CN113583426B - Preparation method of carbon fiber/polyether ketone composite material - Google Patents

Abstract

The invention relates to a preparation method of carbon fiber/polyetherketone ketone composite material. The steps are: (1) dissolving polyetherketoneketone in a solvent at room temperature to obtain a uniform polyetherketoneketone solution; the polyetherketoneketone The polyether ketone ketone can be fully dissolved in the solution; (2) the polyether ketone ketone solution obtained in step (1) is placed in a sealed dipping tank, and the traction carbon fiber bundles are fully immersed in the polyether ketone ketone solution to obtain uniform Impregnated carbon fiber/PEK prepreg; (3) completely removing the residual solvent on the carbon fiber/PEK prepreg obtained in step (2) by heating; (4) using step (3) to obtain The carbon fiber/polyetherketone ketone prepreg bundle is preheated, and then hot-pressed to obtain a carbon fiber/polyetherketone ketone composite material. In the carbon fiber/polyetherketoneketone composite material, the thickness of polyetherketoneketone between carbon fibers is in the range of 1-3 μm, and the utilization rate of carbon fiber tensile strength reaches more than 95%.

Description

A kind of preparation method of carbon fiber/polyetherketoneketone composite material

technical field

The invention belongs to the technical field of polyetherketone ketone composite materials, and relates to a preparation method of a carbon fiber/polyetherketone ketone composite material.

Background technique

In recent years, carbon fiber/PEK composites have been widely used in aerospace, automotive, wind power blades, medical and health care, 3D printing and other fields.

Because polyetherketone ketone belongs to polyaryletherketone polymer, it is generally difficult to dissolve in conventional solvents. For example, polyetheretherketone can only be dissolved in concentrated sulfuric acid, diphenylsulfone, hydrofluoric acid, and the resulting solution is not strictly a solution, but a suspension of polyetheretherketone particles above 100 nm in size. It is also based on this that the current preparation of carbon fiber/polyetheretherketone or carbon fiber/polyetherketoneketone composite materials is mainly based on the lamination method of carbon fiber cloth and polyetheretherketone or polyetherketoneketone, and based on sulfonation modification. wet impregnation method.

For example: Patent CN201510111874.9 discloses a preparation method of carbon fiber fabric reinforced polyetheretherketone composite material. The suspension is obtained by adding polyetheretherketone powder to chloroform or N,N-dimethylformamide of polyarylsulfone , and then poured the suspension on the carbon fiber fabric and used low pressure suction filtration to promote the penetration of the polyetheretherketone powder into the fiber bundle. However, this process uses a suspension of polyetheretherketone, which can only be impregnated on the surface of the carbon fiber fabric, and the polyetheretherketone cannot be effectively impregnated into the interior of the fabric. Patent CN201711429254.5 prepares sulfonated polyetheretherketone through chemical reaction, dissolves it in N,N-dimethylformamide, then soaks carbon fiber fabric in polymer solution, and then uses hot pressing to prepare composite material; since the process dissolves sulfonated polyetheretherketone, but not polyetheretherketone, the obtained composite material is inferior to carbon fiber/polyetheretherketone composite material in mechanical and thermal properties. Patents CN202010419567.8, CN202010419576.7 and CN202010420330.1 disclose the use of modified carbon fiber cloth and polyetheretherketone film, non-woven felt, powder or fiber to prepare carbon fiber/polyetheretherketone composite materials through lamination and compounding. method, etc., this direct composite method also cannot realize the impregnation of polyetheretherketone inside the carbon fiber cloth, and cannot obtain a uniform composite carbon fiber/polyetheretherketone composite material.

Therefore, the above composite structures generally have insufficient and uneven impregnation, and it is difficult for the carbon fibers to be fully covered by the resin matrix. As a result, it is difficult for the molded composite materials to take full advantage of the excellent mechanical properties of carbon fibers, and interlaminar fractures are prone to occur.

Therefore, it is of great significance to study a carbon fiber/PEK composite material with simple development process, good wettability and excellent mechanical properties.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the present invention provides a preparation method of a carbon fiber/polyetherketone ketone composite material; the present invention specifically uses a fluorine-based polar solvent and/or a chlorine-based polar solvent to dissolve at room temperature Polyetherketoneketone (to solve the solubility problem of polyetherketoneketone), then the polyetherketoneketone solution is placed in a sealed dipping tank, and the carbon fiber bundles are pulled to be fully dipped in the solution to obtain uniformly impregnated strip-shaped carbon fiber/polyethylene. The ether ketone ketone pre-impregnated bundle, and then the carbon fiber/polyether ketone ketone pre-impregnated bundle was heated in an oven to fully remove the residual solvent, and finally the carbon fiber/polyether ketone ketone pre-impregnated bundle was flattened and placed in a muffle furnace The carbon fiber/polyetherketoneketone composite material is obtained by preheating, and then placing it in a hot press for hot press molding.

Since polyetherketone ketone contains more ketone bonds, it has higher molecular polarity, so theoretically it has better solubility than other polyaryletherketones. However, the literature (Original Preparation of PEKK Dispersion for Coating by Transfer from a Chloroform Stable Dispersion to an Aqueous Stable Dispersion, by Emulsion/Solvent Evaporation, J. Dispersion Sci. Technol. 2016, 37(3), 360-365.) reported the use of surfactants to promote the dispersion of polyetherketoneketone particles in aqueous solvents method. However, the average size of the polyetherketoneketone particles in the dispersion is still between 120 and 140 nm, the Tyndall phenomenon is not observed, and sedimentation occurs after standing for a short time (eg, 1 h).

The present invention adopts fluorine-based polar solvent and/or chlorine-based polar solvent to realize high-concentration dissolution of polyetherketone ketone at room temperature (with these solvents, high-concentration dissolution is possible because the solvent is a polar solvent and contains fluorine, chlorine polar end), and the viscosity of the obtained solution is lower than 2×10 ³ cP, and the size of the polyetherketone ketone in the solution is less than 20 nm (the size of the polyetherketone ketone in the polyetherketone ketone dispersion is usually above 100 nm, or even larger), which enables the polyetherketoneketone in the solution to be impregnated into the carbon fiber bundles efficiently and uniformly, providing a new technology for the development of carbon fiber/polyetherketoneketone composite materials with simple process, good wettability and excellent mechanical properties.

For achieving the above object, the scheme that the present invention adopts is as follows:

A preparation method of carbon fiber/polyetherketoneketone composite material, the steps are as follows:

(1) dissolving polyetherketoneketone in a solvent at room temperature to obtain a uniform polyetherketoneketone solution;

The solvent is a fluorine-based polar solvent such as trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropionic acid, or a chlorine-based polar solvent such as p-chlorophenol, dichloroacetic acid, dichloro A kind of propionic acid, etc.;

The solvent can also be a mixed solvent formed by one of the above solvents and dichloroethane, wherein the mass content of dichloroethane is 25-75%;

The polyether ketone ketone can be fully dissolved in the polyether ketone ketone solution, and the particle size of the polyether ketone ketone after dissolution is less than 20 nm as determined by dynamic light scattering; and the polyether ketone ketone and the polyether ketone ketone in the polyether ketone ketone solution The mass ratio of the solvent is x:(100-x), wherein x is 5 to 22; when the value of x is 22, the dissolution reaches a saturated state.

(2) The polyetherketoneketone solution obtained in step (1) is placed in a sealed dipping tank (sealed to prevent solvent volatilization), and the carbon fiber bundles are drawn and fully impregnated in the polyetherketoneketone solution to obtain uniformly impregnated carbon fibers/ Polyetherketoneketone prepreg;

(3) completely remove the residual solvent on the carbon fiber/polyetherketoneketone prepreg obtained in step (2) by means of heating (such as being placed in an oven for sufficient heating);

The heating temperature does not exceed the boiling point of the solvent; operation above its boiling point results in extremely poor results;

(4) Preheating the carbon fiber/polyetherketone ketone pre-impregnated bundle obtained in step (3), and then performing hot pressing to obtain a carbon fiber/polyetherketone ketone composite material.

As a preferred solution:

In the above-mentioned preparation method of carbon fiber/polyetherketone ketone composite material, in step (1), high-speed stirring is adopted for dissolving, and the speed of high-speed stirring is 1200-1800rpm, and the stirring time is 6-12h.

As mentioned above, the preparation method of a carbon fiber/polyetherketone ketone composite material, polyetherketone ketone is determined by the monomer ratio (ie T/I ratio) (the molecular weight of the monomers is exactly the same, so it is not emphasized whether it is a mass ratio or a mole. The ratio) is 50:50, 60:40, 70:30, 80:20 or 100:0 terephthaloyl monomer and isophthaloyl monomer are prepared.

The preparation method of a carbon fiber/polyetherketoneketone composite material as described above, the solvent can be trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropionic acid, p-chlorophenol, One of dichloroacetic acid, dichloropropionic acid, etc., or a mixed solvent formed by this solvent and dichloroethane, the concentration of polyetherketoneketone in the polyetherketoneketone solution is preferably 8 to 15 wt%.

The above-mentioned preparation method of a carbon fiber/polyetherketone ketone composite material, in step (2), when dipping, the carbon fiber bundle is kept in a straight state and is pulled (5 to 9 guide rails can be set in the dipping tank, and the carbon fiber The bundle is introduced into the dipping tank, passes through the guide rails up and down in turn, is fully impregnated and then is led out of the dipping tank, and is rolled to form a strip (the rolling process will form a strip) carbon fiber / polyetherketone ketone pre-impregnated bundle), And the traction speed of the carbon fiber bundle is 0.2 to 1 m/min, preferably 0.5 m/min, the dipping time is 1 to 5 min, and the temperature of the polyetherketone ketone solution during dipping is 25 to 30°C.

In the above-mentioned preparation method of a carbon fiber/polyetherketone ketone composite material, in step (3), the heating temperature is 120-180° C., and the heating time is 2-4 hours.

A kind of preparation method of carbon fiber/polyetherketoneketone composite material as above, the concrete steps of step (4) are:

(4.1) Lay up several layers of the carbon fiber/polyetherketone ketone prepreg obtained in step (3) (several layers can be 15 to 45 layers) to obtain a thickness of 1 to 3 mm (15 layers are 1 mm, 30 layer is 2mm) layered prepreg;

(4.2) The layered prepreg obtained in step (4.1) is kept in a compacted state under a pressure lower than 0.05MPa, placed in a mold, and then preheated in a muffle furnace. The preheating temperature is 340～ 400℃, the time is 30～60min;

(4.3) Place the mould equipped with the layered prepreg obtained in step (4.2) in a hot press that has been heated to the same preheating temperature, where the pressure of the layered prepreg is 10-50 MPa Under the condition of hot pressing, the hot pressing time is 60-120min;

(4.4) The mold with the layered prepreg obtained in step (4.3) is taken out and placed at room temperature for natural cooling, and then the mold is opened to obtain a carbon fiber/polyetherketoneketone composite material.

The preparation method of a carbon fiber/polyetherketoneketone composite material as described above, in the carbon fiber/polyetherketoneketone composite material, polyetherketoneketone is completely filled in the voids of carbon fiber bundles, and the thickness of polyetherketoneketone between carbon fibers is in the range of 1 to 3 μm;

The carbon fiber/polyetherketone ketone composite material has a uniform composite structure and high strength and high modulus mechanical properties, and the utilization rate of the carbon fiber tensile strength in the carbon fiber/polyetherketone ketone composite material reaches more than 95%.

The principle of the present invention is:

The invention solves the problem of dissolution of polyetherketoneketone, so that polyetherketoneketone can form polyetherketoneketone particles with a size below 20 nm in a solution, and can be more effectively impregnated into carbon fiber bundles in a dissolved state to obtain The high-efficiency and uniform impregnated composite structure breaks through the technical bottleneck that the existing technology can only achieve partial impregnation of polyetherketone ketone in carbon fiber bundles or carbon fiber cloth, so that the mechanical properties of carbon fibers can be fully utilized in the formed composite materials. , to improve the mechanical properties of composite materials.

beneficial effect

(1) The preparation method of the carbon fiber/polyetherketone ketone composite material of the present invention is simple in process, low in cost, and good in wettability between resin and fiber;

(2) The carbon fiber reinforced thermoplastic resin composite material prepared by the present invention has good comprehensive mechanical properties.

Description of drawings

Fig. 1 is the Tyndall effect diagram of the polyetherketone ketone solution of embodiment 1a;

Fig. 2 is the dynamic light scattering result of the particle size of the polyetherketoneketone of Example 1a after being dissolved in trifluoroacetic acid;

3 is the dynamic light scattering result of the particle size of the polyetherketoneketone of Example 1b after being dissolved in p-chlorophenol;

4 is a schematic diagram of the distribution of the sealed dipping tank and guide rails used in Example 2;

Fig. 5 is the carbon fiber/polyetherketoneketone prepreg microstructure obtained in Example 2 without hot pressing;

6 is the microstructure of the carbon fiber/polyetherketoneketone composite material obtained in Example 3.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1a

Add 12 g of polyetherketone ketone (T/I ratio of 50/50) to 88 g of trifluoroacetic acid, and stir with a magnetic stirrer at 1800 rpm and a temperature of 25 ° C for 12 h to obtain 12 wt% of polyetherketone ketone dissolved. liquid. Using the method of irradiating the polyetherketone ketone solution with laser, obvious Tyndall effect can be observed (as shown in Figure 1), which confirms that the polyetherketone ketone has been fully dissolved. The polyether ketone ketone solution was left standing at room temperature for more than 1 month without sedimentation.

After diluting the polyetherketoneketone solution to 0.05wt%, the particle size of polyetherketoneketone was detected by dynamic light scattering method, and a scattering peak was found at 20 nm (as shown in Figure 2), confirming that the size of polyetherketoneketone can be Below 20 nm, it was further confirmed that the obtained solution was a polyetherketoneketone solution.

Example 1b

The process of configuring the polyether ketone ketone solution is basically the same as that of Example 1a, except that trifluoroacetic acid is replaced with p-chlorophenol, and the obtained polyether ketone ketone solution is irradiated by laser, and obvious butyl The Dahl effect confirmed that the polyetherketone ketone was fully dissolved. The polyether ketone ketone solution was left standing at room temperature for more than 1 month without sedimentation.

After diluting the polyetherketoneketone solution to 0.05wt%, the size of polyetherketoneketone particles was detected by dynamic light scattering method, and a scattering peak was found at 20 nm (as shown in Figure 3), which confirmed that the size of polyetherketoneketone can be Below 20 nm, it was further confirmed that the obtained solution was a polyetherketoneketone solution.

Example 1c

22g of polyetherketone ketone (T/I ratio of 60/40) was added to a mixed solvent of 78g of trifluoroacetic acid (39g) and dichloroethane (39g), using a magnetic stirrer at 1200rpm and a temperature of 30°C Under stirring for 6h, a polyetherketoneketone solution with a solubility of 22 wt% was obtained. By irradiating the polyetherketone ketone solution with laser light, obvious Tyndall effect can be observed, which confirms that the polyetherketone ketone has been fully dissolved. The polyether ketone ketone solution was left standing at room temperature for more than 1 month without sedimentation.

After diluting the polyetherketoneketone solution to 0.05wt%, the particle size of polyetherketoneketone was detected by dynamic light scattering method. The scattering peak was found at 20nm, which confirmed that the size of polyetherketoneketone could be lower than 20nm. The obtained solution was a polyetherketoneketone solution.

Example 2

(1) The configuration concentration is 12wt% polyetherketoneketone (T/I ratio is 50/50)/trifluoroacetic acid-dichloroethane solution:

The process is basically the same as that of Example 1a, except that the trifluoroacetic acid is replaced by a mixed solvent of trifluoroacetic acid and dichloroethane whose mass ratio is 1:1, and the corresponding addition is increased in equal proportions to prepare a solution. The volume is 500ml and the concentration is 12wt% polyetherketoneketone (T/I ratio is 50/50)/trifluoroacetic acid-dichloroethane solution;

(2) Place 500ml of 12wt% polyetherketoneketone (T/I ratio of 50/50)/trifluoroacetic acid-dichloroethane solution (ie, polyetherketoneketone solution) in a sealed immersion tank, and place T300 The carbon fiber bundles (12K) were introduced into the polyetherketone ketone solution using guide rails, and 7 guide rails arranged up and down were used to keep the fiber bundles in a straight state in the solution, and fully impregnated (impregnated) at a speed of 0.5m/min. The time is 2min) and the dipping tank is exported (the schematic diagram of the sealed dipping tank and the distribution of the guide rails is shown in Figure 4). The carbon fiber/PEK pre-impregnated bundles impregnated with the solution were placed in an oven at 120 °C for 4 h to completely remove the residual solvent, and a solvent-free carbon fiber/PEK pre-impregnated bundle was obtained. The microstructure is shown in Figure 5. It can be seen that the polyetherketone ketone is fully impregnated into the carbon fiber, and aggregates into particles with a size below 80 nm, which are uniformly coated on the surface of the carbon fiber.

Example 3

By stacking 15 layers of carbon fiber/polyetherketone ketone prepreg prepared in Example 2 in the mold, it is placed in a muffle furnace together with the mold to maintain a pressureless state (the pressure caused by the self-weight of the mold does not exceed 0.05MPa) Preheat at 360°C for 60min, then transfer to a hot press that has been pre-heated to 360°C, press at 360°C and 50MPa pressure for 120min, after natural cooling, open the mold to obtain carbon fiber/PEEK composite material .

In the carbon fiber/polyetherketoneketone composite material, the polyetherketoneketone is completely filled in the voids of the carbon fiber bundles, as shown in Figure 6, through a large number of observations, it can be determined that the thickness of the polyetherketoneketone between carbon fibers is in the range of 1 to 3 μm;

The carbon fiber/polyetherketone ketone composite material has a uniform composite structure, and the utilization rate of the carbon fiber tensile strength in the carbon fiber/polyetherketone ketone composite material reaches more than 95%.

According to the composite law of composite materials, the tensile strength of the ideal carbon fiber/PEK composite is σ _c =σ _f v _f +σ _m v _m , where σ _f and σ _m are the tensile strength of carbon fiber and PEEK Strength, v _f and v _m =1-v _f are the volume ratios occupied by carbon fibers and polyetherketoneketone. When the diameter of carbon fibers is d=7μm and the thickness of the gap between carbon fibers is δ=2μm, v _m =45%, and σ _c =0.55σ _f +0.45σ _m is obtained by substituting the above formula; where σ _m =0.1GPa. When the carbon fiber used is T300, σ _f =3.5GPa. Thus, the ideal composite strength is σ _c =1.97GPa.

The measured tensile strength of the T300 carbon fiber/PEK composite material obtained by this method reaches 1.872-1.923 GPa, which is 95-97.6% of the ideal result, that is, the utilization rate of carbon fiber tensile strength reaches the same ratio.

Claims (6)

1. a preparation method of carbon fiber/polyetherketoneketone composite material, is characterized in that: (1) Dissolve polyetherketoneketone in a solvent at room temperature to obtain a uniform polyetherketoneketone solution; Described solvent is p-chlorophenol; In the polyether ketone ketone solution, the polyether ketone ketone can be fully dissolved, and the particle size of the polyether ketone ketone after dissolving is lower than 20nm; and the mass ratio of the polyether ketone ketone and the solvent in the polyether ketone ketone solution is x : (100- x ), where x is 5~22; Polyetherketoneketone is prepared from terephthaloyl monomer and isophthaloyl monomer with a monomer ratio of 50:50 or 60:40; The dissolution adopts the method of high-speed stirring, the speed of high-speed stirring is 1200~1800rpm, and the stirring time is 6~12h; (2) Place the polyetherketone ketone solution obtained in step (1) in a sealed dipping tank, and pull the carbon fiber bundles to fully impregnate the polyetherketone ketone solution to obtain a uniformly impregnated carbon fiber/polyetherketone ketone prepreg bundle; (3) The residual solvent on the carbon fiber/polyetherketoneketone prepreg obtained in step (2) is completely removed by heating; The temperature of the heating does not exceed the boiling point of the solvent; (4) Preheating the carbon fiber/polyetherketoneketone pre-impregnated bundle obtained in step (3), and then performing hot pressing to obtain a carbon fiber/polyetherketoneketone composite material. 2. The preparation method of a carbon fiber/polyetherketoneketone composite material according to claim 1, wherein the concentration of the polyetherketoneketone in the polyetherketoneketone solution is 8-15wt%. 3 . The method for preparing a carbon fiber/polyetherketone ketone composite material according to claim 1 , wherein, in step (2), during dipping, the carbon fiber bundle is pulled in a straight state, and the traction of the carbon fiber bundle is 3 . Speed is 0.2～1m/min, immersion time is 1～5min, and the temperature of described polyetherketone ketone solution during immersion is 25～30 ℃. 4. The preparation method of a carbon fiber/polyetherketone ketone composite material according to claim 1, characterized in that, in step (3), the heating temperature is 120-180°C, and the time is 2-4h. 5. The preparation method of a carbon fiber/polyetherketone ketone composite material according to claim 1, wherein the specific steps of step (4) are: (4.1) Lay up several layers of the carbon fiber/PEK prepreg obtained in step (3) to obtain a layered prepreg with a thickness of 1-3 mm; (4.2) The layered prepreg obtained in step (4.1) is kept in a compacted state under a pressure lower than 0.05MPa, placed in a mold, and then preheated in a muffle furnace. The preheating temperature is 340~ 400°C, the time is 30~60min; (4.3) Place the mold with the layered prepreg obtained in step (4.2) in a hot press that has been heated to the same preheating temperature, where the pressure of the layered prepreg is 10-50 MPa. Under the condition of hot pressing, the hot pressing time is 60~120min; (4.4) The mold with the layered prepreg obtained in step (4.3) is taken out and placed at room temperature to cool naturally, and then the mold is opened to obtain a carbon fiber/polyetherketoneketone composite material. 6. The preparation method of a carbon fiber/polyetherketone ketone composite material according to claim 1, wherein, in the carbon fiber/polyetherketone ketone composite material, the polyetherketone ketone is completely filled in the voids of the carbon fiber bundles, And the thickness of polyetherketone ketone between carbon fibers is in the range of 1~3μm; The carbon fiber/polyetherketone ketone composite material has a uniform composite structure, and the utilization rate of the carbon fiber tensile strength in the carbon fiber/polyetherketone ketone composite material reaches more than 95%.

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