Polyether-ether-ketone with low shear viscosity as well as preparation method and application thereof

Abstract

The invention relates to polyether-ether-ketone with low shear viscosity and a preparation method and application thereof. Specifically, the polyetheretherketone satisfies the following properties: i) the polyetheretherketone has a repeating unit represented by the following formula (I): ii) the weight-average molecular weight of the polyetheretherketone is in the range of 15,000 to 45,000, the weight-average molecular weight being measured by GPC; and iii) a nitrobenzoyloxy group is connected to the tail end of a molecular chain of the polyether-ether-ketone. The polyether-ether-ketone has obviously lower shear viscosity at a specific melt flow rate, is not only suitable for injection molding and mold pressing, but also suitable for extrusion of plates and bars which are relatively high in viscosity and cannot be applied by conventional polyether-ether-ketone and preparation of prepregs, and greatly expands the application field of the polyether-ether-ketone. # imgabs0 #

Description

Technical Field

[0001] The present application belongs to the technical field of polymer materials and relates to a polyetheretherketone, and more specifically to a polyetheretherketone having a lower shear viscosity at a given melt flow rate and a preparation method and application thereof. Background Art

[0002] Polyetheretherketone is a special engineering plastic first developed and commercialized by the British ICI company in the late 1970s, and put into industrial production in 1987. Due to its excellent comprehensive properties such as high heat resistance, radiation resistance, corrosion resistance, good dimensional stability, and excellent electrical properties, this material has been widely used in defense, military industry, aerospace, electronic information, petrochemical, medical and health, automobile and other industries since its introduction.

[0003] In order to meet the needs of my country in the fields of national defense, military industry, aerospace, and electronic information, the State Science and Technology Commission has earlier established a project to research and develop polyetheretherketone resins and secondary products as a national key scientific and technological project, and included it in the national development plan project, with relevant domestic scientific research institutes responsible for research and development. After more than ten years of hard work, the polyetheretherketone project has achieved major technological breakthroughs, and has now completed the experimental amplification and in-depth research stages, and has initially acquired the production capacity for industrial production of polyetheretherketone.

[0004] The known synthesis technology of polyetheretherketone is to use 4,4'-difluorobenzophenone and hydroquinone as comonomers and diphenyl sulfone as solvent in the presence of alkali metal salts and polymerize at high temperature (above 300°C). The polyetheretherketone product obtained after such polymerization has a high shear viscosity at a specific melt index and is only suitable for injection molding and molding. Due to its high viscosity, it is not suitable for extrusion of plates and rods and preparation of prepregs. Summary of the invention

[0005] The object of the present application is to provide a polyetheretherketone having a lower shear viscosity at a given melt flow rate, which is suitable for use in the extrusion of plates and rods and the preparation of prepregs.

[0006] In one aspect of the present application, the present application provides a polyetheretherketone, which satisfies the following properties:

[0007] i) The polyetheretherketone has a repeating unit represented by the following formula (I):

[0008]

[0009] ii) the polyetheretherketone has a weight average molecular weight in the range of 15,000 to 45,000, as measured by GPC; and

[0010] iii) A nitrobenzoyloxy group is connected to the molecular chain terminal of the polyetheretherketone.

[0011] By controlling the weight average molecular weight of polyetheretherketone within the above range and introducing a benzoyloxy group at the molecular weight end of polyetheretherketone, it can be ensured that polyetheretherketone has a significantly lower shear viscosity at a specific melt flow rate, so that the obtained polyetheretherketone product is not only suitable for injection molding and compression molding applications, but also suitable for the extrusion of sheets and rods that conventional polyetheretherketone with higher viscosity is usually not applicable, as well as the preparation of prepregs, which greatly expands the application field of polyetheretherketone.

[0012] In some embodiments according to the present application, the nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoyloxy, 3-nitrobenzoyloxy, and 4-nitro-benzoyl.

[0013] In some embodiments according to the present application, the nitrobenzoyloxy group is derived from a compound containing a nitrobenzoyloxy group, and the compound containing a nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitro-benzoic acid, 2-nitrobenzoyl fluoride, 3-nitrobenzoyl fluoride, and 4-nitro-benzoyl acyl fluoride.

[0014] In some embodiments according to the present application, the polyetheretherketone contains 0.7 wt%-2.2 wt%, preferably 0.7 wt% to 0.8 wt% of the nitrobenzoyloxy group, and the weight percentage of the nitrobenzoyloxy group is the weight percentage of the nitrobenzoyloxy fragment in the formed polyetheretherketone molecule.

[0015] By controlling the weight percentage of the nitrobenzoyloxy group connected to the molecular chain end of the polyetheretherketone within the above range, the obtained polyetheretherketone can be ensured to have an appropriate molecular weight, which is conducive to maintaining appropriate mechanical properties, and the shear performance of the obtained polyetheretherketone can be significantly improved, so that it has a significantly lower shear viscosity at a specific melt flow rate. The inventors of the present invention surprisingly found that polyetheretherketone with the same molecular weight and end-capped with nitro groups has a lower shear viscosity than polyetheretherketone without end-capping with nitro groups, which was difficult to predict before the present application.

[0016] In some specific embodiments of the present application, the polyetheretherketone has a structural formula shown in any one of the following formulas (II-1) to (II-3):

[0017]

[0018] Here, n is a positive integer in the range of 50 to 200.

[0019] In some embodiments according to the present application, when the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 380° C., the melt index of the polyetheretherketone at 400° C., 1000° C., -1 The shear viscosity at S is not more than 450 Pa·S, preferably not more than 430 Pa·S, more preferably not more than 405 Pa·S, the melt index is measured according to GB / T-3682, and the shear viscosity is measured according to GB / T 25278-2010.

[0020] In other embodiments according to the present application, compared to a polyetheretherketone having substantially the same melt index and not capped with a nitrobenzoyloxy group, the polyetheretherketone has a shear viscosity reduction of at least 10%, preferably at least 12%, more preferably at least 17%, at 400° C., 1000° C., 1500° C., 2000° C., 3000° C., 5000° C., 6000° C., 7000° C., 8000° C., 9000° C., 15000° C., 6000° C., 7000° C., 8000° C., 9000° C., 6 ... -1 S is measured according to GB / T 25278-2010.

[0021] Another aspect of the present application provides a method for preparing the above-mentioned polyetheretherketone, which comprises the following steps: under an inert atmosphere and in the presence of an alkali metal carbonate, 4,4'-difluorobenzophenone and hydroquinone undergo nucleophilic condensation, and then, during the nucleophilic condensation, a compound containing a nitrobenzoyloxy group is added to the reaction system of the nucleophilic condensation to continue the reaction; and after the reaction is completed, cooling and purifying to obtain the polyetheretherketone.

[0022] In some embodiments according to the present application, the alkali metal carbonate includes sodium carbonate or a mixture of sodium carbonate and potassium carbonate, preferably includes a mixture of sodium carbonate and potassium carbonate, and the molar ratio of the two is in the range of 8.5-9.5:1.

[0023] In some embodiments according to the present application, the molar ratio of the alkali metal carbonate to the hydroquinone is in the range of 1.001-1.15:1, optionally in the range of 1.001-1.005:1.

[0024] In some embodiments according to the present application, the molar ratio of the 4,4'-difluorobenzophenone to the hydroquinone is in the range of 1.001-1.04:1, optionally in the range of 1.001-1.005:1.

[0025] In some embodiments according to the present application, the molar ratio of the compound containing a nitrobenzoyloxy group to the 4,4'-difluorobenzophenone is in the range of 0.095-0.105:1, optionally in the range of 0.099-1.001:1.

[0026] In some embodiments of the present application, during the nucleophilic polycondensation, the temperature is first raised to 220° C. and maintained for 60-70 min; the temperature is then raised to 280° C.; after the nitrobenzoyloxy-containing compound is added, the temperature is then raised to 320° C. and maintained for 50-60 min.

[0027] In some embodiments according to the present application, during the nucleophilic polycondensation, an aromatic sulfone is used as a solvent, and the aromatic sulfone is selected from one or more of diphenyl sulfone, dibenzothiophene dioxide, thiophene dioxide and 4-phenylsulfonylbiphenyl. Preferably, the weight of the solvent is 3 times or more, but not more than 10 times, the weight of 4,4'-difluorobenzophenone.

[0028] The third aspect of the present application provides a plate, which is formed by extruding the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application.

[0029] A fourth aspect of the present application provides a pipe, which is formed by extruding the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application.

[0030] A fifth aspect of the present application provides a prepreg prepared from the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application.

[0031] The sheet, tube and prepreg of the present application contain the polyetheretherketone provided by the present application, and thus have at least the same advantages as the polyetheretherketone. DETAILED DESCRIPTION

[0032] The following is a detailed description of the polyetheretherketone, the preparation method thereof and the related application embodiments of the present application. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there may be cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0033] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0034] If not otherwise specified, all embodiments and optional embodiments of the present application may be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of the present application.

[0035] Unless otherwise specified, all technical features and optional technical features of the present application may be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of the present application.

[0036] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0037] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0038] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0039] If not otherwise specified, in this application, the terms "first", "second", "third", etc. are used to distinguish different objects rather than to describe a specific order or a primary-secondary relationship.

[0040] In the present application, the terms "plurality", "multiplicity" and the like refer to two or more.

[0041] Unless otherwise specified, the terms used in this application have the commonly understood meanings that are commonly understood by those skilled in the art.

[0042] Unless otherwise specified, the values ​​of the parameters mentioned in this application can be measured by various test methods commonly used in the art, for example, they can be measured according to the test methods given in the examples of this application. Unless otherwise specified, the test temperature is 25°C.

[0043] In the context of this application, the term "nitrobenzoyloxy" may be optionally substituted.

[0044] When the above groups (eg, nitrobenzoyloxy) are described as being substituted, the substituent groups may include halogen atoms or heteroatoms.

[0045] The term "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom and the like.

[0046] The term "heteroatom" includes a nitrogen atom, a sulfur atom, a phosphorus atom and the like.

[0047] Since its introduction, polyetheretherketone has been widely used in defense, military industry, aerospace, electronic information, petrochemical, medical and health, automobile and other industries due to its excellent comprehensive properties such as high heat resistance, radiation resistance, corrosion resistance, good dimensional stability and excellent electrical properties. The known synthesis technology of polyetheretherketone is to use 4,4'-difluorobenzophenone and hydroquinone as comonomers and diphenyl sulfone as solvent in the presence of alkali metal salts under high temperature (above 300°C) conditions for polymerization. The polyetheretherketone product obtained after such polymerization has a high shear viscosity at a specific melt index and is only suitable for injection molding and molding. Due to its high viscosity, it is not suitable for extrusion of plates and rods and preparation of prepregs.

[0048] In order to solve the above problems, the inventors of the present application conducted a large number of experiments and in-depth studies, and surprisingly found that the introduction of nitro groups into the molecular chain of polyetheretherketone polymer can achieve significantly lower shear viscosity at a given melt index of polyetheretherketone. The resulting polyetheretherketone has appropriate mechanical strength and is not only suitable for injection molding and compression molding applications, but also suitable for the extrusion of sheets and rods that conventional polyetheretherketone with higher viscosity cannot usually be used, as well as the preparation of prepregs, which greatly expands the application field of polyetheretherketone.

[0049] Therefore, a first aspect of the embodiments of the present application provides a polyetheretherketone, wherein the polyetheretherketone satisfies the following properties:

[0050] i) The polyetheretherketone has a repeating unit represented by the following formula (I):

[0051]

[0052] ii) the polyetheretherketone has a weight average molecular weight in the range of 15,000 to 45,000, as measured by GPC; and

[0053] iii) A nitrobenzoyloxy group is connected to the molecular chain terminal of the polyetheretherketone.

[0054] In this article, the term "weight average molecular weight" has a well-known meaning in the field of polymer materials, which can be measured by instruments and methods known in the art. As an exemplary illustration, for example, a gel chromatography method is used for testing, such as taking a 20 mg PEEK (polyetheretherketone) sample and placing it in a 10 ml cillin bottle, adding 3.15 ml of α-chloronaphthalene with a pipette gun, and placing it in an oscillator at 150 degrees Celsius for 1.5 hours, the sample is completely dissolved in α-chloronaphthalene, and after cooling, 4.20 ml of 1,2,4-trichlorobenzene is added to the cillin bottle, and the vibration is uniform. 2 ml of sample is taken from the cillin bottle with a filter pipette and added to an ampoule, which is sealed with an aluminum cap, and the ampoule is placed on a PL-220 gel chromatograph (GPC) sample tray, at a column temperature of 115 degrees Celsius, a mobile phase of 1 ml / min, an injection volume of 200 μl, a k value of 14.1, and an Alpha value of 0.7, and the weight average molecular weight of the sample is measured.

[0055] In an embodiment of the present application, the weight average molecular weight of the polyetheretherketone is in the range of 15,000 to 45,000, optionally in the range of 20,000 to 45,000, and more optionally in the range of 25,000 to 45,000. For example, the weight average molecular weight of the polyetheretherketone can be 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 31,000, 32,000, 33,000, 34,000, 35,000, 36,000, 37,000, 38,000, 39,000, 40,000, 41,000, 42,000, 43,000, 44,000, 45,000, or a range formed by any two of the above values. When the weight average molecular weight of the polyetheretherketone is within the above range, the obtained polyetheretherketone has appropriate mechanical strength, which is conducive to forming a sheet and a pipe with excellent performance.

[0056] In the embodiment of the present application, the molecular chain end of the polyetheretherketone is connected with a nitrobenzoyloxy group. As described above, the inventors of the present application have found that by introducing a nitrobenzoyloxy group into the molecular chain of the polyetheretherketone polymer, a significantly lower shear viscosity can be achieved at a given melt index of the polyetheretherketone, and the polyetheretherketone obtained thereby has appropriate mechanical strength, and is not only suitable for use as injection molding and molding applications, but also suitable for the extrusion of sheets and rods that conventional polyetheretherketones with higher viscosity are usually unable to apply, as well as the preparation of prepregs, which greatly expands the application field of polyetheretherketone.

[0057] In the present application, the molecular chain of the polyetheretherketone is terminated with nitrobenzoyloxy, which is a nitration product obtained by nucleophilic reaction. The nucleophilic reaction according to the present application is different from the traditional nitration reaction (i.e., the reaction of dehydrating polyetheretherketone with concentrated nitric acid and concentrated sulfuric acid), which uses a nitro compound to graft the entire nitro compound onto the polyetheretherketone molecular chain, and the nitro group does not transfer during the reaction. In contrast, the traditional nitration reaction is to transfer the nitro group of nitric acid to the benzene ring of polyetheretherketone, replacing the position of "hydrogen" on the benzene ring. The method of modifying polyetheretherketone by nucleophilic reaction not only leads to significant differences in structure of the nitro-modified polyetheretherketone formed compared with the traditional nitration method, but also has obvious cost and environmental advantages, avoids the increase in equipment cost due to the use of nitric acid / sulfuric acid, and reduces the environmental risks and pollution caused by the use of nitric acid / sulfuric acid.

[0058] In some embodiments according to the present application, the nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoyloxy, 3-nitrobenzoyloxy, and 4-nitro-benzoyl. The nitrobenzoyloxy group may be derived from a compound containing a nitrobenzoyloxy group. In the present application, a "compound containing a nitrobenzoyloxy group" refers to a compound in which a part of the molecule is a nitrobenzoyloxy group and is reactive with a comonomer for preparing polyetheretherketone, including but not limited to 4,4'-difluorobenzophenone and hydroquinone. As an exemplary illustration, the compound containing a nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitro-benzoic acid, 2-nitrobenzoyl fluoride, 3-nitrobenzoyl fluoride and 4-nitro-benzoyl fluoride; preferably selected from one or more of 2-nitrobenzoic acid, 3-nitrobenzoic acid and 4-nitro-benzoic acid; more preferably selected from one or more of 2-nitrobenzoic acid and 4-nitro-benzoic acid; most preferably selected from 4-nitro-benzoic acid.

[0059] In some embodiments according to the present application, the polyetheretherketone contains 0.7 wt%-2.2 wt%, preferably 0.7 wt% to 0.8 wt% of the nitrobenzoyloxy group, and the weight percentage of the nitrobenzoyloxy group is the weight percentage of the nitrobenzoyloxy fragment in the formed polyetheretherketone molecule.

[0060] By controlling the weight percentage of the nitrobenzoyloxy group connected to the molecular chain end of the polyetheretherketone within the above range, the obtained polyetheretherketone can be ensured to have an appropriate molecular weight, which is conducive to maintaining appropriate mechanical properties, and the shear performance of the obtained polyetheretherketone can be significantly improved, so that it has a significantly lower shear viscosity at a specific melt flow rate. The inventors of the present invention surprisingly found that polyetheretherketone with the same molecular weight having a nitro group end-capping has a lower shear viscosity than polyetheretherketone without a nitro group end-capping, which was difficult to predict before the present application.

[0061] In the present application, the end groups of polyetheretherketone can be determined by any instrument and equipment known in the art. As an exemplary illustration, the end groups of polyetheretherketone are determined by nuclear magnetic resonance spectrometer (NMR), and the specific test method is to take 10 mg of the prepared polyetheretherketone sample, dissolve it in 10 ml of deuterated trifluoroacetic acid at 60 ° C, and add 10 ml of deuterated trifluoroacetic acid after dissolution to prevent crystallization. If polyetheretherketone cannot be dissolved in hot deuterated trifluoroacetic acid, it means that the end group of the polyetheretherketone is prepared by a traditional method, and the polyetheretherketone is a fluorine or hydroxyl end group; if polyetheretherketone can be dissolved in hot deuterated trifluoroacetic acid, it means that the end group of the polyetheretherketone may be a sulfonic acid group, a nitro group, a nitroso group, a hydroxylamine group, a carboxyl group, an ester group, and an aldehyde group. The specific group type needs to be determined by NMR test analysis. Adjust the NMR to a specific test temperature, wait for a while until the internal temperature of the NMR stabilizes near the set value, put the sample to be tested into the NMR, wait for a while until the sample reaches the same temperature as the inside of the NMR; open the parameter setting interface of the nuclear magnetic resonance spectrometer, adjust the parameter values, and observe the changes in the spectrum until the best signal-to-noise ratio and resolution are achieved; after the instrument is adjusted, put the sample into the sample chamber, start the NMR, select the appropriate scanning mode and parameters, start collecting signals, wait for the signal collection to be completed, save the data, and perform subsequent data processing and analysis as needed.

[0062] In some specific embodiments of the present application, the polyetheretherketone has a structural formula shown in any one of the following formulas (II-1) to (II-3):

[0063]

[0064] Here, n is a positive integer in the range of 50 to 200.

[0065] In some embodiments according to the present application, when the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 380° C., the melt index of the polyetheretherketone at 400° C., 1000° C., -1 The shear viscosity at S is not more than 450 Pa·S, preferably not more than 430 Pa·S, more preferably not more than 405 Pa·S, the melt index is measured according to GB / T-3682, and the shear viscosity is measured according to GB / T 25278-2010.

[0066] In this article, melt index is a parameter that characterizes the processing fluidity of a material. Generally, the higher the melt index, the better the processing fluidity of the material; the smaller the melt index, the worse the processing fluidity of the material. In general, a certain melt index corresponds to a certain shear viscosity. The inventors of the present application have found that the polyetheretherketone according to the present invention can have a significantly lower shear viscosity at a certain melt index. For example, when the polyetheretherketone has a melt index of 10g / min-12g / 10min at 380°C, it has a lower shear viscosity at 400°C, 1000°C, and 1500°C. -1 The shear viscosity at 400°C and 1000°C is not more than 450 Pa·s, preferably not more than 430 Pa·s, and more preferably not more than 405 Pa·s, the melt index is measured according to GB / T-3682, and the shear viscosity is measured according to GB / T 25278-2010. Exemplarily, when the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 380°C, the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 400°C and 1000°C. -1 The shear viscosity at S may be no more than 430 Pa·s, no more than 425 Pa·s, no more than 420 Pa·s, no more than 415 Pa·s, no more than 410 Pa·s, no more than 405 Pa·s, no more than 400 Pa·s, no more than 395 Pa·s, no more than 390 Pa·s, no more than 385 Pa·s, no more than 380 Pa·s, no more than 375 Pa·s, no more than 370 Pa·s, no more than 365 Pa·s, no more than 360 Pa·s, no more than 355 Pa·s, but not less than 300 Pa·s, not less than 305 Pa·s, not less than 310 Pa·s, not less than 315 Pa·s, not less than 320 Pa·s, not less than 325 Pa·s, not less than 330 Pa·s, not less than 340 Pa·s, not less than 350 Pa·s or in a range formed by any two of the above values. When the polyetheretherketone has a melt index of 10g / min-12g / 10min at 380°C and the shear viscosity of the polyetheretherketone is within the above range, the obtained polyetheretherketone is suitable for the extrusion of sheets and rods that conventional polyetheretherketone with higher viscosity is usually not applicable, as well as the preparation of prepregs, which greatly expands the application field of polyetheretherketone.

[0067] In other embodiments according to the present application, compared to a polyetheretherketone having substantially the same melt index and not capped with a nitrobenzoyloxy group, the polyetheretherketone has a shear viscosity reduction of at least 10%, preferably at least 12%, more preferably at least 17%, at 400° C., 1000° C., 1500° C., 2000° C., 3000° C., 5000° C., 6000° C., 7000° C., 8000° C., 9000° C., 15000° C., 6000° C., 7000° C., 8000° C., 9000° C., 6 ... -1 S is measured according to GB / T 25278-2010.

[0068] In the context of the present application, the expression "having substantially the same melt index" is directed to two different polyetheretherketones, and when the difference between the melt indexes of the two different polyetheretherketones is within the range of ±6%, the two different polyetheretherketones are considered to have substantially the same melt index. For example, when the melt indexes of polyetheretherketone A and polyetheretherketone B are measured under the same conditions, respectively, the difference between the obtained melt index a and the obtained melt index b is within the range of 6% or less relative to the percentage of the larger melt index of the melt index a and the melt index b. In this case, polyetheretherketone A and polyetheretherketone B are considered to have substantially the same melt index.

[0069] In the context of the present application, the term "shear viscosity reduction" is used to measure the degree of reduction in shear viscosity of different polyetheretherketones with substantially the same melt index. The greater the shear viscosity reduction, the better the performance of the polyetheretherketone, and the more suitable it is for extrusion of sheets, rods and the preparation of prepregs. The shear viscosity reduction is determined by: measuring the shear viscosity of the polyetheretherketone terminated with nitrobenzoyloxy according to the present invention; then measuring the shear viscosity of a polyetheretherketone with substantially the same melt index that is not terminated with nitrobenzoyloxy (i.e., a control polyetheretherketone), preferably, the raw materials and the amount and preparation method of the control polyetheretherketone are the same as those of the polyetheretherketone terminated with nitrobenzoyloxy according to the present invention, the only difference being that no nitrobenzoyloxy-containing compound is added; then, dividing the difference in the above shear viscosities by the shear viscosity of the control polyetheretherketone, thereby obtaining the shear viscosity reduction.

[0070] The inventors of the present application have found that the polyetheretherketone according to the present invention has a significant reduction in shear viscosity compared to polyetheretherketone having substantially the same melt index and not capped with nitrobenzoyloxy groups. For example, the polyetheretherketone according to the present invention has a shear viscosity reduction of at least 10%, preferably at least 12%, and more preferably at least 17%, at 400°C, 1000°C, and 1500°C. -1 S is measured according to GB / T 25278-2010. Exemplarily, the polyetheretherketone according to the present invention has a shear viscosity reduction of at least 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, at least 20%, at least 21%, at least 22%, at least 23%, at least 24%, at least 25% or more. When the polyetheretherketone according to the present invention has the above shear viscosity reduction compared to the polyetheretherketone with substantially the same melt index that is not terminated with nitrobenzoyloxy, the obtained polyetheretherketone is suitable for the extrusion of sheets and rods that conventional polyetheretherketones with higher viscosity are usually not applicable, as well as the preparation of prepregs, which greatly expands the application field of polyetheretherketone.

[0071] In this application, melt index has a meaning known in the art, and can be measured by any instrument and method known in the art. In this application, melt index is measured using a melt flow rate meter according to GB / T-3682, where the instrument temperature is set to 380°C, the weight mass is 5kg, and the cutting time is set to 60s. The specific operation is as follows: take 5g of the measured polyetheretherketone sample, add it to the test barrel of the melt flow rate meter, wait for 5 minutes until the temperature of the blocked polyetheretherketone reaches 380°C, press the test sample with a press rod, put the test weight, wait for the instrument to automatically cut the material, take the cut material segment and weigh the mass with a precision balance, input the mass number into the instrument, and calculate the melt index.

[0072] In this application, shear viscosity has a meaning known in the art, and can be measured by any instrument and method known in the art. In this application, the shear viscosity test method is to use a capillary rheometer to test, according to the national standard GB / T 25278-2010, the instrument temperature is set to 400°C, 10g of blocked polyetheretherketone is added to the instrument barrel, wait for 5 minutes, start the instrument test, and take the test result as 1000 -1 Shear viscosity at S.

[0073] Another aspect of the present application provides a method for preparing the above-mentioned polyetheretherketone, which comprises the following steps: under an inert atmosphere and in the presence of an alkali metal carbonate, 4,4'-difluorobenzophenone and hydroquinone undergo nucleophilic condensation, and then, during the nucleophilic condensation, a compound containing a nitrobenzoyloxy group is added to the reaction system of the nucleophilic condensation to continue the reaction; and after the reaction is completed, cooling and purifying to obtain the polyetheretherketone.

[0074] In some embodiments according to the present application, the alkali metal carbonate includes sodium carbonate or a mixture of sodium carbonate and potassium carbonate, preferably includes a mixture of sodium carbonate and potassium carbonate, and the molar ratio of the two is in the range of 8.5-9.5:1.

[0075] In some embodiments according to the present application, the molar ratio of the alkali metal carbonate to the hydroquinone is in the range of 1.001-1.15:1, optionally in the range of 1.001-1.005:1.

[0076] In some embodiments according to the present application, the molar ratio of the 4,4'-difluorobenzophenone to the hydroquinone is in the range of 1.001-1.04:1, optionally in the range of 1.001-1.005:1.

[0077] In some embodiments according to the present application, the molar ratio of the compound containing a nitrobenzoyloxy group to the 4,4'-difluorobenzophenone is in the range of 0.095-0.105:1, optionally in the range of 0.099-1.001:1.

[0078] In some embodiments of the present application, during the nucleophilic polycondensation, the temperature is first raised to 220° C. and maintained for 60-70 min; the temperature is then raised to 280° C.; after the nitrobenzoyloxy-containing compound is added, the temperature is then raised to 320° C. and maintained for 50-60 min.

[0079] In some embodiments according to the present application, during the nucleophilic polycondensation, an aromatic sulfone is used as a solvent, and the aromatic sulfone is selected from one or more of diphenyl sulfone, dibenzothiophene dioxide, thiophene dioxide and 4-phenylsulfonyl biphenyl, and preferably, the weight of the solvent is 3 times or more, but not more than 10 times, the weight of 4,4'-difluorobenzophenone. Controlling the weight of the solvent within the above range can ensure that the viscosity of the reaction system is within an appropriate range while avoiding environmental pollution and cost increase caused by excessive solvent.

[0080] The above-mentioned method for preparing polyetheretherketone is carried out by a nucleophilic reaction. The nucleophilic reaction according to the present application is different from the traditional nitration reaction (i.e., the reaction of dehydrating polyetheretherketone using concentrated nitric acid and concentrated sulfuric acid), which uses a nitro compound to graft the entire nitro compound onto the polyetheretherketone molecular chain, and the nitro group is not transferred during the reaction. In comparison, the traditional nitration reaction is to transfer the nitro group of nitric acid to the benzene ring of polyetheretherketone, replacing the position of "hydrogen" on the benzene ring. The method of modifying polyetheretherketone using a nucleophilic reaction has obvious cost and environmental advantages compared to the traditional nitration method, avoids the increase in equipment cost due to the use of nitric acid / sulfuric acid, and reduces the environmental risks and pollution caused by the use of nitric acid / sulfuric acid.

[0081] The third aspect of the present application provides a plate, which is formed by extruding the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application. In the context of the present application, the term "plate" refers to a flat rectangular product formed by extrusion, especially melt extrusion.

[0082] The fourth aspect of the present application provides a pipe, which is formed by extruding the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application. In the context of the present application, the term "pipe" refers to an article of an elongated tubular structure formed by extrusion, especially melt extrusion.

[0083] The fifth aspect of the present application provides a prepreg, which is prepared from the polyetheretherketone according to the first aspect of the present application or the polyetheretherketone prepared by the method according to the second aspect of the present application. In the context of the present application, the term "prepreg" refers to a composition of a resin matrix and a reinforcement formed by impregnating fibers or fabrics continuously as reinforcements with a resin matrix, which is an intermediate material for manufacturing a composite material.

[0084] The polyetheretherketone material of the present application has significantly lower shear viscosity, can remain in a molten state for a long time, has very little change in melt index, and has good mechanical properties and flow characteristics, and can be processed to manufacture extruded rods, plates, and prepregs.

[0085] Compared with the existing PEEK, the polyetheretherketone material of this application has the following advantages:

[0086] (1) It has thermal stability and can remain in a molten state for a long time during processing, and its viscosity changes very little, making it easy to process;

[0087] (2) It has good mechanical properties and fluidity, and can be processed into intermediate products such as PEEK films, rods, plates, and pipes. In addition to injection molding and compression molding, it can also be processed by extrusion and is suitable for preparing prepregs.

[0088] Example

[0089] The following examples describe the disclosure of the present application in more detail, and these examples are only for illustrative purposes, as it is obvious to those skilled in the art that various modifications and variations can be made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and the instruments used in the examples are commercially available.

[0090] Test method:

[0091] 1) Weight average molecular weight: The weight average molecular weight of the polyetheretherketone prepared according to the examples and comparative examples of the present invention is measured based on gel chromatography using a PL-220 gel chromatograph (GPC);

[0092] 2) Confirmation of nitrobenzoyloxy terminal groups: The confirmation of nitrobenzoyloxy terminal groups at the molecular chain ends of polyetheretherketones prepared according to the examples and comparative examples of the present invention was achieved by NMR;

[0093] 3) Melt index: The melt index of the polyetheretherketone prepared according to the examples and comparative examples of the present invention is measured using a melt flow rate meter according to GB / T-3682, wherein the instrument temperature is set to 380° C., the weight mass is 5 kg, and the cutting time is set to 60 s.

[0094] 4) Shear viscosity: The shear viscosity of the polyetheretherketone prepared according to the embodiments of the present invention and the comparative examples is tested using a capillary rheometer. According to the national standard GB / T 25278-2010, the instrument temperature is set to 400°C, 10g of blocked polyetheretherketone is added to the instrument barrel, and after waiting for 5 minutes, the instrument test is started, and the test result is taken as 1000. -1 Shear viscosity at S.

[0095] Embodiment 1:

[0096] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 106g (1mol) of sodium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 280℃, add 16.7g (0.1mol) of 4-nitrobenzoic acid, heat and continue to react to 320℃, keep for 50min, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain a blocked polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample. The capped polyetheretherketone is soluble in hot 1,3,5-trichlorobenzene and is shown by NMR analysis to have nitrobenzoyloxy terminal groups.

[0097] Embodiment 2:

[0098] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 95.4g (0.9mol) of sodium carbonate and 13.8g (0.1mol) of potassium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 280℃, add 16.7g (0.1mol) of 4-nitrobenzoic acid, heat and continue to react to 320℃, keep for 50min, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain a blocked polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample. The capped polyetheretherketone is soluble in hot 1,3,5-trichlorobenzene and is shown by NMR analysis to have nitrobenzoyloxy terminal groups.

[0099] Embodiment 3:

[0100] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 95.4g (0.9mol) of sodium carbonate and 13.8g (0.1mol) of potassium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 280℃, add 16.7g (0.1mol) of 2-nitrobenzoic acid, heat and continue to react to 320℃, keep for 50min, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain a blocked polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample. The capped polyetheretherketone is soluble in hot 1,3,5-trichlorobenzene and is shown by NMR analysis to have nitrobenzoyloxy terminal groups.

[0101] Embodiment 4:

[0102] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 95.4g of sodium carbonate (0.9mol) and 13.8g (0.1mol) of potassium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 280℃, add 16.7g (0.1mol) of 3-nitrobenzoic acid, heat and continue to react to 320℃, keep for 50min, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with an appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain a blocked polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample. The capped polyetheretherketone is soluble in hot 1,3,5-trichlorobenzene and is shown by NMR analysis to have nitrobenzoyloxy terminal groups.

[0103] Comparative Example 1:

[0104] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 106g (1mol) of sodium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 320℃, react for a period of time, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample.

[0105] Comparative Example 2:

[0106] Add 218.2g (1mol) of 4,4'-difluorobenzophenone, 110.1g (1mol) of hydroquinone, 95.4g (0.9mol) of sodium carbonate and 13.8g (0.1mol) of potassium carbonate to a three-necked flask, pass argon at a flow rate of 150ml / min, heat the three-necked flask, and stir at a speed of 60rpm after the material in the flask melts. When the temperature rises to 220℃, maintain a constant temperature for one hour, continue to heat to 320℃, react for a period of time, and obtain a viscous polyetheretherketone semi-finished product mixture. The reaction is completed. Pour the mixture into an iron plate while hot, crush it after cooling, wash it with appropriate amount of ethanol 5 times, wash it with distilled water 5 times, and dry it at 150℃ for 6 hours to obtain polyetheretherketone. Test the weight average molecular weight, melt index and shear viscosity of the obtained sample.

[0107] The results of the weight average molecular weight, melt index and shear viscosity of the polyetheretherketone prepared in the above examples are summarized in the following Table 1.

[0108] Table 1: Weight average molecular weight, melt index and shear viscosity of polyetheretherketone

[0109]

[0110]

[0111] The test results show that the polyetheretherketone prepared in the present invention has a significantly lower shear viscosity at a specific melt index, and is particularly suitable for applications such as extruded sheets and rods and prepregs.

[0112] Some exemplary implementations are described below:

[0113] Embodiment 1. A polyetheretherketone, wherein the polyetheretherketone satisfies the following properties:

[0114] i) The polyetheretherketone has a repeating unit represented by the following formula (I):

[0115]

[0116] ii) the polyetheretherketone has a weight average molecular weight in the range of 15,000 to 45,000, as measured by GPC; and

[0117] iii) A nitrobenzoyloxy group is connected to the molecular chain terminal of the polyetheretherketone.

[0118] Embodiment 2. The polyetheretherketone as described in embodiment 1, wherein the nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoyloxy, 3-nitrobenzoyloxy, and 4-nitro-benzoyl.

[0119] Embodiment 3. The polyetheretherketone as described in embodiment 1, wherein the nitrobenzoyloxy group is derived from a compound containing a nitrobenzoyloxy group, and the compound containing a nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitro-benzoic acid, 2-nitrobenzoyl fluoride, 3-nitrobenzoyl fluoride, and 4-nitro-benzoyl fluoride.

[0120] Embodiment 4. The polyetheretherketone as described in embodiment 1, wherein the polyetheretherketone contains 0.7 wt%-2.2 wt%, preferably 0.7 wt% to 0.8 wt% of the nitrobenzoyloxy group, and the weight percentage of the nitrobenzoyloxy group is the weight percentage of the nitrobenzoyloxy fragment in the formed polyetheretherketone molecule.

[0121] Embodiment 5. The polyetheretherketone according to embodiment 1, wherein the polyetheretherketone has a structural formula shown in any one of the following formulas (II-1) to (II-3):

[0122]

[0123] Here, n is a positive integer in the range of 50 to 200.

[0124] Embodiment 6. The polyetheretherketone according to any one of embodiments 1 to 5, wherein when the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 380°C, it has a melt index of 10 g / min-12 g / 10 min at 400°C, 1000 -1 The shear viscosity at s is not more than 450 Pa·s, preferably not more than 430 Pa·s, more preferably not more than 405 Pa·s, the melt index is measured according to GB / T-3682, and the shear viscosity is measured according to GB / T 25278-2010.

[0125] Embodiment 7. The polyetheretherketone of any one of embodiments 1 to 5, wherein the polyetheretherketone has a shear viscosity reduction of at least 10%, preferably at least 12%, more preferably at least 17%, compared to a polyetheretherketone having substantially the same melt index but not capped with nitrobenzoyloxy groups, the shear viscosity being at 400° C., 1000° C., -1 S is measured according to GB / T 25278-2010.

[0126] Embodiment 8. A method for preparing the polyetheretherketone described in any one of embodiments 1-7, the method comprising the following steps:

[0127] i) In an inert atmosphere, in the presence of an alkali metal carbonate, 4,4'-difluorobenzophenone and hydroquinone undergo nucleophilic condensation, and then

[0128] ii) during the nucleophilic polycondensation, adding a compound containing a nitrobenzoyloxy group to the reaction system of the nucleophilic polycondensation to continue the reaction; and then

[0129] iii) After the reaction is completed, cooling and purification are performed to obtain the polyetheretherketone.

[0130] Embodiment 9. The method according to embodiment 8, wherein:

[0131] The alkali metal carbonate comprises sodium carbonate or a mixture of sodium carbonate and potassium carbonate, preferably a mixture of sodium carbonate and potassium carbonate, wherein the molar ratio of the two is in the range of 8.5-9.5:1;

[0132] The molar ratio of the alkali metal carbonate to the hydroquinone is in the range of 1.001-1.15:1;

[0133] The molar ratio of the 4,4'-difluorobenzophenone to the hydroquinone is in the range of 1.001-1.04:1;

[0134] The molar ratio of the compound containing nitrobenzoyloxy group to the 4,4'-difluorobenzophenone is in the range of 0.095-0.105:1.

[0135] Embodiment 10. The method according to embodiment 8 or 9, wherein during the nucleophilic polycondensation, the temperature is first raised to 220°C and maintained for 60-70 minutes; the temperature is then raised to 280°C; after the nitrobenzoyloxy-containing compound is added, the temperature is then raised to 320°C and maintained for 50-60 minutes.

[0136] Embodiment 11. A method according to any one of embodiments 8 to 10, wherein during the nucleophilic polycondensation, an aromatic sulfone is used as a solvent, and the aromatic sulfone is selected from one or more of diphenyl sulfone, dibenzothiophene dioxide, thiophene dioxide and 4-phenylsulfonylbiphenyl, and preferably, the weight of the solvent is 3 times or more, but not more than 10 times, the weight of 4,4'-difluorobenzophenone.

[0137] Embodiment 12. A plate material formed by extruding the polyetheretherketone described in any one of Embodiments 1 to 7 or the polyetheretherketone prepared by the method described in any one of Embodiments 8 to 11.

[0138] Embodiment 13. A rod formed by extruding the polyetheretherketone described in any one of Embodiments 1 to 7 or the polyetheretherketone prepared by the method described in any one of Embodiments 8 to 11.

[0139] Embodiment 14. A prepreg prepared from the polyetheretherketone described in any one of embodiments 1 to 7 or the polyetheretherketone prepared by the method described in any one of embodiments 8 to 11.

[0140] Although the present application is described with reference to a number of implementation modes and examples, a person skilled in the art will recognize, based on the contents disclosed in the present application, that other implementation modes can be designed without departing from the protection scope of the present application.

Claims

1. A polyetheretherketone, wherein the polyetheretherketone satisfies the following properties: i) The polyetheretherketone has a repeating unit represented by the following formula (I): ii) the polyetheretherketone has a weight average molecular weight in the range of 15,000 to 45,000, as measured by GPC; and iii) A nitrobenzoyloxy group is connected to the molecular chain terminal of the polyetheretherketone.

2. The polyetheretherketone according to claim 1, wherein The nitrobenzoyloxy group is selected from one or more of a 2-nitrobenzoyloxy group, a 3-nitrobenzoyloxy group, and a 4-nitro-benzoyl group.

3. The polyetheretherketone according to claim 1, wherein The nitrobenzoyloxy group is derived from a compound containing a nitrobenzoyloxy group, and the compound containing a nitrobenzoyloxy group is selected from one or more of 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitro-benzoic acid, 2-nitrobenzoyl fluoride, 3-nitrobenzoyl fluoride, and 4-nitro-benzoyl acyl fluoride.

4. The polyetheretherketone according to claim 1, wherein The polyetheretherketone contains 0.7 wt%-2.2 wt%, preferably 0.7 wt% to 0.8 wt% of the nitrobenzoyloxy group, wherein the weight percentage of the nitrobenzoyloxy group refers to the weight percentage of the nitrobenzoyloxy fragment in the formed polyetheretherketone molecule.

5. The polyetheretherketone according to claim 1, wherein The polyetheretherketone has a structural formula shown in any one of the following formulas (II-1) to (II-3): Here, n is a positive integer in the range of 50 to 200.

6. The polyetheretherketone according to any one of claims 1 to 5, wherein When the polyetheretherketone has a melt index of 10 g / min-12 g / 10 min at 380°C, its -1 The shear viscosity at s is not more than 450 Pa·s, preferably not more than 430 Pa·s, more preferably not more than 405 Pa·s, the melt index is measured according to GB / T-3682, and the shear viscosity is measured according to GB / T 25278-2010.

7. A method for preparing the polyetheretherketone according to any one of claims 1 to 6, the method comprising the following steps: i) In an inert atmosphere, in the presence of an alkali metal carbonate, 4,4'-difluorobenzophenone and hydroquinone undergo nucleophilic condensation, and then ii) during the nucleophilic polycondensation, adding a compound containing a nitrobenzoyloxy group to the reaction system of the nucleophilic polycondensation to continue the reaction; and then iii) After the reaction is completed, cooling and purification are performed to obtain the polyetheretherketone.

8. A plate formed by extruding the polyetheretherketone according to any one of claims 1 to 6 or the polyetheretherketone prepared by the method according to claim 7.

9. A rod formed by extruding the polyetheretherketone according to any one of claims 1 to 6 or the polyetheretherketone prepared by the method according to claim 7.

10. A prepreg prepared from the polyetheretherketone according to any one of claims 1 to 6 or the polyetheretherketone prepared by the method according to claim 7.

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