Composite phase change material based on polyethylene glycol polymer and preparation method thereof

Abstract

The invention relates to the technical field of organic phase change materials, and discloses a composite phase change material based on polyethylene glycol and a preparation method thereof. According to the composite phase change material, polyethylene glycol is used as a phase change matrix, the polyethylene glycol and itaconic anhydride are subjected to a ring-opening reaction to form a prepolymer, then a catalyst dibenzoyl peroxide is added, double bonds are initiated under the heating condition for a cross-linking curing reaction, and the solid-solid composite phase change material of a three-dimensional cross-linked network structure is constructed and formed. The formed cross-linked network can perform effective solid state confinement on the polyethylene glycol phase change component, so that the material form is kept stable in the phase change process, and the leakage problem of the phase change material is avoided. The composite phase-change material prepared by the invention has higher latent heat storage capacity, stable phase-change temperature interval and good thermal cycle durability, has excellent form retention performance, and can be widely applied to the fields of heat energy storage systems, energy conservation and temperature regulation of building envelope structures, thermal management of electronic devices, temperature control packaging and the like.

Description

Technical Field

[0001] This invention relates to the field of organic phase change materials technology, and in particular to a polyethylene glycol polymer composite phase change material and its preparation method. Background Technology

[0002] Phase change materials (PCMs) are functional materials capable of absorbing or releasing large amounts of latent heat through phase changes within a specific temperature range. They possess advantages such as high energy storage density, adjustable phase change temperature, and high energy utilization efficiency, and are widely used in building energy conservation, solar energy utilization, thermal management of electronic devices, temperature-controlled packaging, and industrial waste heat recovery. Among them, organic PCMs have attracted widespread attention due to their good chemical stability, high phase change enthalpy, non-corrosiveness, and strong reversibility of the phase change process. Polyethylene glycol (PEG), as a typical organic PCM, has advantages such as moderate phase change temperature, high latent heat, low price, wide availability, and environmental friendliness, making it one of the most researched PCM energy storage materials. However, PEG is prone to melt flow during the phase change process, leading to material leakage, which severely limits its application in practical engineering. To address this issue, existing technologies typically employ methods such as porous carrier adsorption, coating, or composite modification to stabilize the morphology of polyethylene glycol (PEG). For example, porous materials like silica gel, expanded graphite, and carbon materials are used for physical adsorption and fixation of PEG, or microencapsulation is used to encapsulate it within a polymer shell to improve stability. However, these methods often suffer from drawbacks such as limited adsorption capacity, reduced phase change enthalpy, complex preparation processes, high costs, and insufficient stability during long-term thermal cycling. Furthermore, some morphologically stable phase change materials utilize cross-linking to construct a three-dimensional network structure to restrict PEG chain movement, but this may still result in low cross-linking efficiency, harsh reaction conditions, or insufficient cycle durability. Therefore, developing a PEG-based composite phase change material with a simple preparation process, low cost, effective leakage suppression, and both high phase change enthalpy and good thermal cycling stability is of significant research and application value.

[0003] The purpose of this invention is to provide a composite phase change material based on polyethylene glycol and its preparation method. By chemically modifying the polyethylene glycol molecular chain and constructing a stable three-dimensional cross-linked network structure, the phase change components of polyethylene glycol are effectively confined and fixed, allowing the material to remain solid during the phase change process. This improves the thermal stability and thermal cycling stability of the material while maintaining a high phase change enthalpy, thus solving the problems of leakage and insufficient cycle life of existing polyethylene glycol phase change materials during use. Summary of the Invention

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solutions.

[0005] This invention provides a method for preparing a polyethylene glycol polymer composite phase change material, comprising the following steps: (1) Polyethylene glycol, itaconic anhydride and catalyst are melt-mixed under oil bath conditions to form a homogeneous reaction system A; (2) The reaction system A obtained in step (1) is heated to cause itaconic anhydride to undergo a ring-opening reaction with the hydroxyl groups at the ends of the polyethylene glycol molecular chain, thereby obtaining prepolymer B; (3) The prepolymer B obtained in step (2) is mixed with the thermally conductive agent under oil bath conditions to form a homogeneous reaction system C; (4) The reaction system C obtained in step (3) is mixed with the catalyst under oil bath conditions to form a homogeneous reaction system D; (5) Transfer the reaction system D obtained in step (4) to an oven for curing reaction to obtain the polyethylene glycol polymer composite phase change material.

[0006] Preferably, the polyethylene glycol in step (1) includes polyethylene glycol 1500, polyethylene glycol 2000, polyethylene glycol 4000, and polyethylene glycol 6000.

[0007] Preferably, the catalyst in step (1) is p-toluenesulfonic acid.

[0008] Preferably, the molar ratio of polyethylene glycol to itaconic anhydride in step (1) is 1:(1.2 ~ 2).

[0009] Preferably, in step (1), the oil bath temperature is 80 ~ 90 ℃, the stirring speed is 300 ~ 600 r / min, and the stirring time is 30 ~ 40 min.

[0010] Preferably, the ring-opening reaction temperature of the acid anhydride in step (2) is 120 ~ 140 ℃, and the stirring time is 2 ~ 4 h.

[0011] Preferably, the catalyst in step (4) includes a free radical polymerization initiator.

[0012] Preferably, the free radical polymerization initiator is benzoyl peroxide.

[0013] Preferably, in step (4), the mass of the catalyst benzoyl peroxide is 1% of the mass of polyethylene glycol.

[0014] Preferably, in step (4), the oil bath temperature is 80 ~ 90 ℃, the stirring speed is 300 ~ 600 r / min, and the stirring time is 20 ~ 30 min.

[0015] Preferably, the thermal conductive agent in step (3) is expanded graphite.

[0016] Preferably, in step (3), the oil bath temperature is 80 ~ 90 ℃, the stirring speed is 300 ~ 600 r / min, and the stirring time is 30 ~ 50 min.

[0017] Preferably, the curing reaction temperature in step (5) is 120 ~ 150 ℃ and the curing time is 0.5 ~ 3 h.

[0018] The present invention provides the preparation method described in the above technical solution and the polyethylene glycol polymer composite phase change material obtained therefrom.

[0019] This invention provides a method for preparing a polyethylene glycol polymer composite phase change material, comprising the following steps: (1) melting and mixing polyethylene glycol, itaconic anhydride, and a catalyst in an oil bath to form a uniform reaction system A; (2) subjecting the reaction system A obtained in step (1) to an anhydride ring-opening reaction to obtain a prepolymer B; (3) mixing the prepolymer B obtained in step (2) with a thermally conductive agent in an oil bath to form a uniform reaction system C; (4) mixing the reaction system C obtained in step (3) with a free radical polymerization initiator in an oil bath to form a uniform reaction system D; (5) transferring the reaction system D obtained in step (4) to an oven for curing reaction to obtain the polyethylene glycol polymer composite phase change material. This invention introduces reactive functional groups into the polyethylene glycol molecular chain by causing itaconic anhydride to undergo a ring-opening reaction with polyethylene glycol, thereby providing stable and controllable reaction sites for subsequent crosslinking reactions; further, through the initiation reaction of a free radical polymerization initiator, a continuous three-dimensional crosslinked network structure is constructed. The resulting cross-linked network effectively confines and fixes the polyethylene glycol (PEG) phase change segments, ensuring the energy storage capacity of PEG during crystallization / melting phase change while effectively suppressing its flow behavior during the phase change process. This significantly improves the material's shape stability and leak resistance. Simultaneously, this three-dimensional cross-linked network structure effectively disperses and buffers the internal stress generated by volume changes during the phase change, significantly reducing structural damage and phase change enthalpy decay during thermal cycling. Consequently, the resulting composite phase change material maintains a stable network framework and a complete energy storage system even under long-term repeated phase change conditions, continuously maintaining a stable phase change temperature plateau and heat storage / release performance, exhibiting excellent thermal cycling stability and operational safety. Attached Figure Description

[0020] Figure 1 shows a DSC image of the polyethylene glycol polymer composite phase change material obtained in Example 1.

[0021] Figure 2 is a chemical structure diagram of the polyethylene glycol polymer composite phase change material and raw materials provided by the present invention. Detailed Implementation

[0022] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0023] Example 1.

[0024] A method for preparing a polyethylene glycol polymer composite phase change material, the specific steps of which are as follows.

[0025] Step 1: According to the molar ratio of raw materials: polyethylene glycol: itaconic anhydride = 1: 2, weigh 20 g of polyethylene glycol 2000, 2.24 g of itaconic anhydride and 0.2 g of p-toluenesulfonic acid and place them in an oil bath at 90 ℃ and mix them. Stir at 400 rpm until the solution is uniform for 30 min to form a uniform reaction system A.

[0026] Step 2: Adjust the oil bath temperature to 130 ℃, the stirring speed to 300 rpm, and the reaction time to 3 h to obtain prepolymer B.

[0027] Step 3: Adjust the oil bath temperature to 100 ℃, add 0.2 g of benzoyl peroxide to prepolymer B, stir at 400 rpm until the solution is uniform, and stir for 30 min to form a uniform reaction system C.

[0028] Step 4: Transfer the reaction system C to an oven at 130 °C for 60 min for reaction curing. Once the reaction curing is complete, the polyethylene glycol polymer composite phase change material can be obtained.

[0029] Example 2.

[0030] Polyethylene glycol polymer composite phase change materials were prepared according to the method in Example 1, except that polyethylene glycol 1500 was used.

[0031] Example 3.

[0032] Polyethylene glycol polymer composite phase change materials were prepared according to the method in Example 1, except that polyethylene glycol 4000 was used.

[0033] Example 4.

[0034] Polyethylene glycol polymer composite phase change materials were prepared according to the method in Example 1, except that polyethylene glycol 6000 was used.

[0035] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A polyethylene glycol polymer composite phase change material and its preparation method, characterized in that... It includes the following steps: Step 1: Polyethylene glycol, itaconic anhydride and catalyst are melt-mixed under oil bath conditions to form a homogeneous reaction system A; Step 2: Under anhydrous and oxygen-free conditions, the reaction system A is subjected to an anhydride ring-opening reaction to obtain prepolymer B; Step 3: The prepolymer B from Step 2 is melt-mixed with the thermally conductive agent under oil bath conditions to form a homogeneous reaction system C; Step 4: Mix the reaction system C obtained in step 3 with the free radical polymerization initiator under oil bath conditions to form a homogeneous reaction system D; Step 5: Transfer the reaction system D obtained in step 4 to an oven for curing reaction to obtain the polyethylene glycol polymer composite phase change material.

2. The preparation method according to claim 1, characterized in that... In step 1, the polyethylene glycol includes polyethylene glycol 1500, polyethylene glycol 2000, polyethylene glycol 4000, and polyethylene glycol 6000.

3. The preparation method according to claim 1, characterized in that... The catalyst in step 1 includes p-toluenesulfonic acid.

4. The preparation method according to claim 1, characterized in that... In step 1, the molar ratio of polyethylene glycol to itaconic anhydride is 1:(1.2 ~ 2).

5. The preparation method according to claim 1, characterized in that... The amount of catalyst used is 1% of the mass of polyethylene glycol, based on the mass percentage.

6. The preparation method according to claim 1, characterized in that... In step 1, the oil bath temperature is 80-90℃, the stirring speed is 300-600 r / min, and the stirring time is 20-40 min.

7. The preparation method according to claim 1, characterized in that... In step 2, the ring-opening reaction of the acid anhydride is carried out at a temperature of 120-140 °C and a stirring time of 2-4 h.

8. The preparation method according to claim 1, characterized in that... The catalyst mentioned in step 3 is a free radical polymerization initiator, preferably benzoyl peroxide, and its addition amount is 1% of the mass of polyethylene glycol.

9. A composite phase change material, characterized in that... The composite phase change material is prepared by the preparation method according to any one of claims 1 to 8.

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