Phase change heat storage fluffy fiber as well as preparation method and application thereof

Abstract

The invention discloses a phase-change heat-storage fluffy fiber and a preparation method thereof. According to the method, polyethylene glycol, microcapsules, fatty acid, paraffin or alkane and the like are used as phase change heat storage materials, elastic polymers such as polystyrene, polyurethane, polyamide and the like are used as elastic spinning materials, and hydrophobic polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, polyvinylidene fluoride and the like are used as hydrophobic spinning materials; the phase-change heat-storage fluffy fiber is prepared in a high-humidity environment through an electrostatic spinning method. The phase-change heat-storage fluffy fiber synthesized by the method is in a flexible fluffy form and has the advantages of good phase-change stability, low heat conductivity coefficient and the like, and the environmental temperature is kept stable through an accompanying heat absorption or heat release effect when phase change occurs at the phase-change temperature; the material can be used as a thermal insulation filling material and has wide application prospects in human body and environment thermal management and other aspects.

Description

Technical Field

[0001] The present invention relates to a method for preparing a phase change heat storage fluffy fiber. Background Art

[0002] When staying in a cold environment for a long time, the human body is prone to cold ischemic injury and hypothermia due to reduced blood circulation and vasoconstriction, accompanied by persistent discomfort, and some severe cases can lead to death. Using air conditioners to warm the space or wearing warm clothes are common ways to resist bad weather, but the former consumes a large amount of energy, while the latter is more energy-efficient. Since natural fibers are easily available, they have long been the main source of thermal insulation materials. However, these fibers usually have a relatively large fiber diameter, thus having a high thermal conductivity, poor heat preservation, and being very heavy, which will cause certain obstacles to the free movement of the human body. In addition, natural fibers have strong hygroscopicity in a humid environment, resulting in a rapid decline in heat preservation performance, and the materials prepared from these fibers are prone to mildew, thus reducing the service life. Compared with natural fibers, synthetic fibers have better moisture-proof and moth-proof potential. At the same time, synthetic fiber materials have significant advantages in heat preservation performance and light weight due to their smaller diameter. The reason for this phenomenon is that the smaller the fiber diameter, the smaller the pore size, which is beneficial to trapping more static air inside the material, thereby improving the heat preservation of the material. Therefore, reducing the fiber diameter and developing ultra-light and high-performance thermal insulation materials are current challenges.

[0003] Electrospun fibers have the advantages of small diameter, diverse fiber combination structures, controllable spinning processes, and diverse raw material sources. However, there is currently little research on their application in thermal insulation materials. Electrospun fibers are usually directly stacked into films, which greatly limits the heat preservation performance of the fibers. However, compared with natural fibers, the mechanical properties of electrospun fluffy fibers are insufficient, which is the main reason why they have not been widely used.

[0004] Phase change materials (PCMs) are an important part of thermal management materials. At the phase change temperature, the endothermic or exothermic effect accompanied by their phase change can achieve the purpose of maintaining the environmental temperature stable. According to the phase change method, they can be divided into three types: solid-solid, solid-liquid, and solid-gas. Among them, solid-liquid phase change materials have a high phase change enthalpy, small volume change, and stable performance, and are one of the main phase change heat storage methods currently studied. However, the problem of easy leakage greatly affects their application. Electrospinning is a commonly used encapsulation technology for preparing flexible PCMs and has been widely used in the preparation of composite fibers. This method can improve the shape stability of the material during the phase change process and prevent the leakage of liquid PCM.

[0005] By using the electrospinning method to load PCM and prepare a fluffy fiber morphology, PCM can be effectively encapsulated, its phase change stability can be improved, and leakage can be prevented. The fluffy fiber has a low thermal conductivity, which can better inhibit heat conduction. The endothermic and exothermic effects of the composite PCM can increase the heat preservation effect. In the face of extremely cold environments, using fibers with a single function cannot achieve an ideal warming effect, but there is little research on bifunctional fibers that combine fluffy fibers with phase change heat storage materials. Therefore, developing a phase change fluffy fiber is of great significance for human and environmental thermal management. Summary of the Invention

[0006] The purpose of the present invention is to provide a phase change heat storage fluffy fiber to solve the problems raised in the above-mentioned background technology.

[0007] First, elastic spinning polymers such as polypropylene, polyurethane, and polyamide, and hydrophobic spinning polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, and polyvinylidene fluoride are placed in a reaction vessel. The mass ratio of the elastic spinning polymer to the hydrophobic spinning polymer is 1:15 - 2:1. N,N-dimethylformamide is added, and it is heated to 40 - 90 °C and continuously stirred for 6 - 48 hours to completely dissolve the polymer resin. Phase change heat storage materials such as polyethylene glycol, microcapsules, fatty acids, paraffin, or alkanes are placed in the polymer resin solution. The mass ratio of the phase change heat storage material to the spinning polymer is 1:20 - 1:2. It is heated in a water bath to 40 - 90 °C and continuously stirred for 0.5 - 6 hours to uniformly disperse the phase change heat storage material and configure a spinning solution. The spinning solution is injected into a syringe for electrospinning. The electrospinning process conditions include a voltage of 6 - 30 kV, a pushing speed of 0.1 - 8 ml / h, a roller rotation speed of 5 - 30 R, a receiving distance of 8 - 20 cm, an environmental temperature of 20 - 60 °C, and an environmental relative humidity of 15 - 90%. The phase change fluffy fiber is placed in an oven at 40 - 100 °C and dried for 6 - 24 hours to finally obtain a flexible fluffy spun fiber, which is the phase change heat storage fluffy fiber.

[0008] Further, 1 g of elastic spinning polymers such as polypropylene, polyurethane, and polyamide, 0.5 - 15 g of hydrophobic spinning polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, and polyvinylidene fluoride are added with 10 ml of N,N-dimethylformamide, heated in a water bath at 60 °C, and continuously stirred for 10 hours to configure a polymer resin solution.

[0009] Further, 0.075 - 8 g of phase change heat storage materials such as polyethylene glycol, microcapsules, fatty acids, paraffin, or alkanes are placed in the polymer resin solution, heated to 60 °C, and continuously stirred for 4 h.

[0010] Further, the electrospinning voltage is 7 kV, the pushing speed is 3 ml / h, the roller rotation speed is 10 R, the receiving distance is 10 cm, the environmental temperature is 30 °C, and the environmental relative humidity is 80%;

[0011] Further, the product in the above step is dried in an oven at 60°C for 8 h.

[0012] Further, the phase change heat storage fluffy fiber is a white flexible fluffy fiber.

[0013] This method physically blends phase change heat storage materials such as polyethylene glycol, microcapsules, fatty acids, paraffin wax or alkanes with elastic spinning polymers such as polypropylene, polyurethane, polyether ester and hydrophobic spinning polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, and polyvinylidene fluoride, and electrospins into phase change heat storage fluffy fibers in a high humidity environment.

[0014] The phase change heat storage fluffy fibers synthesized by this method are in a flexible and fluffy form, and have the advantages of good phase change stability and low thermal conductivity. By maintaining the environmental temperature stability through the endothermic or exothermic effect accompanying the phase change at the phase change temperature, they can be used as thermal insulation filling materials and have broad application prospects in aspects such as human body and environmental thermal management. Description of the Drawings

[0015] Figure 1 It is the differential scanning calorimetry curve of the phase change heat storage fluffy fiber in Example 1 (using polyurethane as the elastic spinning polymer, polyacrylonitrile as the hydrophobic spinning polymer, microcapsules as the phase change heat storage material, the mass ratio of polyurethane to polyacrylonitrile is 1:1, and the mass ratio of microcapsules to spinning polymer is 2:5).

[0016] Figure 2 It is the display picture of the phase change heat storage fluffy fiber in Example 2 (using polyamide as the elastic spinning polymer, polysulfone as the hydrophobic spinning polymer, polyethylene glycol as the phase change heat storage material, the mass ratio of polyamide to polysulfone is 1:2, and the mass ratio of polyethylene glycol to spinning polymer is 1:5).

[0017] Figure 3 It is the time-temperature curve of the application of the phase change heat storage fluffy fiber in Example 3 to the human body in an outdoor simulation experiment (using polyurethane as the elastic spinning polymer, polytetrafluoroethylene as the hydrophobic spinning polymer, polyethylene glycol as the phase change heat storage material, the mass ratio of polyurethane to polytetrafluoroethylene is 1:3, and the mass ratio of polyethylene glycol to spinning polymer is 1:6). Detailed Description of the Invention

[0018] Example 1.

[0019] (1) Take 1 g of polyurethane (molecular weight of 4000), 1 g of polyacrylonitrile (molecular weight of 100000), 10 ml of N,N-dimethylformamide, and heat in a water bath at 70°C for 8 h to prepare a spinning base liquid.

[0020] (2) Take 0.8 g of microcapsules and place them in the product of step (1). The microcapsules are composed of an alkane with 18 carbon atoms as the core material and sodium alginate as the wall material. The mass ratio of the core material to the wall material is 1:1, and the manufacturer is Hefei Xineng Phase Change New Materials Technology Co., Ltd. Heat it in a water bath to 50 °C and stir evenly for 1 h.

[0021] (3) Inject the product of step (2) into a syringe for spinning. The spinning process conditions include a voltage of 10 kV, a pushing speed of 1.5 ml / h, a roller rotation speed of 10 R, a receiving distance of 10 cm, an ambient temperature of 30 °C, and an ambient relative humidity of 90%.

[0022] (4) After spinning, place the product of step (3) in an oven at 50 °C and dry it for 12 h. Finally, obtain phase change heat storage fluffy fibers with polyurethane as the elastic spinning polymer, polyacrylonitrile as the hydrophobic spinning polymer, microcapsules as the phase change heat storage material, the mass ratio of polyurethane to polyacrylonitrile is 1:1, and the mass ratio of microcapsules to the spinning polymer is 2:5. The fiber diameter is 5 microns.

[0023] The prepared phase change heat storage fluffy fibers are white and fluffy fibers, and the differential scanning calorimetry curve is as Figure 1 shown. The fitted melting temperature is 34 °C and the melting enthalpy is 41 J / g.

[0024] Example 2.

[0025] (1) Take 1 g of polyamide (molecular weight 10000), 2 g of polysulfone (molecular weight 20000), 10 ml of N,N-dimethylformamide, and heat it in a water bath at 60 °C for 10 h to prepare a spinning base liquid.

[0026] (2) Take 0.6 g of polyethylene glycol (molecular weight 800) and place it in the product of (1). Heat it in a water bath to 70 °C and stir evenly for 2 h.

[0027] (3) Inject the product of (2) into a syringe for spinning. The spinning process conditions include a voltage of 15 kV, a pushing speed of 2 ml / h, a roller rotation speed of 20 R, a receiving distance of 15 cm, an ambient temperature of 40 °C, and an ambient relative humidity of 80%.

[0028] (4) After spinning, place the product of (3) in an oven at 60 °C and dry it for 15 h. Finally, obtain phase change heat storage fluffy fibers with polyamide as the elastic spinning polymer, polysulfone as the hydrophobic spinning polymer, polyethylene glycol as the phase change material, the mass ratio of polyamide to polysulfone is 1:2, and the mass ratio of polyethylene glycol to the spinning polymer is 1:5. The fiber diameter is 3 microns.

[0029] The prepared phase change heat storage fluffy fibers are white and fluffy fibers.

[0030] Example 3.

[0031] (1) Take 1 g of polyurethane (molecular weight 4000), 3 g of polytetrafluoroethylene (molecular weight 3000000), and 10 ml of N,N-dimethylformamide, heat in a water bath at 70°C for 9 h to prepare a spinning base solution.

[0032] (2) Take 1.5 g of polyethylene glycol (molecular weight 800) and place it in the product of (1), heat it to 75°C in a water bath, and stir it at a constant speed for 2 h.

[0033] (3) The product of (2) was injected into a needle tube for spinning. The spinning process conditions included voltage of 15 kV, injection speed of 2 ml / h, drum speed of 15R, receiving distance of 15 cm, ambient temperature of 25° C., and ambient relative humidity of 70%.

[0034] (4) After the spinning is completed, the product of (3) is placed in an oven at 60°C and dried for 15 hours, and finally a phase change heat storage fluffy fiber is obtained, wherein the fiber has a diameter of 3 μm and the fiber comprises polyurethane as an elastic spinning polymer, polytetrafluoroethylene as a hydrophobic spinning polymer, and polyethylene glycol as a phase change heat storage material, and the mass ratio of polyurethane to polytetrafluoroethylene is 1:3, and the mass ratio of polyethylene glycol to spinning polymer is 1:6.

[0035] The prepared phase change heat storage fluffy fiber is white fluffy fiber.

[0036] Example 4.

[0037] (1) Take 1 g of polystyrene (molecular weight 90,000), 3 g of polytetrafluoroethylene (molecular weight 3,000,000), and 10 ml of N,N-dimethylformamide, heat in a water bath at 70°C for 9 h to prepare a spinning base solution.

[0038] (2) Take 1.5 g of polyethylene glycol (molecular weight 800) and place it in the product of (1), heat it to 75°C in a water bath, and stir it at a constant speed for 2 h.

[0039] (3) The product of (2) was injected into a needle tube for spinning. The spinning process conditions included a voltage of 20 kV, a push injection rate of 2 ml / h, a drum speed of 30 R, a receiving distance of 15 cm, an ambient temperature of 80° C., and an ambient relative humidity of 30%. The electrospinning failed, and the fiber was in the form of a film with a film thickness of 1 mm.

[0040] Figure 2 This is the display picture of Example 2. The phase-change fluffy fiber prepared in Example 2 is folded into a cylinder with r = 2 cm and h = 6 cm. The cylinder is displayed on a small leaf (the leaf area is about 1*3 cm 2 ), the leaves do not bend. This shows that the phase change fluffy fiber has a high degree of fluffiness and is soft and light.

[0041] Figure 3Time-temperature curve of the outdoor simulation experiment in Example 3. Take the phase change fluffy fiber in Example 3, with a mass of 20 g, and make it into gloves. After wearing the gloves in the indoor environment, go outdoors. The indoor environmental temperature is 24 °C, and the human body temperature is about 35 °C. After wearing the gloves in the indoor environment, the temperature inside the gloves continues to rise and remains stable at 33 °C. During this stage, the phase change fluffy fiber undergoes a phase change to store heat. At 500 s, wear the gloves and place them in the cold outdoor environment. The outdoor temperature is about -10 °C, but the temperature inside the gloves does not drop rapidly and remains stable at 28 °C, indicating that during this stage, the phase change fluffy fiber undergoes a phase change to release heat and continuously provide heat source for the human body. At the same time, the fluffy structure of the fiber is beneficial to trapping more static air inside the material, thereby improving the heat preservation performance of the material.

[0042] The above results show that the phase change fluffy fiber of the present invention can be used as a thermal insulation filling material and has broad application prospects in aspects such as human body and environmental thermal management.

Claims

1. A phase change heat storage fluffy fiber, characterized in that: using one or more of polyethylene glycol, microcapsules, fatty acids, paraffin wax or alkanes as the phase change heat storage material, and one or more of elastomeric polymers such as polystyrene, polyurethane, polyamide, etc. as the elastic spinning material, and one or more of hydrophobic polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, polyvinylidene fluoride, etc. as the hydrophobic spinning material, a phase change heat storage fluffy fiber prepared by electrospinning a mixed material of the phase change heat storage material and the spinning materials (elastic spinning material and hydrophobic spinning material); The mass ratio of the phase change heat storage material to the spinning materials (elastic spinning material and hydrophobic spinning material) is 1:20 - 1:2, preferably (1:10 - 1:2); The mass ratio of the elastic spinning polymer to the hydrophobic spinning polymer is 1:15 - 2:1 (preferably 1:10 - 1:1).

2. The phase change heat storage fluffy fiber according to claim 1, characterized in that, the composition of the microcapsules is using alkanes with carbon numbers (5 - 60), preferably (10 - 19) as the core material, and one or several of polymer materials such as sodium alginate, chitosan, hydroxypropyl cellulose, etc. as the wall material, and the ratio of the core material to the wall material is 1:9 - 9:1, preferably (1:1 - 9:1); the carbon number of the fatty acid is (12 - 36), preferably (28 - 24); the carbon number of the alkane is (5 - 60), preferably (10 - 19); the molecular weight range of polyethylene glycol is (400 - 20000), preferably (600 - 8000); the average molecular weight range of polystyrene is (80000 - 160000), preferably (90000 - 120000); the average molecular weight range of polyurethane is (1000 - 6000), preferably (2000 - 5000); the average molecular weight range of polyamide is (5000 - 100000), preferably (10000 - 50000); the average molecular weight range of polyacrylonitrile is (50000 - 250000), preferably (85000 - 150000); the average molecular weight range of polysulfone is (5000 - 60000), preferably (20000 - 50000); the average molecular weight range of polytetrafluoroethylene is (100000 - 8000000), preferably (3000000 - 6000000); the average molecular weight range of polyvinylidene fluoride is (400000 - 600000), preferably (500000 - 600000).

3. A preparation method of the phase change heat storage fluffy fiber according to claim 1 or 2, characterized in that, it has the following technological steps: 1) Place the elastic spinning material in a reaction vessel, place the hydrophobic spinning material in the same reaction vessel, add N,N - dimethylformamide in a mass ratio of the elastic spinning material to the hydrophobic spinning material of 1:15 - 2:1 (preferably 1:10 - 1:1), heat to 40 - 90 °C (preferably 50 - 80 °C), and continuously stir for 6 - 48 hours (preferably 8 - 48 hours) to completely dissolve the polymer and obtain a polymer solution; 2) Place the phase change heat storage material in the polymer solution. The mass ratio of the phase change heat storage material to the polymer resin is 1:20 - 1:2, preferably (1:10 - 1:2). Heat it in a water bath to 40 - 90 °C (preferably 50 - 80 °C) and continuously stir for 0.5 - 6 hours (preferably 1 - 4 hours) to disperse the phase change heat storage material evenly and prepare a spinning solution. 3) Inject the spinning solution into a syringe for electrospinning. The electrospinning process conditions include a voltage of 6 - 30 kV (preferably 10 - 20 kV), a pushing speed of 0.1 - 8 ml / h (preferably 1 - 3 ml / h), a roller rotation speed of 5 - 30 R (preferably 10 - 20 R), a receiving distance of 8 - 20 cm (preferably 10 - 18 cm), an environmental temperature of 20 - 60 °C (preferably 25 - 45 °C), and an environmental relative humidity of 15 - 90% (preferably 70 - 90%). 4) Remove the fluffy fibers and dry them at 40 - 100 °C (preferably 50 - 70 °C) for 6 - 24 hours (preferably 12 - 18 hours) to finally obtain flexible fluffy spun fibers, which are the phase change heat storage fluffy fibers.

4. The phase change heat storage fluffy fibers described in claim 1 or 2 or the phase change heat storage fluffy fibers obtained by the preparation method of claim 3 can be used as a thermal insulation material or a thermal insulation filling material in human body (such as: clothing or bedding) or environmental thermal management.

5. According to the application described in claim 4, it is characterized in that the phase change heat storage fluffy fibers have the advantages of good phase change stability and low thermal conductivity. They undergo a phase change at the phase change temperature and are accompanied by an endothermic or exothermic effect to maintain the environmental temperature stable, and have broad application prospects in aspects such as human body or environmental thermal management as a thermal insulation filling material.

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