A crystalline polyaryletherketone surface-grafted graphene and its preparation method

Abstract

This invention discloses a method for preparing crystalline polyaryletherketone (PAH) surface-grafted graphene, belonging to the field of carbon materials technology. The preparation method includes the following steps: polymerization of an amino-termining agent containing sulfone groups, a difluoro monomer, a bisphenol monomer, and potassium carbonate in sulfolane to obtain an amino-terminated PAH; a diazonium salt reaction of the amino-terminated PAH with nitrite tetrafluoroborate to obtain a diazonium salt-terminated PAH; connecting graphene to a cathode and immersing it in an electrolyte containing the diazonium salt-terminated PAH, applying a reduction potential to react and obtain PAH-grafted graphene; ultrasonically dispersing the PAH-grafted graphene and hydrolyzing it in an acidic environment to obtain crystalline PAH surface-grafted graphene. The crystalline PAH surface-grafted graphene obtained by this invention exhibits better high-temperature and corrosion resistance because the graphene is directly connected to the polymer through high-temperature and corrosion-resistant phenyl and sulfone groups.

Description

Technical Field

[0001] This invention relates to the field of carbon materials technology, specifically to a method for preparing crystalline polyaryletherketone surface-grafted graphene. Background Technology

[0002] Graphene is a two-dimensional carbon material with a large specific surface area and good electrical conductivity, making it a versatile nanomaterial reinforcement. However, due to its large specific surface area and high surface energy, graphene is prone to aggregation and difficult to disperse. Furthermore, the lack of effective interfacial interaction between graphene and crystalline polyaryletherketones (PAKs) results in a relatively weak interface, posing potential risks. Therefore, chemical grafting is needed to improve the dispersibility of graphene and its interfacial interaction with PAKs. Grafting crystalline PAKs onto the graphene surface via chemical bonding presents four challenges:

[0003] (1) In order to ensure that the resin matrix at the interface has good compatibility and that the interface phase also has the same corrosion resistance and high temperature resistance as the polyaryletherketone resin matrix, it is necessary to graft crystalline polyaryletherketone onto the graphene surface.

[0004] (2) The excellent corrosion resistance of crystalline polyarylether ketones means that they have no effective solvent and are difficult to react effectively in the solid state;

[0005] (3) Functional groups such as ester, amide, aliphatic ether, and alkyl groups are generally not heat-resistant, with decomposition temperatures less than or equal to, and usually below, 300°C, which cannot meet the molding requirements of crystalline polyaryletherketones at 400°C. Therefore, grafting is achieved through stable, heat-resistant chemical bonds;

[0006] (4) Chemical bond grafting needs to be achieved efficiently.

[0007] There is limited research both domestically and internationally on grafting polyaryletherketones (PAEs) onto graphene surfaces. Similar studies include: CN113717413A, which discloses a method to modify graphene with a silane coupling agent and graft polytrifluoroethylene (PTFE) onto the graphene surface via a free radical reaction. PAEs are difficult to achieve similar effects through free radical reactions. CN113717413A also discloses a method to graft alkyl groups onto the graphene surface via oxidation, acylation, and amidation reactions. However, the amide bonds introduced by this method cannot meet the 400℃ processing requirements of PAEs. CN118126592A discloses a method to graft polymers onto the graphene surface via in-situ free radical polymerization after phosphoramidation of aromatic aldehyde groups on the graphene surface; this method is also unsuitable for PAE systems. CN113773538A discloses a method to graft polyethylene onto the surface of graphene oxide via a "thiol-olefin" click chemistry reaction. This method not only introduces CS bonds with low thermal stability but is also unsuitable for PAE systems.

[0008] Searching for graphene with similar elemental composition, even though there are methods for grafting carbon materials onto polyaryletherketones, none of them can simultaneously solve the above problems: CN114507356A discloses a method for grafting phenolphthalein-type polyaryletherketones onto the graphene surface via ester groups. Using a reducing agent, the carbonyl groups in the soluble phenolphthalein-type polyaryletherketone (which is not crystalline) are reduced to hydroxyl groups in solution, and then ester groups are formed with the carboxyl groups on the graphene surface through an esterification reaction. This method not only failed to achieve chemical bonding grafting of crystalline polyarylether ketones, but the ester groups also lacked high-temperature resistance. CN105838086B adopted a similar strategy, carrying out a "solid-solid" phase sulfonation reaction between surface-hydroxylated polyarylether ketones (insoluble) and surface-sulfonated graphene under suspension conditions. This not only faced the problem of poor heat resistance of sulfonate structures, but also could not overcome the problem of low efficiency of "solid-solid" phase reactions. CN112940450B disclosed a method for grafting through click chemical reaction between azide functional groups and the graphene surface. Based on methylated polyarylether ketones (non-crystallizable, poor heat resistance), sodium azide was used to convert methyl groups into azide functional groups and then react with graphene to achieve grafting. This method not only fails to achieve chemical bonding grafting of crystalline polyaryletherketones (PAGEs), but also uses highly toxic and explosive sodium azide, making industrialization difficult. CN116874885A discloses a method for grafting soluble biphenyl-resistant PAGEs onto graphene via diazotization. This method has a long grafting reaction time (5-30 hours) and also fails to achieve chemical bonding grafting of crystalline PAGEs. CN109851731B discloses a method for surface functionalization of graphene and chemical bonding grafting with PAGEs via in-situ polymerization. This method involves the polymerization of PAGEs during grafting, resulting in a graphene-doped PAGE composite material, but not a dispersible modified graphene. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0011] A method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, comprising the following steps:

[0012] A sulfonyl chloride compound containing a nitro group and a halobenzene are subjected to sulfonation and reduction reactions in sequence to obtain an amino end-capping agent containing a sulfone group.

[0013] An amino-terminated agent containing sulfone groups, a difluoro monomer, a bisphenol monomer, and potassium carbonate are placed in sulfolane for polymerization to obtain an amino-terminated polyarylene ether.

[0014] The amino-terminated polyarylene ether was reacted with nitrite tetrafluoroborate to obtain the diazonium-terminated polyarylene ether.

[0015] Diazonium-terminated polyarylene ether was formulated into an electrolyte. Graphene was connected to the cathode and immersed in the electrolyte containing diazonium-terminated polyarylene ether. A reduction potential was applied to carry out the reaction, and graphene grafted with polyarylene ether was obtained.

[0016] Graphene grafted with polyarylether was ultrasonically dispersed and then hydrolyzed in an acidic environment to obtain crystalline polyarylether ketone surface-grafted graphene.

[0017] Preferably, the nitrate-containing sulfonyl chloride compound is nitrobenzenesulfonyl chloride or 4-nitrobiphenyl-4-sulfonyl chloride; the halobenzene is chlorobenzene or fluorobenzene.

[0018] Preferably, the step of sequentially subjecting a nitrate-containing sulfonyl chloride compound and a halobenzene to a sulfonation reaction and a reduction reaction to obtain an amino-terminated agent containing a sulfone group specifically includes:

[0019] Under conditions of -5 °C and inert gas protection, a nitrate-containing sulfonyl chloride compound was fully dissolved in a halobenzene, and AlCl3 powder was added in batches; then the mixture was heated to room temperature and stirred; the temperature was further increased to reflux; deionized water was added and refluxed to separate unreacted halobenzene; the mixture was filtered and the filter residue was washed to obtain a crude product; the crude product was recrystallized three times with ethanol and dried to obtain the end-capping agent precursor;

[0020] The end-capping agent precursor was dissolved in methanol, and tin chloride dihydrate was added to the solution and refluxed. The solution was then filtered and the filtrate was collected. The pH of the filtrate was adjusted to not less than 9 using a saturated aqueous solution of Na2CO3. The mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate. The solution was then filtered, the filtrate was collected, and the solvent was removed to obtain an amino end-capping agent containing sulfone groups.

[0021] Preferably, the difluoro monomer is 4,4'-difluorobenzophenone imine and / or difluorodiketone imine; the bisphenol monomer is at least one selected from hydroquinone, biphenyl, 4,4'-dihydroxybenzophenone and 4,4'-dihydroxydiphenyl ether.

[0022] Preferably, the step of polymerizing an amino-terminated agent containing a sulfone group, a difluoro monomer, a bisphenol monomer, and potassium carbonate in sulfolane to obtain an amino-terminated polyarylene ether specifically includes:

[0023] An amino-terminated agent containing sulfone groups, a difluoro monomer, a bisphenol monomer, and potassium carbonate are simultaneously dissolved in sulfolane; then toluene is added, the mixture is heated to an azeotropic state, and the toluene is refluxed for a certain period of time before the toluene is drained; the temperature is then increased to at least 210 °C for further reaction; the mixture is then discharged into ethanol, pulverized, washed, and dried to obtain an amino-terminated polyarylene ether.

[0024] Preferably, the step of reacting amino-terminated polyarylene ethers with nitrite tetrafluoroborate to obtain diazonium-terminated polyarylene ethers specifically includes:

[0025] The amino-terminated polyarylene ether was dissolved in 1,4-dioxane; the above solution was added dropwise to an acetonitrile solution containing nitrite tetrafluoroborate; when the solution turned into a dark brown transparent solution, it was discharged into ether, and the diazonium salt-terminated polyarylene ether was quickly precipitated. The solution was filtered and washed with ether to obtain the diazonium salt-terminated polyarylene ether.

[0026] Preferably, the steps of preparing a diazonium-terminated polyaryl ether as an electrolyte, connecting graphene to the cathode, immersing it in the electrolyte containing the diazonium-terminated polyaryl ether, and applying a reduction potential to carry out the reaction to obtain graphene grafted with polyaryl ether specifically include:

[0027] An electrolyte was prepared by dissolving a diazonium-terminated polyarylene ether and a supporting electrolyte in acetonitrile.

[0028] Graphene was connected to a cathode, immersed in an electrolyte, and subjected to a reduction potential to react. The electrochemically reduced graphene was then washed with acetonitrile and dried to obtain graphene grafted with polyarylene ether.

[0029] Preferably, the supporting electrolyte is tetrabutylammonium tetrafluoroborate.

[0030] Preferably, the step of ultrasonically dispersing graphene grafted with polyarylether ketone and hydrolyzing it in an acidic environment to obtain crystalline polyarylether ketone surface-grafted graphene specifically includes:

[0031] Graphene grafted with polyarylene ether was placed in acetone, mechanically stirred and ultrasonically dispersed, and then hydrochloric acid was added dropwise under the condition of mechanical stirring and ultrasonic dispersion, and the temperature was raised to reflux; then it was filtered and washed, and dried to obtain crystalline polyarylene ether ketone surface-grafted modified graphene.

[0032] Another object of the present invention is to provide a crystalline polyaryletherketone surface-grafted graphene prepared by the above preparation method.

[0033] The present invention provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone. This method prepares an amino-terminant containing sulfone groups and utilizes this sulfone-group-containing amino-terminant to achieve a one-pot preparation of amino-terminated polyarylethers and diazonium-terminated polyarylethers. The surface of graphene is modified using diazonium-terminated polyarylethers, allowing graphene to be directly connected to the polymer via high-temperature and corrosion-resistant phenyl and sulfone groups. Furthermore, the polyaryletherketone grafted onto the graphene surface exhibits crystallinity.

[0034] The raw materials used in this invention are relatively inexpensive, and the amino end-capping agent containing sulfone groups obtained has high reactivity, which can avoid the end-capping polymerization of "polymerization before end-capping" and realize "one-pot" end-capping polymerization, reducing the reaction cycle (omitting the 2-6 h post-end-capping process).

[0035] The crystalline polyaryletherketone surface-grafted graphene obtained by this invention exhibits superior high-temperature and corrosion resistance because the graphene is directly linked to the polymer via high-temperature and corrosion-resistant phenyl and sulfone groups, avoiding the use of ester groups and other functional groups that are not heat- or corrosion-resistant in traditional mechanisms. Furthermore, because the crystalline polyaryletherketone is chemically grafted onto the graphene surface, it also demonstrates enhanced corrosion resistance.

[0036] The preparation method provided by this invention avoids traditional esterification and amidation reactions, and uses electrochemical reduction as the grafting method. Due to the high reaction efficiency (3-5 min), it can realize the batch preparation of crystalline polyaryletherketone surface grafted modified graphene. Attached Figure Description

[0037] Figure 1 The structural formula of the graphene grafted with polyarylene ether obtained in an embodiment of the present invention is shown below.

[0038] Figure 2 The structural formula of the crystalline polyaryletherketone surface-grafted graphene obtained in the embodiments of the present invention is shown below.

[0039] Figure 3 The image shows the Raman spectral characterization results of the crystalline polyaryletherketone surface-grafted graphene prepared in the embodiments of the present invention.

[0040] Figure 4 Cyclic voltammetry curves of the electrochemical reduction grafting reaction provided in embodiments of the present invention. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] This invention first prepares an amino-terminant containing a diphenyl sulfone structure via sulfonation using inexpensive reagents. Leveraging its high reactivity (the higher the electron-withdrawing ability of the para-functional group of fluorobenzene, the higher the substitution reactivity, as evidenced by the significantly lower polymerization reactivity of 4,4'-difluorobenzophenone compared to 4,4'-difluorodiphenyl sulfone), a one-pot polymerization of the amino-terminated polymer is achieved. Based on this, diazonium salt functional groups are directly constructed at the polymer end groups, and the polymer is efficiently grafted onto the graphene surface via an electrochemical reduction reaction (3-5 min). Finally, the polymer grafted onto the graphene surface is converted into crystalline polyarylether ketone via hydrolysis. This invention achieves graphene surface grafting through high-temperature resistant phenylene and sulfone groups.

[0043] The end-capping agent used in this invention is characterized by a diphenyl sulfone structure constructed via sulfonation, where one phenyl group is substituted at the para position with a fluorine or chlorine atom, and the other phenyl group is directly or indirectly linked to an aniline functional group at the para position. The sulfone group located at the para position of the fluorine (chlorine) atom significantly improves the reaction efficiency of the end-capping agent, enabling one-pot end-capping polymerization. The synthesis method involves using a nitrate-containing sulfonyl chloride compound and a halobenzene as raw materials, preparing the end-capping agent precursor via sulfonation; and then reducing the nitro group to an amino group via a reduction reaction (using SnCl2 as the reducing agent) to prepare the end-capping agent. The specific reaction route is as follows:

[0044] ;

[0045] Where X is F or Cl; The structural formula is:

[0046] ;

[0047] Correspondingly, The structural formula is:

[0048] .

[0049] The amino-terminated polyaryl ether prepared in this invention is characterized by being directly prepared via a one-pot polymerization process, with the polymer backbone linked to aniline end groups via sulfone groups. The one-pot polymerization method involves simultaneously dissolving the capping agent, difluoro monomer, bisphenol monomer, and potassium carbonate in sulfolane (solvent), followed by azeotropic dehydration and polymerization to obtain the amino-terminated polyaryl ether. The specific reaction route is as follows:

[0050] ;

[0051] The bisphenol monomer has any of the following structural formulas:

[0052] ;

[0053] .

[0054] The structural formula of the difluorinated monomer is any of the following:

[0055] .

[0056] The structural formula of amino-terminated polyarylethers is any one of the following:

[0057]

[0058] ;

[0059] Wherein, the structural formula of R is any of the following:

[0060] .

[0061] The diazonium-terminated polyarylene ether prepared in this invention is characterized by a polymer backbone linked to a diazonium salt end group of phenyltetrafluoroborate via a sulfone group. The method of preparation is as follows: the diazonium-terminated polyarylene ether is prepared by reacting nitrite tetrafluoroborate with a diazonium salt of aniline end groups. The specific reaction route is as follows:

[0062]

[0063] The diazonium salt-terminated polyarylene ether has any of the following structural formulas:

[0064]

[0065] ;

[0066] Wherein, the structural formula of R1 is any of the following:

[0067] .

[0068] The polyaryl ether-grafted graphene prepared in this invention is characterized by: a highly efficient electrochemical reduction reaction, through which the graphene surface is directly connected to the polyaryl ether via phenyl and sulfone groups. Specifically, the method involves connecting graphene (graphene paper or graphene fiber) to the cathode of an electrolytic cell, immersing it in an electrolyte (containing diazonium salt-terminated polyaryl ether), applying a reduction potential to initiate the reaction, and then washing and drying to obtain polyaryl ether-grafted graphene, the structural formula of which is as follows. Figure 1 As shown. Figure 1 In this context, the structural formula of polyarylethers is any one of the following:

[0069]

[0070] .

[0071] The graphene grafted onto the surface of polyaryletherketone prepared in this embodiment of the invention is characterized by the following: the graphene surface is directly connected to crystalline polyaryletherketone via phenyl and sulfone groups. The method involves hydrolyzing the polyarylether-grafted graphene in an acidic environment to obtain crystalline polyaryletherketone, resulting in graphene grafted onto the surface of crystalline polyaryletherketone, with the structure as shown below. Figure 2 As shown. Figure 2 In this context, the structural formula of crystalline polyaryletherketone is any one of the following:

[0072]

[0073]

[0074] ;

[0075] in addition, Figure 1 and Figure 2 In this context, the structural formula of R2 can be any of the following:

[0076] .

[0077] Specifically, in one embodiment of the present invention, a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone is provided, which includes the following steps:

[0078] S1. Under conditions not exceeding -5 °C and inert gas protection, the nitrate-containing sulfonyl chloride compound is fully dissolved in halobenzene (serving as both solvent and reactant), and AlCl3 powder is added in batches; then the mixture is heated to room temperature and stirred for 3-5 hours; the temperature is further increased to reflux and stirred for 8-10 hours; deionized water is added and refluxed azeotropically to separate unreacted halobenzene; the mixture is filtered, and the filter residue is washed successively with NaOH solution (0.5-1.5 mol / L) and deionized water to obtain the crude product; the crude product is recrystallized three times with ethanol and dried to obtain the end-capping agent precursor;

[0079] S2. Dissolve the end-capping agent precursor in methanol (0.01-0.1 mol / L), add tin chloride dihydrate (5 molar amounts of the end-capping agent precursor) to the solution, and reflux for 5-7 h; then filter and collect the filtrate, and adjust the pH of the filtrate to not less than 9 using a saturated aqueous solution of Na2CO3; extract the mixture twice with ethyl acetate, combine the organic phases, and dry with anhydrous sodium sulfate; then filter, collect the filtrate, and remove the solvent to obtain an amino end-capping agent containing sulfone groups;

[0080] S3. Dissolve the sulfone-containing amino-terminated agent, difluorinated monomer, bisphenol monomer, and potassium carbonate simultaneously in sulfolane (solvent); then add toluene, heat to azeotropic (130-150 °C), maintain toluene reflux for 3-5 hours, and drain the toluene; continue heating to not less than 210 °C for reaction, maintain for 3-5 hours; then discharge into ethanol, pulverize, and wash with ethanol and water three times each, and dry to obtain amino-terminated polyarylene ether;

[0081] S4. Dissolve the amino-terminated polyarylene ether in 1,4-dioxane (amino-terminal equivalent 0.01-0.1 mol / L); add the above solution dropwise to an acetonitrile solution (0.01-0.1 mol / L) containing nitrite tetrafluoroborate (NOBF4); when the solution turns into a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether will quickly precipitate. Filter and wash with ether to obtain the diazonium-terminated polyarylene ether.

[0082] S5. Dissolve diazonium-terminated polyarylene ether (0.01-0.1 g / mL) and supporting electrolyte (0.5-1.5 mM) in acetonitrile to prepare an electrolyte; connect graphene to the cathode, immerse it in the electrolyte, apply a reduction potential of -0.3 V, maintain for 1-5 min, wash the electrochemically reduced graphene with acetonitrile and dry it to obtain graphene grafted with polyarylene ether;

[0083] S6. Place the graphene grafted with polyarylether ketone in acetone (0.01-0.05 g / mL), mechanically stir and ultrasonically disperse for 1-3 hours; under the condition of mechanical stirring and ultrasonic dispersion, add dropwise 1-3 M hydrochloric acid with an equal volume to acetone, heat to reflux and maintain for 20-28 h; then filter, wash several times with deionized water, and dry to obtain crystalline polyarylether ketone surface-grafted modified graphene.

[0084] The nitrate-containing sulfonyl chloride compound is nitrobenzenesulfonyl chloride or 4-nitrobiphenyl-4-sulfonyl chloride; the halobenzene 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 selected from hydroquinone, biphenyl, 4,4'-dihydroxybenzophenone, and 4,4'-dihydroxydiphenyl ether. The supporting electrolyte is tetrabutylammonium tetrafluoroborate.

[0085] The following embodiments are some specific implementation examples and application examples of the present invention in practical applications, but are not limited thereto.

[0086] Example 1: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0087] (1) Under -5 °C and inert gas protection, nitrobenzenesulfonyl chloride (0.1 mol) was fully dissolved in chlorobenzene (chlorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted chlorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol and dried to obtain the end-capping agent precursor (4-chloro-4'-nitrodiphenyl sulfone, corresponding to the above chemical structural formula: R'= R'-1; X= Cl), with a yield of 85%;

[0088] (2) The end-capping agent precursor (4-chloro-4'-nitrodiphenyl sulfone) obtained in step (2) 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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-chloro-4'-aminodiphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-1; X= Cl) was obtained with a yield of 95%;

[0089] (3) Add 0.001 mol of the end-capping agent (4-chloro-4'-aminodiphenyl 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 to sulfolane (solvent); add toluene, heat to azeotropic (130℃), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210℃ and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-1; R=R1-1);

[0090] (4) Dissolve the amino-terminated polyether ether ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyether ether ketone imine (corresponding to the above chemical structural formula: Dia-PI-1; R1=R1-1);

[0091] (5) The diazonium-terminated polyether ether ketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) were dissolved in acetonitrile to form the electrolyte; the graphene paper was connected to the cathode of the electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied and held for 3 min to carry out the electrochemical reduction grafting reaction. The cyclic voltammetry curve of the electrochemical reduction grafting reaction is shown in Figure 1. Figure 4 As shown, graphene paper after electrochemical reduction was cleaned with acetonitrile and dried to obtain graphene grafted with polyetheretherketone imine (corresponding to the above chemical structural formula: PI-1; R2-=R2-1).

[0092] (6) The graphene grafted with polyetheretherketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline polyetheretherketone surface-grafted modified graphene (corresponding to the above chemical structural formula: P-1; R2-=R2-1). The crystalline polyetheretherketone surface-grafted modified graphene obtained above was characterized by Raman spectroscopy, and the results are as follows. Figure 3 As shown, the results indicate that crystalline polyaryletherketone was successfully grafted onto the graphene surface.

[0093] Example 2: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0094] (1) Under -5 °C and inert gas protection, 0.1 mol of 4-nitrobiphenyl-4-sulfonyl chloride was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.15 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 5 hours; the mixture was heated to reflux and stirred for 10 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%;

[0095] (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; filtered and the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained with a yield of 95%;

[0096] (3) Add 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 to sulfolane (solvent); add toluene, heat to azeotropic (130 °C), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210 °C and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyether ether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-2; R=R-2);

[0097] (4) Dissolve the amino-terminated polyether ether ether ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.1 mol / L); add the above solution dropwise to an acetonitrile solution (0.1 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyether ether ether ketone imine (corresponding to the above chemical structural formula: Dia-PI-2; R1=R1-2);

[0098] (5) The diazonium-terminated polyether ether ether ketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) were dissolved in acetonitrile as the electrolyte; the graphene fiber was connected to the cathode of the electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied and maintained for 3 min; the electrochemically reduced graphene fiber was washed with acetonitrile and dried to obtain graphene grafted with polyether ether ether ketone imine (corresponding to the above chemical structural formula: PI-2; R2=R2-2);

[0099] (6) The graphene grafted with polyether ether ether ketone imine obtained in step (5) was placed in acetone (0.05 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline polyether ether ether ketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-2; R2=R2-2).

[0100] Example 3: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0101] (1) Under -5 °C and inert gas protection, 4-nitrobiphenyl-4-sulfonyl chloride (0.1 mol) was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol and dried to obtain the end-capping agent precursor (4-fluoro-4'-(4-nitrophenoxy)diphenyl sulfone, corresponding to the above chemical structural formula: R'= R'-2; X=F), with a yield of 86%;

[0102] (2) The end-capping agent precursor (4-fluoro-4'-(4-nitrophenoxy)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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenoxy)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained with a yield of 95%;

[0103] (3) Add 0.01 mol of the end-capping agent (4-fluoro-4'-(4-aminophenoxy)diphenyl sulfone) obtained in step (2), 0.1 mol of 4,4'-difluorodiketone imine, 0.1 mol of 4,4'-dihydroxydiphenyl ether and 0.13 mol of potassium carbonate to sulfolane (solvent); add toluene, heat to azeotropic (130℃), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210℃ and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyether ether ether ketone ketone imine (corresponding to the above chemical structural formula: NH2-PI-6; R=R-2);

[0104] (4) Dissolve the amino-terminated polyether ether ether ketone ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyether ether ether ketone ketone imine (corresponding to the above chemical structural formula: Dia-PI-6; R1=R1-2);

[0105] (5) The diazonium-terminated polyether ether ether ketone ketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) were dissolved in acetonitrile as the electrolyte; the graphene paper was connected to the cathode of the electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied and held for 3 min; the electrochemically reduced graphene paper was washed with acetonitrile and dried to obtain graphene grafted with polyether ether ether ketone ketone imine (corresponding to the above chemical structural formula: PI-6; R2=R2-2);

[0106] (6) The graphene grafted with polyether ether ether ketone ketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline polyether ether ether ketone ketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-6; R2=R2-2).

[0107] Example 4: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0108] (1) Under -5 °C and inert gas protection, 4-nitrobiphenyl-4-sulfonyl chloride (0.1 mol) was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%;

[0109] (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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained, with a yield of 95%;

[0110] (3) Add 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 to sulfolane (solvent); add toluene, heat to azeotropic (130℃), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210℃ and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyetherketone imine (corresponding to the above chemical structural formula: NH2-PI-4; R=R-2);

[0111] (4) Dissolve the amino-terminated polyetherketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyetherketone imine (corresponding to the above chemical structural formula: Dia-PI-4; R1=R1-2).

[0112] (5) Dissolve the diazonium-terminated polyetherketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) in acetonitrile as the electrolyte; connect the graphene paper to the cathode of the electrolytic cell and immerse it in the electrolyte; apply a reduction potential of -0.3 V and maintain it for 5 min; wash the electrochemically reduced graphene paper with acetonitrile and dry it to obtain graphene grafted with polyetherketone imine (corresponding to the above chemical structural formula: PI-4; R2=R2-2);

[0113] (6) The graphene grafted with polyetherketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, washed 3 times with deionized water, and dried to obtain crystalline polyetherketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-4; R2=R2-2).

[0114] Example 5: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0115] (1) Under -5 °C and inert gas protection, 0.1 mol of 4-nitrobiphenyl-4-sulfonyl chloride was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%;

[0116] (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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained with a yield of 95%;

[0117] (3) Add 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'-difluorodione imine, 0.1 mol of hydroquinone and 0.13 mol of potassium carbonate to sulfolane (solvent); add toluene, heat to azeotropic (130°C), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210°C and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-5; R=R-2);

[0118] (4) Dissolve the amino-terminated polyether ether ketone ketimide obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyether ether ketone ketimide (corresponding to the above chemical structural formula: Dia-PI-5; R1=R1-2);

[0119] (5) Dissolve the diazonium-terminated polyetheretherketoneketoneimide (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) in acetonitrile as the electrolyte; connect the graphene paper to the cathode of the electrolytic cell and immerse it in the electrolyte; apply a reduction potential of -0.3 V and maintain it for 4 min; wash the electrochemically reduced graphene paper with acetonitrile and dry it to obtain graphene grafted with polyetheretherketoneketoneimide (corresponding to the above chemical structural formula: PI-5; R2-=R2-2);

[0120] (6) The graphene grafted with polyether ether ketone ketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline polyether ether ketone ketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-5; R2=R2-2).

[0121] Example 6: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0122] (1) Under -5 °C and inert gas protection, 4-nitrobiphenyl-4-sulfonyl chloride (0.1 mol) was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%;

[0123] (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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained with a yield of 95%;

[0124] (3) Add 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 biphenylol and 0.13 mol of potassium carbonate to sulfolane (solvent); add toluene, heat to azeotropic (130°C), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210°C and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated biphenyl polyether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-3; R=R-2);

[0125] (4) Dissolve the amino-terminated biphenyl polyether ether ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated biphenyl polyether ether ketone imine (corresponding to the above chemical structural formula: Dia-PI-3; R1=R1-2);

[0126] (5) The diazonium-terminated biphenyl polyether ether ketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) were dissolved in acetonitrile as the electrolyte; the graphene paper was connected to the cathode of the electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied and held for 3 min; the electrochemically reduced graphene paper was washed with acetonitrile and dried to obtain graphene grafted with biphenyl polyether ether ketone imine (corresponding to the above chemical structural formula: PI-3; R2=R2-2);

[0127] (6) The graphene grafted with biphenyl polyether ether ketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline biphenyl polyether ether ketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-3; R2=R2-2).

[0128] Example 7: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0129] (1) Under -5 °C and inert gas protection, 4-nitrobiphenyl-4-sulfonyl chloride (0.1 mol) was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%.

[0130] (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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X= F) was obtained, with a yield of 95%;

[0131] (3) Add 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'-difluorodione imine, 0.1 mol of biphenyl hydroquinone and 0.13 mol of potassium carbonate to sulfolane (solvent); add toluene, heat to azeotropic (130℃), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210℃ and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated biphenyl polyether ether ketone imine (corresponding to the above chemical structural formula: NH2-PI-7; R=R-2);

[0132] (4) Dissolve the amino-terminated biphenyl polyether ether ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated biphenyl polyether ether ketone imine (corresponding to the above chemical structural formula: Dia-PI-7; R1=R1-2);

[0133] (5) The diazonium-terminated biphenyl polyether ether ketone ketimide (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) were dissolved in acetonitrile as the electrolyte; the graphene paper was connected to the cathode of the electrolytic cell and immersed in the electrolyte; a reduction potential of -0.3 V was applied and held for 3 min; the electrochemically reduced graphene paper was washed with acetonitrile and dried to obtain graphene grafted with biphenyl polyether ether ketone ketimide (corresponding to the above chemical structural formula: PI-7; R2-=R2-2);

[0134] (6) The graphene grafted with biphenyl polyether ether ketone ketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, washed 3 times with deionized water, and dried to obtain crystalline biphenyl polyether ether ketone ketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-7; R2=R2-2).

[0135] Example 8: This example provides a method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, specifically including the following steps:

[0136] (1) Under -5 °C and inert gas protection, 4-nitrobiphenyl-4-sulfonyl chloride (0.1 mol) was fully dissolved in fluorobenzene (fluorobenzene was used as both solvent and reactant), and AlCl3 powder (0.12 mol) was added in 5 batches; the mixture was heated to room temperature and stirred for 3 hours; the mixture was heated to reflux and stirred for 8 hours; deionized water was added and refluxed to separate unreacted fluorobenzene; the mixture was filtered, and the filter residue (crude product) was washed successively with NaOH solution (1 mol / L) and deionized water; the mixture was recrystallized three times with ethanol 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%;

[0137] (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 the filtrate was collected, and the pH of the filtrate was adjusted to 9 using a saturated aqueous solution of Na2CO3; the mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate; after filtration, collection of the filtrate and removal of the solvent, the end-capping agent (4-fluoro-4'-(4-aminophenyl)diphenyl sulfone, corresponding to the above chemical structural formula: R''= R''-2; X=F) was obtained with a yield of 95%;

[0138] (3) Add 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'-difluorodiketone imine, 0.1 mol of 4,4'-dihydroxybenzophenone and 0.13 mol of potassium carbonate to sulfolane (solvent); add toluene, heat to azeotropic (130℃), maintain azeotropic reflux of toluene and water for 4 hours, then drain the toluene; heat to 210℃ and maintain for 4 hours; discharge into ethanol and pulverize; wash with ethanol and water 3 times each, and dry to obtain amino-terminated polyetherketone etherketone imine (corresponding to the above chemical structural formula: NH2-PI-8; R=R-2);

[0139] (4) Dissolve the amino-terminated polyetherketone ketone imine obtained in step (3) in 1,4-dioxane (amino-terminal equivalent 0.01 mol / L); add the above solution dropwise to an acetonitrile solution (0.01 mol / L) containing 1.5 times the amino-terminal equivalent of nitrite tetrafluoroborate; when the solution becomes a dark brown transparent solution, discharge it into ether, and the diazonium-terminated polyarylene ether precipitates rapidly. Filter and wash with ether to obtain the diazonium-terminated polyetherketone ketone imine (corresponding to the above chemical structural formula: Dia-PI-8; R1=R1-2);

[0140] (5) Dissolve the diazonium-terminated polyetherketone imine (0.01 g / mL) obtained in step (4) and the supporting electrolyte (tetrabutylammonium tetrafluoroborate, 1 mM) in acetonitrile as the electrolyte; connect the graphene paper to the cathode of the electrolytic cell and immerse it in the electrolyte; apply a reduction potential of -0.3 V and hold for 3 min; wash the electrochemically reduced graphene paper with acetonitrile and dry it to obtain graphene grafted with polyetherketone imine (corresponding to the above chemical structural formula: PI-8; R2=R2-2);

[0141] (6) The graphene grafted with polyetherketone imine obtained in step (5) was placed in acetone (0.01 g / mL), mechanically stirred and ultrasonically dispersed for 2 hours; under the condition of mechanical stirring and ultrasonic dispersion, 2 M hydrochloric acid of the same volume as acetone was added dropwise; the temperature was raised to reflux and maintained for 24 h; filtered, and washed 3 times with deionized water, and dried to obtain crystalline polyetherketone surface grafted modified graphene (corresponding to the above chemical structural formula: P-8; R2-=R2-2).

[0142] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification.

Claims

1. A method for preparing graphene grafted onto the surface of crystalline polyaryletherketone, characterized in that, Includes the following steps: A sulfonyl chloride compound containing a nitro group and a halobenzene are subjected to sulfonation and reduction reactions in sequence to obtain an amino end-capping agent containing a sulfone group. An amino-terminated agent containing sulfone groups, a difluoro monomer, a bisphenol monomer, and potassium carbonate are placed in sulfolane for polymerization to obtain an amino-terminated polyarylene ether. The amino-terminated polyarylene ether was reacted with nitrite tetrafluoroborate to obtain the diazonium-terminated polyarylene ether. Diazonium-terminated polyarylene ether was formulated into an electrolyte. Graphene was connected to the cathode and immersed in the electrolyte containing diazonium-terminated polyarylene ether. A reduction potential was applied to carry out the reaction, and graphene grafted with polyarylene ether was obtained. Graphene grafted with polyarylether was ultrasonically dispersed and then hydrolyzed in an acidic environment to obtain crystalline polyarylether ketone surface-grafted graphene.

2. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1, characterized in that, The nitrate-containing sulfonyl chloride compound is nitrobenzenesulfonyl chloride or 4-nitrobiphenyl-4-sulfonyl chloride; the halobenzene is chlorobenzene or fluorobenzene.

3. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1 or 2, characterized in that, The steps of subjecting a nitrate-containing sulfonyl chloride compound and a halobenzene to sequential sulfonation and reduction reactions to obtain an amino-terminated agent containing a sulfone group specifically include: Under conditions of -5 °C and inert gas protection, a nitrate-containing sulfonyl chloride compound was fully dissolved in a halobenzene, and AlCl3 powder was added in batches; then the mixture was heated to room temperature and stirred; the temperature was further increased to reflux; deionized water was added and refluxed to separate unreacted halobenzene; the mixture was filtered and the filter residue was washed to obtain a crude product; the crude product was recrystallized three times with ethanol and dried to obtain the end-capping agent precursor; The end-capping agent precursor was dissolved in methanol, and tin chloride dihydrate was added to the solution and refluxed. The solution was then filtered and the filtrate was collected. The pH of the filtrate was adjusted to not less than 9 using a saturated aqueous solution of Na2CO3. The mixture was extracted twice with ethyl acetate, and the organic phases were combined and dried with anhydrous sodium sulfate. The solution was then filtered, the filtrate was collected, and the solvent was removed to obtain an amino end-capping agent containing sulfone groups.

4. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1, characterized in that, The difluoro monomer is 4,4'-difluorobenzophenone imine and / or difluorodiketone imine; the bisphenol monomer is at least one of hydroquinone, biphenyl, 4,4'-dihydroxybenzophenone and 4,4'-dihydroxydiphenyl ether.

5. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1 or 4, characterized in that, The steps of polymerizing an amino-terminated agent containing a sulfone group, a difluoro monomer, a bisphenol monomer, and potassium carbonate in sulfolane to obtain an amino-terminated polyarylene ether specifically include: An amino-terminated agent containing sulfone groups, a difluoro monomer, a bisphenol monomer, and potassium carbonate are simultaneously dissolved in sulfolane; then toluene is added, the mixture is heated to an azeotropic state, and the toluene is refluxed for a certain period of time before the toluene is drained; the temperature is then increased to at least 210 °C for further reaction; the mixture is then discharged into ethanol, pulverized, washed, and dried to obtain an amino-terminated polyarylene ether.

6. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1, characterized in that, The steps of reacting amino-terminated polyarylene ethers with nitrite tetrafluoroborate to obtain diazonium-terminated polyarylene ethers specifically include: The amino-terminated polyarylene ether was dissolved in 1,4-dioxane; the above solution was added dropwise to an acetonitrile solution containing nitrite tetrafluoroborate; when the solution turned into a dark brown transparent solution, it was discharged into ether, and the diazonium salt-terminated polyarylene ether was quickly precipitated. The solution was filtered and washed with ether to obtain the diazonium salt-terminated polyarylene ether.

7. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1, characterized in that, The steps of preparing a diazonium-terminated polyaryl ether as an electrolyte, connecting graphene to a cathode, immersing it in the electrolyte containing the diazonium-terminated polyaryl ether, and applying a reduction potential to initiate a reaction to obtain graphene grafted with polyaryl ether specifically include: An electrolyte was prepared by dissolving a diazonium-terminated polyarylene ether and a supporting electrolyte in acetonitrile. Graphene was connected to a cathode, immersed in an electrolyte, and subjected to a reduction potential to react. The electrochemically reduced graphene was then washed with acetonitrile and dried to obtain graphene grafted with polyarylene ether.

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

9. The method for preparing crystalline polyaryletherketone surface-grafted graphene according to claim 1, characterized in that, The steps of ultrasonically dispersing graphene grafted with polyarylether ketone and hydrolyzing it under acidic conditions to obtain crystalline polyarylether ketone surface-grafted graphene specifically include: Graphene grafted with polyarylene ether was placed in acetone, mechanically stirred and ultrasonically dispersed, and then hydrochloric acid was added dropwise under the condition of mechanical stirring and ultrasonic dispersion, and the temperature was raised to reflux; then it was filtered and washed, and dried to obtain crystalline polyarylene ether ketone surface-grafted modified graphene.

10. A crystalline polyaryletherketone surface-grafted graphene prepared by any one of the preparation methods described in claims 1-9.

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