阅读说明：本技术 一种复合纤维及其制备方法和电子元件 (Composite fiber, preparation method thereof and electronic component ) 是由 祝渊 曾少博 吕尤 杨景西 蒋文龙 于 2021-06-23 设计创作，主要内容包括：本发明公开了一种复合纤维及其制备方法和电子元件,该复合纤维的制备方法包括将可生物降解水溶性聚合物、导热填料与溶剂混合配置纺丝液,再采用纺丝液进行纺丝,制备初生复合纤维；其中,在进行纺丝之前对纺丝液进行分子链解缠结处理；和/或,在进行纺丝之后,对初生复合纤维进行拉伸处理。通过以上方式,在高分子基体中添加导热填料以在其中构构筑导热通道,以及对纺丝液进行分子链解缠结处理提高分子结晶度和取向度,和/或对初生复合纤维进行拉伸处理以优化导热填料在高分子纤维基体中的取、排列,使得所制得的复合纤维具有高导热率。(The invention discloses a composite fiber, a preparation method thereof and an electronic element, wherein the preparation method of the composite fiber comprises the steps of mixing a biodegradable water-soluble polymer, a heat-conducting filler and a solvent to prepare a spinning solution, and spinning by adopting the spinning solution to prepare a nascent composite fiber; wherein, before spinning, molecular chain disentanglement treatment is carried out on the spinning solution; and/or, after spinning, drawing the as-spun composite fiber. Through the mode, the heat-conducting filler is added into the high-molecular matrix to construct a heat-conducting channel, molecular chain disentangling treatment is carried out on the spinning solution to improve the molecular crystallinity and the orientation degree, and/or stretching treatment is carried out on the nascent composite fiber to optimize the taking and arrangement of the heat-conducting filler in the high-molecular fiber matrix, so that the prepared composite fiber has high heat conductivity.)

1. A preparation method of composite fiber is characterized by comprising the following steps:

s1, mixing a biodegradable water-soluble polymer, a heat-conducting filler and a solvent to prepare a spinning solution;

s2, spinning by adopting the spinning solution to prepare nascent composite fibers;

wherein, before spinning, the spinning solution is subjected to molecular chain disentanglement treatment; and/or, after spinning, drawing the as-spun composite fiber.

2. The method for producing a conjugate fiber according to claim 1, wherein the molecular chain disentangling treatment is at least one selected from the group consisting of ultrasonic treatment, shaking, shearing, stirring, extrusion, centrifugation, deaeration, and addition of boric acid; and/or the stretching treatment is at least one selected from spinneret stretching, wet stretching, normal-temperature air stretching and hot stretching.

3. The method for preparing a composite fiber according to claim 1, wherein the step S1 specifically includes: dispersing a heat-conducting filler in a solvent to obtain a first dispersion liquid; and then dispersing and dissolving the biodegradable water-soluble polymer in the first dispersion liquid to prepare the spinning solution.

4. The method for preparing a conjugate fiber according to claim 3, further comprising, before dispersing and dissolving a biodegradable water-soluble polymer in the first dispersion liquid, removing impurities from the biodegradable water-soluble polymer; preferably, the impurity removal treatment comprises water washing and drying; further preferably, ultrasonic and/or vibration is used to assist the water washing during the water washing.

5. The method of producing a composite fiber according to claim 3, wherein in step S1, the thermally conductive filler is dispersed in a solvent by an auxiliary dispersion treatment; the auxiliary dispersion treatment comprises at least one of adding a heat-conducting filler modified dispersing agent, ultrasonic treatment, oscillation treatment, grinding treatment and centrifugal treatment; preferably, the thermally conductive filler-modifying dispersant is selected from anionic surfactants and/or nonionic surfactants.

6. The method for preparing the composite fiber according to claim 1, further comprising at least one of extraction and water washing treatment after the spinning and before the drawing treatment; and/or, further comprising heat setting after the stretching treatment; preferably, after the heat setting, oiling and drying treatment are also included.

7. The method for preparing a composite fiber according to claim 1, wherein in step S2, the spinning is wet spinning or dry-wet spinning; preferably, the coagulation bath used in the spinning process comprises at least one of saturated aqueous sodium sulfate solution, methanol, ethanol.

8. The method for producing a composite fiber according to any one of claims 1 to 7, wherein in step S1, the biodegradable water-soluble polymer is at least one selected from polyvinyl alcohol and polylactic acid; and/or the heat conducting filler is a carbon material; preferably, the carbon material is selected from at least one of carbon nanotubes, carbon fibers, graphite flakes, graphene oxide;

further preferably, in step S1, the mass ratio of the heat conductive filler to the biodegradable water-soluble polymer in the spinning solution is (0.1-30): 100.

9. a composite fiber produced by the method for producing a composite fiber according to any one of claims 1 to 8.

10. An electronic component characterized by being produced from the composite fiber according to claim 9.

Technical Field

The invention relates to the technical field of heat-conducting high polymer materials, in particular to a composite fiber, a preparation method thereof and an electronic element.

Background

With the rapid development of the microelectronic industry, the integration level of electronic components is increased, the heat flux density of a circuit board is continuously improved, and the requirements of various fields in the electronic industry on materials capable of realizing effective heat conduction and heat dissipation are continuously upgraded. The existing heat conducting and radiating materials cannot keep up with the development steps of the electronic industry, and the effective heat management of electronic components becomes a research hotspot. The traditional metal-based, ceramic-based and carbon-based heat conduction materials have the defects of poor corrosion resistance, poor insulation performance, poor impact resistance, poor mechanical property and the like, which limit the further application of the materials in the electronic industry, so that new heat conduction materials with small volume, light weight, strong deformability, good corrosion resistance, good insulation performance and good heat conduction performance are urgently needed to be found.

The polymer-based fiber is expected to become a novel thermal management material suitable for the electronic industry due to the characteristics of light weight, acid and alkali resistance, easy production, good insulating property, excellent mechanical property and the like. However, the intrinsic thermal conductivity of the existing polymer fibers is generally low, which limits further application thereof in the field of electronic thermal management. Therefore, how to improve the thermal conductivity of the polymer fiber and meet the requirements of the polymer fiber in practical application becomes a problem to be solved urgently.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a composite fiber, a preparation method thereof and an electronic component.

In a first aspect of the present invention, a method for preparing a composite fiber is provided, which comprises the following steps:

s1, mixing a biodegradable water-soluble polymer, a heat-conducting filler and a solvent to prepare a spinning solution;

s2, spinning by adopting the spinning solution to prepare nascent composite fibers;

wherein, before spinning, the spinning solution is subjected to molecular chain disentanglement treatment; and/or, after spinning, drawing the as-spun composite fiber.

According to the preparation method of the composite fiber, at least the following beneficial effects are achieved: the preparation method adopts biodegradable water-soluble polymer as a high molecular matrix, adds heat-conducting filler, prepares nascent composite fiber through spinning, and constructs a heat-conducting channel in the high molecular matrix through the addition of the heat-conducting filler, thereby improving the heat conductivity of the composite fiber. In addition, the thermal conductivity of the conjugate fiber can be further improved by subjecting the spinning solution to a molecular chain disentanglement treatment and/or a drawing treatment of the as-spun conjugate fiber. The method has the advantages that the crystallinity and the orientation degree of a high molecular chain can be regulated and controlled by carrying out molecular chain disentangling treatment on the spinning solution, so that the molecular entanglement degree of the high molecular chain is low, the high crystallinity is realized, the defects and the interfaces in the high molecules are reduced, the phonon scattering is further reduced, the phonon transmission efficiency is improved, and the heat conductivity of the composite fiber can be improved; the orientation and arrangement of the heat-conducting filler in the polymer fiber matrix can be optimized by stretching the nascent composite fiber, the heat-conducting filler in the polymer fiber matrix is uniformly dispersed and is continuously or sectionally arranged and oriented along the axial direction of the fiber, and the polymer matrix and the heat-conducting filler are high in synergetic orientation, so that the heat conductivity of the composite fiber can be improved. Therefore, the composite fiber with high thermal conductivity can be prepared by adopting the preparation method of the composite fiber.

In some embodiments of the present invention, the molecular chain disentangling treatment is at least one selected from the group consisting of sonication, shaking, shearing, stirring, extrusion, centrifugation, debubbling, addition of boric acid; and/or the stretching treatment is at least one selected from spinneret stretching, wet stretching, normal-temperature air stretching and hot stretching. Due to the fact that the thermal conductivity of the final product fiber can be improved through proper stretching, a heat conduction channel constructed by the heat conduction filler can be broken through excessive stretching, and the thermal conductivity of the final product fiber is reduced, the proper stretching multiple needs to be controlled in the stretching treatment process, and the stretching multiple is generally controlled to be 2-9 times.

In some embodiments of the present invention, step S1 specifically includes: dispersing a heat-conducting filler in a solvent to obtain a first dispersion liquid; and then dispersing and dissolving the biodegradable water-soluble polymer in the first dispersion liquid to prepare the spinning solution.

In some embodiments of the present invention, before dispersing and dissolving the biodegradable water-soluble polymer in the first dispersion, the method further comprises removing impurities from the biodegradable water-soluble polymer; preferably, the impurity removal treatment comprises water washing and drying; further preferably, ultrasonic and/or vibration is used to assist the water washing during the water washing.

In some embodiments of the present invention, in step S1, the thermally conductive filler is dispersed in the solvent by means of an auxiliary dispersion process; the auxiliary dispersion treatment comprises at least one of adding a heat-conducting filler modified dispersing agent, ultrasonic treatment, oscillation treatment, grinding treatment and centrifugal treatment. The heat-conducting filler modified dispersant can adopt anionic surfactant and/or nonionic surfactant, wherein the anionic surfactant can specifically adopt Sodium Dodecyl Sulfate (SDS), sodium dodecyl benzene sulfonate (NaDDBS) and the like, and the nonionic surfactant can adopt at least one of polyethylene glycol octyl phenyl ether (Triton X-100), TNWDIS, TNADIS, TNEDIS and TNKDIS. The mass ratio of the heat-conducting filler modified dispersant to the heat-conducting filler is generally controlled to be (0.1-300): 100.

in some embodiments of the invention, at least one of extraction and water washing treatment is further included after the spinning and before the stretching treatment; and/or, further comprising heat setting after the stretching treatment; preferably, after the heat setting, oiling and drying treatment are also included.

In some embodiments of the present invention, in step S2, the spinning is wet spinning or dry-wet spinning; preferably, the coagulation bath used in the spinning process comprises at least one of saturated aqueous sodium sulfate solution, methanol, ethanol.

In some embodiments of the present invention, in step S1, the biodegradable water-soluble polymer is selected from at least one of polyvinyl alcohol, polylactic acid; and/or the heat conducting filler is a carbon material; preferably, the carbon material is selected from at least one of carbon nanotubes, carbon fibers, graphite flakes, graphene oxide; further preferably, in step S1, the mass ratio of the heat conductive filler to the biodegradable water-soluble polymer in the spinning solution is (0.1-30): 100.

in addition, in step S1, the solvent may be at least one selected from water, dimethyl sulfoxide, and ethylene glycol.

In a second aspect of the present invention, a composite fiber is provided, which is prepared by any one of the methods for preparing the composite fiber provided by the first aspect of the present invention.

The composite fiber can be applied to the preparation of electronic components (such as chips and the like) on electronic products such as mobile phones, computers and the like, so that the third aspect of the invention provides an electronic component which is prepared from any one of the composite fibers provided by the second aspect of the invention.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is a small angle X-ray diffraction pattern of fibers of the products of examples 1-6 and comparative examples 1-4.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.

Example 1

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 0.6g of carbon material modified dispersant TNWDIS at normal temperature, adding into 100g of DMSO solution, and stirring for 20min by using a magnetic stirrer to uniformly disperse the TNWDIS; adding 2g of Carbon Nanotubes (CNTs) of TNSM2 model, and stirring by using a magnetic stirrer to ensure that the carbon nanotubes are completely wetted by a DMSO solution of a solvent instead of floating on the water surface; then ultrasonically treating for 5min, taking out the dispersion liquid, standing in ice water, cooling, defoaming, and continuing ultrasonic treatment for 30 min; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles, wherein the centrifugal rate is 2000r/min, and the centrifugal time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nano Tube (CNTs) dispersion liquid, and the final dispersion liquid is marked as a first dispersion liquid A₁. Drying the lower precipitate to constant weight, denoted as G₁The actual content of carbon nanotubes in the dispersion is 2-G₁。

S2, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; then 15g of PVA that had been washed with water was weighed out and slowly poured in portions into the first dispersion A prepared in step S1₁In the preparation method, a magnetic stirrer is used for stirring while feeding so that the PVA is dispersed in the first dispersion liquid A₁Uniformly dispersing the PVA/CNTs dispersion liquid, stirring for 20min, putting the PVA/CNTs dispersion liquid into a 50 ℃ oven, and preserving heat for 2h to ensure that the PVA is in the first dispersion liquid A₁Fully swelling; then the temperature of the oven is adjusted to 80 ℃, and the temperature is kept for 6h, so that PVA is dispersed in the first dispersion liquid A₁Slowly dissolving; then taking out the PVA/CNTs dispersion liquid, cooling the dispersion liquid to room temperature, measuring the viscosity of the dispersion liquid to be 31502mPa & s, then carrying out ultrasonic treatment on the dispersion liquid for 30min, disentangling the PVA macromolecular chains by virtue of the ultrasonic treatment, facilitating the PVA macromolecular chains to be straightened and oriented in the subsequent processing process, and measuring the viscosity of the dispersion liquid to be 18463mPa & s; and finally standing and defoaming for later use to obtain the CNTs/PVA spinning solution.

And S3, carrying out wet spinning on the CNTs/PVA spinning solution prepared in the step S2 at normal temperature by using a wet spinning machine, setting the speed of a metering pump to be 10r/min, using absolute ethyl alcohol for a coagulating bath, and collecting the fibers subjected to the coagulating bath to obtain the CNTs/PVA nascent fibers.

S4, stretching the CNTs/PVA as-spun fibers collected in the step S3 by air at normal temperature, wherein the stretching multiple is set to be 1.5 times; then carrying out multi-pass hot stretching operation, namely one-pass hot stretching: the hot stretching multiple is 3 times, the hot stretching temperature is set to be 200 ℃, and the second hot stretching is carried out: the hot stretching multiple is 2 times, and the hot stretching temperature is 220 ℃; then carrying out heat setting operation, selecting constant tension heat setting, and setting the heat setting temperature to be 220 ℃; then drying by using a hot roller, and finally collecting finished fibers by using an unreeling machine.

Example 2

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 2g of Carbon Nanotubes (CNTs) of TNSM2 model at normal temperature, adding the weighed materials into 100g of DMSO solution, and stirring the mixture by using a magnetic stirrer to ensure that the carbon nanotubes are completely wetted by the DMSO solution; then carrying out ultrasonic treatment for 5min, taking out the dispersion liquid, standing in ice water, cooling, defoaming, and continuing ultrasonic treatment for 30min in total; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles, wherein the centrifugal rate is 2000r/min, and the centrifugal time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nano Tube (CNTs) dispersion liquid, and the final dispersion liquid is marked as a first dispersion liquid A₂. Drying the lower precipitate to constant weight, denoted as G₂The actual content of carbon nanotubes in the dispersion is 2-G₂。

S2, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; 15g of the PVA that had been washed with water were then weighed out and slowly poured in portions into the first dispersion A in step S1₂In the preparation method, a magnetic stirrer is used for stirring while feeding so that the PVA is dispersed in the first dispersion liquid A₂Uniformly dispersing the PVA/CNTs in the mixed solution, stirring the mixed solution for 20min, and then putting the DMSO dispersion solution of the PVA/CNTs into a 50 ℃ oven for heat preservation for 2h to ensure that the PVA is in the first dispersion solution A₂Medium infinite swelling; then the temperature of the oven is adjusted to 80 ℃, and the temperature is kept for 6h, so that PVA is dispersed in the first dispersion liquid A₂Slowly dissolving; and then taking out the DMSO dispersion liquid of the PVA/CNTs, carrying out ultrasonic treatment on the DMSO dispersion liquid for 30min after the DMSO dispersion liquid is cooled to room temperature, disentangling the PVA macromolecular chains by virtue of the ultrasonic treatment, facilitating the straightening orientation of the PVA macromolecular chains in the subsequent processing process, and finally standing and defoaming for later use.

S3, same as step S3 in example 1.

S4, the CNTs/PVA primary fiber is used for extracting DMSO at room temperature by using methanol (100%), and other operations are the same as the step S4 in the example 1.

Example 3

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 0.6g of carbon material modified dispersant TNWDIS at normal temperature, adding a blending solution of 58g of dimethyl sulfoxide (DMSO) and 42mL of deionized water, and stirring for 20min by using a magnetic stirrer to uniformly disperse the TNWDIS; adding 2g of Carbon Nanotubes (CNTs) of TNSM2 model, stirring by using a magnetic stirrer, and completely wetting the carbon nanotubes by the DMSO/water blending solution instead of floating on the water surface; then carrying out ultrasonic treatment for 5min, taking out the dispersion liquid, standing in ice water, cooling, defoaming, and continuing ultrasonic treatment for 30min in total; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles; the centrifugation speed is 2000r/min, and the centrifugation time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nano Tube (CNTs) dispersion liquid, and the final dispersion liquid is marked as a first dispersion liquid A₃. Drying the lower precipitate to constant weight, denoted as G₃The actual content of carbon nanotubes in the dispersion is 2-G₃。

S2, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; then 15g of PVA that had been washed with water were weighed out and slowly poured in portions into the first dispersion A prepared in step S1₃In the preparation method, a magnetic stirrer is used for stirring while feeding so that the PVA is dispersed in the first dispersion liquid A₃Uniformly dispersing the PVA/CNTs dispersion liquid, stirring for 20min, putting the PVA/CNTs dispersion liquid into a 50 ℃ oven, and preserving heat for 2h to ensure that the PVA is in the first dispersion liquid A₃Fully swelling; then the temperature of the oven is adjusted to 80 ℃, and the temperature is kept for 6h, so that PVA is dispersed in the first dispersion liquid A₃Slowly dissolving; then taking out the DMSO/water dispersion liquid of the PVA, and standing and defoaming the PVA after the DMSO/water dispersion liquid of the PVA is cooled to room temperature for later use.

S3, same as step S3 in example 1.

S4, the CNTs/PVA primary fiber is used for extracting DMSO at room temperature by using methanol (100%), and other operations are the same as the step S4 in the example 1.

Example 4

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 0.6g of carbon material modified dispersant TNWDIS at normal temperature, adding into 100g of DMSO solution, and stirring for 20min by using a magnetic stirrer to uniformly disperse the TNWDIS; adding 2g of Carbon Nanotubes (CNTs) of TNSM2 model, and stirring by using a magnetic stirrer to ensure that the carbon nanotubes are completely wetted by a dispersant DMSO solution instead of floating on the water surface; then carrying out ultrasonic treatment for 5min, taking out the dispersion liquid, standing in ice water, cooling, defoaming, and continuing ultrasonic treatment for 30min in total; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles, wherein the centrifugal rate is 2000r/min, and the centrifugal time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nano Tube (CNTs) dispersion liquid, and the final dispersion liquid is marked as a first dispersion liquid A₄. Drying the lower precipitate to constant weight, denoted as G₄The actual content of carbon nanotubes in the dispersion is 2-G₄。

S2, same as step S2 in example 1.

S3, same as step S3 in example 1.

S4, extracting DMSO from the CNTs/PVA primary fibers collected in the step S3 at room temperature by using methanol (100%), and then winding the fibers on a winding machine.

Example 5

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 0.5g of carbon material modified dispersant sodium dodecyl benzene sulfonate (NaDDBS) at normal temperature, adding into 100mL of deionized water, and stirring for 20min by using a magnetic stirrer to ensure that the NaDDBS is uniformly dispersed; adding 2g of Graphene Oxide (GO), and stirring by using a magnetic stirrer to ensure that the GO is completely wetted by the aqueous solution of the dispersant instead of floating on the water surface; then ultrasonic treatment is carried out for 5min, the dispersion liquid is taken out and stood in ice water for cooling and defoaming,continuing to perform ultrasonic treatment for 30 min; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles, wherein the centrifugal rate is 2000r/min, and the centrifugal time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nano Tube (CNTs) dispersion liquid, and the final dispersion liquid is marked as a first dispersion liquid A₅. Drying the lower precipitate to constant weight, denoted as G₅The actual content of carbon nanotubes in the dispersion is 2-G₅。

S2, weighing 20g of PVA powder (model PVA-1788, alcoholysis degree 88%, polymerization degree 1700) at normal temperature, and preparing the GO/PVA spinning solution by the steps which are basically the same as the step S2 in the example 1.

And S3, carrying out wet spinning on the GO/PVA spinning solution prepared in the step S2 by using a wet spinning machine at normal temperature, setting the speed of a metering pump to be 10r/min, using a saturated sodium sulfate aqueous solution for a first coagulation bath, using an unsaturated sodium sulfate aqueous solution for a second coagulation bath, and collecting fibers subjected to 2 coagulation baths to obtain GO/PVA nascent fibers.

S4, same as step S4 in example 1.

Example 6

The embodiment prepares the composite fiber, and the specific process comprises the following steps:

s1, weighing 0.3g of carbon material modified dispersant Sodium Dodecyl Sulfate (SDS) at normal temperature, adding into 100mL of deionized water, and stirring for 20min by using a magnetic stirrer to uniformly disperse the Sodium Dodecyl Sulfate (SDS); 1.5g of carbon fibers were added and stirred with a magnetic stirrer so that the carbon fibers were completely wetted with the aqueous dispersant solution, rather than floating on the water surface. The other operations are the same as step S1 in embodiment 1.

S2, weighing 20g of PVA powder (model PVA-1799, alcoholysis degree 99%, polymerization degree 1700) at normal temperature, and performing the same other steps as the step S2 in the example 1 to prepare the carbon fiber/PVA spinning solution.

And S3, carrying out dry-jet wet spinning on the carbon fiber/PVA spinning solution prepared in the step S2 by using a wet spinning machine at normal temperature, setting the speed of a metering pump to be 8r/min, using a saturated sodium sulfate aqueous solution for a first coagulation bath, using an unsaturated sodium sulfate aqueous solution for a second coagulation bath, carrying out wet stretching in the second coagulation bath, setting the stretching ratio to be 1.2 times, and collecting the fibers subjected to wet stretching to be called as carbon fiber/PVA nascent fibers.

S4, stretching the carbon fiber/PVA nascent fiber collected in the step S3 by air at normal temperature, wherein the stretching multiple is set to be 1.2 times; then carrying out multi-pass hot stretching operation, namely one-pass hot stretching: the hot stretching multiple is 3 times, the hot stretching temperature is set to be 220 ℃, and the second hot stretching is carried out: the hot stretching multiple is 2 times, and the hot stretching temperature is 230 ℃; then carrying out heat setting operation, selecting constant tension heat setting, and setting the heat setting temperature to be 230 ℃; then oiling operation is carried out, then drying treatment is carried out by using a hot roller, and finally finished fibers are collected by using an unreeling machine.

Comparative example 1

The PVA fiber is prepared by the comparative example, and the specific process comprises the following steps:

s1, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; then weighing PVA15g washed by water, slowly pouring the PVA into 100g of DMSO solution in batches, using a magnetic stirrer to stir while feeding so that the PVA is uniformly dispersed in the DMSO solution, stirring for 20min, and then putting the PVA/DMSO dispersion into a 50 ℃ oven for heat preservation for 2h so that the PVA is infinitely swelled in the DMSO solution; and then adjusting the temperature of the oven to 80 ℃, and keeping the temperature for 6 hours to slowly dissolve the PVA in the DMSO solution to obtain the PVA/DMSO spinning solution.

And S2, carrying out wet spinning on the PVA/DMSO spinning solution prepared in the S1 at normal temperature by using a wet spinning machine, setting the speed of a metering pump to be 10r/min, using absolute ethyl alcohol as a coagulating bath, collecting the fibers subjected to the coagulating bath to be called PVA nascent fibers, and collecting the PVA nascent fibers by using an unreeling machine.

Comparative example 2

The PVA fiber is prepared by the comparative example, and the specific process comprises the following steps:

s1, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; then weighing 15g of PVA washed by water, slowly pouring the weighed 15g of PVA in batches into 85mL of deionized water, stirring while feeding by using a magnetic stirrer to uniformly disperse the PVA in the water, stirring for 20min, and then putting the PVA water dispersion into a 50 ℃ oven for heat preservation for 2h to fully swell the PVA in the water; then, adjusting the temperature of the oven to 80 ℃, and preserving the heat for 6 hours to ensure that the PVA is slowly dissolved in the water; and then taking out the PVA water dispersion, carrying out ultrasonic treatment on the PVA water dispersion for 30min after the PVA water dispersion is cooled to room temperature, disentangling the PVA macromolecular chains by virtue of the ultrasonic treatment, facilitating the PVA macromolecular chains to be straightened and oriented in the subsequent processing process, and finally standing and defoaming for later use.

And S2, carrying out wet spinning on the PVA spinning solution prepared in the step S1 at normal temperature by using a wet spinning machine, setting the speed of a metering pump to be 10r/min, using absolute ethyl alcohol as a coagulating bath, and collecting fibers subjected to the coagulating bath to obtain PVA nascent fibers.

S3, stretching the PVA nascent fiber collected in the step S2 by air at normal temperature, wherein the stretching multiple is set to be 1.5 times; then carrying out multi-pass hot stretching operation, namely one-pass hot stretching: the hot stretching multiple is 3 times, the hot stretching temperature is set to be 200 ℃, and the second hot stretching is carried out: the hot stretching multiple is 2 times, and the hot stretching temperature is 220 ℃; then carrying out heat setting operation, selecting constant tension heat setting, and setting the heat setting temperature to be 220 ℃; then drying by using a hot roller, and finally collecting finished fibers by using an unreeling machine.

Comparative example 3

The PVA fiber is prepared by the comparative example, and the specific process comprises the following steps:

s1, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; then weighing 15g of PVA washed by water, slowly pouring the weighed PVA into 100g of DMSO solution in batches, using a magnetic stirrer to stir while feeding so as to uniformly disperse the PVA in the DMSO, and after stirring for 20min, putting the PVA/DMSO dispersion into a 50 ℃ oven to keep the temperature for 2h so as to fully swell the PVA in the DMSO; then, adjusting the temperature of the oven to 80 ℃, and preserving the heat for 6 hours to ensure that the PVA is slowly dissolved in the DMSO; and then taking out the PVA/DMSO dispersion liquid, carrying out ultrasonic treatment on the PVA/DMSO dispersion liquid for 30min after the PVA/DMSO dispersion liquid is cooled to room temperature, disentangling the macromolecular chains of the PVA by virtue of the ultrasonic treatment, facilitating the macromolecular chains to be straightened and oriented in the subsequent processing process, and finally standing and defoaming for later use.

S2, same as step S2 in comparative example 2.

S3, same as step S3 in comparative example 2.

Comparative example 4

The comparative example prepares a composite fiber, and the specific process comprises the following steps:

s1, weighing 0.6g of carbon material modified dispersant TNWDIS at normal temperature, adding into 100g of DMSO solution, and stirring for 20min by using a magnetic stirrer to uniformly disperse the TNWDIS; adding 2g of Carbon Nanotubes (CNTs) of TNSM2 model, and stirring by using a magnetic stirrer to ensure that the carbon nanotubes are completely wetted by a DMSO solution of a solvent instead of floating on the water surface; then carrying out ultrasonic treatment for 5min, taking out the dispersion liquid, standing in ice water, cooling, defoaming, and continuing ultrasonic treatment for 30min in total; after the ultrasonic treatment is finished, centrifugally settling the dispersion liquid to remove undispersed agglomerated particles, wherein the centrifugal rate is 2000r/min, and the centrifugal time is 30 min; after the centrifugation is finished, the upper layer liquid passes through 300-mesh filter cloth to obtain the final Carbon Nanotube (CNTs) dispersion liquid, which is marked as a first dispersion liquid A1. The lower layer was dried and precipitated to constant weight, designated G1, with the actual carbon nanotube content in the dispersion being 2-G1.

S2, weighing 20g of PVA powder (model PVA-224, alcoholysis degree 88%, polymerization degree 2400), washing with deionized water, and drying at 60 ℃ in an oven to remove impurities such as sodium acetate and low molecular polymer in the raw materials; weighing 15g of PVA washed by water, slowly pouring the weighed 15g of PVA in batches into the first dispersion liquid A1 prepared in the step S1, using a magnetic stirrer to feed and stir the PVA at the same time so that the PVA is uniformly dispersed in the first dispersion liquid A1, stirring the mixture for 20min, and then putting the PVA/CNTs dispersion liquid into a 50 ℃ oven to keep the temperature for 2h so that the PVA is fully swelled in the first dispersion liquid A1; then, the temperature of the oven is adjusted to 80 ℃, and the temperature is kept for 6 hours, so that the PVA is slowly dissolved in the first dispersion liquid A1; then taking out the PVA/CNTs dispersion liquid, cooling the dispersion liquid to room temperature, measuring the viscosity of the dispersion liquid to be 31502mPa & s, then carrying out ultrasonic treatment on the dispersion liquid for 30min, disentangling the PVA macromolecular chains by virtue of the ultrasonic treatment, facilitating the PVA macromolecular chains to be straightened and oriented in the subsequent processing process, and measuring the viscosity of the dispersion liquid to be 18463mPa & s; and finally standing and defoaming for later use to obtain the CNTs/PVA spinning solution.

And S3, carrying out wet spinning on the CNTs/PVA spinning solution prepared in the step S2 at normal temperature by using a wet spinning machine, setting the speed of a metering pump to be 10r/min, using absolute ethyl alcohol for a coagulating bath, and collecting the fibers subjected to the coagulating bath to obtain the CNTs/PVA nascent fibers.

S4, stretching the CNTs/PVA as-spun fibers collected in the step S3 by air at normal temperature, wherein the stretching multiple is set to be 1.5 times; then carrying out multi-pass hot stretching operation, namely one-pass hot stretching: the hot stretching multiple is 3 times, the hot stretching temperature is set to be 200 ℃, and the second hot stretching is carried out: the hot stretching multiple is 3 times, and the hot stretching temperature is 220 ℃; then carrying out heat setting operation, selecting constant tension heat setting, and setting the heat setting temperature to be 220 ℃; then drying by using a hot roller, and finally collecting finished fibers by using an unreeling machine.

Test examples

The thermal diffusivity of the finished fibers obtained in the above examples and comparative examples was measured by a flash method according to ASTM E1461, the specific heat capacity was measured by a differential scanning calorimeter, the density was measured by a density balance, and the thermal conductivity of each finished fiber was calculated according to "thermal diffusivity x specific heat capacity x density". The thermal conductivity of the finished fibers prepared in the above examples and comparative examples is shown in table 1 below:

TABLE 1 thermal conductivity of finished fibers of examples and comparative examples

As can be seen from table 1 above, the finished fibers of the above examples and comparative examples have good thermal conductivity, wherein, in the preparation process of the pure PVA fibers of comparative example 2 and comparative example 3, the spinning solution is subjected to molecular chain disentanglement treatment before spinning, and the nascent fibers are subjected to stretching treatment after spinning, so that the pure PVA fibers have high crystallinity, and the internal high molecular chains thereof have good disentanglement orientation, so that the thermal conductivity of the pure PVA fibers prepared in comparative example 2 and comparative example 3 is much higher than that of the pure PVA fibers prepared in comparative example 1 without the above treatment. As can be seen from the comparison of examples 1, 2, 5, and 6 with comparative examples 2 and 3, the thermal conductivity of the composite fiber can be improved by adding the thermal conductive filler to the polymer matrix, which forms the thermal conductive channel in the polymer matrix; and the thermal conductivity of the composite fiber prepared by the carbon fiber as the heat-conducting filler is higher than that of the composite fiber prepared by the CNTs as the heat-conducting filler, and the thermal conductivity of the composite fiber prepared by the CNTs as the heat-conducting filler is higher than that of the composite fiber prepared by the GO as the heat-conducting filler. By comparing examples 1, 3, 5, when the dope solvent is different, the thermal conductivity of the finished fiber prepared by dissolving DMSO or water is higher. The thermal conductivity test results of the composite fibers in comparative examples 1-6 show that the thermal conductivity of the composite fibers prepared by the method is obviously improved compared with the composite fibers prepared by one treatment method alone, wherein the composite fibers are prepared by disentangling the spinning solution with molecular chains before spinning and stretching the nascent fibers after spinning.

In addition, the observation and test of the product fibers prepared in the above examples and comparative examples are performed by using a small angle X-ray diffractometer, and the results are shown in FIG. 1, wherein (a) to (j) in FIG. 1 correspond to the small angle X-ray diffraction patterns of the product fibers prepared in examples 1 to 6 and comparative examples 1 to 4, respectively. Among them, the more concentrated the dispersion rings on the equatorial ring, the better the orientation of the polymer chains of the product fibers. By comparing example 1 and comparative example 4, which are identical except that the stretching ratios are different, wherein the stretching ratio of example 1 is 9, the stretching ratio of comparative example 4 is 13.5, and the two-dimensional wide-angle X-ray diffraction patterns of the two are shown in fig. 1 (a) and fig. 1 (j), it is found that the diffusion ring of comparative example 4 is more concentrated, but the comparison thermal conductivity data is larger than that of example 1, which shows that the stretching ratio is too large, the thermal conductivity is not necessarily increased, and the thermal conduction channel which is originally overlapped in the composite fiber can be broken. In the fiber preparation process, the spinning solution is subjected to molecular chain disentanglement treatment before spinning, and the nascent fiber is subjected to stretching treatment after spinning, so that the orientation of the high molecular chain can be improved, and the thermal conductivity of the material can be further improved.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.