Low-thermal-conductivity phase-change aerogel material as well as preparation method and application thereof

Abstract

The invention discloses a low-thermal-conductivity phase change aerogel material as well as a preparation method and application thereof. The phase change enthalpy value of the material is 50J / g to 110J / g; the phase change temperature is 0-60 DEG C; and the heat conductivity coefficient is 0.08 W / (m.K)-0.1 W / (m.K). The novel low-thermal-conductivity phase-change material is generated by curing polydimethylsiloxane (PDMS) and the phase-change microcapsules. The phase change aerogel material is simple in synthesis process, relatively high in phase change enthalpy value and good in phase change cycle stability. The method has important application prospects in the two aspects of heat energy collection and heat insulation temperature control.

Description

Technical Field

[0001] This application relates to a low thermal conductivity phase change aerogel material, its preparation method and application, belonging to the field of phase change materials. Background Technology

[0002] The development of novel and efficient thermal insulation and temperature control materials is crucial to meeting the growing demands for thermal management. Porous aerogels possess the characteristics of thermal insulation and temperature control, and are lightweight and porous. However, the complex preparation and high processing costs of traditional aerogel materials have limited their commercial application.

[0003] Phase change materials (PCMs) can absorb and release a large amount of latent heat during phase transition while maintaining a constant temperature. Therefore, they can be used as functional materials for thermal management to achieve heat energy storage and temperature control. They have wide applications in heat harvesting, building temperature control, and industrial waste heat recovery.

[0004] Thermal insulation and temperature control materials have important application prospects; however, existing thermal insulation and temperature control materials are costly and have complex preparation conditions, which cannot meet the needs of large-scale applications. Summary of the Invention

[0005] Given the complex synthesis process and high cost of existing low thermal conductivity porous aerogel materials, they cannot meet application requirements. Therefore, it is necessary to develop and synthesize a novel low thermal conductivity porous phase change material with a simple synthesis method, high phase change enthalpy, and low thermal conductivity, which has significant research and application value.

[0006] This invention combines porous aerogels with phase change materials to prepare a novel porous, low-thermal-conductivity phase change framework, achieving a combination of latent heat control and aerogel-based temperature control, which can meet the requirements of effective temperature control under instantaneous high power. Simultaneously, the preparation conditions are mild, the process cost is low, and it has the potential for large-scale applications.

[0007] According to one aspect of this application, a low thermal conductivity phase change aerogel material is provided, wherein the phase change enthalpy of the low thermal conductivity phase change aerogel material is 50 J / g to 110 J / g;

[0008] The phase transition temperature of the low thermal conductivity phase change aerogel material is 0℃~60℃.

[0009] The thermal conductivity of the low thermal conductivity phase change aerogel material is 0.08 W / (m·K) to 0.1 W / (m·K).

[0010] According to another aspect of this application, a method for preparing the above-mentioned low thermal conductivity phase change aerogel material is provided, comprising the following steps:

[0011] Phase change microcapsules and a template agent were stirred and mixed evenly, then mixed evenly with polydimethylsiloxane (PDMS) prepolymer diluted with n-hexane and a curing agent. The mixture was then subjected to pressure molding and vacuum curing. The cured material was then subjected to thorough desalination in a water bath and dried to obtain the low thermal conductivity phase change material.

[0012] Polydimethylsiloxane (PDMS) prepolymer is cured with phase change microcapsules to form a porous phase change framework. The template agent is washed away with water to obtain the porous structure.

[0013] Specifically, it includes the following steps:

[0014] Hexane, polydimethylsiloxane, curing agent, phase change microcapsules, and template agent are mixed, pressurized, cured, washed with water, and dried to obtain the low thermal conductivity phase change aerogel material.

[0015] The curing agent is SYLGARD 184DOW CORNING;

[0016] The template agent is selected from any one of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, and aluminum chloride;

[0017] The phase change microcapsules have a phase change temperature of 20–60°C.

[0018] The phase change microcapsules have a phase change enthalpy of 180–230 J / g.

[0019] The mass ratio of n-hexane to polydimethylsiloxane is 5-10:1;

[0020] The mass ratio of polydimethylsiloxane to curing agent is 10:1 to 2;

[0021] The mass ratio of polydimethylsiloxane to phase change microcapsules is 1:0.5-5;

[0022] The mass ratio of the phase change microcapsule to the inorganic salt template agent is 1:8 to 15.

[0023] The pressure for the pressure molding process is 1-5 MPa;

[0024] The curing temperature is 60–120°C;

[0025] The curing time is 3 to 20 hours.

[0026] According to another aspect of this application, an application of the above-mentioned low thermal conductivity phase change aerogel material is provided as a thermal insulation and temperature control material.

[0027] The beneficial effects that this application can produce include:

[0028] (1) A novel low thermal conductivity phase change material and its synthesis method are provided;

[0029] (2) The synthesis method is simple, and the resulting material has high enthalpy, low thermal conductivity and high hydrophobicity.

[0030] (3) This application describes a novel low thermal conductivity phase change material generated by curing polydimethylsiloxane (PDMS) with phase change microcapsules. The phase change aerogel material has a simple synthesis process, high phase change enthalpy, and good phase change cycle stability. It has significant application prospects in both heat harvesting and thermal insulation temperature control. Attached Figure Description

[0031] Figure 1 This is a DSC diagram of the phase change aerogel material in the embodiments of this application. Detailed Implementation

[0032] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0033] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0034] Example 1

[0035] (1) Accurately weigh 1g of PDMS and 0.1g of curing agent, dissolve them in 10ml of n-hexane, and stir to mix evenly; accurately weigh 1g of phase change microcapsules and 9g of sodium chloride, and stir to mix evenly; mix the PDMS-n-hexane solution with the phase change microcapsules and sodium chloride and stir to mix evenly.

[0036] (2) The mixture is pressurized and molded at a pressure of 2 MPa;

[0037] (3) Place the pressure-molded phase change material in an oven and cure it at 80°C for 10 hours;

[0038] (4) Place the cured material in an 80°C water bath for desalination treatment.

[0039] (5) Place the fully desalinated material in an oven for drying.

[0040] The thermal conductivity of the low thermal conductivity phase change aerogel of this invention is approximately 0.09 W / mK, resulting in a significant improvement in thermal insulation performance.

[0041] Example 2

[0042] (1) Accurately weigh 1g of PDMS and 0.1g of curing agent, dissolve them in 10ml of n-hexane, and stir to mix evenly; accurately weigh 1g of phase change microcapsules and 13g of sodium chloride, and stir to mix evenly; mix the PDMS-n-hexane solution with the phase change microcapsules and sodium chloride and stir evenly.

[0043] (2) The mixture is pressurized and molded at a pressure of 2 MPa;

[0044] (3) Place the pressure-molded phase change material in an oven and cure it at 80°C for 10 hours;

[0045] (4) Place the cured material in an 80°C water bath for desalination treatment.

[0046] (5) Place the fully desalinated material in an oven for drying.

[0047] The thermal conductivity of the low thermal conductivity phase change aerogel of this invention is approximately 0.14 W / mK, thus improving its thermal insulation performance.

[0048] Comparative Example 1

[0049] (1) Accurately weigh 1g of PDMS, 0.1g of curing agent, 1g of phase change microcapsules, and 6g of sodium chloride, and stir to mix evenly; mix the PDMS-n-hexane solution with the phase change microcapsules and sodium chloride and stir evenly.

[0050] (2) The mixture is pressurized and molded at a pressure of 2 MPa;

[0051] (3) Place the pressure-molded phase change material in an oven and cure it at 80°C for 10 hours;

[0052] (4) Place the cured material in an 80°C water bath for desalination treatment.

[0053] (5) Place the fully desalinated material in an oven for drying.

[0054] Undiluted PDMS has a high viscosity, making it difficult to mix evenly, and is an amorphous phase change material with low thermal conductivity.

[0055] Test Example 1

[0056] To test the phase change thermal properties of the phase change material obtained in Example 1, differential scanning calorimetry (DSC) analysis was performed. The test conditions were: heating and cooling rate: 10 °C / min; temperature range: 0-70 °C. The results are as follows: Figure 1 As shown, the phase change material prepared in Example 1 has a melting initiation temperature of 38.68℃, a melting peak temperature of 45.22℃, and a melting peak enthalpy of 98.60 J / g; a crystallization initiation temperature of 41.70℃, a crystallization peak temperature of 32.51℃, and a crystallization peak enthalpy of 100.85 J / g.

[0057] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A low thermal conductivity phase change aerogel material, characterized in that, The phase change enthalpy of the low thermal conductivity phase change aerogel material is 50 J / g to 110 J / g; The phase transition temperature of the low thermal conductivity phase change aerogel material is 0℃~60℃. The thermal conductivity of the low thermal conductivity phase change aerogel material is 0.08 W / (m·K) to 0.1 W / (m·K).

2. A method for preparing the low thermal conductivity phase change aerogel material according to claim 1, characterized in that, Includes the following steps: Hexane, polydimethylsiloxane, curing agent, phase change microcapsules, and template agent are mixed, pressurized, cured, washed with water, and dried to obtain the low thermal conductivity phase change aerogel material.

3. The preparation method according to claim 2, characterized in that, The curing agent is SYLGARD 184DOW CORNING; The inorganic salt template agent is selected from any one of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, and aluminum chloride; The phase change microcapsules have a phase change temperature of 20–60°C. The phase change microcapsules have a phase change enthalpy of 180–230 J / g.

4. The preparation method according to claim 2, characterized in that, The mass ratio of n-hexane to polydimethylsiloxane is 5-10:1; The mass ratio of polydimethylsiloxane to curing agent is 10:1 to 2; The mass ratio of polydimethylsiloxane to phase change microcapsules is 1:0.5-5; The mass ratio of the phase change microcapsule to the inorganic salt template agent is 1:8 to 15.

5. The preparation method according to claim 2, characterized in that, The pressure for the pressure molding process is 1-5 MPa; The curing temperature is 60–120°C; The curing time is 3 to 20 hours.

6. An application of the low thermal conductivity phase change aerogel material according to claim 1, characterized in that, As a heat insulation and temperature control material.

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