阅读说明：本技术 一种具有电磁屏蔽性能的聚醚醚酮纤维复合纸及其制备方法 (Polyether-ether-ketone fiber composite paper with electromagnetic shielding performance and preparation method thereof ) 是由 栾加双 丛鑫 王贵宾 张淑玲 张梅 杨砚超 吴同华 王晟道 盖须召 于 2020-05-07 设计创作，主要内容包括：一种具有电磁屏蔽性能的聚醚醚酮纤维复合纸及其制备方法,属于复合纸技术领域。解决了现有技术中聚醚醚酮纤维纸成纸性差、纸张性能低以及纸张的浸渍喷涂液中碳纳米管易于团聚与添加含量有限等问题。本发明的纤维复合纸的制备方法,先用聚醚醚酮的可溶性聚合物前驱体包覆多壁碳纳米管,然后采用结晶性聚醚醚酮包覆的多壁碳纳米管作为纺丝填料制备导电聚醚醚酮纤维,再利用导电聚醚醚酮纤维制得聚醚醚酮导电纤维纸,最后使用浸渍喷涂液喷涂导电纤维纸,得到具有电磁屏蔽性能的聚醚醚酮纤维复合纸。该纤维复合纸具有良好的机械强度、耐热性能、散热性能、阻燃性能、耐电压强度和电磁屏蔽性能,可以应用在高温电磁屏蔽防护、电气绝缘等领域。(A polyether-ether-ketone fiber composite paper with electromagnetic shielding performance and a preparation method thereof belong to the technical field of composite paper. Solves the problems that the prior art has poor paperability and low paper performance of the polyetheretherketone fiber paper, and the carbon nano-tubes in the dipping spraying liquid of the paper are easy to agglomerate and have limited addition content and the like. The preparation method of the fiber composite paper comprises the steps of coating the multi-walled carbon nano-tube with a soluble polymer precursor of polyether-ether-ketone, preparing conductive polyether-ether-ketone fiber by using the multi-walled carbon nano-tube coated with crystalline polyether-ether-ketone as a spinning filler, preparing the polyether-ether-ketone conductive fiber paper by using the conductive polyether-ether-ketone fiber, and spraying the conductive fiber paper by using dipping spraying liquid to obtain the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance. The fiber composite paper has good mechanical strength, heat resistance, heat dissipation performance, flame retardant performance, voltage resistance and electromagnetic shielding performance, and can be applied to the fields of high-temperature electromagnetic shielding protection, electrical insulation and the like.)

1. A preparation method of polyether-ether-ketone fiber composite paper with electromagnetic shielding performance is characterized by comprising the following steps:

firstly, dissolving a soluble polymer precursor of polyetheretherketone in an organic solvent, dispersing a multi-walled carbon nanotube in the organic solvent, ultrasonically mixing the two uniformly, adding acid into a mixed solution for hydrolysis, washing the mixed solution to be neutral, and drying the mixed solution to obtain a crystalline polyetheretherketone-coated multi-walled carbon nanotube;

uniformly dispersing the obtained crystalline polyether-ether-ketone-coated multi-walled carbon nanotubes in pure polyether-ether-ketone powder, drying the obtained mixed powder, extruding, granulating and spinning to obtain polyether-ether-ketone conductive fibers;

step two, carrying out oil removal treatment on the polyether-ether-ketone conductive fiber obtained in the step one, drying and then chopping, and carrying out surfactant treatment on the obtained chopped fiber and then drying to obtain a polyether-ether-ketone conductive fiber section;

uniformly dispersing the obtained polyether-ether-ketone conductive fiber section and aramid pulp in a water solution containing a dispersing agent to obtain fiber slurry, and drying after vacuum filtration to obtain polyether-ether-ketone fiber base paper with electromagnetic shielding performance;

dissolving a soluble polymer precursor of polyether-ether-ketone in an organic solvent, dispersing the multi-walled carbon nano-tube in the organic solvent, and ultrasonically mixing the multi-walled carbon nano-tube and the organic solvent uniformly to obtain an impregnation spraying liquid;

step four, spraying the dipping spraying liquid obtained in the step three on the polyetheretherketone fiber base paper with the electromagnetic shielding performance obtained in the step two, drying to remove the organic solvent, performing first hot pressing to prepare polyetheretherketone fiber composite paper with the electromagnetic shielding performance, the surface of which is not hydrolyzed, performing hydrolytic reduction on the polyetheretherketone fiber composite paper with the electromagnetic shielding performance under an acidic condition, drying, and performing second hot pressing to obtain the polyetheretherketone fiber composite paper with the electromagnetic shielding performance;

the soluble polymer precursor of the polyether-ether-ketone is ketimine polyether-ether-ketone or 1,4 dioxolane polyether-ether-ketone respectively.

2. The method for preparing polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 1, wherein in the first step, the organic solvent is N-methylpyrrolidone or N, N-dimethylacetamide; the length of the multi-wall carbon nano tube is 1-2 mu m; the acid is one or more of hydrochloric acid, sulfuric acid and benzenesulfonic acid, and the addition amount of the acid is 1-5% of the volume of the mixed solution in terms of the addition volume; in the mixed solution, the mass ratio of the multi-walled carbon nanotube to the soluble polymer precursor of the polyether-ether-ketone is 1 (10-50).

3. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 1, wherein in the first step,

the melt index of the pure polyether-ether-ketone powder is 81-142g/10 min;

the content of the multi-walled carbon nanotubes in the prepared polyether-ether-ketone conductive fiber is 1 to 5 weight percent;

extruding, granulating and spinning to obtain the polyether-ether-ketone conductive fiber, wherein the process comprises the following steps: firstly, performing melt extrusion granulation on mixed powder by using a torque rheometer, then adding the dried granules into a high-temperature spinning machine, melting and plasticizing the granules in a charging barrel of the extruder, then feeding the granules into a melt metering pump, forming a plurality of melt strands through a filtering system and a spinning assembly system, performing drafting shaping through a drafting system by a guide roller, and finally winding to obtain the polyether-ether-ketone conductive fiber; wherein the heating temperature of the fluid in the high-temperature spinning machine is 350-360 ℃; the temperature of the feeding section of the extruder barrel is 280-330 ℃, the temperature of the plasticizing section is 370-400 ℃, and the temperature of the feeding section is 380-410 ℃; the spinning extrusion temperature is 380-410 ℃, and the pressure is 5-20 MPa; the stretching temperature is 140-220 ℃, the stretching multiple is 1-3 times, the first-stage stretching multiple is 1.2-2.1, and the second-stage stretching multiple is 1.9-0.8; the winding speed is 100-800 m/min.

4. The method for preparing polyetheretherketone fiber composite paper with electromagnetic shielding performance according to claim 1, wherein in the second step, the oil removing agent is one or more of petroleum ether, acetone and ethyl acetate, the surfactant is one or more of sodium dodecylbenzene sulfonate, sodium dodecylsulfate and Triton X-100 Triton, the dispersant is one or more of sodium polyoxyethylene polyacrylate and polyvinyl alcohol, and the concentration of the dispersant in the aqueous solution containing the dispersant is 0.5 × 10^-3-2×10^-3moL/L。

5. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 1, wherein in the second step,

in the polyether-ether-ketone fiber base paper with the electromagnetic shielding performance, the polyether-ether-ketone fiber base paper with the electromagnetic shielding performance accounts for 85-98 wt%, and the aramid pulp accounts for 2-15 wt%;

the polyether-ether-ketone conductive fiber section consists of 53-65 wt% of skeleton fibers and 35-47 wt% of precipitation fibers, wherein the skeleton fibers are polyether-ether-ketone conductive fiber sections with the length of 5-10 mm; the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 2-5 mm;

the aramid pulp is one or more of aramid 1313 fibers and aramid 1414 fibers.

6. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 5, wherein the skeleton fiber is a polyetheretherketone conductive fiber section with a length of 6mm, and the fibrid is a polyetheretherketone conductive fiber section with a length of 2 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 6mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 3 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 5mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 3 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 5mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 2 mm;

or the skeleton fiber and the precipitation fiber are all polyether-ether-ketone conductive fiber sections with the length of 4 mm.

7. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 1, wherein in the third step, the organic solvent is one or more of N-methylpyrrolidone, N-dimethylacetamide and tetrahydrofuran; the multi-wall carbon nano-tube is a carboxylic acid modified multi-wall carbon nano-tube, and the length of the multi-wall carbon nano-tube is 1-2 mu m.

8. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding performance of claim 1, wherein in the dipping and spraying solution of the third step, the solid content of the soluble polymer precursor of polyetheretherketone is 6 wt% to 15 wt%, and the solid content of the multi-walled carbon nanotubes is 0.5 wt% to 3 wt%.

9. The method for preparing the polyetheretherketone fiber composite paper with electromagnetic shielding property of claim 1, wherein in the fourth step,

the first hot pressing temperature is 130-;

the acidification treatment process is that the polyether-ether-ketone fiber composite paper with the surface not hydrolyzed and electromagnetic shielding performance is added into concentrated hydrochloric acid, and heating reflux is carried out for more than 12 h;

the second hot pressing temperature is 180-;

the solid content in the dipping and spraying liquid accounts for 1-2% of the total mass of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance.

10. The peek fiber composite paper with em shielding property prepared by the method for preparing the peek fiber composite paper with em shielding property of any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of composite paper, and particularly relates to polyether-ether-ketone fiber composite paper with electromagnetic shielding performance and a preparation method thereof.

Background

Polyether ether ketone (PEEK) is a variety of polyaryletherketone polymers with the most excellent performance, and the PEEK has various excellent performances such as high modulus, high strength, high toughness, impact resistance, fatigue resistance, flame retardance, high temperature resistance, corrosion resistance, high electrical insulation, radiation resistance, creep resistance and the like. The PEEK fiber is prepared by high-temperature melt spinning, and is successfully applied to the high-technology fields of aerospace, aviation, nuclear energy, information, communication, electronic and electric appliances, petrochemical industry, mechanical manufacturing, automobiles and the like. Therefore, the development of functional polyetheretherketone fiber paper is a necessary and important supplement to the special fiber paper category.

The patent with publication number CN107254800A discloses a polyether-ether-ketone fiber paper and a preparation method thereof, wherein polyether-ether-ketone fibers are used as main raw materials, the method proves the feasibility of the polyether-ether-ketone fiber paper, and the prepared polyether-ether-ketone fiber paper can achieve certain performance and application. However, the binder used in this method is a PEEK resin solution diluted by diphenyl sulfone or sulfolane, and the treatment process must be performed at a high temperature, and at the high temperature, diphenyl sulfone destroys the structure of the fiber, resulting in poor paper forming property, thereby affecting the performance of the paper.

The patent with publication number CN110373955A discloses a composite paper of polyetheretherketone fiber and a preparation method thereof, which comprises preparing base paper of polyetheretherketone fiber by vacuum filtration, impregnating, hot-pressing, acidifying and hydrolyzing to obtain the composite paper of polyetheretherketone fiber. The composite paper prepared by the method has good tightness, mechanical strength, heat resistance and voltage resistance, and can be used in the fields of high-temperature protection, electrical insulation, honeycomb structures and the like. But the prepared fiber paper has single performance and does not have the functions of electromagnetic shielding and the like.

The patent with publication number CN103088462A discloses a preparation method of a polyetheretherketone monofilament with electromagnetic shielding function, which comprises melting, filtering and single-hole spinning a spinning-grade polyetheretherketone resin, a heat stabilizer, a functional powder material (carbon nanotubes, graphene or metal powder) and an organic polymer additive in a spinning extruder to form the polyetheretherketone monofilament. However, this method has two disadvantages: firstly, the prepared polyether-ether-ketone monofilament has a relatively small length-diameter ratio; and secondly, the added functional powder material is not modified, and the unmodified functional powder material is easy to agglomerate, so that the fiber spinnability is poor, and the prepared monofilament has a rough surface and cannot be used for preparing multifilament.

The patent with publication number CN109627679A discloses a high-conductivity polyether-ether-ketone composite material and a preparation method thereof, wherein the high-conductivity composite material is prepared by taking polyether-ether-ketone as a matrix and adding reinforcing fibers, graft modified carbon nanotubes, a wear-resistant agent and the like. However, the graft modified carbon nanotube used in the method is grafted by polymethyl methacrylate, and the thermal decomposition of the polymethyl methacrylate is 160-210 ℃ (the source is elastomer, 2019-08-25, 29 (4): page 25, line ten in 24-29), and the processing temperature of the polyetheretherketone cannot be met; in addition, other soluble substances are introduced, so that the crystallinity, high temperature resistance and corrosion resistance of the polyether-ether-ketone are influenced to a certain extent.

The patent with publication number CN108102292A discloses a preparation method of a conductive polyetheretherketone composite material, which finally obtains an optimal formula to prepare the conductive composite material after a large number of comparative tests on a polyetheretherketone base material, a conductive filler and an additive. However, in this method, after the multi-walled carbon nanotubes are dispersed in dimethylacetamide, polyetherimide is added to the system, and polyetherimide is easily hydrolyzed under an alkaline condition, so that crystallinity, high temperature resistance, and corrosion resistance of polyetheretherketone are affected to some extent.

The patent with publication number CN102321338A discloses a polyetheretherketone-based composite electromagnetic shielding material and a preparation method thereof, in which conductive fillers (carbon black, graphite, carbon fibers, single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes) and polyethersulfone for dispersing the conductive fillers are mixed into polyetheretherketone, and the polyetheretherketone-based composite electromagnetic shielding material is obtained by injection molding. The patent material can only be used for preparing section bars by injection molding, and can not be used for preparing flexible materials such as fiber paper and the like.

The development of social science and technology has higher demand on materials, so that the materials have excellent comprehensive properties. In addition to the electromagnetic shielding performance, the flexibility and light weight of the electromagnetic shielding material are becoming two important indicators examined, especially in the field with special requirements (weight reduction and flexibility are used as influencing factors). The development of special engineering plastics adapting to severe environment is limited to rigid materials at present. Therefore, the development of flexible lightweight materials with electromagnetic shielding may still be the focus of research and development.

Disclosure of Invention

In view of the above, the invention provides the composite paper of polyetheretherketone fiber with electromagnetic shielding performance and the preparation method thereof, in order to solve the technical problems in the prior art that the paperiness of the polyetheretherketone fiber paper is poor, the performance of the paper is low, the carbon nanotubes in the dipping and spraying liquid of the paper are easy to agglomerate, the addition content is limited, and the like.

The technical scheme adopted by the invention for solving the technical problems is as follows.

The invention provides a preparation method of polyether-ether-ketone fiber composite paper with electromagnetic shielding performance, which comprises the following steps:

firstly, dissolving a soluble polymer precursor of polyetheretherketone in an organic solvent, dispersing a multi-walled carbon nanotube in the organic solvent, ultrasonically mixing the two uniformly, adding acid into a mixed solution for hydrolysis, washing the mixed solution to be neutral, and drying the mixed solution to obtain a crystalline polyetheretherketone-coated multi-walled carbon nanotube;

uniformly dispersing the obtained crystalline polyether-ether-ketone-coated multi-walled carbon nanotubes in pure polyether-ether-ketone powder, drying the obtained mixed powder, extruding, granulating and spinning to obtain polyether-ether-ketone conductive fibers;

step two, carrying out oil removal treatment on the polyether-ether-ketone conductive fiber obtained in the step one, drying and then chopping, and carrying out surfactant treatment on the obtained chopped fiber and then drying to obtain a polyether-ether-ketone conductive fiber section;

uniformly dispersing the obtained polyether-ether-ketone conductive fiber section and aramid pulp in a water solution containing a dispersing agent to obtain fiber slurry, and drying after vacuum filtration to obtain polyether-ether-ketone fiber base paper with electromagnetic shielding performance;

dissolving a soluble polymer precursor of polyether-ether-ketone in an organic solvent, dispersing the multi-walled carbon nano-tube in the organic solvent, and ultrasonically mixing the multi-walled carbon nano-tube and the organic solvent uniformly to obtain an impregnation spraying liquid;

step four, spraying the dipping spraying liquid obtained in the step three on the polyetheretherketone fiber base paper with the electromagnetic shielding performance obtained in the step two, drying to remove the organic solvent, performing first hot pressing to prepare polyetheretherketone fiber composite paper with the electromagnetic shielding performance, the surface of which is not hydrolyzed, performing hydrolytic reduction on the polyetheretherketone fiber composite paper with the electromagnetic shielding performance under an acidic condition, drying, and performing second hot pressing to obtain the polyetheretherketone fiber composite paper with the electromagnetic shielding performance;

the soluble polymer precursor of the polyether-ether-ketone is ketimine polyether-ether-ketone or 1,4 dioxolane polyether-ether-ketone respectively.

Preferably, in the first step, the organic solvent is N-methylpyrrolidone or N, N-dimethylacetamide; the length of the multi-wall carbon nano tube is 1-2 mu m; the acid is one or more of hydrochloric acid, sulfuric acid and benzenesulfonic acid, and the addition amount of the acid is 1-5% of the volume of the mixed solution in terms of the addition volume; in the mixed solution, the mass ratio of the multi-walled carbon nanotube to the soluble polymer precursor of the polyether-ether-ketone is 1 (10-50).

Preferably, in the first step,

the melt index of the pure polyether-ether-ketone powder is 81-142g/10 min;

the content of the multi-walled carbon nanotubes in the prepared polyether-ether-ketone conductive fiber is 1 to 5 weight percent;

extruding, granulating and spinning to obtain the polyether-ether-ketone conductive fiber, wherein the process comprises the following steps: firstly, performing melt extrusion granulation on mixed powder by using a torque rheometer, then adding the dried granules into a high-temperature spinning machine, melting and plasticizing the granules in a charging barrel of the extruder, then feeding the granules into a melt metering pump, forming a plurality of melt strands through a filtering system and a spinning assembly system, performing drafting shaping through a drafting system by a guide roller, and finally winding to obtain the polyether-ether-ketone conductive fiber; wherein the heating temperature of the fluid in the high-temperature spinning machine is 350-360 ℃; the temperature of the feeding section of the extruder barrel is 280-330 ℃, the temperature of the plasticizing section is 370-400 ℃, and the temperature of the feeding section is 380-410 ℃; the spinning extrusion temperature is 380-410 ℃, and the pressure is 5-20 MPa; the stretching temperature is 140-220 ℃, the stretching multiple is 1-3 times, the first-stage stretching multiple is 1.2-2.1, and the second-stage stretching multiple is 1.9-0.8; the winding speed is 100-800 m/min.

Preferably, in the second step, the oil removing agent is one or more of petroleum ether, acetone and ethyl acetate, the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and Triton X-100, the dispersant is one or more of polyethylene oxide polyacrylic acid sodium salt and polyvinyl alcohol, and the concentration of the dispersant in the aqueous solution containing the dispersant is 0.5 × 10^-3-2×10^-3moL/L。

Preferably, in the second step, the first step,

in the polyether-ether-ketone fiber base paper with the electromagnetic shielding performance, the polyether-ether-ketone fiber base paper with the electromagnetic shielding performance accounts for 85-98 wt%, and the aramid pulp accounts for 2-15 wt%;

the polyether-ether-ketone conductive fiber section consists of 53-65 wt% of skeleton fiber and 35-47 wt% of fibrid, wherein the skeleton fiber is the polyether-ether-ketone conductive fiber section with the length of 5-10 mm; the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 2-5 mm;

the aramid pulp is one or more of aramid 1313 fibers and aramid 1414 fibers.

More preferably, the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 6mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 2 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 6mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 3 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 5mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 3 mm;

or the skeleton fiber is a polyether-ether-ketone conductive fiber section with the length of 5mm, and the precipitation fiber is a polyether-ether-ketone conductive fiber section with the length of 2 mm;

or the skeleton fiber and the precipitation fiber are all polyether-ether-ketone conductive fiber sections with the length of 4 mm.

Preferably, in the third step, the organic solvent is one or more of N-methylpyrrolidone, N-dimethylacetamide and tetrahydrofuran; the multi-wall carbon nano-tube is a carboxylic acid modified multi-wall carbon nano-tube, and the length of the multi-wall carbon nano-tube is 1-2 mu m.

Preferably, in the dipping and spraying solution of the third step, the solid content of the soluble polymer precursor of the polyetheretherketone is 6 wt% -15 wt%, and the solid content of the multi-walled carbon nanotube is 0.5 wt% -3 wt%.

Preferably, in the fourth step,

the first hot pressing temperature is 130-;

the acidification treatment process is that the polyether-ether-ketone fiber composite paper with the surface not hydrolyzed and electromagnetic shielding performance is added into concentrated hydrochloric acid, and heating reflux is carried out for more than 12 h;

the second hot pressing temperature is 180-;

the solid content in the dipping and spraying liquid accounts for 1-2% of the total mass of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance.

The invention also provides the polyether-ether-ketone fiber composite paper with the electromagnetic shielding property, which is prepared by the preparation method of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding property.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the preparation method of the polyetheretherketone fiber composite paper with the electromagnetic shielding performance, the carbon nano tubes are coated by the soluble polymer precursor for preparing the polyetheretherketone, so that the agglomeration of the carbon nano tubes in the processing process is inhibited, the dispersibility of the carbon nano tubes in the polyetheretherketone is improved, and the obtained conductive fibers have more uniform conductivity and better spinnability.

2. The preparation method of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance utilizes soluble polymer precursor of polyether-ether-ketoneThe impregnation spraying liquid prepared by the body and the carbon nano tube uniformly impregnates the base paper, and the conductive carbon nano tube is added into the impregnation spraying liquid, so that the electromagnetic shielding performance of the polyether-ether-ketone electromagnetic shielding paper is greatly improved, and the specific electromagnetic shielding effectiveness (special SE) is detected by tests_T) Can reach 70-80 dB/mm.

3. According to the preparation method of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance, the conductive fibers and the dipping and spraying liquid both use soluble polymer precursors of polyether-ether-ketone, and other soluble or low-thermal-stability substances are not introduced, so that the overall corrosion resistance and the thermal stability of the material are improved, and tests show that the weight of the polyether-ether-ketone fiber composite paper with different proportions is reduced by 5% at the temperature of 560-585 ℃.

4. The polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance has good mechanical strength, heat resistance, heat dissipation performance, flame retardant performance, voltage resistance and electromagnetic shielding performance, can be applied to the fields of high-temperature electromagnetic shielding protection, electrical insulation and the like, and is particularly suitable for the problems of electromagnetic waves and heating and in severe environments.

5. The polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance can be freely cut as a flexible material, has strong plasticity, and can be easily used in a narrow space.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is apparent that the drawings disclosed below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 shows conductive fibers of polyetheretherketone prepared in example 1 of the present invention;

FIG. 2 is a polyether ether ketone based conductive fiber segment prepared in example 5 of the present invention;

in fig. 3, (a1) - (e1) are respectively the morphology charts of the peek fiber base paper with electromagnetic shielding performance prepared in examples 1-5 of the present invention; (a2) - (e2) are respectively the morphology diagrams of the peek fiber composite paper with electromagnetic shielding performance prepared in the embodiments 1-5 of the present invention;

fig. 4 is a cross-Sectional Electron Microscope (SEM) image of the peek fiber composite paper having electromagnetic shielding properties prepared in example 5 of the present invention, wherein (a) is 800 times and (b) is 1600 times.

FIG. 5 is a Thermogravimetric (TGA) curve of a PEEK fiber composite paper with electromagnetic shielding property prepared in example 5 of the present invention;

fig. 6 is an electromagnetic shielding performance graph of the peek fiber composite paper with electromagnetic shielding performance prepared in embodiments 5, 6, 7, and 8 of the present invention.

Detailed Description

For a further understanding of the invention, preferred embodiments of the invention are disclosed below, but it is to be understood that these disclosures are merely illustrative of the features and advantages of the invention, and are not limiting of the claimed invention.

The preparation method of the polyether-ether-ketone fiber paper with the electromagnetic shielding performance comprises the following steps:

step one, preparing polyether-ether-ketone conductive fibers

1.1 dissolving a soluble polymer precursor of the polyetheretherketone in an organic solvent, dispersing the multi-walled carbon nanotube in the organic solvent, ultrasonically mixing the two uniformly, adding acid into the mixed solution for hydrolysis, washing the mixed solution to be neutral (pH 7), and drying the mixed solution to obtain the crystalline polyetheretherketone-coated multi-walled carbon nanotube;

1.2 uniformly dispersing the crystalline polyetheretherketone-coated multi-walled carbon nanotubes obtained in the step 1.1 in pure polyetheretherketone powder, drying the obtained mixed powder, extruding, granulating and spinning to obtain the polyetheretherketone conductive fibers;

step two, preparing raw paper of polyether-ether-ketone fiber with electromagnetic shielding performance

2.1, carrying out oil removal treatment on the polyether-ether-ketone conductive fiber obtained in the step one, drying and then chopping, and carrying out surfactant treatment on the obtained chopped fiber and then drying to obtain a polyether-ether-ketone conductive fiber section;

2.2, uniformly dispersing the polyether-ether-ketone conductive fiber section obtained in the step 2.1 and aramid pulp in a water solution containing a dispersing agent to obtain fiber slurry, and drying after vacuum filtration to obtain polyether-ether-ketone fiber base paper with electromagnetic shielding performance;

step three, preparing dipping spraying liquid

Dissolving a soluble polymer precursor of polyether-ether-ketone in an organic solvent, dispersing multi-walled carbon nanotubes in the organic solvent, and ultrasonically mixing the multi-walled carbon nanotubes and the organic solvent uniformly to obtain an impregnation spraying solution;

step four, preparing the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance

And (3) spraying the dipping spraying liquid obtained in the step two on the polyetheretherketone fiber base paper with the electromagnetic shielding performance obtained in the step one, drying to remove the organic solvent, carrying out first hot pressing to obtain the polyetheretherketone fiber composite paper with the electromagnetic shielding performance, the surface of which is not hydrolyzed, carrying out hydrolytic reduction on the polyetheretherketone fiber composite paper with the electromagnetic shielding performance under an acidic condition, drying, and carrying out second hot pressing to obtain the polyetheretherketone fiber composite paper with the electromagnetic shielding performance.

In the technical scheme, in the first step, the soluble polyether-ether-ketone precursor is ketimine polyether-ether-ketone or 1,4 dioxolane polyether-ether-ketone; in the third step, the soluble polyether-ether-ketone precursor is ketimine polyether-ether-ketone or 1,4 dioxolane polyether-ether-ketone;

wherein, the structural formula of the ketimine polyether ether ketone is as follows:

the structural formula of the 1,4 dioxolane polyether ether ketone is as follows:

both ketimine polyetheretherketone and 1,4 dioxolane polyetheretherketone are prior art prepared from pure polyetheretherketone having a melt index of 81-142g/10 min. In the first step and the third step, the same soluble polyether-ether-ketone precursor can be adopted, and different soluble polyether-ether-ketone precursors can also be adopted.

The soluble polymer precursor of the polyether-ether-ketone has good solubility, can be reduced into the polyether-ether-ketone through hydrolysis, and recovers the crystallization property after the temperature is raised to the glass transition temperature. By utilizing the dissolvability of the multi-walled carbon nanotube, the multi-walled carbon nanotube is dissolved in an organic solvent and is ultrasonically mixed with the organic solvent in which the multi-walled carbon nanotube is dispersed, so that the multi-walled carbon nanotube is uniformly coated (physically adsorbed) with soluble polyetheretherketone to generate the multi-walled carbon nanotube coated with crystalline polyetheretherketone. The multi-walled carbon nano-tube coated by the crystalline polyether-ether-ketone not only has good solvent resistance and high-temperature service performance, but also can be cocrystallized with special engineering plastics such as polyether-ether-ketone and the like to provide good interface interaction. According to the invention, soluble polyether-ether-ketone on the surface of the multi-walled carbon nano tube coated with crystalline polyether-ether-ketone is acidized and reduced, and then is uniformly mixed with polyether-ether-ketone through high stirring, so that the purpose of uniform mixing can be achieved. The soluble polymer precursor of the polyether-ether-ketone is used as the main component of the dipping spraying liquid, and simultaneously, the requirements of uniform dispersion of multi-walled carbon nanotubes, solvent resistance, high-temperature use, dipping spraying and improvement of interface bonding strength are met.

In the technical scheme, in the step 1.1, the organic solvent is N-methylpyrrolidone (NMP) or N, N-Dimethylacetamide (DMAC). Multi-walled carbon nanotubes are commercially available and preferably 1-2 μm in length. The acid is one or more of hydrochloric acid, sulfuric acid and benzenesulfonic acid, the acid is used for reducing the soluble polyether-ether-ketone precursor, and the addition amount of the acid is only required to meet the action, and preferably is 1-5% of the volume of the mixed solution by volume. The temperature and time of the ultrasonic treatment are not particularly limited, and the effect can be achieved, and the ultrasonic treatment at 50 ℃ is preferably carried out for 8 hours. In the mixed solution, the concentration of the soluble polymer precursor of the polyetheretherketone is 20-50g/L, the content of the multi-walled carbon nanotube is 1 wt% -2 wt%, and the mass ratio of the multi-walled carbon nanotube to the soluble polymer precursor of the polyetheretherketone is 1 (10-50).

In the technical scheme, in the step 1.2, the multi-wall carbon nano tubes coated with the crystalline polyether-ether-ketone are uniformly dispersed in pure polyether-ether-ketone powder through a high-speed stirrer. The content of the multi-wall carbon nanotubes in the prepared polyether-ether-ketone conductive fiber is 1 wt% -5 wt%, and preferably 1 wt% -2 wt%. The melt index of the polyetheretherketone powder is 81-142g/10 min. The drying conditions are preferably: drying in an oven at 120 ℃ for 2-4 h. Extruding, granulating and spinning to obtain the polyether-ether-ketone conductive fiber, wherein the process comprises the following steps: firstly, carrying out melt extrusion granulation on mixed powder by using a double-screw torque rheometer, then adding the dried granules into a high-temperature spinning machine, melting and plasticizing the granules in a charging barrel of the extruder, then feeding the granules into a melt metering pump, forming a plurality of strands of melt strands through a filtering system and a spinning assembly system, carrying out drafting shaping through a drafting system through a guide roller, and finally winding to obtain the polyether-ether-ketone conductive fiber. Preferably: the heating temperature of the fluid in the high-temperature spinning machine is 350-360 ℃; the temperature of the feeding section of the extruder barrel is 280-330 ℃, the temperature of the plasticizing section is 370-400 ℃, and the temperature of the feeding section is 380-410 ℃; the temperature of the melt pipeline and the metering pump is 390-420 ℃; the temperature of the spinning assembly and the head is 380-400 ℃; the spinning extrusion temperature is 380-410 ℃, and the pressure is 5-20 MPa; the stretching temperature is 140-220 ℃, and the stretching multiple is 1-3 times; the primary stretching multiple is 1.2-2.1, and the secondary stretching multiple is 1.9-0.8; the winding speed is 100-800 m/min.

According to the technical scheme, in the step 2.1 of the second step, the oil removing agent treatment is to place the fibers into the oil removing agent, ultrasonically stir, clean and filter, the oil removing agent is one or more of petroleum ether, acetone and ethyl acetate, the surfactant treatment is to add the polyether-ether-ketone conductive fiber section into an aqueous solution containing a surfactant, stir until the polyether-ether-ketone conductive fiber section is defibered and dispersed to be in a single state, and then filter, the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and Triton X-100, and the concentration of the aqueous solution containing the surfactant is usually 0.5 × 10^-3-2×10^-3Between moL/L; stirring at room temperature for 20-40min to disperse the conductive fiber segment of polyether-ether-ketone into single fiber. The drying temperature is not particularly limited, and the drying effect can be achieved.

According to the technical scheme, in the step two 2.2, the proportion of the polyether-ether-ketone conductive fiber section and the aramid pulp is limited, preferably, the treated polyether-ether-ketone conductive fiber accounts for 85-98 wt% of the mass of the raw paper of the polyether-ether-ketone fiber with the electromagnetic shielding property, the aramid pulp accounts for 2-15 wt% of the total mass of the raw paper of the polyether-ether-ketone fiber with the electromagnetic shielding property, the lengths of the preferably used chopped fibers (the polyether-ether-ketone conductive fiber section) are not uniform, because longer chopped fibers are easy to agglomerate in the dispersing process, and shorter chopped fibers cannot form a good lap network, the fiber paper is prepared by using different short fibers with different contents, wherein the longer fiber section plays a role in constructing a frame (called skeleton fiber), the shorter fiber section plays a role in filling (called as fibrid fiber), the prepared fiber paper has good paper forming property, the skeleton fiber is a conductive fiber section with the length range of 5-6mm, preferably, the conductive fiber section with the length ranging from 5-6mm, the length of 5-6mm, the polyether-ether-ketone conductive fiber section with the weight content ranging from 53 wt%, the weight of the dispersant, the dispersant is preferably, the polyethylene-65-35-65-47-5-4-5-4-mm, and the polyethylene-4-47-4-^-3-2×10^-3moL/L. The dispersion method is sufficient stirring. The stirring time and the rotating speed are not particularly limited, the dispersion effect can be achieved, the stirring speed is 8000-25000 r/min, and the stirring time is 40-90 min. Vacuum filtration and drying are all in the prior art. The drying temperature is not particularly limited, and the drying effect can be achieved.

In the technical scheme, in the third step, the organic solvent is one or more of N-methyl pyrrolidone (NMP), N-dimethylacetamide (THF) and tetrahydrofuran (DMAC). In the dipping and spraying liquid, the solid content of the soluble polymer precursor of the polyether-ether-ketone is 6 wt% -15 wt%, and the solid content of the multi-wall carbon nano tube is 0.5 wt% -3 wt%. The acidified multi-walled carbon nanotube has better dispersibility in an organic solvent, so the multi-walled carbon nanotube modified by carboxylic acid is preferred.

According to the technical scheme, in the fourth step, a high-pressure spray gun is adopted for spraying. The first hot pressing has the effect that the multi-walled carbon nanotubes in the dipping spraying liquid and the soluble polymer precursor of the polyether-ether-ketone are better dispersed and bonded between the pores formed by lapping the polyether-ether-ketone conductive fibers; the first hot pressing temperature is preferably 130-250 ℃, the pressure is preferably 3-13MPa, and the time is preferably 3-25 min. The process of acidification treatment comprises the following steps: adding the polyether-ether-ketone fiber composite paper with the surface not hydrolyzed and with the electromagnetic shielding performance into concentrated hydrochloric acid, and heating and refluxing for more than 12 h. The second hot pressing has the function of enabling the molecular chain of the reduced polyether-ether-ketone to be rearranged, oriented and crystallized to improve the performance, and the second hot pressing temperature is preferably 180-270 ℃, the pressure is 3-13MPa, and the time is 3-25 min. The drying temperature can reach the drying effect, and the drying equipment usually adopts a high-temperature oven. The solid content of the dipping spraying liquid accounts for 1-2% of the total mass of the polyether-ether-ketone fiber composite paper with the electromagnetic shielding performance.

The present invention is further illustrated by the following examples.