energy storage material is mixed with one or more of a styrene-acrylic emulsion, a pure acrylic emulsion and an ethylene-propylene emulsion to form the building coating with the phase change energy storage function. Compared with the existing composite phase change energy storage material, the composite phase change energy storage coating can be randomly mixed according to needs, and the architectural decoration effect cannot be influenced. However, the phase-change material has the defects of easy leakage of an organic phase, low heat conductivity coefficient of the microcapsule, low heat storage and release rate and the like.

The solid-liquid phase-change materials described in most patents have working properties such as high phase-change enthalpy and good stability. However, the preparation methods all have certain defects, the synthesized phase-change material has low thermal conductivity, too single variety of raw materials and easy leakage, and the phase-change material has adverse effects on long-term service. Therefore, the phase-change material with stable form needs to be designed and prepared, and the inner pores of the porous ceramsite material are relatively large in size compared with the surface pores, so that the porous ceramsite material can be physically adsorbed with the phase-change material, is an ideal phase-change material loading carrier, and is low in price and rich in sources. The prepared composite phase-change material not only has higher phase-change enthalpy and thermal conductivity, but also has good waterproof performance, so that the phase-change latent heat material can be stably stored in pores of the ceramsite, the leakage is avoided when the phase change occurs in the material, the possibility of cracking in the stirring and construction processes is avoided, and the composite phase-change material has good application value.

Disclosure of Invention

The invention aims to provide a method for preparing a phase change latent heat material by using cross-linked polyoxyethylene ether. The phase-change latent heat material with excellent performance is finally obtained by copolymerizing acrylic ester and polyoxyethylene ether, then performing cross-linking polymerization on the copolymerized acrylic ester, unsaturated carboxylic acid and polyoxyethylene ether to obtain cross-linked polyoxyethylene ether, storing the cross-linked polyoxyethylene ether in ceramsite and covering a layer of waterproof polymer film on the surface of the ceramsite. The invention designs and synthesizes the cross-linked polyoxyethylene ether with excellent phase change performance based on the composition of organic and inorganic materials, takes the ceramsite as a carrier, can effectively ensure the stability in the stirring and construction processes, and simultaneously shows more excellent application value and development prospect than the traditional phase change latent heat material due to the low price of the raw materials.

The invention provides a method for preparing a phase change latent heat material from cross-linked polyoxyethylene ether, which is characterized in that the cross-linked polyoxyethylene ether is synthesized by a polymerization and cross-linking method, and the conditions and the steps for adsorbing, filling and coating waterproof paint by ceramsite are as follows:

(1) polymerization reaction: firstly, adding polyoxyethylene ether and an organic solvent into a reactor, stirring and heating to 60-130 ℃, adding a molecular weight regulator, then dropwise adding a mixed solution of acrylic ester and an initiator for 1-10 hours, continuing to react for 0.5-5 hours at constant temperature after dropwise adding, and removing the organic solvent by reduced pressure distillation to obtain a polymerization product;

(2) and (3) crosslinking reaction: adding the polymerization product obtained in the step (1) and polyoxyethylene ether into solvent water, stirring, heating to 50-100 ℃, adding a molecular weight regulator, respectively dropwise adding an unsaturated carboxylic acid aqueous solution with the mass fraction of 20-50% and an initiator aqueous solution with the mass fraction of 5-50% for 1-10 hours, continuing to perform constant-temperature reaction for 1-5 hours after dropwise adding is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain the cross-linked polyoxyethylene ether;

(3) and (3) ceramsite adsorption: heating the cross-linked polyoxyethylene ether obtained in the step (2) to 50-80 ℃ to a molten state, heating ceramsite with the particle size range of 4-6mm to 60-100 ℃, keeping the temperature for 2-8 hours, adding the ceramsite into the molten cross-linked polyoxyethylene ether, immersing the ceramsite into the molten cross-linked polyoxyethylene ether, stirring the ceramsite for 12-48 hours, cooling the ceramsite to 15-35 ℃, immersing the ceramsite into the waterproof coating, stirring the waterproof coating for 5-30 seconds, taking the waterproof coating out, and air-drying the waterproof coating for 2-8 hours to obtain a phase-change latent heat material;

wherein the organic solvent in the step (1) is methanol, ethanol, p-xylene, 200# solvent oil, glycol, toluene or cyclohexane, and the ratio of the dosage to the mass sum of acrylate and polyoxyethylene ether is 2-10: 1; the molecular weight regulator in the step (1) is isopropanol, n-dodecyl mercaptan or isooctyl 3-mercaptopropionate, and the ratio of the dosage to the sum of the mole numbers of the acrylate and the polyoxyethylene ether is 0.001-0.04: 1; the acrylate in the step (1) is methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate or amyl acrylate; the polyoxyethylene ether in the step (1) is allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether or ethylene glycol monovinyl polyoxyethylene ether, and the molar ratio of the dosage to the acrylate is 0.2-1: 1; the initiator in the step (1) is azobisisobutyronitrile, azobisisoheptonitrile, dibenzoyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxybenzoate or di-tert-butyl peroxide, and the ratio of the dosage to the sum of the mole numbers of the acrylic ester and the polyoxyethylene ether is 0.001-0.04: 1;

the mass ratio of the using amount of the solvent water in the step (2) to the polymerization product obtained in the step (1) is 0.5-3: 1; the molecular weight regulator in the step (2) is isopropanol, thioglycolic acid or mercaptopropionic acid, and the ratio of the using amount to the sum of the mole numbers of unsaturated carboxylic acid and polyoxyethylene ether is 0.001-0.05: 1; the solute of the unsaturated carboxylic acid aqueous solution in the step (2) is acrylic acid, methacrylic acid, itaconic acid, maleic anhydride or fumaric acid, and the molar ratio of the solute amount to the acrylate in the step (1) is 2-50: 1; the polyoxyethylene ether in the step (2) is allyl polyoxyethylene ether, methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether or ethylene glycol monovinyl polyoxyethylene ether, and the molar ratio of the dosage to the unsaturated carboxylic acid is 0.2-1: 1; the solute of the initiator aqueous solution in the step (2) is potassium persulfate, sodium persulfate or ammonium persulfate, and the molar ratio of the solute amount to the acrylate in the step (1) is 0.1-0.3: 1;

the ceramsite in the step (3) is fly ash ceramsite, clay ceramsite, shale ceramsite, garbage ceramsite, diatomite ceramsite, coal gangue ceramsite or perlite tailing powder ceramsite, and the mass ratio of the dosage of the ceramsite to the cross-linked polyoxyethylene ether obtained in the step (2) is 50: 1; the waterproof coating in the step (3) is a polyurethane waterproof coating, an acrylate waterproof coating, an epoxy resin waterproof coating, an asphalt waterproof coating, a polyurea waterproof coating or an organosilicon waterproof coating, and the mass ratio of the usage amount to the cross-linked polyoxyethylene ether obtained in the step (2) is 1: 1.

the crosslinked polyoxyethylene ether in the step (2) is characterized by having a structural expression as follows:

wherein R is₁Is methyl, ethyl, propyl, butyl or pentyl; r₂Is methyl, allyl, isobutenyl, isopentenyl or ethylene glycol monovinyl; r₃Is hydrogen radical or carboxyl; r₄Is hydrogen radical, methyl or methylene carboxyl;

wherein a, b, c, d, e, f, g, h are positive integers representing the number of individual repeat units distributed in the polymerization in a random manner;

wherein n is a positive integer representing the number of repeating units in the polyoxyethylene ether, and n is in the range of 5 to 120.

Compared with the prior art, the method of the invention has the following beneficial effects:

1. the invention starts from the theory of molecular structure design, obtains the cross-linked polyoxyethylene ether through graft polymerization, forms the composite phase-change latent heat material by being adsorbed with ceramsite, coats a layer of waterproof material on the surface, can be applied to the fields of buildings, heat-insulating materials and the like, is an innovation and a breakthrough in the direction of the phase-change latent heat material, and widens the thought and the direction for the subsequent deep development of new-variety phase-change latent heat materials.

2. Compared with the traditional phase change latent heat material, the preparation process is simple, the process is simple and controllable, the required raw materials are common and easy to obtain, the price is low, the used reaction steps of polymerization, crosslinking and the like belong to common operation processes, the method does not depend on a complex catalytic system or expensive reagents, no special requirements are required on equipment, industrialization is easy to realize, the product competitiveness and the development prospect are improved, and the potential application field is very wide.

3. The synthesized cross-linked polyoxyethylene ether has a similar I-shaped structure, and a hydrogen bond structure is formed between a side chain and a side chain due to the existence of groups such as ether bonds in a branched chain, so that the structural stability of the polymer can be improved, and high phase change property, low concentration and high viscosity are realized. The product is a cross-linked polyoxyethylene ether phase change latent heat material with unique advantages, and shows good application prospect and market competitiveness.

4. The phase-change latent heat material synthesized by the invention not only has higher performance indexes such as phase-change enthalpy and thermal conductivity, but also has good surface waterproof performance, so that the phase-change latent heat material can be stably stored in pores of ceramsite, thereby ensuring that the phase-change latent heat material cannot leak due to solid-liquid phase transformation in the phase-change process, keeping better integrity and not cracking in the stirring and construction processes, and showing good economic benefit and performance advantages.

5. The phase change latent heat material reported by the invention is different from the traditional phase change latent heat material, the preparation process of the organic phase change component is environment-friendly, the condition is mild, the production energy consumption is low, no toxic and harmful substance is generated, the used inorganic ceramsite carrier is low in cost, stable in performance, excellent in adaptability in concrete matrix materials, and free of harm and pollution to people and the environment, and is beneficial to large-scale popularization and application.

Drawings

FIG. 1 Infrared Spectrum of Cross-Linked Polyoxyethylene Ether

FIG. 2 breakage Rate of latent Heat of phase Change Material

Detailed Description

The present invention is described in further detail below with reference to examples, but the practice of the present invention is not limited thereto.

Example 1

Firstly, adding 0.300g of allyl polyoxyethylene ether and 330.468g of No. 200 solvent oil into a reactor, stirring and heating to 130 ℃, adding 0.616g of n-dodecyl mercaptan, dropwise adding a mixed solution of 10.000g of butyl acrylate and 0.183g of tert-butyl hydroperoxide for 3 hours, continuing constant-temperature reaction for 5 hours after dropwise adding is finished, and removing No. 200 solvent oil by reduced pressure distillation to obtain a polymerization product; adding the polymerization product and 280.800g of ethylene glycol monovinyl polyoxyethylene ether into 357.240g of solvent water, stirring, heating to 50 ℃, adding 3.010g of isopropanol, respectively dropwise adding 191.123g of maleic anhydride solution with the mass fraction of 40% and 25.300g of potassium persulfate aqueous solution with the mass fraction of 25% for 5 hours, continuing to perform constant-temperature reaction for 1 hour after the dropwise addition is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain cross-linked polyoxyethylene ether A; heating crosslinked polyoxyethylene ether A to a molten state at 50 ℃, heating 21668.750g of fly ash ceramsite with the particle size of 4mm to 75 ℃, keeping the temperature constant for 3 hours, adding the fly ash ceramsite into the molten crosslinked polyoxyethylene ether A, immersing the fly ash ceramsite into the molten crosslinked polyoxyethylene ether A, stirring the mixture for 48 hours, cooling the mixture to 15 ℃, immersing the mixture into 433.375g of asphalt waterproof coating, stirring the mixture for 25 seconds, taking the mixture out, and air-drying the mixture for 8 hours to obtain a phase-change latent heat material;

example 2

Firstly, 144.000g of methyl allyl polyoxyethylene ether and 770.000g of ethanol are added into a reactor, stirred and heated to 80 ℃, 1.295g of n-dodecyl mercaptan is added, then a mixed solution of 10.000g of ethyl acrylate and 0.595g of azobisisoheptonitrile is added dropwise for 8 hours, after the dropwise addition is finished, the constant temperature reaction is continued for 0.5 hour, and the ethanol is removed by reduced pressure distillation to obtain a polymerization product; adding the polymerization product and 540.000g of isopentenyl polyoxyethylene ether into 1338g of solvent water, stirring, heating to 75 ℃, adding 5.766g of isopropanol, respectively dropwise adding 644.999g of methacrylic acid solution with the mass fraction of 20% and 95.199g of sodium persulfate aqueous solution with the mass fraction of 5% for 10 hours, continuing to perform constant-temperature reaction for 2 hours after dropwise adding is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain cross-linked polyoxyethylene ether B; heating the cross-linked polyoxyethylene ether B to 70 ℃ to a molten state, heating 41770.500g of clay ceramsite with the particle size of 5mm to 60 ℃, keeping the temperature constant for 5 hours, adding the clay ceramsite into the molten cross-linked polyoxyethylene ether B, immersing the clay ceramsite into the molten cross-linked polyoxyethylene ether B, stirring the mixture for 30 hours, cooling the mixture to 20 ℃, immersing the clay ceramsite into 835.410g of acrylic ester waterproof coating, stirring the mixture for 30 seconds, taking the mixture out, and air-drying the mixture for 2 hours to obtain a phase-change latent heat material;

example 3

Firstly, 105.600g of isopentenyl polyoxyethylene ether and 639.622g of p-xylene are added into a reactor, stirred and heated to 100 ℃, 0.029g of 3-isooctyl mercaptopropionate is added, then a mixed solution of 10.000g of propyl acrylate and 1.120g of dibenzoyl peroxide is dropwise added for 4 hours, constant-temperature reaction is continued for 5 hours after the dropwise addition is finished, and the p-xylene is removed by reduced pressure distillation to obtain a polymerization product; adding the polymerization product and 739.290g of ethylene glycol monovinyl polyoxyethylene ether into 968.266g of solvent water, stirring, heating to 90 ℃, adding 6.351g of mercaptopropionic acid, respectively dropwise adding 457.52g of itaconic acid solution with the mass fraction of 50% and 10.032g of ammonium persulfate aqueous solution with the mass fraction of 50% for 8 hours, continuing to perform constant-temperature reaction for 3 hours after the dropwise addition is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain cross-linked polyoxyethylene ether C; heating the cross-linked polyoxyethylene ether C to 80 ℃ to a molten state, heating 54714.600g of shale ceramsite with the particle size of 6mm to 65 ℃, keeping the temperature constant for 8 hours, adding the shale ceramsite into the molten cross-linked polyoxyethylene ether C, immersing the shale ceramsite into the molten cross-linked polyoxyethylene ether C, stirring the mixture for 25 hours, cooling the mixture to 30 ℃, immersing the shale ceramsite into 1096.292g of epoxy resin waterproof coating, stirring the mixture for 5 seconds, taking the mixture out, and air-drying the mixture for 7 hours to obtain a phase-change latent heat material;

example 4

Firstly, 111.36g of allyl polyoxyethylene ether and 364.08g of methanol are added into a reactor, stirred and heated to 75 ℃, 0.195g of isopropanol is added, then a mixed solution of 10.000g of methyl acrylate and 0.533g of azobisisobutyronitrile is added dropwise for 1 hour, after the dropwise addition is finished, the constant-temperature reaction is continued for 5 hours, and the methanol is removed by reduced pressure distillation to obtain a polymerization product; adding the polymerization product and 1393.920g of methyl allyl polyoxyethylene ether into 1811.920g of solvent water, stirring, heating to 100 ℃, adding 22.470g of thioglycolic acid, respectively dropwise adding 836.000g of 50% acrylic acid aqueous solution and 7.850g of 40% potassium persulfate aqueous solution for 8 hours, continuing constant-temperature reaction for 5 hours after dropwise adding is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain cross-linked polyoxyethylene ether D; heating the cross-linked polyoxyethylene ether D to 55 ℃ to a molten state, heating 97980.900g of diatomite ceramsite with the particle size of 4mm to 100 ℃, keeping the temperature constant for 1 hour, adding the diatomite ceramsite into the molten cross-linked polyoxyethylene ether D, immersing the diatomite ceramsite into the molten cross-linked polyoxyethylene ether D, stirring the mixture for 12 hours, cooling the mixture to 35 ℃, immersing the mixture into 1959.618g of polyurethane waterproof coating, stirring the mixture for 10 seconds, taking the mixture out, and air-drying the mixture for 3 hours to obtain a phase-change latent heat material;

example 5

Firstly, 100.800g of methyl allyl polyoxyethylene ether and 886.400g of toluene are added into a reactor, stirred and heated to 60 ℃, 0.269g of isopropanol is added, then a mixed solution of 10.000g of amyl acrylate and 0.491g of di-tert-butyl peroxide is added dropwise for 0.5 hour, after the dropwise addition is finished, the constant-temperature reaction is continued for 4 hours, and the toluene is removed by reduced pressure distillation to obtain a polymerization product; adding the polymerization product and 504.000g of ethylene glycol monovinyl polyoxyethylene ether into 1121.620g of solvent water, stirring, heating to 90 ℃, adding 9.362g of 3g of isooctyl mercaptopropionate, respectively dropwise adding 541.660g of 45 mass percent fumaric acid aqueous solution and 46.648g of 25 mass percent sodium persulfate aqueous solution for 1 hour, continuing constant-temperature reaction for 4 hours after dropwise addition is finished, and removing the solvent water by reduced pressure distillation after the reaction is finished to obtain cross-linked polyoxyethylene ether E; heating the cross-linked polyoxyethylene ether E to 80 ℃ to a molten state, heating 44016.550g of coal gangue ceramsite with the particle size of 5mm to 90 ℃, keeping the temperature constant for 3 hours, adding the coal gangue ceramsite into the molten cross-linked polyoxyethylene ether E, immersing the coal gangue ceramsite into the molten cross-linked polyoxyethylene ether E, stirring the mixture for 12 hours, cooling the mixture to 35 ℃, immersing the mixture into 880.331g of polyurea waterproof coating, stirring the mixture for 20 seconds, taking the mixture out, and air-drying the mixture for 2 hours to obtain a phase-change latent heat material;

effects of the implementation

1. Characterization of the Infrared Spectrum

As can be seen from FIG. 1, the crosslinked polyoxyethylene ether is 2900cm^-1An absorption peak appears at the left and the right, which is the stretching vibration peak of-CH 2 and is 3383cm^-1The wide peak appearing at the left and right is the stretching vibration peak of-OH, which is 1710cm^-1The characteristic peak appearing on the left and right sides is a C ═ O symmetric absorption vibration peak. Analysis from the above characteristic absorption peaks indicates that the reaction monomers synthesized have a similar I-shaped structure, which is substantially consistent with the expected structure.

1. Crosslink density

TABLE 1

Sample name	Crosslink Density/10^-4mol×mL^-1
		Cross-linked polyoxyethylene ether A	7.54
Crosslinked polyoxyethylene ether B	8.13
		Cross-linked polyoxyethylene ether C	7.68
Crosslinked polyoxyethylene ether D	7.38
		Cross-linked polyoxyethylene ether E	8.34

From Table 1, it can be confirmed that the crosslinked polyoxyethylene ether produced by the present invention has an expected molecular structure.

3. Breakage rate

Weighing a small amount of phase change latent heat material, dispersing the phase change latent heat material in water, shearing for 10min at the rotating speed of 4000r/min, then washing, filtering, drying, weighing the mass of the phase change latent heat material, and calculating the damage rate of the phase change latent heat material by using the following formula:

phase change latent heat material (%) - (W)₀-W_t)/W₀×100

In the formula, W₀-mass of phase change latent heat material before shearing; w_tThe quality of the phase change latent heat material intact after shearing.

As can be seen from FIG. 2, the embodiment of the invention has low breakage rate, no leakage caused by solid-liquid phase transformation after multiple uses, and good integrity and no fracture during stirring and construction processes.

4. Phase change latent heat material stability

A melting/solidification cycle experiment is carried out on the phase change latent heat material by using a constant-temperature metal bath instrument, the heating time is 25min, the heating termination temperature is 85 ℃, the temperature is kept constant for 5min, then the material is cooled to 65 ℃, and the cooling time is 15 min. And (5) testing the latent heat value and the thermal conductivity of the phase-change latent heat material for 100 times and 200 times respectively in a circulating way.

TABLE 2

As can be seen from Table 2, the increase of the cycle period has little influence on the thermal conductivity and the latent heat value of the phase change latent heat material, the latent heat values and the thermal conductivities of the five embodiments are high, the service life is long, and the phase change latent heat material has good application prospects and market competitiveness.

5. Temperature regulating effect of concrete

The material mixing ratio of the concrete is shown in table 3, the used comparative example is the concrete with the same mass of phase change latent heat material replaced by stone, and the proportion of the other components is unchanged. The concrete test block is placed in a standard curing room with the temperature of 20 ℃ and the relative humidity of 98 percent for curing for 28 days. The test block was tested by a multipoint heat flow meter and the test results are shown in table 4.

TABLE 3 concrete mix ratio (kg/m)³)

TABLE 4

As can be seen from Table 4, compared with the comparative examples, the concrete added with the concrete of the embodiment of the invention can absorb certain heat because of solid-liquid phase change in the heating process, so that the temperature rise of the surface of the concrete is delayed; after the surface of the concrete stops heating, the phase change latent heat material releases heat due to solid-liquid phase change, so that the temperature of the surface of the concrete is reduced and delayed, and the temperature regulation effect is achieved.

Claims

1. A method for preparing a phase change latent heat material from cross-linked polyoxyethylene ether is characterized in that the cross-linked polyoxyethylene ether is synthesized by a polymerization-then-cross-linking method, and the conditions and the steps for adsorbing, filling and coating waterproof paint by ceramsite are as follows:

2. the method of claim 1, wherein the cross-linked polyoxyethylene ether has the structural formula: