阅读说明：本技术 复合壁材相变微胶囊及其制备方法和应用 (Composite wall material phase change microcapsule and preparation method and application thereof ) 是由 杨晶磊 安金亮 黄良康 于 2020-05-13 设计创作，主要内容包括：本发明涉及一种复合壁材相变微胶囊及其制备方法和应用,属于建筑保温材料技术领域。该方法包括以下步骤：准备表面活性剂水相、准备芯材有机相、微胶囊乳液的制备、界面聚合反应、硅醇溶液的制备、有机硅改性得到相变微胶囊。上述通过有机硅改性制备得到的微胶囊有着良好的热稳定性和耐腐蚀性,其放热焓能达到121.3J/g,能够满足建筑领域控温的需求。且还有着优异的循环性能,经过-20-60℃上千次循环后,相变微胶囊的热焓为焓值保持率在90％以上,可作为建筑保温材料广泛应用。(The invention relates to a composite wall material phase change microcapsule, a preparation method and application thereof, and belongs to the technical field of building heat insulation materials. The method comprises the following steps: preparing a surfactant aqueous phase, preparing a core material organic phase, preparing a microcapsule emulsion, carrying out interfacial polymerization reaction, preparing a silanol solution, and modifying organic silicon to obtain the phase-change microcapsule. The microcapsule prepared by modifying the organic silicon has good thermal stability and corrosion resistance, the heat release enthalpy of the microcapsule can reach 121.3J/g, and the requirement of temperature control in the field of buildings can be met. And the heat enthalpy-enthalpy retention rate of the phase-change microcapsules is more than 90 percent after thousands of cycles at the temperature of-20-60 ℃, and the phase-change microcapsules can be widely applied as building heat-insulating materials.)

1. The preparation method of the composite wall material phase change microcapsule is characterized by comprising the following steps:

preparing a surfactant water phase: taking a surfactant aqueous solution, heating and stirring to obtain a surfactant aqueous phase at a preset temperature;

preparing a core material organic phase: mixing the organic phase-change material with isocyanate and cyclohexane, and performing ultrasonic dispersion to obtain a core material organic phase;

preparation of microcapsule emulsion: adding the obtained core material organic phase into the obtained surfactant aqueous phase, mixing and shearing to obtain microcapsule emulsion;

interfacial polymerization reaction: adding an organic amine solution into the obtained microcapsule emulsion, heating, adding a first organic silicon solution, and reacting to obtain a microcapsule solution;

preparation of silanol solution: mixing a silane monomer and acid, and stirring for reaction to obtain a silanol solution;

modification of organic silicon: and cooling the microcapsule solution, adding the microcapsule solution into the silanol solution, adding a second organic silicon solution, reacting, washing with water after the reaction is finished, filtering, and drying to obtain the phase-change microcapsule.

2. The preparation method of the composite wall material phase change microcapsule according to claim 1, wherein the molar ratio of the first organic silicon to the second organic silicon is 1.2-1.8: 1 polydimethylsiloxane: a glycol siloxane;

the silane monomer is selected from: at least one of methyltrimethoxysilane, dodecyltrimethoxysilane, and octadecyltrimethoxysilane.

3. The preparation method of the composite wall material phase change microcapsule according to claim 1, wherein the concentrations of the first organic silicon solution and the second organic silicon solution are both 0.3 ± 0.1 wt%, the concentration of the organic amine solution is 1 ± 0.2 wt%, and the concentration of the surfactant aqueous solution is 0.42-0.48 wt%.

4. The method according to any one of claims 1 to 3, wherein the surfactant is selected from the group consisting of: at least one of polyvinyl alcohol and OP-10;

the organic phase change material is selected from: at least one of paraffin, straight-chain paraffin and hard fatty acid ester;

the isocyanate is selected from: at least one of phenylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate;

the organic amine is selected from: long chain monomeric polyethylenimine.

5. The preparation method of the composite wall material phase change microcapsule according to claim 1, wherein the raw materials of the composite wall material phase change microcapsule are set according to the following parts by weight:

6. the preparation method of the composite wall material phase change microcapsule according to claim 5, wherein the core material organic phase is prepared from the following raw materials in parts by weight:

5 plus or minus 1 portion of organic phase-change material

Isocyanate 1 +/-0.2 part

Cyclohexane 5 +/-1 part

The silanol solution is prepared from the following raw materials in parts by weight:

6 +/-2 parts of silane monomer

12 +/-4 parts of hydrochloric acid with the pH value of 3.

7. The preparation method of the composite wall material phase-change microcapsule as claimed in claim 1, wherein the preparation of the surfactant aqueous phase is carried out at the predetermined temperature of 40-45 ℃; in the interfacial polymerization reaction, heating to 55-60 ℃; in the organic silicon modification, the microcapsule solution is cooled to 30-35 ℃ and then added into the silanol solution.

8. The preparation method of the composite wall material phase change microcapsule according to claim 1, wherein the stirring speed is set to 300 ± 100rpm for preparing the surfactant aqueous phase;

setting the ultrasonic power to be 600 +/-50 w and the ultrasonic time to be 5 +/-2 min in the core material preparation organic phase;

in the preparation of the microcapsule emulsion, the solution is sheared for 10 +/-2 min at the speed of 1500rpm of 1000-;

in the interfacial polymerization reaction, the reaction time is 2 plus or minus 0.5 hr;

in the preparation of the silanol solution, the stirring speed is set to be 200 plus or minus 20rpm, and the reaction time is set to be 1 plus or minus 0.2 hr.

9. The composite wall material phase change microcapsule prepared by the preparation method of the composite wall material phase change microcapsule according to any one of claims 1 to 8.

10. The use of the composite wall material phase change microcapsule of claim 9 as a building insulation material.

Technical Field

The invention relates to the technical field of building heat-insulating materials, in particular to a composite wall material phase-change microcapsule and a preparation method and application thereof.

Background

Energy is a material basis on which human beings rely for survival, and is a key factor for promoting economic development and social progress. In 2004, the energy consumption of the world is counted, and China is the second largest energy consuming country in the world after the United states. With the rapid development of global industrialization, the world energy is increasingly depleted, which seriously hinders social development and brings serious environmental problems such as ecological deterioration and climate warming caused by improper utilization of energy, so that improvement of energy use efficiency and development and application of renewable resources become important issues facing human beings.

China is a big building country, and the building industry is one of the important components of national economy. With the advance of urbanization in China, the building area is increased at a speed of 16-20 hundred million square meters newly increased every year, wherein more than 95% of buildings belong to high-energy-consumption buildings. The related data show that the total area of the existing buildings in China is about 430 hundred million square meters, the total area of the accumulated energy-saving buildings is about 28.5 hundred million square meters, and the accumulated energy-saving buildings only account for 16.1 percent of the total amount of the existing buildings in cities and towns. According to the statistical data of the building energy consumption of the Ministry of national construction in 1996-200 years, the total energy consumption of the building industry accounts for about 1/3 of the total energy consumption of China, so that the energy utilization efficiency of the building field is improved, the building energy consumption is reduced, and the remarkable influence on relieving the energy crisis, protecting the environment and promoting the economic growth is realized.

The concept of building energy conservation is formally proposed as early as the 70 s in the 20 th century, the primary meaning is to reduce the use of energy in buildings, the energy is reasonably used on the premise of meeting the requirement of living comfort level, the energy utilization efficiency is improved, the purposes of reducing the energy consumption of heating and air conditioning, hot water supply, electricity and cooking are achieved, and the concept has important significance in promoting economic sustainable development and building resource-saving and environment-friendly society. At present, the phase-change material is fused with the traditional building material to prepare the light building material with the phase-change energy storage capacity by utilizing the characteristics that the phase-change material can store and release a large amount of heat energy when in phase change and the temperature of the phase-change material is basically unchanged, namely, the energy can be stored or released in the form of phase-change latent heat, the conversion of the energy between different time and space positions is realized, the heat storage performance of a building is effectively improved, the indoor temperature fluctuation is reduced, and the research of improving the comfort level is a hotspot of scholars at home and abroad at present.

Microcapsules are fine particles produced by assembling solid and liquid materials using a film material. The microcapsule embedding substance is a core material, and the film material of the outer layer of the microcapsule is a shell material. Preparation of microcapsules starting in the thirties of the last century, cod liver oil microcapsules were synthesized for the first time by fisheries on the coast of the atlantic ocean in the united states; later, it was discovered that gelatin microcapsules that could be prepared using complex coacervation techniques were successfully applied to carbonless copy paper. At present, the traditional preparation methods of microcapsules include complex coacervation method, in-situ polymerization method, interfacial polymerization method, spray drying method and the like. The microcapsule has the performances of controlling release, increasing system stability, reducing system volatility, protecting an embedding material, isolating different components, changing the state of the material and the like, and is widely applied to the industries of biological medicine chemical coatings, agricultural foods, daily cosmetics and the like.

At present, the problem of efficient use of renewable energy sources is a major concern, and thermal energy storage systems offer the possibility of energy storage, latent heat storage being the most efficient way of thermal energy storage. Phase change materials, which are the most important latent heat storage materials, store heat by phase transformation of the material. However, when the phase change material is changed, the volume of the phase change material changes, and the liquid material solution leaks, and the heat conduction efficiency is low when the phase change material is in a solid state, which is a big problem that prevents the phase change material from being widely used. The appearance of the microcapsule technology makes the wide application of the traditional phase change material possible, the microcapsule can isolate the phase change material from the outside, so that the phase change occurs in the microcapsule, and the problems of easy leakage and poor reutilization property when the phase change material undergoes phase change are solved.

Organosilicon, i.e., organosilicon compounds, are compounds which contain Si-C bonds and have at least one organic radical directly bonded to the silicon atom, and compounds in which an organic radical is bonded to the silicon atom via oxygen, sulfur, nitrogen, or the like are also conventionally used as organosilicon compounds. Among them, the polysiloxane having a siloxane bond (-Si-O-Si-) as a skeleton is the most abundant, most studied and most widely used class of organosilicon compounds, and accounts for about 90% or more of the total amount. Organosilicon materials have a unique structure: firstly, sufficient methyl on Si atom shields the high-energy polysiloxane main chain; secondly, the C-H has no polarity, so that the interaction force among molecules is very weak; and the bond length of the Si-O bond is longer, and the bond angle of the Si-O-Si bond is large. And the Si-O bond is a covalent bond with 50% of ionic bond characteristics (the covalent bond has directionality, and the ionic bond has no directionality).

The organic silicon has unique structure, has the performances of inorganic materials and organic materials, has the basic properties of low surface tension, small viscosity-temperature coefficient, high compressibility, high gas permeability and the like, has the excellent characteristics of high and low temperature resistance, electrical insulation, oxidation resistance stability, weather resistance, flame retardancy, hydrophobicity, corrosion resistance, no toxicity, no odor, physiological inertia and the like, is widely applied to the industries of aerospace, electronics and electricity, construction, transportation, chemical industry, textile, food, light industry, medical treatment and the like, and is mainly applied to sealing, adhesion, lubrication, coating, surface activity, demolding, defoaming, foam inhibition, water prevention, moisture prevention, inert filling and the like. With the continuous increase of the quantity and varieties of organic silicon, the application field is continuously widened, a unique important product system in the new chemical material field is formed, and a plurality of varieties are indispensable and cannot be replaced by other chemicals. The basic structural unit of the organosilicon product is composed of silicon-oxygen links, and the side chains are connected with other various organic groups through silicon atoms. Therefore, the structure of the organic silicon product contains both organic groups and inorganic structures, and the special composition and molecular structure integrate the characteristics of organic matters and the functions of inorganic matters.

Compared with other high polymer materials, the most outstanding performances of the organic silicon product are as follows: the heat resistance characteristic is that the organic silicon product takes silicon-oxygen (Si-O) bond as a main chain structure, the bond energy of the C-C bond is 82.6 kilocalories per gram molecule, and the bond energy of the Si-O bond is 121 kilocalories per gram molecule in the organic silicon, so the heat stability of the organic silicon product is high, and the chemical bond of the molecule is not broken and not decomposed at high temperature (or radiation irradiation). The organosilicon can resist high temperature and low temperature, and can be used in a wide temperature range. The change of the chemical property or the physical and mechanical property with the temperature is small; ② weather resistance, the main chain of the organic silicon product is-Si-O-, and no double bond exists, therefore, the organic silicon product is not easy to be decomposed by ultraviolet light and ozone. The organic silicon has better thermal stability, irradiation resistance and weather resistance than other high molecular materials. The service life of the organic silicon in the natural environment can reach dozens of years; and thirdly, the main chain of the organic silicon is very flexible and has low surface tension and surface energy, and the intermolecular action force of the main chain is much weaker than that of a hydrocarbon, so that the main chain has low viscosity, low surface tension, small surface energy and strong film forming capability compared with the hydrocarbon with the same molecular weight. This low surface tension and low surface energy are the main reasons for its versatile use: excellent performances of hydrophobicity, defoaming, stable foam, adhesion resistance, lubrication, glazing and the like.

At present, a lot of reports on the synthesis of phase change microcapsules are reported in China, but the synthesized phase change microcapsule material still has many defects, such as poor thermal stability, poor corrosion resistance, poor cycle performance and poor compatibility with building materials, wherein a large part of reasons are that volume change can be generated when the phase change material is subjected to solid-liquid conversion, an organic shell layer coated by the microcapsule cannot absorb stress caused by the volume change, so that the phase change microcapsule has poor stability, the binding capacity of shell layer particles is limited, and the shell layer particles are separated under a stress state, so that the shell layer is broken, the phase change material is leaked, and the application of the phase change microcapsule in the field of buildings is greatly limited. Most shell materials adopted for coating the phase change material are high polymer materials, the high polymer materials have the defects of easy decomposition and easy aging as well known, the stability of the phase change microcapsule obtained by coating a single-layer high polymer material is extremely poor, and in order to solve the problem that the single-layer shell phase change microcapsule material is easy to leak, the double-layer high polymer material is adopted for coating the phase change material, so that the stability of the phase change microcapsule is improved, but the problem is not solved fundamentally. In addition, the phase-change material and the polymer shell material are both organic materials, have poor compatibility with building materials, are difficult to be directly applied, and are easy to burn, so that the application of the phase-change microcapsule material in the field of building temperature control is limited.

For example, it has been reported that a urea resin and an olefin polymer are used to coat an organic phase change material to obtain a double-shell microcapsule, in which the urea resin is the outermost shell, the urea resin shell has poor thermal stability and aging resistance, and the shell layer is aged and yellowed after being left for several months. There are also reports that the modified urea-formaldehyde resin shell has poor thermal stability although the aging resistance is improved by using the paraffin phase-change microcapsule with melamine modified urea-formaldehyde resin as the wall material. In addition, researchers also adopt one or more of the combination of the mixtures of the gum arabic polyoxyethylene lauryl ether 30, the sorbitan oleate, the sorbitan 80 and the polyoxyethylene sorbitol Yu monooleate 80 as an emulsifier, adopt polyurea resin as an inner shell and silica as an outer shell, and adsorb the two shells onto the phase-change material through electrostatic force to prepare the microcapsule for encapsulating the phase-change material.

Disclosure of Invention

Therefore, it is necessary to provide a method for preparing a composite wall material phase change microcapsule, which can solve the problems of poor thermal stability, poor corrosion resistance, poor cycle performance, poor compatibility with building materials, and the like in the conventional technology.

A preparation method of a composite wall material phase change microcapsule comprises the following steps:

preparing a surfactant water phase: taking a surfactant aqueous solution, heating and stirring to obtain a surfactant aqueous phase at a preset temperature;

preparing a core material organic phase: mixing the organic phase-change material with isocyanate and cyclohexane, and performing ultrasonic dispersion to obtain a core material organic phase;

preparation of microcapsule emulsion: adding the obtained core material organic phase into the obtained surfactant aqueous phase, mixing and shearing to obtain microcapsule emulsion;

interfacial polymerization reaction: adding an organic amine solution into the obtained microcapsule emulsion, heating, adding a first organic silicon solution, and reacting to obtain a microcapsule solution;

preparation of silanol solution: mixing a silane monomer and acid, and stirring for reaction to obtain a silanol solution;

modification of organic silicon: and cooling the microcapsule solution, adding the microcapsule solution into the silanol solution, adding a second organic silicon solution, reacting, washing with water after the reaction is finished, filtering, and drying to obtain the phase-change microcapsule.

The phase-change microcapsule wall material of the composite wall material is SiO₂The polyurea composite material is prepared by mixing polyurea shell reaction monomer isocyanate, a phase-change material and cyclohexane, emulsifying by using surfactant solution such as polyvinyl alcohol or OP-10 with specific concentration to obtain emulsion droplets with uniform particle size and regular and stable shape, adding organic amine solution to generate interfacial polymerization, wherein the obtained polyurea shell is of a net structure, adding organic silicon solution with specific concentration, and realizing physical coupling effect of organic silicon to compact the net polyurea shell and prevent the phase-change material from leaking, and subsequently forming SiO₂The particles can completely coat the whole capsule, SiO, under the coupling action of the organic silicon₂The strength of the shell layer is improved to obtain SiO₂Polyurea composite wall material phase change microcapsules; in addition, the organic silicon has high and low temperature resistance, weather resistance and corrosion resistance, the microcapsule prepared by modifying the organic silicon has good thermal stability and corrosion resistance, the enthalpy of the microcapsule can reach 121.3J/g, the requirement of temperature control in the field of buildings can be met, the enthalpy of the phase-change microcapsule which is not modified by the organic silicon is only 110.3J/g, and the coating rate of the phase-change microcapsule modified by the organic silicon is higher; after the phase change microcapsule is heated for a plurality of hours at the temperature of 80 ℃, the phase change microcapsule still keeps intact and has excellent cycle performance, the enthalpy value of the phase change microcapsule is still kept above 90 percent after thousands of cold and hot impact cycles at the temperature of-20-60 ℃, and the enthalpy value of the phase change microcapsule which is not modified by organic silicon is 73.1 percent after thousands of cycles.

In one embodiment, the first silicone and the second silicone are each present in a molar ratio of 1.2 to 1.8: 1 polydimethylsiloxane: a glycol siloxane;

the silane monomer is selected from: at least one of methyltrimethoxysilane, dodecyltrimethoxysilane, and octadecyltrimethoxysilane.

In experiments, the inventor finds that if the organic silicon needs to be physically coupled with the shell material, the type of the organic silicon needs to be screened, and if the organic silicon is not properly selected, for example, methyl vinyl chlorosilane, vinyl trichlorosilane, phenyl chlorosilane and the like are selected, chemical coupling can occur, the reaction speed is too high, and the coating of the shell layer of the microcapsule is not facilitated. The polydimethylsiloxane and the ethylene glycol siloxane in the proportion are selected, so that the microcapsule has the advantages of moderate reaction speed and uniform and compact coating of the shell layer of the microcapsule.

In one embodiment, the concentrations of the first organic silicon solution and the second organic silicon solution are both 0.3 +/-0.1 wt%, the concentration of the organic amine solution is 1 +/-0.2 wt%, and the concentration of the surfactant aqueous solution is 0.42-0.48 wt%. In practice, it is found that if the concentration of the organic silicon is too high, the microcapsules can be agglomerated, and the coating of the shell layer is not facilitated, and if the concentration is too low, the coupling effect is weak, and the shell layer is not densely coated.

In one embodiment, the surfactant is selected from: at least one of polyvinyl alcohol and OP-10;

the organic phase change material is selected from: at least one of paraffin, straight-chain paraffin and hard fatty acid ester;

the isocyanate is selected from: at least one of phenylene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), and Hexamethylene Diisocyanate (HDI);

the organic amine is selected from: long chain monomeric polyethylenimine.

In one embodiment, the composite wall material phase change microcapsule comprises the following raw materials in parts by weight:

in one embodiment, the raw materials of the core material organic phase are arranged according to the following parts by weight:

5 plus or minus 1 portion of organic phase-change material

Isocyanate 1 +/-0.2 part

Cyclohexane 5 +/-1 part

The silanol solution is prepared from the following raw materials in parts by weight:

6 +/-2 parts of silane monomer

12 +/-4 parts of hydrochloric acid with the pH value of 3.

In one embodiment, the preparation of the surfactant aqueous phase is carried out at a predetermined temperature of 40-45 ℃; in the interfacial polymerization reaction, heating to 55-60 ℃; in the organic silicon modification, the microcapsule solution is cooled to 30-35 ℃ and then added into the silanol solution.

In one embodiment, the preparation of the surfactant water phase is carried out by setting the stirring speed to be 300 +/-100 rpm;

setting the ultrasonic power to be 600 +/-50 w and the ultrasonic time to be 5 +/-2 min in the core material preparation organic phase;

in the preparation of the microcapsule emulsion, the solution is sheared for 10 +/-2 min at the speed of 1500rpm of 1000-;

in the interfacial polymerization reaction, the reaction time is 2 plus or minus 0.5 hr;

in the preparation of the silanol solution, the stirring speed is set to be 200 plus or minus 20rpm, and the reaction time is set to be 1 plus or minus 0.2 hr.

The invention discloses a composite wall material phase change microcapsule prepared by the preparation method of the composite wall material phase change microcapsule.

In one embodiment, the core material is an organic phase change material, and the shell material is SiO₂A polyurea composite.

In one embodiment, the mass ratio of the core material is 55-75%, and the mass ratio of the shell material is 25-45%.

In one embodiment, the phase change microcapsules have a particle size in the range of 5-100 μm.

The invention also discloses application of the composite wall material phase change microcapsule as a building thermal insulation material.

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

according to the preparation method of the composite wall material phase change microcapsule, the surfactant such as polyvinyl alcohol and OP-10 is adopted, the emulsification effect is obviously improved under a specific concentration, the particle diameter of the microcapsule obtained by emulsification under the same shearing force is smaller than that of Arabic gum, the effect duration is long, and the microspheres are still intact after the microcapsule is placed for a plurality of hours after the shearing force is applied.

And the isocyanate monomer, the phase-change material and cyclohexane are mixed and then subjected to ultrasonic treatment, so that the combination of the polyurea shell and the phase-change material can be promoted, the phase-change material is coated by the shell, and the yield is improved.

According to the composite wall material phase change microcapsule obtained by the invention, the microcapsule is modified by adding the organic silicon, so that the compactness of the net-shaped polyurea shell is improved, and the SiO can be enabled to be under the unique physical coupling effect of the organic silicon₂The particles form a shell with higher strength, so that the microcapsule is well protected, in addition, the organic silicon has good high and low temperature resistance, weather resistance and corrosion resistance, after the organic silicon is modified, the heat stability and the corrosion resistance of the microcapsule are improved, and after thousands of cycles, the enthalpy retention rate is over 90 percent.

Drawings

FIG. 1 is an SEM photograph of a polyurea shell in an experimental example;

FIG. 2 is a SEM image of phase change microcapsules in an experimental example;

FIG. 3 is a DSC of phase-change microcapsules of example 1 in an experimental example;

FIG. 4 is a DSC chart of phase-change microcapsules of comparative example 1 in the experimental example;

FIG. 5 is a DSC chart of phase-change microcapsules of example 5 in experimental examples;

FIG. 6 is a DSC chart of phase-change microcapsules of example 6 in experimental examples;

FIG. 7 is a DSC chart of the phase change microcapsule cycle test of example 1 in the experimental example;

FIG. 8 is a DSC chart of phase change microcapsule cycle test of comparative example 1 in the experimental example.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In the following examples, wt% represents mass%.

Example 1

A composite wall material phase change microcapsule is prepared by the following method:

the first step is as follows: a surfactant aqueous phase was prepared, 62 parts of 0.42 wt% polyvinyl alcohol surfactant solution (prepared in advance), and the surfactant solution was heated uniformly by setting the water bath temperature to 40 ℃ and the mechanical stirring rotation speed to 300 rpm.

The second step is that: preparing a core material organic phase, mixing 5 parts of 28 ℃ phase-change paraffin, 1 part of HDI and 5 parts of cyclohexane, putting the mixed organic phase into an ultrasonic device, setting the power to be 600w, and performing ultrasonic treatment for 5min to uniformly disperse the oil phase.

The third step: and (3) preparing a microcapsule emulsion, adjusting the mechanical rotation speed to 1000rpm, slowly adding the core material organic phase obtained in the second step into a surfactant water phase, shearing at a high speed for 10min, and then reducing the mechanical rotation speed to 300rpm to obtain the emulsion.

The fourth step: and (3) performing interfacial polymerization, namely slowly dripping 10 parts of 1 wt% PEI solution (long chain monomer polyethyleneimine prepared in advance) into the microcapsule emulsion obtained in the third step, heating to 55 ℃, adding 5 parts of 0.3 wt% first organic silicon solution, and reacting for 2 hours to obtain a microcapsule solution.

The fifth step: a silanol solution was prepared, 6 parts methyltrimethoxysilane and 12 parts hydrochloric acid having pH 3 were mixed, and the mixture was hydrolyzed by magnetic stirring at 200rpm for 1 hour to obtain a silanol solution.

And a sixth step: and (3) modifying organic silicon, namely cooling the microcapsule solution after the fourth step of reaction to 35 ℃, slowly adding the silanol solution obtained in the fifth step, adding 4 parts of 0.3 wt% of second organic silicon solution, reacting for 4 hours, washing by using deionized water for 3 times, performing suction filtration, and drying to obtain phase-change microcapsule powder.

The first organic silicon and the second organic silicon are used in a molar ratio of 1.5: 1 polydimethylsiloxane: ethylene glycol siloxane.

Example 2

A composite wall material phase change microcapsule is prepared by the following method:

the first step is as follows: a surfactant aqueous phase was prepared, 62 parts of 0.455 wt% polyvinyl alcohol surfactant solution (prepared in advance), and the surfactant solution was uniformly heated by setting the water bath temperature at 45 ℃ and the mechanical stirring rotation speed at 300 rpm.

The second step is that: preparing a core material organic phase, mixing 5 parts of tetradecanol phase-change material, 1 part of HDI and 5 parts of cyclohexane, putting the mixed organic phase into an ultrasonic device, setting the power to be 600w, and performing ultrasonic treatment for 5min to uniformly disperse the oil phase.

The third step: and (3) preparing a microcapsule emulsion, namely adjusting the mechanical rotation speed to 1200rpm, slowly adding the core material organic phase obtained in the second step into a surfactant water phase, shearing at a high speed for 10min, and then reducing the mechanical rotation speed to 350rpm to obtain the emulsion.

The fourth step: and (3) performing interfacial polymerization, namely slowly dripping 10 parts of 1 wt% PEI solution (long chain monomer polyethyleneimine prepared in advance) into the microcapsule emulsion obtained in the third step, heating to 60 ℃, adding 5 parts of 0.3 wt% first organic silicon solution, and reacting for 2 hours to obtain a microcapsule solution.

The fifth step: a silanol solution was prepared, 6 parts methyltrimethoxysilane and 12 parts hydrochloric acid having pH 3 were mixed, and the mixture was hydrolyzed by magnetic stirring at 200rpm for 1 hour to obtain a silanol solution.

And a sixth step: and (3) modifying organic silicon, namely cooling the microcapsule solution after the fourth step of reaction to 35 ℃, slowly adding the silanol solution obtained in the fifth step, adding 4 parts of 0.3 wt% of second organic silicon solution, reacting for 4 hours, washing by using deionized water for 3 times, performing suction filtration, and drying to obtain phase-change microcapsule powder.

The first organic silicon and the second organic silicon are used in a molar ratio of 1.5: 1 polydimethylsiloxane: ethylene glycol siloxane.

Example 3

A composite wall material phase change microcapsule is prepared by the following method:

the first step is as follows: a surfactant aqueous phase was prepared, 62 parts of 0.48 wt% polyvinyl alcohol surfactant solution (prepared in advance), and the surfactant solution was heated uniformly by setting the water bath temperature to 40 ℃ and the mechanical stirring rotation speed to 300 rpm.

The second step is that: preparing a core material organic phase, mixing 5 parts of octadecane phase change material, 1 part of MDI and 5 parts of cyclohexane, putting the mixed organic phase into an ultrasonic device, setting the power to be 600w, and performing ultrasonic treatment for 5min to uniformly disperse the oil phase.

The third step: and (3) preparing a microcapsule emulsion, adjusting the mechanical rotation speed to 1500rpm, slowly adding the core material organic phase obtained in the second step into a surfactant water phase, shearing at a high speed for 10min, and then reducing the mechanical rotation speed to 400rpm to obtain the emulsion.

The fourth step: and (3) performing interfacial polymerization, namely slowly dripping 10 parts of 1 wt% PEI solution (long chain monomer polyethyleneimine prepared in advance) into the microcapsule emulsion obtained in the third step, heating to 55 ℃, adding 5 parts of 0.3 wt% first organic silicon solution, and reacting for 2 hours to obtain a microcapsule solution.

The fifth step: a silanol solution was prepared, and 6 parts of dodecyltrimethoxysilane and 12 parts of hydrochloric acid having pH 3 were mixed and hydrolyzed by magnetic stirring at 200rpm for 1 hour to obtain a silanol solution.

And a sixth step: and (3) modifying organic silicon, namely cooling the microcapsule solution after the fourth step of reaction to 35 ℃, slowly adding the silanol solution obtained in the fifth step, adding 4 parts of 0.3 wt% of second organic silicon solution, reacting for 4 hours, washing by using deionized water for 3 times, performing suction filtration, and drying to obtain phase-change microcapsule powder.

The first organic silicon and the second organic silicon are used in a molar ratio of 1.5: 1 polydimethylsiloxane: ethylene glycol siloxane.

Example 4

A composite wall material phase change microcapsule is prepared by the following method:

the first step is as follows: a surfactant aqueous phase was prepared, 62 parts of 0.42 wt% OP-10 surfactant solution (prepared in advance), and the surfactant solution was heated uniformly by setting the water bath temperature at 45 ℃ and the mechanical stirring speed at 300 rpm.

The second step is that: preparing a core material organic phase, mixing 5 parts of 35 ℃ paraffin phase change material, 1 part of MDI and 5 parts of cyclohexane, putting the mixed organic phase into an ultrasonic device, setting the power to be 600w, and performing ultrasonic treatment for 5min to uniformly disperse the oil phase.

The third step: and (3) preparing a microcapsule emulsion, adjusting the mechanical rotation speed to 1500rpm, slowly adding the core material organic phase obtained in the second step into a surfactant water phase, shearing at a high speed for 10min, and then reducing the mechanical rotation speed to 400rpm to obtain the emulsion.

The fourth step: and (3) performing interfacial polymerization, namely slowly dripping 10 parts of 1 wt% PEI solution (long chain monomer polyethyleneimine prepared in advance) into the microcapsule emulsion obtained in the third step, heating to 60 ℃, adding 5 parts of 0.3 wt% organic silicon solution, and reacting for 2 hours to obtain a microcapsule solution.

The fifth step: a silanol solution was prepared, and 6 parts of octadecyltrimethoxysilane and 12 parts of hydrochloric acid having pH 3 were mixed and hydrolyzed by magnetic stirring at 200rpm for 1 hour to obtain a silanol solution.

And a sixth step: and (3) modifying organic silicon, namely cooling the microcapsule solution after the fourth step of reaction to 35 ℃, slowly adding the silanol solution obtained in the fifth step, adding 4 parts of 0.3 wt% of second organic silicon solution, reacting for 4 hours, washing by using deionized water for 3 times, filtering, and drying. Obtaining the phase-change microcapsule powder.

The first organic silicon and the second organic silicon are used in a molar ratio of 1.5: 1 polydimethylsiloxane: ethylene glycol siloxane.

Example 5

A composite wall material phase change microcapsule prepared by a method similar to that of example 1 except that: the organosilicon used is polydimethylsiloxane.

Example 6

A composite wall material phase change microcapsule prepared by a method similar to that of example 1 except that: the organosilicon used is ethylene glycol siloxane.

Comparative example 1

A composite wall material phase change microcapsule prepared by a method similar to that of example 1 except that: the first silicone solution and the second silicone solution were not added during the preparation.

Examples of the experiments

And (3) taking the composite wall material phase change microcapsule prepared in the embodiment and the comparative example to perform performance test.

Firstly, observing under a mirror.

1. The product obtained after the interfacial polymerization reaction in example 1 was taken and observed under a mirror, as shown in FIG. 1. It can be seen that the polyurea shell obtained by interfacial polymerization after the organic amine solution is added is a net structure.

2. The composite wall material phase change microcapsule prepared in example 1 was observed under a mirror, as shown in fig. 2, to obtain SiO₂Polyurea composite wall material phase change microcapsules.

And secondly, testing the performance.

1. Enthalpy energy testing.

The phase change microcapsules prepared in examples 1 and 5 to 6 and comparative example 1 were tested according to the following method:

weighing 5-10mg of sample in a crucible, and testing in a differential scanning calorimeter according to the following parameters: cooling to 0 ℃, keeping the temperature for 1min, heating to 60 ℃ at a speed of 5 ℃/min, keeping the temperature for 1min, and cooling to 0 ℃ at a speed of 5 ℃/min.

The test results are shown in fig. 3-6, wherein fig. 3 is a DSC diagram of the phase-change microcapsule of example 1, fig. 4 is a DSC diagram of the phase-change microcapsule of comparative example 1, and fig. 5-6 are DSC diagrams of the phase-change microcapsules of examples 5-6, respectively.

As can be seen from the figure, the phase-change microcapsule prepared by the invention has good thermal stability and corrosion resistance, particularly, the phase-change microcapsule of the embodiment 1 has the heat release enthalpy of 121.3J/g (as shown in figure 3), and can meet the temperature control requirement in the building field, while the heat enthalpy of the phase-change microcapsule which is not modified by organosilicon in the comparative example 1 is 110.3J/g (as shown in figure 4), which indicates that the coating rate of the phase-change microcapsule modified by organosilicon is higher.

And when the polydimethylsiloxane and the ethylene glycol siloxane are organic silicon in a specific proportion, the organic silicon has the best effect on the modification of the shell layer of the phase-change microcapsule and the best improvement on the strength of the phase-change microcapsule.

2. And (4) testing the heat content of the circulation.

The phase change microcapsules prepared in example 1 and comparative example 1 were taken and tested as described above after 0-week, 300-week, 500-week and 1000-week cycles at-20 to 60 c, respectively.

The test results are shown in fig. 7-8, wherein fig. 7 is a DSC chart of the phase-change microcapsule of example 1, and fig. 8 is a DSC chart of the phase-change microcapsule of comparative example 1.

As can be seen from the figure, the phase-change microcapsule prepared by the invention has excellent cycle performance, the enthalpy retention rate of the phase-change microcapsule is over 90 percent after thousands of cycles at-20 to 60 ℃ (as shown in figure 7), and the enthalpy retention rate of the phase-change microcapsule which is not modified by organic silicon in comparative example 1 is 73.1 percent after one thousand cycles (as shown in figure 8).

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.