Composite phase-change material and preparation method thereof

A composite phase change material and mixed solution technology, applied in the field of materials, can solve the problems of large volume change, small thermal conductivity, and easy volatility, and achieve the effects of simple preparation process, low phase transition temperature, and good thermal stability

Inactive Publication Date: 2007-10-24
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although inorganic phase change materials have the advantages of large phase change latent heat, high energy storage density, high thermal conductivity, and low price, there are corrosion, supercooling and phase separation phenomena; organic phase change materials have better formability in solid state Generally, supercooling and phase separation are not easy to occur, the material is less corrosive, and the performance is

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The raw material of this embodiment adopts:

[0021] Polyethylene glycol (molecular weight 2000 analytically pure AR)

[0022] Absolute ethanol (analytically pure AR with a density of 0.79g / ml)

[0023] Ethyl orthosilicate (analytical pure AR)

[0024] Concentrated hydrochloric acid (5mol / L)

[0025] distilled water

[0026] The preparation method comprises the following steps:

[0027] 1: First mix 4 grams of polyethylene glycol with a molecular weight of 2000 and 15 ml of absolute ethanol, and heat to 80°C for 5 minutes with a magnetic stirrer to form a mixed solution;

[0028] 2: Add 3.47 grams of ethyl orthosilicate dropwise to the mixed solution in step 1, stir for 15 minutes, then add 1.2 grams of water dropwise, adjust the pH value of the solution to 1 with hydrochloric acid, and stir rapidly at room temperature for 3 hours;

[0029] 3: The sol obtained in step 2 was synthesized at 40°C for 24 hours to form a gel; dried at 80°C for 24 hours to obtain a polye...

Embodiment 2-4

[0034] The properties of polyethylene glycol / silicon dioxide composite phase change material prepared by the present invention are as follows:

[0035] polyethylene glycol

molecular weight

Composite dense

Degree(g / cm3)

composite phase

Variable temperature(℃)

composite phase

Enthalpy change(J / g)

composite storage

energy density

(J / cm3)

2000

1.278

45.55

96.23

122.98

4000

1.287

47.20

111.9

144.01

6000

1.301

52.74

123.3

160.41

10000

1.303

56.38

131.3

170.69

[0036] In the present invention, the mol ratio of tetraethyl orthosilicate to water is the water of 2~6, and reaction equation

[0037] (C 2 h 5 ) 4 SiO 4 +4H 2 O=Si(OH) 4 +4C 2 h 5 Oh

[0038] Si(OH) 4 =2H 2 O+SiO 2

[0039] The pH value range can be between 0.5 and 2. Sin...

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Abstract

The invention discloses a composite phase-changing material and making method, which comprises the following steps: 1) blending carbowax with molecular weight at 2000-10000 and anhydrous alcohol with weight rate at 0. 21-0. 34; heating to stir; forming the composite liquid; 2) dripping p-ethyl-siliconic acid with weight rate at 0. 61-0. 87 corresponding to carbowax at 0. 61-0. 87 into the composite solution in the step 1); stirring; adding water with molar weight at 2:1-6:1 corresponding to p-ethyl-siliconic acid; adjusting pH value of solution at 0. 5-2; stirring under normal temperature; 3) aging the sol in the step 2) for 24h under 40 deg. c; forming the gel; drying under high temperature to obtain the carbowax/silica composite phase-changing material. The invention stablizes the shape and good heat stability, which forms even composite phase-changing material.

Description

technical field [0001] The invention relates to material technology, in particular to composite phase-change materials. Background technique [0002] With the development of advanced infrared detection and guidance technology, various military targets on the future battlefield are facing severe threats. Infrared stealth technology, as an effective means to improve the survivability and defense penetration capability of weapon systems, has been highly concerned by countries all over the world. Phase change materials can absorb or release energy during the phase change process, forming an isothermal or nearly isothermal process to achieve the purpose of temperature control, so they are widely used in industry, agriculture, military, aviation, civil and other fields. [0003] Phase change materials (phase change materials PCM for short) used for temperature control mainly include inorganic phase change materials and organic phase change materials. Although inorganic phase cha...

Claims

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Application Information

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IPC IPC(8): C09K5/06
Inventor 邓龙江杜世发陈良翁小龙
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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