阅读说明：本技术 一种水泥基定形相变材料的制备方法 (Preparation method of cement-based shape-stabilized phase change material ) 是由 杜银飞 刘谱晟 魏唐中 马聪 于 2019-11-18 设计创作，主要内容包括：本发明公开了一种水泥基定形相变材料的制备方法,属于相变材料制备技术领域,本发明利用水泥的胶凝特性和相变材料聚乙二醇的水溶性,使用聚乙二醇水溶液拌合水泥,水泥与溶液中的水发生水化反应,而聚乙二醇由于过饱和而逐渐结晶析出,并且被生成的水化产物包裹,当水泥最终水化完成,聚乙二醇就牢牢地被水化产物所封装。本发明所述的水泥基定形相变材料具有相变材料封装率高、稳定性好、制备工艺简单、成本低廉等优点,能够广泛应用于如热能储存、建筑节能等诸多领域。由于水泥的水化和聚乙二醇的结晶析出是同时进行的,造成水化产物和聚乙二醇链段互相缠绕,形成了稳固的封装体系,确保了制备的水泥基定形相变材料在发生相变时不会泄露。(The invention discloses a preparation method of a cement-based shape-stabilized phase-change material, which belongs to the technical field of phase-change material preparation. The cement-based shape-stabilized phase change material has the advantages of high phase change material packaging rate, good stability, simple preparation process, low cost and the like, and can be widely applied to various fields such as heat energy storage, building energy conservation and the like. As the hydration of the cement and the crystallization precipitation of the polyethylene glycol are carried out simultaneously, the hydration product and the polyethylene glycol chain segment are intertwined, a stable packaging system is formed, and the prepared cement-based shape-stabilized phase-change material is ensured not to be leaked when the phase change occurs.)

1. The preparation method of the cement-based shape-stabilized phase change material is characterized by comprising the following steps of:

s1, weighing the following raw materials in parts by weight: 100 parts of cement, 80-150 parts of polyethylene glycol aqueous solution, 5-15 parts of mineral admixture, 1-5 parts of accelerator and 0.1-1 part of thickener;

s2, weighing the dry materials in proportion, and putting the dry materials into a mixing pot for dry mixing;

s3, slowly pouring the polyethylene glycol aqueous solution and other liquid materials into a mixing pot;

s4, starting a cement paste mixer, firstly stirring at a low speed, then stirring at a high speed, and pouring the paste into a test mold after stirring is finished;

and S5, after standard maintenance, crushing the test piece into powder or particles, and finishing the preparation of the cement-based shape-stabilized phase-change material.

2. The method for preparing the cement-based shape-stabilized phase change material as claimed in claim 1, wherein the concentration of the polyethylene glycol aqueous solution is 40-70 wt%, and the relative molecular mass of the polyethylene glycol is 500-6000.

3. The method for preparing a cement-based set phase change material according to claim 1, wherein the cement is one or more of portland cement, portland slag cement, portland pozzolan cement, portland fly ash cement, composite portland cement, sulphoaluminate cement, ferro-aluminate cement, phosphate cement, and ultra-fine cement.

4. The method for preparing the cement-based shape-stabilized phase change material according to claim 1, wherein the mineral admixture is one or more of silica fume, fly ash, slag and limestone powder, and the fineness is higher than 1000 meshes.

5. The method of claim 1, wherein the setting accelerator is one or more of an aluminous clinker-carbonate setting accelerator, an aluminous clinker-alunite setting accelerator, a water glass setting accelerator, and an alkali-free setting accelerator.

6. The method of claim 1, wherein the thickener is one or more of a propylene-based thickener, a cellulose-based thickener and a polysaccharide-based thickener.

7. The method for preparing the cement-based shape-stabilized phase change material as claimed in claim 1, wherein in the step S2, the dry materials are weighed proportionally and put into a mixing pot for dry mixing for 1-2 min.

8. The method for preparing the cement-based shape-stabilized phase change material according to claim 1, wherein in the step S4, the low-speed stirring is performed for 120-150S, the stirring is stopped for 15-30S, the high-speed stirring is performed for 120-150S, and then the slurry is poured into a test mold.

9. The method for preparing a cement-based shape-stabilized phase change material as claimed in claim 1, wherein in step S5, the test pieces can be pulverized into cement-based shape-stabilized phase change materials with different particle sizes as required.

10. The cement-based shape-stabilized phase-change material prepared by the method for preparing the cement-based shape-stabilized phase-change material according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of phase change material preparation, and particularly relates to a preparation method of a cement-based shape-stabilized phase change material, which is applied to the fields of heat energy storage, building energy conservation and the like.

Background

In recent years, with the increase in greenhouse gas emissions and the shortage of fossil energy supplies, how to improve energy utilization efficiency has become a focus of attention. The heat energy storage technology can recover waste heat, relieve the contradiction between heat energy supply and demand, and is an important environmental protection technology for improving the energy utilization efficiency. Thermal energy storage technologies include latent heat storage, sensible heat storage, and chemical heat storage. Among them, the latent heat storage technology developed based on the characteristic that the phase change material can absorb or release a large amount of heat when undergoing phase change is the most effective and widely applied heat storage technology.

Phase change materials can be classified into solid-solid phase change materials, solid-liquid phase change materials, solid-gas phase change materials, and liquid-gas phase change materials. Solid-liquid phase change heat storage materials are considered to be the most feasible and practical phase change heat storage materials in view of enthalpy and volume change during phase change. In practical applications of solid-liquid phase change materials, they are often encapsulated in order to prevent leakage during the phase change. Common encapsulation methods such as microcapsule phase change materials have the defects of low physical strength, easy crushing of shell materials and the like, or composite shape-stabilized phase change materials prepared by using a physical adsorption method, but the method also has the defects of low encapsulation rate of the phase change materials, easy residual phase change materials on the surface and the like. Therefore, the invention provides the novel cement-based shape-stabilized phase-change material and the preparation method thereof, and the prepared cement-based shape-stabilized phase-change material has high encapsulation efficiency, good stability, simple preparation process and low cost, and can be widely applied to various fields such as heat energy storage, building energy conservation and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide the preparation method of the cement-based shape-stabilized phase-change material with simple preparation process and low cost, the phase-change material has high encapsulation rate and good stability, and the prepared cement-based shape-stabilized phase-change material can be widely applied to the fields of heat energy storage, building energy conservation and the like.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a preparation method of a cement-based shape-stabilized phase change material, which comprises the following steps:

s1, weighing the following raw materials in parts by weight: 100 parts of cement, 80-150 parts of polyethylene glycol aqueous solution, 5-15 parts of mineral admixture, 1-5 parts of accelerator and 0.1-1 part of thickener;

s2, weighing the dry materials in proportion, and putting the dry materials into a mixing pot for dry mixing;

s3, slowly pouring the polyethylene glycol aqueous solution and other liquid materials into a mixing pot;

s4, starting a cement paste mixer, firstly stirring at a low speed, then stirring at a high speed, and pouring the paste into a test mold after stirring is finished;

and S5, after standard maintenance, crushing the test piece into powder or particles, and finishing the preparation of the cement-based shape-stabilized phase-change material.

Furthermore, the concentration of the polyethylene glycol aqueous solution is 40-70 wt%, and the relative molecular mass of the polyethylene glycol is 500-6000.

Further, the cement is one or more of portland cement, portland slag cement, portland pozzolana cement, portland fly ash cement, composite portland cement, sulphoaluminate cement, ferro-aluminate cement, phosphate cement and superfine cement.

Further, the mineral admixture is one or a mixture of more of silica fume, fly ash, slag and limestone powder, and the fineness is higher than 1000 meshes.

The accelerating agent is one or more of an aluminum oxide clinker-carbonate accelerating agent, an aluminum oxide clinker-alunite accelerating agent, a water glass accelerating agent and an alkali-free accelerating agent.

Further, the thickener may be one or more of a propylene-based thickener, a cellulose-based thickener and a polysaccharide-based thickener.

Further, in the step S2, the dry materials are weighed in proportion and placed into a mixing pot to be dry-mixed for 1-2 min.

Further, in the step S4, the slurry is firstly stirred at a low speed for 120-150S, stopped for 15-30S, then stirred at a high speed for 120-150S, and then poured into a test mold.

Further, in the step S5, standard curing is required for at least 58 days.

Further, in step S5, the cured test piece may be crushed into cement-based shape-stabilized phase change materials with different particle sizes as required.

According to the invention, by utilizing the gelling property of cement and the water solubility of the phase-change material polyethylene glycol, the polyethylene glycol aqueous solution is used for mixing the cement, the cement and water in the solution generate a hydration reaction, the polyethylene glycol is gradually crystallized and precipitated due to supersaturation and is wrapped by a generated hydration product, and when the cement is finally hydrated, the polyethylene glycol is firmly encapsulated by the hydration product. The cement-based shape-stabilized phase change material has the advantages of high phase change material packaging rate, good stability, simple preparation process, low cost and the like, and can be widely applied to various fields such as heat energy storage, building energy conservation and the like.

Compared with the prior art, the invention has the beneficial technical effects that:

1) as the hydration of the cement and the crystallization precipitation of the polyethylene glycol are carried out simultaneously, the hydration product and the polyethylene glycol chain segment are intertwined, a stable packaging system is formed, and the prepared cement-based shape-stabilized phase-change material is ensured not to be leaked when the phase change occurs.

2) The cement-based shape-stabilized phase change material prepared by the invention has the advantages of high phase change material encapsulation rate, good stability, simple preparation process, low cost and the like, and can be widely applied to various fields such as heat energy storage, building energy conservation and the like due to the excellent physical property, chemical stability and thermal stability of the cement material.

3) By adding the superfine mineral admixture with the active effect, the thickening agent and the accelerating agent, the hydration speed, the hydration degree and the physical strength of the cement-based shape-stabilized phase-change material are improved.

Drawings

FIG. 1 is a scanning electron micrograph of a plain cement paste specimen prepared in comparative example 1;

FIG. 2 is a scanning electron micrograph of a cementitious shape-stabilized phase change material prepared according to example 1;

FIG. 3 is a differential scanning calorimetry trace of the cementitious shaped phase change material prepared in example 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention, and the present invention is further described with reference to the drawings and the specific embodiments below.