A method for regulating the thermal properties of a phase change material and a phase change material

Abstract

The application provides a method for regulating the thermal performance of a phase change material and the phase change material, and the method comprises the following steps: uniformly mixing and stirring an olefin material, a graftable high molecular prepolymer, a crosslinking high molecular prepolymer and a catalyst to obtain the phase change material; in the method, the olefin material is grafted with the graftable high molecular prepolymer, and then is crosslinked with the crosslinking high molecular prepolymer to form a covalent bond network; or the olefin material is grafted with the graftable high molecular prepolymer, and then is dissolved in the crosslinking high molecular prepolymer to form a covalent bond network after self-crosslinking. The phase change material synthesized by the method has a solid-solid phase change characteristic, and leakage of the phase change material during use can be avoided. Different moduli of the material before and after phase change can be designed according to the same method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material preparation and synthesis, and particularly relates to a method for regulating thermal properties of phase change materials and a phase change material. BACKGROUND

[0002] Phase change materials can be used as energy storage materials in engineering fields, but the currently widely used energy storage materials have some drawbacks: 1. Most energy storage materials are thermoplastic polymer materials such as paraffin, which will be accompanied by liquefaction when phase changing at high temperature, and thus easily lead to leakage of the material, failure of the material, and damage of the device; 2. Most thermoplastic polymer materials used in phase change materials have a single composition and a certain purity, which leads to a relatively fixed phase change temperature point and enthalpy value of the material, and thus cannot meet the special temperature requirements of some working conditions. Although paraffin has a complex composition and can undergo phase change within a certain range, this feature can only be passively understood and cannot be used in the design of phase change materials meeting special working conditions.

[0003] Therefore, it is extremely important to invent a method for adjusting the phase change temperature point and enthalpy value of phase change materials to target values for the design and application of materials. SUMMARY

[0004] The purpose of the present application is to provide a method for regulating the phase change point, enthalpy value and other thermal properties of phase change materials so as to reach the target values of material design and expand the use range of the phase change materials.

[0005] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0006] The present application provides a method for regulating thermal properties of phase change materials, which comprises: uniformly mixing and stirring olefin materials, graftable polymer prepolymers, crosslinking polymer prepolymers and catalysts to obtain phase change materials; in the method, the olefin materials are grafted with the graftable polymer prepolymers, and then crosslinked with the crosslinking polymer prepolymers to form a covalent bond network; or the olefin materials are grafted with the graftable polymer prepolymers, and then dissolved in the crosslinking polymer prepolymers to form a covalent bond network after self-crosslinking.

[0007] Further, the graftable polymer prepolymers after grafting the olefin materials exist in the form of being crosslinked with other polymer prepolymers, being dissolved in a polymer crosslinking network or both.

[0008] Further, the ratio of the components in the method is as follows: 0.1-99.9 parts of olefin materials, 0.1-99.9 parts of graftable polymer prepolymers, 0.1-99.9 parts of crosslinking polymer prepolymers, and 0.1-1 parts of catalysts.

[0009] Further, the homogenous mixing device is a planetary mixer, a kneader or a high-speed mixer.

[0010] Further, the olefin material is a phase change material of hexadecene and / or octadecene.

[0011] Further, the graftable high-molecular pre-polymer is a hydrogen-containing silicone oil capable of addition reaction with the olefin material.

[0012] Further, the cross-linked high-molecular pre-polymer is a polydimethylsiloxane pre-polymer.

[0013] Further, the catalyst is at least one of chloroplatinic acid, chloroplatinic acid-isopropyl alcohol complex and chloroplatinic acid-divinyltetramethyldisiloxane complex.

[0014] The present application also provides a phase change material prepared by the method for regulating the thermal performance of the phase change material.

[0015] Further, the phase change temperature of the phase change material can be adjusted in the range of 0-200℃, and the enthalpy value can be adjusted in the range of 0-500J / g.

[0016] Compared with the prior art, the technical solution provided by the present application has at least the following advantages:

[0017] The present application provides a method for regulating the thermal performance of a phase change material and the phase change material. The longer the olefin molecular chain and the higher the grafting rate, the higher the phase change point of the phase change material. In the case that the phase change silicone oil only dissolves in the high-molecular cross-linked network and does not cause additional cross-linking, the higher the mass ratio, the greater the enthalpy value. If the phase change silicone oil causes additional cross-linking with the cross-linked network, the enthalpy value of the prepared material changes, and the phase change point also increases accordingly.

[0018] In addition, the phase change material synthesized by the method has solid-solid phase change characteristics, which can avoid leakage of the phase change material during use. The different moduli before and after phase change of the material can be designed according to the same method. BRIEF DESCRIPTION OF DRAWINGS

[0019] One or more embodiments are illustrated by way of example in the figures that form a part of this patent document, and in which like reference numbers indicate corresponding elements in the drawings, its application examples and to which in particular the principles of the present application apply, and in which:

[0020] Figure 1 is a graph of the enthalpy value and phase change point test results of the phase change material prepared by the embodiments of the present application. DETAILED DESCRIPTION

[0021] The inventors find that the olefin molecular chain is grafted with the side chain hydrogen-containing siloxane to form a phase-changeable silicone oil, and then the phase-changeable silicone oil is crosslinked with other siloxane polymer prepolymers or dissolved in a high molecular crosslinked network formed by crosslinking of siloxane prepolymers, and finally a high molecular material with phase change characteristics is obtained. By selecting olefin molecular chains of different lengths or controlling the grafting rate of the olefin molecular chain and the side chain hydrogen-containing siloxane, the phase change point of the synthesized phase-changeable material can be changed. In the case that the phase-changeable silicone oil only dissolves in the high molecular crosslinked network and does not occur additional crosslinking, the enthalpy value of the prepared phase-changeable material can be controlled by changing the mass ratio of the phase-changeable silicone oil and the crosslinkable siloxane prepolymer. Selecting side chain hydrogen-containing siloxanes with different hydrogen contents can also adjust the phase change point of the synthesized phase-changeable material. By synergistically controlling the above points, phase-changeable materials with different phase change points and enthalpy values can be designed and prepared within a certain range.

[0022] The present application provides a method for regulating the thermal performance of a phase-changeable material, the method comprising:

[0023] The olefin material, the graftable high molecular prepolymer, the crosslinking high molecular prepolymer, and the catalyst are uniformly mixed and stirred to obtain the phase-changeable material;

[0024] In the method, the olefin material is grafted with the graftable high molecular prepolymer, and then crosslinked with the crosslinking high molecular prepolymer to form a covalent bond network;

[0025] Alternatively, the olefin material is grafted with the graftable high molecular prepolymer, and then dissolved in the crosslinking high molecular prepolymer to form a covalent bond network after self-crosslinking. In the present application, the specific regulation method is to change the molecular weight of the phase-changeable material, i.e. to adjust the length of the olefin material molecular chain or the grafting rate between the olefin material and the side chain hydrogen-containing silicone oil to change the phase change point of the finally prepared material (the molecular weight of the phase-changeable material is positively correlated with the phase change point); the content of the olefin material in the prepared material is controlled to adjust the enthalpy value of the material (the enthalpy value is linearly and positively correlated with the content of the olefin).

[0026] Further, the high molecular prepolymer after grafting the olefin material exists in the form of being crosslinked with other high molecular prepolymers or being dissolved in a high molecular crosslinked network or both. The grafted high molecular prepolymer is either crosslinked with the crosslinking high molecular prepolymer to become part of the crosslinked high molecular network or dispersed in the high molecular crosslinked network formed by crosslinking of the high molecular crosslinking prepolymer in a monomer form. Both means that part of the grafted prepolymer participates in crosslinking and part of the grafted prepolymer is dispersed in the form of a monomer.

[0027] The present application also provides a phase-changeable material prepared by the above method for regulating the thermal performance of a phase-changeable material.

[0028] Further, the phase change temperature point of the phase change material can be adjusted in the range of 0℃-200℃, and the enthalpy value can be adjusted in the range of 0J / g-500J / g

[0029] The application will be described in detail below with reference to specific embodiments. It should be noted that the units of "parts" are used in the following examples, and "mass parts" are used unless otherwise specified.

[0030] Example 1

[0031] (A) 22 parts by mass of side chain hydrogen-containing silicone oil is subjected to a progressive addition reaction with 58 parts of hexadecene to obtain 80 parts of grafted hexadecene side chain hydrogen-containing silicone oil, which is synthesized for standby use. The synthesis operation is a well-known part and does not need to be described in detail.

[0032] (B) 80 parts of grafted hexadecene side chain hydrogen-containing silicone oil, 20 parts of polydimethylsiloxane prepolymer are added to a high-speed mixing stirrer for high-speed stirring at room temperature. The specific parameters can be set as 1000 rpm stirring for 60 seconds, followed by 1200 rpm stirring for 45 seconds, followed by 1500 rpm stirring for 30 seconds, and finally 1800 rpm stirring for 15 seconds.

[0033] (C) After sufficient stirring, chloroplatinic acid-divinyltetramethyldisiloxane complex (0.1 parts) is added.

[0034] (D) Continue stirring at 1000 rpm for 45 seconds, followed by 1200 rpm for 30 seconds, and 1500 rpm for 15 seconds under a vacuum degree of -90.0 kPa at 20℃.

[0035] (E) After heating and curing, test standby

[0036] Example 2

[0037] The operation is basically consistent with that of Example 1, except that the parts of the synthesized material are changed to 70 parts of grafted hexadecene side chain hydrogen-containing silicone oil (19 parts of side chain hydrogen-containing silicone oil, 51 parts of hexadecene) and 30 parts of polydimethylsiloxane prepolymer.

[0038] Example 3

[0039] The operation is basically consistent with that of Example 1, except that the parts of the synthesized material are changed to 60 parts of grafted hexadecene side chain hydrogen-containing silicone oil (16.5 parts of side chain hydrogen-containing silicone oil, 43.5 parts of hexadecene) and 40 parts of polydimethylsiloxane prepolymer.

[0040] Example 4

[0041] The operation is basically consistent with that of Example 1, except that the parts of the synthesized material are changed to 50 parts of grafted hexadecene side chain hydrogen-containing silicone oil (13.5 parts of side chain hydrogen-containing silicone oil, 36.5 parts of hexadecene) and 50 parts of polydimethylsiloxane prepolymer.

[0042] Example 5

[0043] The operation is basically consistent with that of Example 1, except that the parts of synthetic material are changed to 80 parts of grafted hexadecene side chain hydrogen-containing silicone oil (27.7 parts of side chain hydrogen-containing silicone oil, 52.3 parts of hexadecene) and 20 parts of polydimethylsiloxane prepolymer.

[0044] Example 6

[0045] The operation is basically consistent with that of Example 1, except that the parts of synthetic material are changed to 80 parts of grafted hexadecene side chain hydrogen-containing silicone oil (18 parts of side chain hydrogen-containing silicone oil, 62 parts of hexadecene) and 20 parts of polydimethylsiloxane prepolymer.

[0046] Example 7

[0047] The operation is basically consistent with that of Example 1, except that the parts of synthetic material are changed to 50 parts of grafted octadecene side chain hydrogen-containing silicone oil (10 parts of side chain hydrogen-containing silicone oil, 40 parts of octadecene) and 50 parts of polydimethylsiloxane prepolymer.

[0048] Comparative Example 1

[0049] 100 parts of hexadecene

[0050] Comparative Example 2

[0051] 100 parts of octadecene

[0052] Material phase transition enthalpy value and phase transition temperature point test:

[0053] The materials are tested by using differential scanning calorimetry (DSC), and the phase transition temperature point and enthalpy value of the materials are tested. The DSC tester is used to measure Examples 1-4, and the test results of the phase change material enthalpy value and phase change point are as follows: Figure 1 , and the specific test values are shown in the following table:

[0054] Phase transition point (°C) Enthalpy value (J / g) Example 1 26.64 5.42 Example 2 25.82 4.56 Example 3 25.79 3.57 Example 4 25.54 2.72

[0055] The test results show that the phase change point of the material changes with the change of the molecular weight of the phase change material part. In this test, Examples 1-4, because the grafting rate of the side chain hydrogen-containing silicone oil silicone oil and hexadecene is unchanged, and exists in the form of free monomer in the dimethylsiloxane crosslinked network, so the molecular weight of the phase change material is consistent, and the test phase change point does not change; the material enthalpy value and the content of the phase change material (herein, hexadecene) are linearly related.

[0056] The phase transition temperature point and enthalpy value of Examples 1, 5-7, and Comparative Examples 1-2 are tested by using a DSC tester, and the test results are shown in the following table:

[0057] Phase transition point (°C) Enthalpy value (J / g) Example 1 26.64 5.42 Example 5 20.19 4.34 Example 6 31.67 5.82 Example 7 38.9 22.24 Comparative Example 1 5 138.67 Comparative Example 2 18 124.11

[0058] The test results show that the grafting rates of Examples 5 and 6 are different from that of Example 1 (Example 5 is lower than Example 1, and Example 6 is higher than Example 1), which results in different molecular weights of the phase change materials after grafting, the change of the phase change points, and the positive correlation between the phase change points and the molecular weights of the phase change materials. Although the grafting rate of Example 7 is the same as that of Example 1, the molecular weight of octadecene in Example 7 is greater than that of hexadecene in Example 1, so the molecular weight of the phase change material after grafting is greater, and the phase change point is higher. In the comparative examples, the molecular weights of hexadecene and octadecene are the smallest, so the phase change points are very low. The test results also prove that the enthalpy of the material is positively correlated with the content of the phase change material.

[0059] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present application, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A method of modulating the thermal performance of a phase change material, characterized by, The method comprises: The olefin material, the graftable high molecular prepolymer, the crosslinking high molecular prepolymer, and the catalyst are uniformly mixed and stirred to obtain the phase change material; In the method, the olefin material is grafted with the graftable high molecular prepolymer, and then is crosslinked with the crosslinking high molecular prepolymer to form a covalent bond network; Alternatively, the olefin material is grafted with the graftable high molecular prepolymer, and then is dissolved in the crosslinking high molecular prepolymer to form a covalent bond network; The graftable high molecular prepolymer after grafting the olefin material exists in the form of being crosslinked with other high molecular prepolymers or being dissolved in a high molecular crosslinking network or both; The phase change material prepared by the method for regulating the thermal performance of the phase change material has a solid-solid phase change characteristic; The olefin material is a phase change material of hexadecene and / or octadecene; the graftable high molecular prepolymer is a hydrogen-containing silicone oil capable of undergoing an addition reaction with the olefin material; and the crosslinking high molecular prepolymer is a polydimethylsiloxane prepolymer.

2. The method of claim 1, wherein, The ratio of the raw materials in the method is as follows in terms of mass parts: 0.1-99.9 parts of the olefin material, 0.1-99.9 parts of the graftable high molecular prepolymer, 0.1-99.9 parts of the crosslinking high molecular prepolymer, and 0.1-1 part of the catalyst.

3. The method of claim 1, wherein the phase change material is a chalcogenide. The device for the uniform mixing and stirring is a planetary mixer, a kneader, or a high-speed mixing and stirring device.

4. The method of claim 1, wherein the phase change material is a chalcogenide. The catalyst is at least one selected from chloroplatinic acid, chloroplatinic acid-isopropyl alcohol complex, and chloroplatinic acid-divinyltetramethyldisiloxane complex.

5. The phase change material prepared by the method for regulating the thermal performance of the phase change material according to any one of claims 1-4.

6. The phase change material of claim 5, wherein, The phase change temperature of the phase change material can be adjusted in the range of 0-200℃, and the enthalpy value can be adjusted in the range of 0-500 J / g.

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