Preparation method of PVDF-HFP-TFE / LMs fiber woven body

Abstract

The invention relates to a preparation method of a PVDF (Polyvinylidene Fluoride)-HFP (Hydroxyfluoropropylene)-TFE (Tetrafluoroethylene) / LMs (Lactic Matrix) fiber woven body, which comprises the following steps: preparation of a PVDF-HFP-TFE solution: dissolving PVDF-HFP-TFE in methyl ethyl ketone (MEK) to prepare a PVDF-HFP-TFE spinning solution; pVDF-HFP-TFE / LMs fibers are prepared, specifically, the PVDF-HFP-TFE / LMs fibers are prepared through a three-axis needle head, deionized water is injected into an outer layer opening of a spinning nozzle, a PVDF-HFP-TFE spinning solution is injected into a middle layer opening of the spinning nozzle, liquid metal is injected into an inner layer opening of the spinning nozzle, PVDF-HFP-TFE / LMs trickles are extruded and then make contact with water flow on the outermost layer, then the trickles enter a coagulating bath, and the PVDF-HFP-TFE / LMs fibers are formed. And preparation of the PVDF-HFP-TFE / LMs fiber woven body.

Description

Technical Field

[0001] The invention relates to a method for preparing a PVDF-HFP-TFE / LMs fiber braided body, which can be used in the field of human body thermal management and belongs to the field of thermal conductive composite materials. Background Art

[0002] Thermally conductive fiber is a special fiber material with excellent thermal conductivity and is widely used in many fields. These fibers are usually made of polymer materials, such as polyimide, polystyrene, etc., and are made to have good thermal conductivity through special processes. First of all, the main feature of thermally conductive fiber is its high thermal conductivity. Due to the material selection and structural design of the fiber itself, thermally conductive fiber can effectively transfer heat and has excellent thermal conductivity. This makes it particularly popular in occasions where efficient heat dissipation or heat conduction is required, such as electronic devices, fiber optic communication equipment and other fields. Secondly, thermally conductive fibers also have good mechanical properties and softness. They can be made into various shapes and sizes according to different needs, such as fibers, films or composite materials, suitable for various complex application environments. At the same time, these fibers usually have good wear resistance and chemical stability, and can operate stably for a long time under harsh conditions.

[0003] In the field of fiber materials, polymer matrices have become an important choice in smart wearable devices due to their excellent flexibility and comfort. However, single polymer materials have limitations in thermal management performance. Therefore, combining these materials with fillers with excellent thermal conductivity has become an effective way to improve thermal management performance.

[0004] With the rapid development of smart technology, wearable devices have gradually been integrated into people's daily lives. These devices can not only monitor health and track sports, but also provide various real-time data feedback. However, in order to improve the user experience and functionality of these devices, the performance of materials is crucial. Among the many material properties, thermal management performance has become one of the key factors for wearable devices. Since wearable devices often come into direct contact with the skin, their thermal management performance directly affects the user's comfort and the effectiveness of the device.

[0005] Therefore, developing a new type of fiber braid to achieve more efficient thermal management and meet the needs of wearable devices by optimizing the material ratio and weaving process is an important direction in current technological research. Summary of the invention

[0006] The present invention is based on coaxial wet spinning technology, with polyvinylidene fluoride-hexafluoropropylene-tetrafluoroethylene (PVDF-HFP-TFE) as the sheath layer and gallium indium liquid metal (EGaIn, melting point of 25°C, abbreviated as LMs) as the core layer, to prepare polyvinylidene fluoride-hexafluoropropylene-tetrafluoroethylene / gallium indium liquid metal (PVDF-HFP-TFE / LMs) fiber with a core-sheath structure. PVDF-HFP-TFE / LMs composite fiber has good mechanical tensile properties, thermal stability, compression resilience and thermal conductivity, and is an ideal high thermal conductivity core-sheath fiber material. The fibers are placed on a woven board and plain woven to obtain a PVDF-HFP-TFE / LMs high thermal conductivity fiber braid. The technical purpose of the present invention is achieved through the following technical scheme.

[0007] A method for preparing a PVDF-HFP-TFE / LMs fiber braid, comprising the following steps:

[0008] Step 1, Preparation of PVDF-HFP-TFE Solution

[0009] The PVDF-HFP-TFE was dissolved in methyl ethyl ketone (MEK) to prepare a PVDF-HFP-TFE spinning solution.

[0010] Step 2, Preparation of PVDF-HFP-TFE / LMs Fibers

[0011] PVDF-HFP-TFE / LMs fibers were prepared using a three-axis needle. Deionized water was injected into the outer layer of the spinneret, the PVDF-HFP-TFE spinning solution obtained in step 1 was injected into the middle layer of the spinneret, and liquid metal (LMs) was injected into the inner layer of the spinneret. After the PVDF-HFP-TFE / LMs stream was extruded, it came into contact with the outermost water flow and then entered the coagulation bath to precipitate fibers to form PVDF-HFP-TFE / LMs fibers.

[0012] Step 3, preparation of PVDF-HFP-TFE / LMs fiber braid

[0013] The prepared PVDF-HFP-TFE / LMs fibers are woven to obtain a PVDF-HFP-TFE / LMs fiber woven body with a mesh structure.

[0014] 1. The method for preparing a fiber braided body according to claim 1, characterized in that in step 1, a PVDF-HFP-TFE solution with a concentration of 300-400 mg / ml is prepared.

[0015] 2 . The method for preparing a fiber braided body according to claim 1 , characterized in that in step 1, a PVDF-HFP-TFE solution with a concentration of 360 mg / ml is prepared.

[0016] 3. The method for preparing a fiber braid according to claim 1, characterized in that in step 2, the overall spinning speed is 0.8-1.2 cm s -1 The flow rate of the outermost deionized water is controlled at 1.6-2.4 ml min -1 The flow rate of the middle layer PVDF-HFP-TFE spinning solution is controlled at 1.6-2.4ml min -1 , while the LMs flow rate is controlled at 1.0~2.0ml min -1 between.

[0017] 4. The method for preparing a fiber braid according to claim 1, characterized in that in step 2, a coagulation bath is carried out in water, and the PVDF-HFP-TFE / LMs fiber is formed by drying.

[0018] 5 . The method for preparing a fiber braid according to claim 1 , characterized in that in step 2, a coagulation bath is performed in silicone oil to form PVDF-HFP-TFE / LMs fibers.

[0019] 6 . The method for preparing a fiber braided body according to claim 1 , wherein the liquid metal (LMs) is gallium-indium liquid metal (LMs).

[0020] The present invention weaves high thermal conductivity and high resilience PVDF-HFP-TFE / LMs fibers to obtain a PVDF-HFP-TFE / LMs fiber braid with a mesh structure, and its thermal conductivity along the plane direction is 9.0 Wm -1 K -1 , while the thermal conductivity in the direction perpendicular to the braid is 6.0 W m -1 K -1 It has good flexibility and can fit human skin well. It is expected to be used in fields such as human thermal management. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the tensile stress-strain curve of pure PVDF-HFP-TFE fiber.

[0022] Figure 2 Scanning electron microscopy and corresponding element mapping of PVDF-HFP-TFE / LMs fiber.

[0023] Figure 3 400MHz for PVDF-HFP-TFE 1HNMR spectrum. DETAILED DESCRIPTION

[0024] Three embodiments of the present invention are provided below to further illustrate the present invention, but not to limit the scope of the present invention.

[0025] Example 1

[0026] 1) Preparation of PVDF-HFP-TFE solution: 3.6 g PVDF-HFP-TFE was dissolved in 10 ml MEK and stirred at 70° C. for 3 h to prepare a PVDF-HFP-TFE solution with a concentration of 360 mg / ml.

[0027] 2) Preparation of PVDF-HFP-TFE / LMs fibers: Since solvent replacement can occur quickly between MEK and water, a coaxial wet spinning method was used with a three-axis needle (three layers, inner, middle and outer) to prepare PVDF-HFP-TFE / LMs fibers. This embodiment adopts a coaxial wet spinning method, the outer port of the spinneret is connected to a needle tube A containing 10 ml of deionized water, the middle port of the spinneret is connected to a needle tube B containing 10 ml of PVDF-HFP-TFE spinning stock solution, and the inner port of the spinneret is connected to a needle tube C containing 10 ml of gallium-indium liquid metal (LMs, mass ratio: Ga mass fraction is 75%, In mass fraction is 25%). The needle tubes are squeezed at the same time, and the PVDF-HFP-TFE / LMs thin stream is squeezed out and quickly contacts with the outermost water flow, and then enters a coagulation bath (water at a temperature of 25°C), where it precipitates in the water to form fibers. The obtained fibers are taken out of the water and dried at room temperature for 1.5 hours to obtain PVDF-HFP-TFE / LMs fibers.

[0028] 3) Preparation of PVDF-HFP-TFE / LMs fiber braid: The prepared single PVDF-HFP-TFE / LMs fiber was braided using a braiding machine to obtain a PVDF-HFP-TFE / LMs fiber braid with a mesh structure.

[0029] The thermal conductivity along the plane direction was measured by DRL-2A thermal conductivity tester and was 9.1 W m -1 K -1 , while the thermal conductivity in the direction perpendicular to the braid is 5.9 W m -1 K -1 .

[0030] Example 2

[0031] 1) Preparation of PVDF-HFP-TFE solution: 7.2 g of PVDF-HFP-TFE was dissolved in 20 ml of DMF and stirred at 70° C. for 3 h to prepare a PVDF-HFP-TFE solution with a concentration of 360 mg / ml.

[0032] 2) Preparation of PVDF-HFP-TFE / LMs fibers: A coaxial wet spinning method was used, with the outer opening of the spinneret connected to a needle tube A containing 5 ml of deionized water, the middle opening of the spinneret connected to a needle tube B containing 5 ml of PVDF-HFP-TFE spinning solution, and the inner opening of the spinneret connected to a needle tube C containing 5 ml of gallium-indium liquid metal (LMs). The needle tubes were squeezed at the same time, and the PVDF-HFP-TFE / LMs thin stream was squeezed out and quickly contacted with the outermost water flow, and then entered a coagulation bath (water at a temperature of 25°C), where it precipitated in the water to form fibers. The obtained fibers were taken out of the water and dried at room temperature for 1.5 h to obtain PVDF-HFP-TFE / LMs fibers.

[0033] 3) Preparation of PVDF-HFP-TFE / LMs fiber braid: The prepared single PVDF-HFP-TFE / LMs fiber was braided using a braiding machine to obtain a PVDF-HFP-TFE / LMs fiber braid with a mesh structure.

[0034] Compared with Example 1, the only difference is that the solvent used to dissolve PVDF-HFP-TFE in step 1) is DMF. The test result of Example 2 is that its thermal conductivity along the plane direction is 9.2 W m -1 K -1 , while the thermal conductivity perpendicular to the braid is 6.1 W m -1 K -1 .

[0035] Example 3

[0036] 1) Preparation of PVDF-HFP-TFE solution: 3.6 g PVDF-HFP-TFE was dissolved in 10 ml MEK and stirred at 70° C. for 3 h to prepare a PVDF-HFP-TFE solution with a concentration of 360 mg / ml.

[0037] 2) Preparation of PVDF-HFP-TFE / LMs fibers: A coaxial wet spinning method was used, with the outer opening of the spinneret connected to a needle tube A containing 2 ml of deionized water, the middle opening of the spinneret connected to a needle tube B containing 2 ml of PVDF-HFP-TFE spinning stock solution, and the inner opening of the spinneret connected to a needle tube C containing 2 ml of gallium-indium liquid metal (LMs). The needle tubes were squeezed at the same time, and the PVDF-HFP-TFE / LMs thin stream was squeezed out and quickly contacted with the outermost water stream, and then entered a coagulation bath (silicone oil at a temperature of 85°C), where it precipitated in the silicone oil to form fibers. The obtained fibers were taken out of the silicone oil and dried at room temperature for 1.5 h to obtain PVDF-HFP-TFE / LMs fibers.

[0038] 3) Preparation of PVDF-HFP-TFE / LMs fiber braid: The prepared single PVDF-HFP-TFE / LMs fiber was braided using a braiding machine to obtain a PVDF-HFP-TFE / LMs fiber braid with a mesh structure.

[0039] Compared with Example 1, the only difference is that the coagulation bath used to prepare the fiber in step 2) is silicone oil at a temperature of 85°C. The test results of Example 3 show that its thermal conductivity along the plane direction is 8.9 W m -1 K -1 , while the thermal conductivity in the direction perpendicular to the braid is 8.7 W m -1 K -1 .

[0040] The liquid metal selected in each embodiment of the present invention is gallium-indium liquid metal. In specific practice, other liquid metals may also be selected, and the temperature of the coagulation bath may be adaptively adjusted.

[0041] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A method for preparing a PVDF-HFP-TFE / LMs fiber braid, comprising the following steps: Step 1, Preparation of PVDF-HFP-TFE Solution Dissolving PVDF-HFP-TFE in methyl ethyl ketone (MEK) to prepare a PVDF-HFP-TFE spinning solution; Step 2, Preparation of PVDF-HFP-TFE / LMs Fibers PVDF-HFP-TFE / LMs fibers are prepared using a three-axis needle, deionized water is injected into the outer layer of the spinneret, the PVDF-HFP-TFE spinning solution obtained in step 1 is injected into the middle layer of the spinneret, and liquid metal (LMs) is injected into the inner layer of the spinneret. After the PVDF-HFP-TFE / LMs thin stream is extruded, it contacts with the outermost water stream and then enters a coagulation bath to precipitate fibers to form PVDF-HFP-TFE / LMs fibers; Step 3, preparation of PVDF-HFP-TFE / LMs fiber braid The prepared PVDF-HFP-TFE / LMs fibers are woven to obtain a PVDF-HFP-TFE / LMs fiber woven body with a mesh structure.

2. The method for preparing a fiber braid according to claim 1, It is characterized in that In step 1, a PVDF-HFP-TFE solution with a concentration of 300-400 mg / ml is prepared.

3. The method for preparing a fiber braid according to claim 1, It is characterized in that In step 1, a PVDF-HFP-TFE solution with a concentration of 360 mg / ml is prepared.

4. The method for preparing a fiber braid according to claim 1, It is characterized in that In step 2, the overall spinning speed is 0.8-1.2 cm s -1 The flow rate of the outermost deionized water is controlled at 1.6-2.4 ml min -1 The flow rate of the middle layer PVDF-HFP-TFE spinning solution is controlled at 1.6-2.4ml min -1 , while the LMs flow rate is controlled at 1.0~2.0ml min -1 between.

5. The method for preparing a fiber braid according to claim 1, It is characterized in that In step 2, a coagulation bath is performed in water, and PVDF-HFP-TFE / LMs fibers are formed after drying.

6. The method for preparing a fiber braid according to claim 1, It is characterized in that In step 2, a coagulation bath is performed in silicone oil to form PVDF-HFP-TFE / LMs fibers.

7. The method for preparing a fiber braid according to claim 1, It is characterized in that The liquid metal (LMs) is gallium-indium liquid metal (LMs).

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