Preparation method of high-thermal-conductivity core-sheath fiber material

Abstract

The invention discloses a preparation method of a high-thermal-conductivity core-sheath fiber material, and TPU / BN-LMs fiber with a core-sheath structure is prepared by using a coaxial wet spinning technology and taking thermoplastic polyurethane elastomer / boron nitride (TPU / BN) as a sheath layer and liquid metal (LMs) as a core layer. The TPU / BN-LMs composite fiber has good mechanical tensile property, thermal stability, compression resilience and thermal conductivity, and is an ideal high-thermal-conductivity core sheath fiber material. The material solves the problem that the current polymer fiber cannot have both heat conduction and resilience, provides a new research thought for designing and preparing a novel high-heat-conduction and high-resilience polymer fiber material, and can be widely applied to the fields of human body intelligent heat management, intelligent heat control and the like in the future.

Description

Technical Field

[0001] The invention relates to a method for preparing a high thermal conductivity core-sheath fiber material, which can be used for thermal control of battery temperature and belongs to the field of thermal conductive composite materials. Background Art

[0002] Polymer thermal conductive fibers have excellent thermal conductivity and mechanical properties. They are basic materials for the development of the national economy, strategic materials for national defense and military industry, and cutting-edge materials for emerging industries. They have very broad development prospects. However, with the development of society and scientific and technological progress, single-component fibers are increasingly unable to meet people's growing needs, while multi-component fibers can achieve performance integration and optimization. The "lab-on-fiber" concept proposed in recent years pays more attention to the combination of multiple materials, the construction of multi-level structures, and the development of multiple functions, becoming the future development trend of polymer thermal conductive fibers.

[0003] The research group of Professor Cheng Zhengdi of Donghua University prepared a polyethylene oxide / polyacrylic acid (PEO / PAA) hydrogen bond composite fiber with a fiber breaking elongation of up to 1200%. The hydrogen bonds formed between PAA and PEO act as dynamic crosslinking points, giving the fiber elastic recovery. However, the thermal conductivity of the fiber is only 0.4 W m -1 K -1 , and cannot become an ideal polymer thermal conductive fiber material. The research group of Kang Feiyu from Tsinghua University added graphene oxide (GO) to the electrospun polyethylene oxide (PEO) fibers to improve the molecular chain orientation of the electrospun PEO fibers. When the molecular chain orientation was the highest, the thermal conductivity of the PEO electrospun fibers reached 22.9 Wm -1 K -1 Compared with bulk polymers, the thermal conductivity is increased by two orders of magnitude, but the fiber has no resilience. Therefore, it is very innovative and challenging to prepare a polymer fiber composite material with both high thermal conductivity and high resilience. Summary of the invention

[0004] The present invention is based on coaxial wet spinning technology, with thermoplastic polyurethane elastomer / boron nitride (TPU / BN) as the sheath layer and liquid metal (LMs) as the core layer, to prepare thermoplastic polyurethane elastomer / boron nitride-liquid metal (TPU / BN-LMs) fiber with core-sheath structure. TPU / BN-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.

[0005] The technical purpose of the present invention is achieved through the following technical solutions.

[0006] A method for preparing a high thermal conductivity core sheath fiber material is carried out according to the following steps:

[0007] Step 1, Preparation of TPU / BN

[0008] TPU was added to N, N-dimethylformamide (DMF) solvent, and magnetic stirring was performed at 25°C for 2 hours to completely dissolve TPU in DMF to obtain a precursor solution. A certain amount of BN was then dispersed in a mixed solvent containing DMF, ultrasonically treated for 1 hour, and then added to the precursor solution. The mixture was stirred at room temperature for 12 hours to obtain a TPU / BN spinning solution, with the contents of TPU and BN being 18wt% and ~3.0wt%, respectively.

[0009] Step 2, Preparation of TPU / BN-LMs Fibers

[0010] Using the coaxial wet spinning method, TPU / BN spinning solution was injected into the No. I port of the spinneret, and liquid metal (LMs) was injected into the No. II port of the spinneret. The TPU / BN-LMs stream was pressed out from the spinneret hole and entered into the coagulation bath (silicone oil at a temperature of 85°C). When the TPU / BN-LMs stream reached the critical concentration, 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 hour.

[0011] In step 2, the spinning speed was 0.5 cm s -1 The TPU / BN spinning solution flow rate was controlled at 1.0 mL min -1 , while the LMs flow rate is 0.5-1.0 mL min -1 Changes between.

[0012] The present invention uses thermoplastic polyurethane elastomer, boron nitride and liquid metal as raw materials, and utilizes the coaxial wet spinning method to synthesize a TPU / BN-LMs fiber composite material with high thermal conductivity and high resilience, which solves the problem that current polymer fibers cannot have both thermal conductivity and resilience, and provides a new research idea for the design and preparation of new polymer fiber materials with high thermal conductivity and high resilience, which may be widely used in the fields of human intelligent thermal management, intelligent thermal control and so on in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing the preparation mechanism and components of TPU / BN-LMs fibers.

[0014] Figure 2 This is the cross-sectional view of TPU / BN-LMs fiber. DETAILED DESCRIPTION

[0015] 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.

[0016] Example 1

[0017] 1) Preparation of TPU / BN: 18 g of TPU was added into a beaker containing 50 g of DMF, and magnetic stirring was performed at 25°C for 2 h to completely dissolve TPU in DMF to obtain a precursor solution. Then 3 g of BN was dispersed in a mixed solvent of 30 g of DMF, ultrasonically treated for 1 h, and then added to the precursor solution. The mixture was stirred at room temperature for 12 h to obtain a TPU / BN spinning solution.

[0018] 2) Preparation of TPU / BN-LMs fibers: The wet coaxial spinning method was adopted. The No. I port of the spinneret was connected to the needle tube A containing 10 mL of TPU / BN spinning solution, and the No. II port of the spinneret was connected to the needle tube B containing 10 mL of liquid metal (LMs). The needle tubes were squeezed at the same time, and a thin stream of TPU / BN-LMs was pressed out from the spinneret hole into the coagulation bath (silicone oil at a temperature of 85°C) and precipitated to form fibers. The obtained fibers were taken out of the silicone oil and dried at room temperature for 1 hour to obtain TPU / BN-LMs fibers.

[0019] The thermal conductivity was measured by the Hot Disk TPS3500 thermal constant analyzer flat module and was 10.0 W m -1 K -1 , by using XQ-1C electronic universal testing machine, its maximum tensile ratio was measured to be 400% and the maximum stress was 3.9MPa.

[0020] Example 2

[0021] 1) Preparation of TPU / BN: 9 g of TPU was added into a beaker containing 25 g of DMF, and magnetically stirred at 25 °C for 2 h to completely dissolve TPU in DMF to obtain a precursor solution. Then 1.5 g of BN was dispersed in a mixed solvent of 15 g of DMF, ultrasonically treated for 1 h, and then added to the precursor solution. The mixture was stirred at room temperature for 12 h to obtain the TPU / BN spinning solution.

[0022] 2) Preparation of TPU / BN-LMs fibers: The wet coaxial spinning method was adopted. The No. I port of the spinneret was connected to the needle tube A containing 5 ml of TPU / BN spinning solution, and the No. II port of the spinneret was connected to the needle tube B containing 5 mL of liquid metal (LMs). The needle tubes were squeezed at the same time, and a thin stream of TPU / BN-LMs was pressed out from the spinneret hole into a coagulation bath (silicone oil at a temperature of 80°C) and precipitated to form fibers. The obtained fibers were taken out of the silicone oil and dried at room temperature for 1 hour to obtain TPU / BN-LMs fibers.

[0023] The thermal conductivity was measured by the Hot Disk TPS3500 thermal constant analyzer flat module and was 9.8 W m -1 K -1, by using XQ-1C electronic universal testing machine, its maximum tensile ratio was measured to be 390% and the maximum stress was 3.8MPa.

[0024] Example 3

[0025] 1) Preparation of TPU / BN: 13.5 g of TPU was added into a beaker containing 37.5 g of DMF, and magnetically stirred at 25 °C for 2 h to completely dissolve TPU in DMF to obtain a precursor solution. Then 2.25 g of BN was dispersed in a mixed solvent of 22.5 g of DMF, ultrasonically treated for 1 h, and then added to the precursor solution. The mixture was stirred at room temperature for 12 h to obtain the TPU / BN spinning solution.

[0026] 2) Preparation of TPU / BN-LMs fibers: The wet coaxial spinning method was adopted. The No. I port of the spinneret was connected to the needle tube A containing 10 mL of TPU / BN spinning solution, and the No. II port of the spinneret was connected to the needle tube B containing 10 mL of liquid metal (LMs). The needle tubes were squeezed at the same time, and a thin stream of TPU / BN-LMs was pressed out from the spinneret hole into a coagulation bath (silicone oil at a temperature of 83°C) and precipitated to form fibers. The obtained fibers were taken out of the silicone oil and dried at room temperature for 1 hour to obtain TPU / BN-LMs fibers.

[0027] The thermal conductivity was measured by the Hot Disk TPS3500 thermal constant analyzer flat module and was 10.2 W m -1 K -1 , by using XQ-1C electronic universal testing machine, its maximum tensile ratio was measured to be 420% and the maximum stress was 4.0MPa.

[0028] 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 high thermal conductivity core sheath fiber material, characterized in that The preparation steps are as follows: 1) Preparation of TPU / BN: TPU was added to N,N-dimethylformamide (DMF) solvent, and magnetic stirring was performed at 25°C for 2 hours to completely dissolve TPU in DMF to obtain a precursor solution. A certain amount of BN was then dispersed in a mixed solvent containing DMF, ultrasonically treated for 1 hour, and then added to the precursor solution. The mixture was stirred at room temperature for 12 hours to obtain a TPU / BN spinning solution, with the contents of TPU and BN being 18wt% and ~3.0wt%, respectively. 2) Preparation of TPU / BN-LMs fibers: The wet coaxial spinning method was adopted, and TPU / BN spinning solution was injected into the No. I port of the spinneret, and liquid metal (LMs) was injected into the No. II port of the spinneret. The TPU / BN-LMs thin stream was pressed out from the spinneret hole and entered into the coagulation bath (silicone oil at a temperature of 85°C). When the TPU / BN-LMs thin stream reached the critical concentration, 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 hour.

2. The preparation method according to claim 1, characterized in that In step 1), a TPU / BN spinning solution is obtained, wherein the contents of TPU and BN are 18 wt % and 3.0 wt % respectively.

3. The preparation method according to claim 1, characterized in that The spinning speed in step 2) is 0.5 cm s -1 The TPU / BN spinning solution flow rate was controlled at 1.0 mL min -1 , while the LMs flow rate was controlled at 0.5-1.0 mL min -1 between.

4. A high thermal conductivity core-sheath fiber composite material prepared according to the preparation method according to any one of claims 1 to 4.

5. Application of the TPU / BN-LMs high thermal conductivity core-sheath fiber material according to claim 5 in the field of thermal conduction.

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