Crystalline polyarylene ether ketone surface grafted carbon fiber and method for preparing the same

Abstract

The application discloses crystalline polyarylene ether ketone surface grafted carbon fibers and a preparation method thereof, and belongs to the technical field of carbon materials, wherein the preparation method comprises the following steps: placing an amino-terminated agent containing a sulfone group, a difluoromonomer, a bisphenol monomer and potassium carbonate in a sulfolane to perform a polymerization reaction, so as to obtain an amino-terminated polyarylene ether; performing a diazonium salt reaction on the amino-terminated polyarylene ether and a nitrite salt of tetrafluoroboric acid, so as to obtain a diazonium salt-terminated polyarylene ether; connecting the carbon fibers to a cathode, immersing the carbon fibers in an electrolyte containing the diazonium salt-terminated polyarylene ether, and applying a reduction potential to perform a reaction, so as to obtain polyarylene ether grafted carbon fibers; and performing a hydrolysis reaction on the polyarylene ether grafted carbon fibers in an acidic environment, so as to obtain crystalline polyarylene ether ketone surface grafted carbon fibers. The crystalline polyarylene ether ketone surface grafted and modified carbon fibers prepared by the application have better high-temperature resistance and corrosion resistance, because the carbon fibers are directly connected with the polymer through the high-temperature resistant and corrosion resistant phenyl and sulfone groups.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon materials, and particularly relates to a crystalline polyaryletherketone surface grafted carbon fiber and a preparation method thereof. BACKGROUND

[0002] Carbon fiber reinforced resin matrix composite materials are often applied to various fields such as sea, land, air and space, and face various harsh service environments. The service capability thereof depends on the type of resin matrix. Crystalline polyaryletherketone is a kind of special engineering plastic, has the advantages of chemical stability, corrosion resistance (not soluble in tetrahydrofuran, nitrogen methyl pyrrolidone, halogenated hydrocarbon and other commonly used organic solvents at room temperature), water resistance and high temperature resistance (for example, the crystalline melting temperature of polyether ether ketone is 343 DEG C), and is a resin matrix with excellent performance. However, the above-mentioned advantages of crystalline polyaryletherketone also bring the problem of poor interfacial bonding ability with carbon fiber, which will lead to the weak interface phase as a short board and reduce the performance of the composite material. In order to improve the interfacial performance of carbon fiber and crystalline polyaryletherketone, the interaction between the two needs to be enhanced. Chemical bond is the strongest interaction, so grafting crystalline polyaryletherketone on the surface of carbon fiber through chemical bond is one of the effective means to improve the interfacial interaction between the two. There are four problems in grafting crystalline polyaryletherketone on the surface of carbon fiber through chemical bond.

[0003] (1) In order to ensure that the interface phase has good compatibility with the resin matrix, and the interface phase also has the same corrosion resistance and high temperature resistance as the resin matrix, the crystalline polyaryletherketone needs to be grafted on the surface of carbon fiber;

[0004] (2) The excellent corrosion resistance of crystalline polyaryletherketone leads to no effective solvent, and it is difficult to effectively react in solid state;

[0005] (3) Ester bond, amide bond, aliphatic ether bond and alkyl functional group are usually not resistant to high temperature, and the decomposition temperature is less than or equal to usually less than 300 DEG C, which cannot meet the molding requirement of crystalline polyaryletherketone of 400 DEG C. Therefore, stable high-temperature chemical bond needs to be used for grafting;

[0006] (4) In order to ensure the continuity of carbon fiber, the chemical bond grafting needs to be realized efficiently on the carbon fiber production line.

[0007] A large number of carbon fiber surface modification methods based on chemical grafting have been developed at home and abroad, but they cannot solve the above problems at the same time. For example, CN103806281B discloses a carbon fiber surface grafting method by carbon fiber surface oxidation, acyl chloride (public basic knowledge: requires a water-free environment) and esterification (public basic knowledge: requires a water-free environment), which is difficult to implement continuously on the carbon fiber production line, and the ester group cannot meet the processing conditions of crystalline polyaryletherketone at 400°C; CN105131332B discloses a carbon fiber surface grafting method based on azide and alkyne click chemistry reaction, which realizes chemical grafting after oxidation, silane coupling agent treatment, azidation and click chemistry reaction, but this method not only has a long surface reaction period, but also needs to use a large amount of highly toxic and highly explosive sodium azide (200-500g of sodium azide is needed for the preparation of 1kg of carbon fiber), which has low industrialization potential; CN118087246A discloses a carbon fiber surface modification method based on electrochemical free radical surface polymerization, but since polyaryletherketone cannot be prepared by free radical polymerization, this method is not suitable for polyaryletherketone resin matrix. CN104195835B discloses a method for grafting polyethyleneimine onto the surface of carbon fiber by supercritical treatment, but supercritical treatment requires high pressure of 5-7MPa, which has high requirements for equipment. In addition, the polymers grafted by the above inventions are not resistant to high temperature and do not have compatibility with crystalline polyaryletherketone.

[0008] CN106192366B discloses a carbon fiber surface grafting method based on triazine structure, although triazine structure can withstand high temperature of 400°C, but the reaction period of triazine structure needs 20-40h, which is also difficult to implement on the carbon fiber production line; CN114318878B discloses a grafting method based on "thiol-alkene" click chemistry, which grafts polyphenyl sulfide onto the surface of carbon fiber, but the alkyl C-S chemical bond generated by "thiol-alkene" click chemistry cannot be stable at 400°C; CN112457629B discloses a carbon fiber surface grafting method using amino silane coupling agent and imidization reaction, although the imide structure has high thermal stability, but the alkyl group and C-N bond in the silane coupling agent may become weak links at high temperature;

[0009] CN110820315B discloses a method for grafting carbon fiber surface by electrochemical reduction of carbon fiber surface alkyne group, sizing agent alkyne group, hydrolysis, alkyne thermal crosslinking, which successfully grafts crystalline polyaryletherketone on the surface of carbon fiber by using heat stable chemical bond, but the method is expensive in monomer (such as requiring palladium catalyst) and complex in synthesis (such as low activity of end-capping agent, resulting in the need for polymerization before end-capping for sizing agent preparation). Relatedly, CN113105620B discloses a preparation method of amino-terminated polyaryletherketone, which uses an amino end-capping agent containing a benzophenone structure and prepares amino-terminated polyaryletherketone by a two-step method (polymerization before end-capping), which is caused by the low activity of the amino end-capping agent containing the benzophenone structure. SUMMARY

[0010] The present application aims to provide a preparation method of crystalline polyaryletherketone surface grafted carbon fiber to solve the problems in the background art.

[0011] To achieve the above-mentioned purpose, the embodiments of the present application provide the following technical solutions:

[0012] A preparation method of crystalline polyaryletherketone surface grafted carbon fiber, comprising the following steps:

[0013] sulfonating and reducing the nitro-containing sulfonyl chloride compound and the halobenzene in sequence to obtain an amino end-capping agent containing a sulfone group;

[0014] polymerizing the amino end-capping agent containing a sulfone group, a difluoro monomer, a bisphenol monomer and potassium carbonate in a sulfolane to obtain an amino-terminated polyarylether;

[0015] carrying out a diazonium salt reaction on the amino-terminated polyarylether with a nitrite salt of tetrafluoroboric acid to obtain a diazonium salt-terminated polyarylether;

[0016] preparing an electrolyte from the diazonium salt-terminated polyarylether, connecting the carbon fiber to a cathode, immersing the carbon fiber in the electrolyte containing the diazonium salt-terminated polyarylether, and applying a reduction potential to carry out a reaction to obtain a carbon fiber grafted with polyarylether;

[0017] carrying out a hydrolysis reaction on the carbon fiber grafted with polyarylether in an acidic environment to obtain a crystalline polyaryletherketone surface grafted carbon fiber.

[0018] Preferably, the nitro-containing sulfonyl chloride compound is at least one of nitrobenzenesulfonyl chloride, 4-nitro-biphenyl-4-sulfonyl chloride and 4-(4-nitrophenoxy)benzenesulfonyl chloride; and the halobenzene is chlorobenzene or fluorobenzene.

[0019] Preferably, the step of sulfonating and reducing the nitro-containing sulfonyl chloride compound and the halobenzene in sequence to obtain an amino end-capping agent containing a sulfone group specifically comprises:

[0020] The nitro-containing sulfonyl chloride compound is dissolved in halogenated benzene under the condition of not more than -5 ℃ and inert gas protection, and AlCl3 powder is added in batches; then it is stirred at room temperature; it is continuously heated to reflux; deionized water is added to separate the unreacted halogenated benzene by azeotropic reflux; it is filtered, and the filter residue is washed to obtain a crude product; the crude product is recrystallized three times with ethanol, and is dried to obtain an end-capping agent precursor;

[0021] After the end-capping agent precursor is dissolved in methanol, tin chloride dihydrate is added to the solution, and reflux is performed; then filtration is performed, and the filtrate is collected; the pH value of the filtrate is adjusted to not less than 9 using a saturated aqueous Na2CO3 solution; the mixture is extracted twice with ethyl acetate, and the organic phases are combined and dried with anhydrous sodium sulfate; then the filtrate is collected after filtration, and the solvent is removed to obtain a sulfone-containing amino end-capping agent.

[0022] Preferably, the bifluoromonomer is at least one of 4,4'-difluorobenzophenone imine and difluorodiketone imine; and the bisphenol monomer is at least one of hydroquinone, diphenol, 4,4'-dihydroxybenzophenone, and 4,4'-dihydroxy diphenyl ether.

[0023] Preferably, the step of polymerizing the sulfone-containing amino end-capping agent, the bifluoromonomer, the bisphenol monomer, and potassium carbonate in sulfolane to obtain an amino end-capped polyarylether includes:

[0024] The sulfone-containing amino end-capping agent, the bifluoromonomer, the bisphenol monomer, and potassium carbonate are simultaneously dissolved in sulfolane; then toluene is added, and the temperature is raised to the azeotropic temperature; after toluene reflux is maintained for a certain period of time, the toluene is discharged; the temperature is continuously raised to not less than 210 ℃ for reaction; then the product is discharged into ethanol, and is crushed, washed, and dried to obtain an amino end-capped polyarylether.

[0025] Preferably, the step of performing diazonium salt reaction on the amino end-capped polyarylether with nitrous salt tetrafluoroborate to obtain a diazonium salt end-capped polyarylether includes:

[0026] The amino end-capped polyarylether is dissolved in 1,4-dioxane; the solution is added dropwise to an acetonitrile solution containing nitrous salt tetrafluoroborate; when the solution turns into a dark brown transparent solution, the product is discharged into diethyl ether, and the diazonium salt end-capped polyarylether is quickly precipitated, filtered, and washed with diethyl ether to obtain the diazonium salt end-capped polyarylether.

[0027] Preferably, the step of preparing an electrolyte from the diazonium salt end-capped polyarylether, connecting carbon fibers to a cathode, immersing the carbon fibers in the electrolyte containing the diazonium salt end-capped polyarylether, and applying a reduction potential for reaction to obtain carbon fibers grafted with polyarylether includes:

[0028] The diazonium salt end-capped polyarylether and a supporting electrolyte are dissolved in acetonitrile to prepare an electrolyte.

[0029] The carbon fiber is connected with the cathode, immersed in the electrolyte, and reacts by applying a reduction potential, the carbon fiber after electrochemical reduction is cleaned with acetonitrile and dried to obtain the carbon fiber grafted with polyarylether.

[0030] Preferably, the supporting electrolyte is tetrabutylammonium tetrafluoroborate.

[0031] Preferably, the step of hydrolyzing the carbon fiber grafted with polyarylether in an acidic environment to obtain the crystalline polyarylether ketone surface grafted carbon fiber specifically comprises:

[0032] The carbon fiber grafted with polyarylether is placed in acetone, and hydrochloric acid is added dropwise, and the temperature is raised to reflux; then filtering and washing treatment, drying to obtain the crystalline polyarylether ketone surface grafted modified carbon fiber.

[0033] Another object of the present application is to provide a crystalline polyarylether ketone surface grafted carbon fiber prepared by the above preparation method.

[0034] The preparation method of the crystalline polyarylether ketone surface grafted carbon fiber provided by the present application, the amino capping agent containing sulfonyl is prepared, and the amino capping agent containing sulfonyl is used to realize the "one-pot" preparation of the amino capping polyarylether and the diazonium salt capping polyarylether; the surface of the carbon fiber is modified by the diazonium salt capping polyarylether, the carbon fiber can be directly connected with the polymer through the high-temperature-resistant and corrosion-resistant phenyl and sulfonyl, and the polyarylether ketone grafted on the surface of the carbon fiber has crystallinity.

[0035] The raw materials used in the present application are relatively low in price, the amino capping agent containing sulfonyl prepared has high reactivity, can avoid the capping polymerization of "capping after polymerization", realizes the "one-pot" capping polymerization, and reduces the reaction period (omits 2-6 h of the post-capping process).

[0036] The crystalline polyarylether ketone surface grafted modified carbon fiber prepared by the present application has better high-temperature resistance and corrosion resistance because the carbon fiber is directly connected with the polymer through the high-temperature-resistant and corrosion-resistant phenyl and sulfonyl, and avoids the use of ester groups and other functional groups that are not resistant to high temperature and corrosion in the traditional mechanism.

[0037] The preparation method provided by the present application avoids the traditional esterification and amidation reactions, and uses electrochemical reduction as the grafting method, which has high reaction efficiency (3-5 min), so that batch preparation of the crystalline polyarylether ketone surface grafted modified carbon fiber can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1Structural formula of carbon fiber grafted with polyarylether prepared in the embodiment of the present application;

[0039] Figure 2 Structural formula of carbon fiber grafted with crystalline polyarylether ketone prepared in the embodiment of the present application;

[0040] Figure 3 Raman spectrum characterization result graph of carbon fiber grafted with crystalline polyarylether ketone prepared in the embodiment of the present application;

[0041] Figure 4 Cyclic voltammogram of electrochemical reduction grafting reaction provided in the embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0043] The embodiment of the present application first prepares an amino capping agent containing a diphenyl sulfone structure by a sulfonation reaction using a low-cost reagent, realizes “one-pot” polymerization of the amino-capped polymer by using the characteristic that the reactivity is high (the electron-withdrawing ability of the fluorobenzene para-functional group is higher, the substitution reactivity is higher, which is reflected in that the polymerization reactivity of 4,4'-difluorobenzophenone is significantly lower than that of 4,4'-difluorodiphenyl sulfone), directly constructs a diazonium salt functional group on the end group of the polymer, and efficiently realizes the purpose of grafting the polymer on the surface of the carbon fiber (1-5 min) through an electrochemical reduction reaction. Finally, the polymer grafted on the surface of the carbon fiber is converted into a crystalline polyarylether ketone through a hydrolysis reaction. The embodiment of the present application realizes the grafting on the surface of the carbon fiber through the phenylene group and the sulfone group which are resistant to high temperature.

[0044] The capping agent used in the embodiment of the present application has the following characteristics: the diphenyl sulfone structure constructed by a sulfonation reaction is used as a base element, one of the benzene groups is substituted by a fluorine or chlorine atom at the para position, and the other benzene group is directly or indirectly connected to an aniline functional group. Among them, the sulfone group at the para position of the fluorine (chlorine) atom can significantly improve the reaction efficiency of the capping agent, and “one-pot” capping polymerization can be realized. The synthesis method is as follows: a sulfonamide compound containing a nitro group and a halobenzene are used as raw materials, a capping agent precursor is prepared by a sulfonation reaction, and the nitro group is reduced to an amino group by a reduction reaction (the reducing agent is SnCl2) to prepare the capping agent. The specific reaction route is as follows:

[0045] ;

[0046] Among them, X is F or Cl; The structural formula of the amino-terminated polyarylether is as follows:

[0047] ;

[0048] Correspondingly, The structural formula of the amino-terminated polyarylether is as follows:

[0049] .

[0050] The amino-terminated polyarylether prepared by the embodiment of the application has the following characteristics: the amino-terminated polyarylether is directly prepared by one-pot polymerization, and the polymer main chain is connected to the aniline end group through a sulfone group. The one-pot polymerization method is as follows: the end-capping agent, the difluoromonomer, the bisphenol monomer and potassium carbonate are simultaneously dissolved in sulfolane (solvent), and the amino-terminated polyarylether is obtained after water is removed by azeotropic distillation. The specific reaction route is as follows:

[0051] ;

[0052] The structural formula of the bisphenol monomer is as follows:

[0053] ;

[0054] .

[0055] The structural formula of the difluoromonomer is as follows:

[0056] .

[0057] The structural formula of the amino-terminated polyarylether is as follows:

[0058]

[0059] ;

[0060] The structural formula of R is as follows:

[0061] .

[0062] The diazonium salt-terminated polyarylether prepared by the embodiment of the application has the following characteristics: the polymer main chain is connected to the phenyl tetrafluoroboric acid diazonium salt end group through a sulfone group. The implementation is as follows: the diazonium salt-terminated polyarylether is prepared by the reaction of tetrafluoroboric acid nitrite and the diazonium salt of the aniline end group. The specific reaction route is as follows:

[0063]

[0064] The structural formula of the diazonium salt-terminated polyarylether is as follows:

[0065]

[0066] ;

[0067] wherein R1 is of any one of the following structures:

[0068] .

[0069] The polyarylether surface grafted carbon fiber prepared in the embodiment of the present application is characterized in that: through the high-efficiency electrochemical reduction reaction, the carbon fiber surface is directly connected with the polyarylether through the phenyl and the sulfone group. The specific method is as follows: the carbon fiber is connected with the cathode of the electrolytic cell, is immersed in the electrolyte (containing the diazonium salt capped polyarylether), a reduction potential is applied for reaction, and after washing and drying, the carbon fiber grafted with the polyarylether is obtained, and the structure is as shown in Figure 1 . Figure 1 wherein the structure of the polyarylether is any one of the following structures:

[0070]

[0071] .

[0072] The polyarylether ketone surface grafted carbon fiber prepared in the embodiment of the present application is characterized in that: the carbon fiber surface is directly connected with the crystalline polyarylether ketone through the phenyl and the sulfone group, and the method is as follows: the carbon fiber grafted with the polyarylether is hydrolyzed into the crystalline polyarylether ketone in an acidic environment, and the crystalline polyarylether ketone surface grafted carbon fiber is obtained, and the structure is as shown in Figure 2 . Figure 2 wherein the structure of the crystalline polyarylether ketone is any one of the following structures:

[0073]

[0074]

[0075] ;

[0076] In addition, Figure 1 and Figure 2 wherein the structure of R2 is any one of the following structures:

[0077] .

[0078] Specifically, in one embodiment of the present application, a preparation method of the crystalline polyarylether ketone surface grafted carbon fiber is provided, which comprises the following steps:

[0079] S1, under the condition of not more than -5 ℃ and inert gas protection, the sulfonyl chloride compound containing nitro group is fully dissolved in halogenated benzene (both as solvent and as reactant), and AlCl3 powder is added in batches; then it is stirred at room temperature for 3-5 hours; it is continuously heated to reflux and stirred for 8-10 hours; deionized water is added to separate the unreacted halogenated benzene by azeotropic reflux; the filter residue is washed with NaOH solution (0.5-1.5 mol / L) and deionized water in turn to obtain a crude product; the crude product is recrystallized three times with ethanol and dried to obtain a capping agent precursor;

[0080] S2, after the capping agent precursor is dissolved in methanol (0.01-0.1 mol / L), tin chloride dihydrate (5 times the molar amount of the capping agent precursor) is added to the solution, and refluxed for 5-7 h; then the filtrate is collected by filtration, and the pH value of the filtrate is adjusted to not less than 9 using a saturated aqueous Na2CO3 solution; the mixture is extracted twice with ethyl acetate, and the organic phase is dried with anhydrous sodium sulfate; then the filtrate is collected by filtration and the solvent is removed to obtain an amino capping agent containing a sulfone group;

[0081] S3, the amino capping agent containing a sulfone group, the bifluoromonomer, the bisphenol monomer and potassium carbonate are simultaneously dissolved in sulfolane (solvent); then toluene is added, heated to azeotrope (130-150 ℃), and maintained at toluene reflux for 3-5 h, then the toluene is discharged; continue to heat to not less than 210 ℃ for reaction, maintain for 3-5 hours; then discharge into ethanol, crush, and wash with ethanol and water for 3 times in turn, and dry to obtain an amino capping polyarylether;

[0082] S4, the amino capping polyarylether is dissolved in 1,4-dioxane (amino end group equivalent 0.01-0.1 mol / L); the above solution is added dropwise into an acetonitrile solution (0.01-0.1 mol / L) containing nitrosyl tetrafluoroborate (NOBF4); when the solution turns into a dark brown transparent solution, discharge into diethyl ether, quickly precipitate diazonium salt capping polyarylether, filter and wash with diethyl ether to obtain diazonium salt capping polyarylether;

[0083] S5, the diazonium salt capping polyarylether (0.01-0.1 g / mL) and a supporting electrolyte (0.5-1.5 mM) are dissolved in acetonitrile to prepare an electrolyte; the carbon fiber is connected with a cathode and immersed in the electrolyte, and a reduction potential of -0.3 V is applied for 1-5 min; the electrochemically reduced carbon fiber is washed with acetonitrile and dried to obtain a carbon fiber grafted with polyarylether;

[0084] S6, the carbon fiber grafted with polyarylether is placed in acetone (0.01-0.05 g / mL), and 1-3 M hydrochloric acid is added dropwise in an amount equal to that of the acetone, and then heated to reflux for 20-28 h; then filtered, washed with deionized water for multiple times, and dried to obtain the crystalline polyarylether ketone surface grafted modified carbon fiber.

[0085] wherein the nitro-containing sulfonyl chloride compound is at least one of nitrobenzenesulfonyl chloride, 4-nitro-biphenyl-4-sulfonyl chloride, and 4-(4-nitrophenoxy)benzenesulfonyl chloride; the halogenated benzene is chlorobenzene or fluorobenzene, preferably fluorobenzene. The difluoro monomer is 4,4'-difluorobenzophenone imine and / or difluorodiketone imine; the bisphenol monomer is at least one of hydroquinone, biphenol, 4,4'-dihydroxybenzophenone, and 4,4'-dihydroxydiphenyl ether. The supporting electrolyte is tetrabutylammonium tetrafluoroborate.

[0086] The following examples are some specific implementation cases and application cases of the present application in practical application, but are not limited thereto.

[0087] Example 1: The example provides a preparation method of crystalline polyarylether ketone surface grafted carbon fiber, specifically comprising the following steps:

[0088] (1) Under the condition of -5 ℃ and inert gas protection, nitrobenzenesulfonyl chloride (0.1 mol) is fully dissolved in chlorobenzene (chlorobenzene is used as a solvent and also as a reactant), and AlCl3 powder (0.12 mol) is added in 5 batches; the temperature is raised to room temperature, and stirred for 3 hours; the temperature is raised to reflux, and stirred for 8 hours; deionized water is added for azeotropic reflux to separate the unreacted chlorobenzene; the filter residue (crude product) is filtered and washed with NaOH solution (1 mol / L) and deionized water in sequence; the end-capping agent precursor (4-chloro-4'-nitro diphenyl sulfone, corresponding to the above chemical structural formula: R'=R'-1; X=Cl) is obtained by recrystallization with ethanol three times and drying, with a yield of 85%;

[0089] (2) The end-capping agent precursor (4-chloro-4'-nitro diphenyl sulfone) obtained in step (2) is dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) is added to the solution; reflux for 6 h; filter and collect the filtrate, and adjust the pH value of the filtrate to 9 using a saturated Na2CO3 aqueous solution; the mixture is extracted with ethyl acetate twice, and the combined organic phase is dried with anhydrous sodium sulfate; after filtration, the filtrate is collected and the solvent is removed to obtain the end-capping agent (4-chloro-4'-aminodiphenyl sulfone, corresponding to the above chemical structural formula: R''=R''-1; X=Cl), with a yield of 95%;

[0090] (3) 0.001 mol of the end-capping agent (4-chloro-4'-amino diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorobenzophenone imine, 0.1 mol of hydroquinone and 0.13 mol of potassium carbonate were simultaneously added into a sulfolane (solvent); toluene was added, and the temperature was raised to the azeotropic point (130°C); after toluene and water were azeotropically refluxed for 4 hours, the toluene was discharged; the temperature was raised to 210°C, and maintained for 4 hours; the product was discharged into ethanol, and pulverized; the product was washed with ethanol and water for 3 times, respectively, and dried to obtain an amino end-capped polyether ether ketone imine (corresponding to the chemical structural formula: NH2-PI-1; R = R1-1);

[0091] (4) The amino end-capped polyether ether ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into an acetonitrile solution (0.01 mol / L) containing 1.5 times of the amino end group equivalent of nitrous salt of tetrafluoroboric acid; when the solution became a dark brown transparent solution, the product was discharged into diethyl ether, and the diazonium salt end-capped polyaryl ether was quickly precipitated, filtered and washed with diethyl ether to obtain a diazonium salt end-capped polyether ether ketone imine (corresponding to the chemical structural formula: Dia-PI-1; R1 = R1-1);

[0092] (5) The diazonium salt end-capped polyether ether ketone imine (0.01 g / mL) obtained in step (4) was dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fiber was connected to the cathode of an electrolytic cell, and immersed in the electrolyte; a reduction potential of -0.3 V was applied for 3 min to perform an electrochemical reduction grafting reaction, and the cyclic voltammogram of the electrochemical reduction grafting reaction is shown in Figure 4 ; the carbon fiber after electrochemical reduction was washed with acetonitrile and dried to obtain a carbon fiber grafted with polyether ether ketone imine (corresponding to the chemical structural formula: PI-1; R2 = R2-1);

[0093] (6) The carbon fiber grafted with polyether ether ketone imine obtained in step (5) was immersed in acetone (0.01 g / mL); 2 M hydrochloric acid was added dropwise in an amount equal to that of acetone; the temperature was raised to reflux, and maintained for 24 h; the product was filtered, washed with deionized water for 3 times, and dried to obtain a crystalline polyether ether ketone surface grafted and modified carbon fiber (corresponding to the chemical structural formula: P-1; R2 = R2-1). The crystalline polyether ether ketone surface grafted and modified carbon fiber prepared above was subjected to Raman spectrum characterization, and the results are shown in Figure 3 , which shows that the crystalline polyaryl ether ketone is successfully grafted on the surface of the carbon fiber.

[0094] Example 2: The example provides a preparation method of a crystalline polyaryl ether ketone surface grafted carbon fiber, which specifically comprises the following steps:

[0095] (1) 4-nitro-biphenyl-4-sulfonyl chloride (0.1 mol) was dissolved in fluorobenzene (fluorobenzene as solvent and reactant) at -5 ℃ under inert gas protection, and AlCl3 powder (0.15 mol) was added in 5 batches; the temperature was raised to room temperature, and stirred for 5 hours; the temperature was raised to reflux, and stirred for 10 hours; deionized water was added to separate the unreacted fluorobenzene by azeotropic reflux; the filter residue (crude product) was filtered and washed with NaOH solution (1 mol / L) and deionized water in turn; recrystallized with ethanol for three times and dried to obtain the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R'=R'-2; X=F), with a yield of 88%;

[0096] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) was dissolved in methanol (0.1 mol / L), and tin chloride dihydrate (0.5 mol / L) was added to the solution; refluxed for 6 h; the filtrate was collected after filtration, and the pH value of the filtrate was adjusted to 9 using a saturated aqueous Na2CO3 solution; the mixture was extracted with ethyl acetate twice, and the organic phase was dried with anhydrous sodium sulfate after being combined; the filtrate was collected after filtration, and the solvent was removed to obtain the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''=R''-2; X=F), with a yield of 95%;

[0097] (3) 0.02 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorobenzophenone imine, 0.1 mol of 4,4'-dihydroxydiphenyl ether and 0.13 mol of potassium carbonate were simultaneously added to sulfolane (solvent); toluene was added, and the temperature was raised to azeotropy (130 ℃), and toluene and water were azeotropically refluxed for 4 hours, and then the toluene was discharged; the temperature was raised to 210 ℃, and maintained for 4 hours; the product was discharged into ethanol and crushed; washed with ethanol and water for 3 times in turn, and dried to obtain the amino-terminated polyether ether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-2; R=R-3);

[0098] (4) The amino-terminated polyether ether ether ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.1 mol / L); the above solution was added dropwise into an acetonitrile solution (0.1 mol / L) containing 1.5 times of the amino end group equivalent of nitrite tetrafluoroborate; when the solution body became a dark brown transparent solution, the product was discharged into diethyl ether, and the diazonium salt-terminated polyaryl ether was quickly precipitated, which was filtered and washed with diethyl ether to obtain the diazonium salt-terminated polyether ether ether ketone imine (corresponding to the above chemical structural formula: Dia-PI-2; R1=R1-3);

[0099] (5) The diazonium salt end-capped polyether ether ether ketone imine (0.01 g / mL) obtained in step (4) is dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fibers are connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V is applied for 3 min; the electrochemically reduced carbon fibers are washed with acetonitrile and dried to obtain carbon fibers grafted with polyether ether ether ketone imine (corresponding to the chemical structural formula: PI-2; R2=R2-3 above);

[0100] (6) The carbon fibers grafted with polyether ether ether ketone imine obtained in step (5) are placed in acetone (0.05 g / mL); after dropwise addition of 2 M hydrochloric acid in an equal volume of acetone; the temperature is raised to reflux and maintained for 24 h; filtration and washing with deionized water for 3 times, and drying to obtain crystalline polyether ether ether ketone surface grafted and modified carbon fibers (corresponding to the chemical structural formula: P-2; R2=R2-3 above).

[0101] Example 3: The embodiment provides a preparation method of crystalline polyaryletherketone surface grafted carbon fibers, which specifically comprises the following steps:

[0102] (1) 4-(4-nitrophenoxy)benzenesulfonyl chloride (0.1 mol) is fully dissolved in fluorobenzene (fluorobenzene is used as a solvent and also as a reactant) under the condition of -5 ℃ and inert gas protection, and AlCl3 powder (0.12 mol) is added in 5 batches; the temperature is raised to room temperature, and stirring is performed for 3 hours; the temperature is raised to reflux, and stirring is performed for 8 hours; deionized water is added for azeotropic reflux to separate unreacted fluorobenzene; the filter residue (crude product) is filtered and washed with NaOH solution (1 mol / L) and deionized water in sequence; the end-capping agent precursor (4-fluoro-4'-(4-nitrophenoxy)diphenyl sulfone, corresponding to the chemical structural formula: R'=R'-3; X=F above) is recrystallized with ethanol for three times and dried to obtain an end-capping agent precursor (4-fluoro-4'-(4-nitrophenoxy)diphenyl sulfone, corresponding to the chemical structural formula: R'=R'-3; X=F above) with a yield of 85%;

[0103] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenoxy)diphenyl sulfone) obtained in step (1) is dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) is added to the solution; reflux is performed for 6 h; the filtrate is filtered and collected, and the pH value of the filtrate is adjusted to 9 using a saturated Na2CO3 aqueous solution; the mixture is extracted with ethyl acetate twice, and the combined organic phase is dried with anhydrous sodium sulfate; after filtration, the filtrate is collected and the solvent is removed to obtain an end-capping agent (4-fluoro-4'-(4-aminophenoxy)diphenyl sulfone, corresponding to the chemical structural formula: R''= R''-3; X= F above) with a yield of 95%;

[0104] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenoxy)diphenylsulfone) obtained in step (2), 0.1 mol of 4,4'-difluorodiketimine, 0.1 mol of 4,4'-dihydroxydiphenyl ether and 0.13 mol of potassium carbonate are simultaneously added into a ring butane sulfone (solvent); toluene is added, and the temperature is raised to azeotropic (130°C), and after toluene and water are azeotropically refluxed for 4 hours, the toluene is discharged; the temperature is raised to 210°C, and maintained for 4 hours; the product is discharged into ethanol, and pulverized; the product is washed with ethanol and water for 3 times respectively, and dried to obtain an amino end-capped polyether ether ether ketone ketone imine (corresponding to the chemical structural formula: NH2-PI-6; R=R-2);

[0105] (4) the amino end-capped polyether ether ether ketone ketone imine obtained in step (3) is dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution is added dropwise into an acetonitrile solution (0.01 mol / L) containing 1.5 times of the amino end group equivalent of nitrous salt of tetrafluoroboric acid; when the solution becomes a dark brown transparent solution, the product is discharged into diethyl ether, and the diazonium salt end-capped polyarylether is quickly precipitated, filtered and washed with diethyl ether to obtain a diazonium salt end-capped polyether ether ether ketone ketone imine (corresponding to the chemical structural formula: Dia-PI-6; R1=R1-2);

[0106] (5) the diazonium salt end-capped polyether ether ether ketone ketone imine (0.01 g / mL) obtained in step (4) is dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fiber is connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V is applied for 3 min; the carbon fiber after electrochemical reduction is washed with acetonitrile and dried to obtain a carbon fiber grafted with polyether ether ether ketone ketone imine (corresponding to the chemical structural formula: PI-6; R2=R2-2);

[0107] (6) the carbon fiber grafted with polyether ether ether ketone ketone imine obtained in step (5) is placed in acetone (0.01 g / mL); 2 M hydrochloric acid is added dropwise in an amount equal to that of acetone; the temperature is raised to reflux, and maintained for 24 h; the product is filtered, washed with deionized water for 3 times, and dried to obtain a crystalline polyether ether ether ketone ketone surface grafted and modified carbon fiber (corresponding to the chemical structural formula: P-6; R2=R2-2).

[0108] Example 4: The example provides a preparation method of a crystalline polyarylether ketone surface grafted carbon fiber, which specifically comprises the following steps:

[0109] (1) 4-nitro-biphenyl-4-sulfonyl chloride (0.1 mol) was dissolved in fluorobenzene (fluorobenzene as solvent and reactant) at -5 ℃ under inert gas protection, and AlCl3 powder (0.12 mol) was added in 5 batches; the temperature was raised to room temperature, and stirred for 3 hours; the temperature was raised to reflux, and stirred for 8 hours; deionized water was added to separate the unreacted fluorobenzene by azeotropic reflux; the filter residue (crude product) was washed with NaOH solution (1 mol / L) and deionized water in sequence; recrystallized with ethanol for three times and dried to obtain the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R'=R'-2; X=F), with a yield of 86%;

[0110] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) was dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) was added to the solution; refluxed for 6 h; filtered and collected the filtrate, and the pH value of the filtrate was adjusted to 9 using a saturated aqueous Na2CO3 solution; the mixture was extracted twice with ethyl acetate, and the organic phase was combined and dried with anhydrous sodium sulfate; after filtration, the filtrate was collected and the solvent was removed to obtain the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''=R''-2; X=F), with a yield of 95%;

[0111] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorobenzophenone imine, 0.1 mol of 4,4'-dihydroxybenzophenone and 0.13 mol of potassium carbonate were simultaneously added to sulfolane (solvent); toluene was added, and the temperature was raised to azeotropy (130 ℃), and toluene and water were azeotropically refluxed for 4 hours, and then the toluene was discharged; the temperature was raised to 210 ℃, and maintained for 4 hours; discharged into ethanol and crushed; washed with ethanol and water for 3 times in sequence, and dried to obtain the amino-terminated polyether ketone imine (corresponding to the above chemical structural formula: NH2-PI-4; R=R-3);

[0112] (4) The amino-terminated polyether ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into a solution of nitroso tetrafluoroborate (0.01 mol / L) in acetonitrile containing 1.5 times of the amino end group equivalent; when the solution body became a dark brown transparent solution, it was discharged into diethyl ether, and the diazonium salt-terminated polyarylether was quickly precipitated, and was filtered and washed with diethyl ether to obtain the diazonium salt-terminated polyether ketone imine (corresponding to the above chemical structural formula: Dia-PI-4; R1=R1-3);

[0113] (5) The diazonium salt end-capped polyether ketone imine (0.01 g / mL) obtained in step (4) is dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fibers are connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V is applied for 5 min; the electrochemically reduced carbon fibers are washed with acetonitrile and dried to obtain polyether ketone imine grafted carbon fibers (corresponding to the chemical structural formula: PI-4; R2=R2-3);

[0114] (6) The polyether ketone imine grafted carbon fibers obtained in step (5) are placed in acetone (0.01 g / mL); after adding 2 M hydrochloric acid dropwise in an equal volume of acetone; the temperature is raised to reflux and maintained for 24 h; filtration and washing with deionized water for 3 times, and drying to obtain crystalline polyether ketone surface grafted modified carbon fibers (corresponding to the chemical structural formula: P-4; R2=R2-3).

[0115] Example 5: The embodiment provides a preparation method of crystalline polyaryletherketone surface grafted carbon fibers, which specifically comprises the following steps:

[0116] (1) 4-nitro-biphenyl-4-sulfonyl chloride (0.1 mol) is fully dissolved in fluorobenzene (fluorobenzene is used as a solvent and also as a reactant) under the condition of -5 ℃ and inert gas protection, and AlCl3 powder (0.12 mol) is added in 5 batches; the temperature is raised to room temperature, and stirring is performed for 3 hours; the temperature is raised to reflux, and stirring is performed for 8 hours; deionized water is added for azeotropic reflux to separate the unreacted fluorobenzene; the filter residue (crude product) is washed with NaOH solution (1 mol / L) and deionized water in sequence; the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the chemical structural formula: R'=R'-2; X=F) is obtained by recrystallization with ethanol for three times and drying, and the yield is 86%;

[0117] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) is dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) is added to the solution; reflux is performed for 6 h; the filtrate is collected after filtration, and the pH value of the filtrate is adjusted to 9 using a saturated Na2CO3 aqueous solution; the mixture is extracted twice with ethyl acetate, and the organic phase is dried with anhydrous sodium sulfate after being combined; the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the chemical structural formula: R''=R''-2; X=F) is obtained after filtration, collection of the filtrate and removal of the solvent, and the yield is 95%;

[0118] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenylsulfone) obtained in step (2), 0.1 mol of 4,4'-difluorodiketimine, 0.1 mol of hydroquinone and 0.13 mol of potassium carbonate were simultaneously added into a sulfolane (solvent); toluene was added, and the temperature was raised to the azeotropic point (130°C); after the toluene and water were azeotropically refluxed for 4 hours, the toluene was removed; the temperature was raised to 210°C, and maintained for 4 hours; the product was discharged into ethanol, and pulverized; the product was washed with ethanol and water for 3 times, respectively, and dried to obtain an amino end-capped polyether ether ketone ketone imine (corresponding to the chemical structural formula: NH2-PI-5; R = R-3);

[0119] (4) The amino end-capped polyether ether ketone ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into an acetonitrile solution (0.01 mol / L) containing 1.5 times of the amino end group equivalent of nitrous salt of tetrafluoroboric acid; when the solution became a dark brown transparent solution, the product was discharged into diethyl ether, and the diazonium salt end-capped polyarylether was quickly precipitated, filtered and washed with diethyl ether to obtain a diazonium salt end-capped polyether ether ketone ketone imine (corresponding to the chemical structural formula: Dia-PI-5; R1= R1-3);

[0120] (5) The diazonium salt end-capped polyether ether ketone ketone imine (0.01 g / mL) obtained in step (4) was dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); the carbon fiber was connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied for 4 min; the carbon fiber after electrochemical reduction was washed with acetonitrile and dried to obtain a carbon fiber grafted with polyether ether ketone ketone imine (corresponding to the chemical structural formula: PI-5; R2-= R2-3);

[0121] (6) The carbon fiber grafted with polyether ether ketone ketone imine obtained in step (5) was placed in acetone (0.01 g / mL); 2 M hydrochloric acid was added dropwise in an amount equal to that of acetone; the temperature was raised to reflux, and maintained for 24 h; the product was filtered, washed with deionized water for 3 times, and dried to obtain a crystalline polyether ether ketone ketone surface grafted and modified carbon fiber (corresponding to the chemical structural formula: P-5; R2= R2-3).

[0122] Example 6: The example provides a preparation method of a crystalline polyarylether ketone surface grafted carbon fiber, which specifically comprises the following steps:

[0123] (1) 4-nitro-biphenyl-4-sulfonyl chloride (0.1 mol) was dissolved in fluorobenzene (fluorobenzene as solvent and reactant) at -5 ℃ under inert gas protection, and AlCl3 powder (0.12 mol) was added in 5 batches; the temperature was raised to room temperature, and stirred for 3 hours; the temperature was raised to reflux, and stirred for 8 hours; deionized water was added to separate the unreacted fluorobenzene by azeotropic reflux; the filter residue (crude product) was washed with NaOH solution (1 mol / L) and deionized water in sequence; recrystallized with ethanol for three times and dried to obtain the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the chemical structural formula above: R'=R'-2; X=F), with a yield of 86%;

[0124] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) was dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) was added to the solution; refluxed for 6 h; filtered and collected the filtrate, and the pH value of the filtrate was adjusted to 9 using a saturated aqueous Na2CO3 solution; the mixture was extracted twice with ethyl acetate, and the organic phase was combined and dried with anhydrous sodium sulfate; after filtration, the filtrate was collected and the solvent was removed to obtain the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the chemical structural formula above: R''=R''-2; X=F), with a yield of 95%;

[0125] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorobenzophenone imine, 0.1 mol of biphenyl diol and 0.13 mol of potassium carbonate were simultaneously added to sulfolane (solvent); toluene was added, and the temperature was raised to azeotropy (130 ℃), and toluene and water were azeotropically refluxed for 4 hours, and then the toluene was discharged; the temperature was raised to 210 ℃, and maintained for 4 hours; discharged into ethanol and crushed; washed with ethanol and water in sequence for 3 times, and dried to obtain the amino end-capped biphenyl type polyether ether ketone imine (corresponding to the chemical structural formula above: NH2-PI-3; R=R-3);

[0126] (4) The amino end-capped biphenyl type polyether ether ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into a solution of nitroso tetrafluoroborate in acetonitrile (0.01 mol / L) containing 1.5 times the amino end group equivalent; when the solution turned into a dark brown transparent solution, it was discharged into diethyl ether, and the diazonium salt end-capped polyarylether was quickly precipitated, and filtered and washed with diethyl ether to obtain the diazonium salt end-capped biphenyl type polyether ether ketone imine (corresponding to the chemical structural formula above: Dia-PI-3; R1=R1-3);

[0127] (5) The diazonium salt end-capped biphenyl polyether ether ketone imine (0.01 g / mL) obtained in step (4) is dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fibers are connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V is applied for 3 min; the electrochemically reduced carbon fibers are washed with acetonitrile and dried to obtain carbon fibers grafted with biphenyl polyether ether ketone imine (corresponding to the chemical structural formula: PI-3; R2=R2-3 above);

[0128] (6) The carbon fibers grafted with biphenyl polyether ether ketone imine obtained in step (5) are placed in acetone (0.01 g / mL); after adding 2 M hydrochloric acid dropwise in an equal volume of acetone; the temperature is raised to reflux and maintained for 24 h; filtration, washing with deionized water for 3 times, and drying to obtain crystalline biphenyl polyether ether ketone surface grafted and modified carbon fibers (corresponding to the chemical structural formula: P-3; R2=R2-3 above).

[0129] Example 7: The embodiment provides a preparation method of crystalline polyaryletherketone surface grafted carbon fibers, which specifically comprises the following steps:

[0130] (1) Under the conditions of -5 ℃ and inert gas protection, 4-nitro biphenyl-4-sulfonyl chloride (0.1 mol) is fully dissolved in fluorobenzene (fluorobenzene is used as a solvent and also as a reactant), and AlCl3 powder (0.12 mol) is added in 5 batches; the temperature is raised to room temperature, and stirred for 3 hours; the temperature is raised to reflux, and stirred for 8 hours; deionized water is added for azeotropic reflux to separate the unreacted fluorobenzene; the filter residue (crude product) is filtered and washed with NaOH solution (1 mol / L) and deionized water in sequence; the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the chemical structural formula: R'=R'-2; X=F) is recrystallized with ethanol for three times and dried to obtain, with a yield of 86%.

[0131] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) is dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) is added to the solution; reflux for 6 h; filter and collect the filtrate, and adjust the pH of the filtrate to 9 with a saturated Na2CO3 aqueous solution; the mixture is extracted twice with ethyl acetate, and the combined organic phase is dried with anhydrous sodium sulfate; after filtration, the filtrate is collected and the solvent is removed to obtain the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the chemical structural formula: R''=R''-2; X=F), with a yield of 95%.

[0132] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenylsulfone) obtained in step (2), 0.1 mol of 4,4'-difluorodiketimine, 0.1 mol of hydroquinone, and 0.13 mol of potassium carbonate were simultaneously added to a cyclobutan sulfone (solvent); toluene was added, and the temperature was raised to the azeotropic point (130°C); after toluene and water were azeotropically refluxed for 4 hours, the toluene was removed; the temperature was raised to 210°C, and maintained for 4 hours; the product was discharged into ethanol and pulverized; the product was washed with ethanol and water for 3 times, respectively, and dried to obtain an amino end-capped biphenyl polyether ether ketone ketone imine (corresponding to the chemical structural formula: NH2-PI-7; R = R-3);

[0133] (4) The amino end-capped biphenyl polyether ether ketone ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into an acetonitrile solution (0.01 mol / L) containing 1.5 times of the amino end group equivalent of nitrous acid tetrafluoroborate; when the solution became a dark brown transparent solution, the product was discharged into diethyl ether, and the diazonium salt end-capped polyarylether was quickly precipitated, filtered, and washed with diethyl ether to obtain a diazonium salt end-capped biphenyl polyether ether ketone ketone imine (corresponding to the chemical structural formula: Dia-PI-7; R1= R1-3);

[0134] (5) The diazonium salt end-capped biphenyl polyether ether ketone ketone imine (0.01 g / mL) obtained in step (4) was dissolved in acetonitrile as an electrolyte with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM); carbon fiber was connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied for 3 min; the carbon fiber after electrochemical reduction was washed with acetonitrile and dried to obtain a carbon fiber grafted with a biphenyl polyether ether ketone ketone imine (corresponding to the chemical structural formula: PI-7; R2-= R2-3);

[0135] (6) The carbon fiber grafted with a biphenyl polyether ether ketone ketone imine obtained in step (5) was placed in acetone (0.01 g / mL); 2 M hydrochloric acid was added dropwise in an equal volume of acetone; the temperature was raised to reflux, and maintained for 24 h; the product was filtered, washed with deionized water for 3 times, and dried to obtain a crystalline biphenyl polyether ether ketone ketone surface grafted modified carbon fiber (corresponding to the chemical structural formula: P-7; R2= R2-3).

[0136] Example 8: The embodiment provides a preparation method of a crystalline polyaryletherketone surface grafted carbon fiber, which specifically comprises the following steps:

[0137] (1) 4-nitro-biphenyl-4-sulfonyl chloride (0.1 mol) was dissolved in fluorobenzene (fluorobenzene as solvent and reactant) at -5 ℃ under inert gas protection, and AlCl3 powder (0.12 mol) was added in 5 batches; the temperature was raised to room temperature, and stirred for 3 hours; the temperature was raised to reflux, and stirred for 8 hours; deionized water was added to separate the unreacted fluorobenzene by azeotropic reflux; the filter residue (crude product) was filtered and washed with NaOH solution (1 mol / L) and deionized water in turn; recrystallized with ethanol for three times and dried to obtain the end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R'=R'-2; X=F), with a yield of 86%;

[0138] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenyl)diphenyl sulfone) obtained in step (1) was dissolved in methanol (0.01 mol / L), and tin chloride dihydrate (0.05 mol / L) was added to the solution; refluxed for 6 h; filtered and collected the filtrate, and the pH value of the filtrate was adjusted to 9 using a saturated aqueous Na2CO3 solution; the mixture was extracted twice with ethyl acetate, and the organic phase was combined and dried with anhydrous sodium sulfate; after filtration, the filtrate was collected and the solvent was removed to obtain the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''=R''-2; X=F), with a yield of 95%;

[0139] (3) 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorodiketimine, 0.1 mol of 4,4'-dihydroxybenzophenone and 0.13 mol of potassium carbonate were simultaneously added to sulfolane (solvent); toluene was added, and the temperature was raised to azeotropy (130 ℃), and toluene and water were azeotropically refluxed for 4 hours, and then the toluene was discharged; the temperature was raised to 210 ℃, and maintained for 4 hours; discharged into ethanol and crushed; washed with ethanol and water for 3 times in turn, and dried to obtain the amino-terminated polyether ketone ether ketone ketone imine (corresponding to the above chemical structural formula: NH2-PI-8; R=R-3);

[0140] (4) The amino-terminated polyether ketone ether ketone ketone imine obtained in step (3) was dissolved in 1,4-dioxane (amino end group equivalent 0.01 mol / L); the above solution was added dropwise into a solution of nitroso tetrafluoroborate in acetonitrile (0.01 mol / L) containing 1.5 times the amino end group equivalent; when the solution turned into a dark brown transparent solution, it was discharged into diethyl ether, and the diazonium salt-terminated polyarylether was quickly precipitated, and filtered and washed with diethyl ether to obtain the diazonium salt-terminated polyether ketone ether ketone ketone imine (corresponding to the above chemical structural formula: Dia-PI-8; R1=R1-3);

[0141] (5) The diazonium salt end-capped polyether ketone ether ketone ketone imine (0.01 g / mL) obtained in step (4) is dissolved in acetonitrile with a supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) as an electrolyte; carbon fiber is connected to the cathode of an electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V is applied for 3 min; the electrochemically reduced carbon fiber is washed with acetonitrile and dried to obtain carbon fiber grafted with polyether ketone ether ketone ketone imine (corresponding to the chemical structural formula: PI-8; R2=R2-3);

[0142] (6) The carbon fiber grafted with polyether ketone ether ketone ketone imine obtained in step (5) is placed in acetone (0.01 g / mL); 2 M hydrochloric acid is added dropwise in an amount equal to that of acetone; the temperature is raised to reflux and maintained for 24 h; filtration is performed and the product is washed with deionized water three times and dried to obtain crystalline polyether ketone ether ketone ketone surface grafted modified carbon fiber (corresponding to the chemical structural formula: P-8; R2-=R2-3).

[0143] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification.

Claims

1. A method for producing a crystalline polyarylene ether ketone surface-grafted carbon fiber, characterized by, The method comprises the following steps: The sulfuryl chloride compound containing nitro group and halogenated benzene are sequentially subjected to sulfonation reaction and reduction reaction to obtain an amino capping agent containing sulfone group; The amino capping agent containing sulfone group, difluoro monomer, bisphenol monomer and potassium carbonate are placed in sulfolane to perform polymerization reaction, so as to obtain an amino capping polyarylether; The amino capping polyarylether is subjected to diazonium salt reaction with nitrite salt of tetrafluoroboric acid, so as to obtain a diazonium salt capping polyarylether; The diazonium salt capping polyarylether is prepared into an electrolyte, carbon fiber is connected with a cathode, and is immersed in the electrolyte containing the diazonium salt capping polyarylether, so as to perform reaction under a reduction potential, so as to obtain carbon fiber grafted with polyarylether; The carbon fiber grafted with polyarylether is subjected to hydrolysis reaction in an acidic environment, so as to obtain crystalline polyarylether ketone surface grafted carbon fiber.

2. The method of producing a crystalline polyarylene ether ketone surface- grafted carbon fiber according to claim 1, characterized by, The sulfuryl chloride compound containing nitro group is at least one of nitrobenzenesulfonyl chloride, 4-nitro biphenyl-4-sulfonyl chloride and 4-(4-nitrophenoxy) benzene sulfonyl chloride; and the halogenated benzene is chlorobenzene or fluorobenzene.

3. The method of producing a crystalline polyarylene ether ketone surface- grafted carbon fiber according to claim 1 or 2, characterized by, The step of sequentially performing sulfonation reaction and reduction reaction on the sulfuryl chloride compound containing nitro group and halogenated benzene to obtain an amino capping agent containing sulfone group specifically comprises the following steps: The sulfuryl chloride compound containing nitro group is fully dissolved in halogenated benzene under the condition of not more than-5 ℃ and inert gas protection, and AlCl3 powder is added in batches; then the temperature is raised to room temperature for stirring; the temperature is continuously raised to reflux; deionized water is added for azeotropic reflux to separate unreacted halogenated benzene; the filter residue is filtered and washed to obtain a crude product; the crude product is recrystallized three times with ethanol and dried to obtain a capping agent precursor; After the capping agent precursor is dissolved in methanol, tin chloride dihydrate is added to the solution and refluxed; then the filtrate is filtered and collected, the pH value of the filtrate is adjusted to not less than 9 with saturated aqueous Na2CO3 solution; the mixture is extracted twice with ethyl acetate, and the organic phase is dried with anhydrous sodium sulfate; then the filtrate is filtered, collected and the solvent is removed to obtain an amino capping agent containing sulfone group.

4. The method for preparing crystalline polyaryletherketone surface-grafted carbon fibers according to claim 1, wherein: The difluoro monomer is 4,4'-difluorobenzophenone imine and / or difluorodiketone imine; and the bisphenol monomer is at least one of hydroquinone, biphenol, 4,4'-dihydroxybenzophenone and 4,4'-dihydroxy diphenyl ether.

5. The method of producing a crystalline polyarylene ether ketone surface- grafted carbon fiber according to claim 1 or 4, characterized by, The step of placing the amino capping agent containing sulfone group, difluoro monomer, bisphenol monomer and potassium carbonate in sulfolane to perform polymerization reaction to obtain an amino capping polyarylether specifically comprises the following steps: The amino capping agent containing sulfone group, difluoro monomer, bisphenol monomer and potassium carbonate are simultaneously dissolved in sulfolane; then toluene is added, the temperature is raised to azeotropy, toluene is maintained to reflux for a certain time, and then toluene is discharged; the temperature is continuously raised to not less than 210 ℃ for reaction; then the product is discharged into ethanol, crushed, washed and dried to obtain an amino capping polyarylether.

6. The method of claim 1, wherein the carbon fiber is surface grafted with a crystalline poly(arylene ether ketone) having a structure represented by formula (1) : ###0001### (1) wherein A represents a divalent aromatic group, and n represents an integer of 2 to 10. The step of performing diazonium salt reaction on the amino capping polyarylether with nitrite salt of tetrafluoroboric acid to obtain a diazonium salt capping polyarylether specifically comprises the following steps: The amino-terminated polyarylether is dissolved in 1,4-dioxane; the solution is added dropwise into a solution of nitroso tetrafluoroborate in acetonitrile; when the solution becomes a dark brown transparent solution, it is discharged into ether, and the diazonium-terminated polyarylether is precipitated rapidly, filtered and washed with ether to obtain the diazonium-terminated polyarylether.

7. The method of claim 1, wherein the carbon fiber is surface grafted with a crystalline poly(arylene ether ketone) having a structure represented by formula (1) : ###00001### (1) wherein A represents a divalent aromatic group, and n represents an integer of 2 to 10. The diazonium-terminated polyarylether is prepared into an electrolyte, carbon fibers are connected to a cathode and immersed in the electrolyte containing the diazonium-terminated polyarylether, and a reduction potential is applied to carry out the reaction to obtain the carbon fibers grafted with polyarylether, which specifically comprises: The diazonium-terminated polyarylether and a supporting electrolyte are dissolved in acetonitrile to prepare an electrolyte; The carbon fibers are connected to a cathode and immersed in the electrolyte, and a reduction potential is applied to carry out the reaction, and the carbon fibers after electrochemical reduction are washed with acetonitrile and dried to obtain the carbon fibers grafted with polyarylether.

8. The method for preparing crystalline polyaryletherketone surface-grafted carbon fibers according to claim 7, characterized in that: The supporting electrolyte is tetrabutylammonium tetrafluoroborate.

9. The method of claim 1, wherein the carbon fiber is surface grafted with a crystalline poly(arylene ether ketone) having a structure represented by formula (1) : ###0002### (1) wherein A represents a divalent aromatic group, and n represents an integer of 2 to 10. The carbon fibers grafted with polyarylether are subjected to hydrolysis reaction in an acidic environment to obtain the crystalline polyarylether ketone surface-grafted carbon fibers, which specifically comprises: The carbon fibers grafted with polyarylether are placed in acetone, and hydrochloric acid is added dropwise, and the temperature is raised to reflux; then, filtration and washing treatment are carried out, and the carbon fibers are dried to obtain the crystalline polyarylether ketone surface-grafted and modified carbon fibers.

10. Crystalline polyarylether ketone surface-grafted carbon fibers prepared by the preparation method of any one of claims 1-9.

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