Moisture-induced flexible self-healing phase change temperature control material and preparation and application thereof

Abstract

The application discloses a moisture-induced flexible self-healing phase change temperature control material and a preparation method thereof. The method uses erythritol and polyethylene glycol as phase change materials, polyvinyl alcohol-polyvinyl pyrrolidone as a supporting carrier, and a moisture-induced flexible self-healing phase change temperature control material is formed through physical mixing. The phase change material synthesized by the method has the advantages of stable phase change latent heat, no leakage, good stability, self-healing and cold crystallization, and has a wide application prospect in heat management and controllable release of heat.

Description

Technical Field

[0001] This invention relates to a moisture-induced flexible self-healing phase change temperature-controlled material and its preparation method. Background Technology

[0002] The development and utilization of new energy sources and the improvement of energy efficiency have become key research and development priorities for various countries. Utilizing phase change materials to balance energy supply and demand can effectively improve energy efficiency, achieving the goals of energy conservation and environmental protection. It has broad application prospects in energy, aerospace, construction, agriculture, and chemical industries, and has become a global research hotspot.

[0003] Phase change materials (PCAs) absorb or release a large amount of latent heat during phase transitions, exhibiting advantages such as high heat storage density, small size, constant temperature control, significant energy-saving effects, wide range of phase change temperature selection, and ease of control. Therefore, they are widely used in energy storage and temperature control. However, PCAs suffer from leakage problems during use. To address this issue, many methods have been proposed to prepare shape-stable composite PCAs, including porous material adsorption, microcapsule encapsulation, and polymer support. However, these composite PCAs lack self-healing properties and cannot be reused, resulting in resource waste. Commercially available self-healing composite PCAs require high temperatures for healing, have low phase change enthalpy, low stability, complex preparation processes, and are not suitable for mass production, leading to low production efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a moisture-induced flexible self-healing phase change temperature-controlled material to solve the problems mentioned in the background art.

[0005] The synthesis of water molecule-induced flexible self-healing phase change temperature-controlled materials includes the following steps:

[0006] First, place polyvinyl alcohol and polyvinylpyrrolidone separately into three-necked flasks, add deionized water, and then place the round-bottom flasks in an oil bath and heat to 40-100℃ for 2-8 hours to completely dissolve them in the deionized water. Next, place a polyvinyl alcohol and polyvinylpyrrolidone solution with a solute mass ratio of 1:0.2-1:0.6 into a three-necked round-bottom flask, and then place the round-bottom flasks in an oil bath and heat to 40-100℃ for 2-8 hours with constant stirring. Then, add erythritol and / or polyethylene glycol in a mass ratio of 1:1-1:3 with polyvinyl alcohol and polyvinylpyrrolidone, and continue stirring for 2-8 hours. After the reaction is complete, place the resulting mixture in a watch glass and then place it in an oven at 60-80℃ for 2-10 hours. Finally, a white film is obtained, which is the water molecule-induced flexible self-healing phase change temperature-controlled material.

[0007] Furthermore, 1g of polyvinyl alcohol was dissolved in 10ml of deionized water, and the reaction temperature was 90℃, with a reaction time of 6 hours.

[0008] Further, 0.2-0.6g of polyvinylpyrrolidone was dissolved in 10ml of deionized water, and the reaction temperature was 80℃, and the reaction time was 2 hours.

[0009] Furthermore, in the above steps, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone solutes is 1:0.2, the reaction temperature is 80°C, and the reaction time is 2 hours.

[0010] Furthermore, in the above steps, the mass ratio of erythritol or polyethylene glycol to polyvinyl alcohol and polyvinylpyrrolidone is 2:1, the reaction temperature is 80°C, and the reaction time is 2 hours.

[0011] Furthermore, the product in the above step is dried in an oven at 80°C for 8 hours.

[0012] Furthermore, the water molecule-induced flexible self-healing phase change temperature control material is a white thin film.

[0013] This method uses erythritol or polyethylene glycol as the phase change material and polyvinyl alcohol-polyvinylpyrrolidone as the support carrier to physically blend and synthesize a water-induced flexible self-healing phase change temperature control material. The self-healing phase change material synthesized by this method has advantages such as healing properties, high latent heat of phase change, cold crystallization, simple preparation process, and good thermal stability. Cold crystallization is a phenomenon where no heat is released during cooling, but heat is released during crystallization, which allows for better control of energy storage and release. Furthermore, the repair process is simple and convenient; healing can be achieved simply by adding water to the damaged area, or it can self-heal in high humidity environments such as 85% humidity. It possesses multiple flexible self-healing mechanisms, enabling it to better adapt to temperature control and energy storage scenarios in complex configurations. Attached Figure Description

[0014] Figure 1 Differential scanning calorimetry curves of water molecule-induced flexible self-healing phase change temperature-controlled materials (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.6, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1).

[0015] Figure 2 Differential scanning calorimetry curves of water molecule-induced flexible self-healing phase change temperature-controlled materials (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.4, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1).

[0016] Figure 3Differential scanning calorimetry curves of water molecule-induced flexible self-healing phase change temperature-controlled materials (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1).

[0017] Figure 4 Differential scanning calorimetry curves of water molecule-induced flexible self-healing phase change temperature-controlled materials (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1).

[0018] Figure 5 Images of the dripping repair process of a water molecule-induced flexible self-healing phase change temperature-controlled material (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1).

[0019] Figure 6 Thermogravimetric curves of a water molecule-induced flexible self-healing phase change temperature-controlled material (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1).

[0020] Figure 7 A flexible demonstration image of a water molecule-induced flexible self-healing phase change temperature control material (using erythritol as the phase change material, with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2, and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1). Detailed Implementation

[0021] Example 1

[0022] (1) Take 1g of polyvinyl alcohol (molecular weight 120000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 90℃. Stir at a constant speed for 6 hours.

[0023] (2) Take 0.6g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0024] (3) After the reaction is complete, pour the products of (1) and (2) into a three-necked flask, then add 1.6g of erythritol into the three-necked flask, and then heat the three-necked flask in an oil bath to 80°C and stir at a constant speed for 2 hours.

[0025] (4) The product obtained in (3) was placed in a petri dish and then dried in an oven at 80°C for 2 hours to obtain a self-healing phase change film with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.6 and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1.

[0026] The prepared self-healing phase change material is a white thin film, and the differential scanning calorimetry curve is shown below. Figure 1 As shown, the fitted melting temperature is 100.3℃ and the melting enthalpy is 62.8J / g.

[0027] Example 2

[0028] (1) Take 1g of polyvinyl alcohol (molecular weight 120000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 90℃. Stir at a constant speed for 6 hours.

[0029] (2) Take 0.4g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0030] (3) After the reaction is complete, pour the products of (1) and (2) into a three-necked flask, then add 1.4g of erythritol into the three-necked flask, and then heat the three-necked flask in an oil bath to 80°C and stir at a constant speed for 2 hours.

[0031] (4) The product obtained in (3) was placed in a petri dish and then dried in an oven at 80°C for 2 hours to obtain a self-healing phase change film with a mass ratio of polyvinyl alcohol and polyvinylpyrrolidone of 1:0.4 and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1.

[0032] The prepared self-healing phase change material is a white thin film, and the differential scanning calorimetry curve is shown below. Figure 2 As shown, the fitted melting temperature is 96.8℃ and the melting enthalpy is 66.0J / g.

[0033] Example 3

[0034] (1) Take 1g of polyvinyl alcohol (molecular weight 120000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 90℃. Stir at a constant speed for 6 hours.

[0035] (2) Take 0.2g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0036] (3) After the reaction is complete, pour the products of (1) and (2) into a three-necked flask, then add 1.2g of erythritol into the three-necked flask, and then heat the three-necked flask in an oil bath to 80°C and stir at a constant speed for 2 hours.

[0037] (4) The product obtained in (3) was placed in a petri dish and then dried in an oven at 80°C for 2 hours to obtain a self-healing phase change film with a mass ratio of polyvinyl alcohol and polyvinylpyrrolidone of 1:0.2 and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 1:1.

[0038] The prepared self-healing phase change material is a white thin film, and the differential scanning calorimetry curve is shown below. Figure 3 As shown, the fitted melting temperature is 89.7℃ and the melting enthalpy is 93.7J / g.

[0039] Example 4

[0040] (1) Take 1g of polyvinyl alcohol (molecular weight 120000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 90℃. Stir at a constant speed for 6 hours.

[0041] (2) Take 0.2g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0042] (3) After the reaction is complete, pour the products of (1) and (2) into a three-necked flask, then add 2.4g of erythritol into the three-necked flask, and then heat the three-necked flask in an oil bath to 80°C and stir at a constant speed for 2 hours.

[0043] (4) The product obtained in (3) was placed in a petri dish and then dried in an oven at 80°C for 2 hours to obtain a self-healing phase change film with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2 and a mass ratio of erythritol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1.

[0044] The prepared self-healing phase change material is a white thin film, and the differential scanning calorimetry curve is shown below. Figure 4 As shown, the fitted melting temperature is 98.7℃ and the melting enthalpy is 191.5J / g.

[0045] Example 5

[0046] (1) Take 1g of polyvinyl alcohol (molecular weight 120000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 90℃. Stir at a constant speed for 6 hours.

[0047] (2) Take 0.2g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0048] (3) After the reaction is complete, pour the products of (1) and (2) into a three-necked flask, then add 2.4g of polyethylene glycol (molecular weight 1000) into the three-necked flask, and then put the three-necked flask into an oil bath and heat it to 80°C. Stir at a constant speed for 2 hours.

[0049] (4) The product obtained in (3) was placed in a petri dish and then dried in an oven at 80°C for 2 hours to obtain a self-healing phase change film with a mass ratio of polyvinyl alcohol to polyvinylpyrrolidone of 1:0.2 and a mass ratio of polyethylene glycol to polyvinyl alcohol and polyvinylpyrrolidone of 2:1.

[0050] Example 6

[0051] (1) Take 0.6g of polyvinylpyrrolidone (molecular weight 90000) and place it in a three-necked flask. Add 10ml of deionized water and then place the three-necked flask in an oil bath and heat it to 80℃. Stir at a constant speed for 2 hours.

[0052] (2) After the reaction is complete, take 2.4g of erythritol and put it into a three-necked flask. Then put the three-necked flask into an oil bath and heat it to 80°C. Stir at a constant speed for 2 hours.

[0053] (3) The product obtained in (2) was placed in a petri dish and then dried in an oven at 80°C for 2 hours. The dried product did not form a film and could not maintain a stable shape.

[0054] The water molecule-induced self-healing phase change temperature-controlling material of this invention is a thin film. The highest phase change enthalpy is 191.5 J / g. Figure 5This document describes the microscopic and macroscopic processes and healing mechanism of the healing process in Example 4. Two identical rectangular phase change films were dyed red and blue, respectively. The two red and blue composite materials were then brought close together, and water was dripped into the gap between their contacting ports (from above the contacting ports towards the contact points). The films were then placed under natural environmental conditions (35% relative humidity, 20°C) for healing. After 5 minutes, the two red and blue composite materials healed into a single unit. Macroscopic images show that the red and blue composite materials have joined together. To better observe the healing process, a microscopic analyzer was used. It was observed that the red and blue samples gradually came into contact, and after the water evaporated, they were completely joined together, with the gap almost completely disappearing. The healing mechanism is due to the introduction of hydrogen bonds, which endow the composite phase change material with healing properties. The addition of water disrupts the hydrogen bonds in the composite material, thereby increasing the migration rate of the composite material at the interface surface. Driven by the density gradient in the network, polyvinyl alcohol, polyvinylpyrrolidone, and erythritol migrate into the gaps between the interface surfaces. As moisture evaporates from the healing area, hydrogen bonds will reform between -OH and -C=O.

[0055] Figure 6 The thermogravimetric curve for Example 4 was measured under a nitrogen atmosphere at a heating rate of 10°C / min starting from room temperature. Analysis showed that the initial decomposition temperature of the composite material was 276.8°C, which is much higher than its phase transition temperature range, indicating that the phase transition film exhibits good thermal stability.

[0056] Figure 7 The image shown is a demonstration of the flexibility of Example 4. The phase change film can be folded and bent, indicating that the material has good flexibility.

[0057] The above results indicate that the water molecule-induced flexible self-healing phase change temperature control material of the present invention has broad application prospects in the development of next-generation thermal management technology.

Claims

1. A moisture-induced flexible self-healing phase change temperature-controlled material, characterized in that: A phase change temperature control material is prepared by mixing erythritol as the phase change material and polyvinyl alcohol and polyvinylpyrrolidone as the support carrier.

2. The phase change temperature control material according to claim 1, characterized in that, The material is composed of erythritol, a phase change material, and polyvinyl alcohol and polyvinylpyrrolidone, a supporting carrier. The mass ratio of polyvinyl alcohol to polyvinylpyrrolidone in the support is 1:0.2-1:0.6, and the mass ratio of phase change material to support is 1:1-3:

1.

3. The phase change temperature control material according to claim 1 or 2, characterized in that, The molecular weight range of polyvinyl alcohol is 25,000-300,000; The molecular weight range of polyvinylpyrrolidone is 30,000-90,000.

4. A method for preparing a moisture-induced flexible self-healing phase change temperature-controlled material as described in claim 1, 2, or 3, characterized in that, It has the following process steps: 1) Place polyvinyl alcohol in a container, add water, heat to 80-100℃, and stir continuously for 4-8 hours until it is completely dissolved in the water; wherein: 0.1-1g of polyvinyl alcohol needs to be dissolved in 10ml of water. Place polyvinylpyrrolidone in another container, then add water and heat to 70-100℃, stirring continuously for 1-4 hours until it is completely dissolved in the water; wherein: 0.1-1.2g of polyvinylpyrrolidone needs to be dissolved in 10ml of water; 2) Mix polyvinyl alcohol and polyvinylpyrrolidone solutions with a solute mass ratio between 1:0.2 and 1:0.6, and then heat the mixture to 60-100℃ for 1-4 hours, stirring constantly during the process; 3) Add erythritol in a mass ratio of 1:1 to 3:1 with the total mass of polyvinyl alcohol and polyvinylpyrrolidone, and continue stirring for 1-4 hours. Then pour the viscous mixture into a petri dish and dry it at 60-80℃ for 2-8 hours to obtain a white film-like product, which is the self-healing phase change material.

5. The application of a moisture-induced flexible self-healing phase change temperature-controlled material as described in claim 1, 2, or 3, or a phase change temperature-controlled material prepared by the method of claim 4, characterized in that, It can be used as a phase change material in thermal management processes or in the storage and controlled release of heat to control the storage and release of energy.

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