A polyaryletherketone and a process for preparing a polyaryletherketone by electrophilic substitution

Abstract

The application belongs to the technical field of high molecular polymers, and particularly relates to a kind of poly (aryl ether ketone) and electrophilic substitution process for preparing poly (aryl ether ketone). The electrophilic substitution process for preparing poly (aryl ether ketone) is as follows: mixing aryl ether compound monomer with two active hydrogens, aromatic acyl chloride monomer and solvent, adding Lewis acid catalyst under the condition of-15~5℃ to obtain a reaction system, heating the system to 10~20℃ for reaction, cooling the obtained reaction liquid after reaction, and obtaining poly (aryl ether ketone) through post-treatment; the molar ratio of the molar amount of Lewis acid catalyst to the molar amount of aryl ether compound monomer is 0.5:1~1:1. The poly (aryl ether ketone) and the electrophilic substitution process for preparing poly (aryl ether ketone) provided by the application effectively control the pinan-ol end group side reaction and branched structure side reaction in the process of electrophilic substitution for preparing poly (aryl ether ketone), and simultaneously obtain poly (aryl ether ketone) product with suitable bulk density.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, specifically relating to a polyarylether ketone and a process for preparing polyarylether ketone by electrophilic substitution. Background Technology

[0002] Polyaryletherketone (PAEK) is a high-performance, semi-crystalline thermoplastic engineering plastic. There are two main methods for its preparation: nucleophilic substitution and electrophilic substitution. Nucleophilic substitution mainly produces industrial products such as polyetheretherketone (PEEK) and polyetherketone (PEK), while electrophilic substitution mainly produces industrial products such as polyetherketoneketone (PEKK) and polyetherketoneetherketoneketone (PEKEKK). The main chain of the PAEK molecule consists of alternating ether bonds (-O-) and ketone bonds (-CO-) connecting aromatic rings. Its unique chemical structure endows the material with excellent mechanical properties, outstanding high-temperature resistance (long-term operating temperature can reach 250–260℃), and excellent chemical corrosion resistance, superior radiation resistance, extremely low hydrogen permeability, and good flame retardancy and electrical insulation properties. These comprehensive properties make PAEK irreplaceable in high-end fields such as aerospace, petrochemicals, electronics, semiconductors, automotive, and medical implant materials.

[0003] CN113166396A discloses a nucleophilic substitution method using bis(halobenzoyl)benzene monomers and bis(hydroxybenzoyl)benzene monomers in diphenyl sulfone as solvent, catalyzed by alkali metal carbonates, to prepare PEKK molecules with regular molecular chains and excellent thermal stability. However, the monomer synthesis process used in this nucleophilic route is complex and difficult to purify, resulting in high monomer costs and hindering its large-scale industrial application.

[0004] The electrophilic substitution method for preparing polyaryletherketones (PEKKs) generally uses aluminum trichloride as a catalyst and acyl chlorides and aromatic ethers as monomers. The acyl chlorides are typically isophthaloyl chloride and terephthaloyl chloride, and the aromatic ethers are diphenyl ether, 1,4-bis(4-phenoxybenzoyl)benzene, and 4,4'-diphenoxybenzophenone (EKE). When the aromatic ether is diphenyl ether or 1,4-bis(4-phenoxybenzoyl)benzene, the resulting product is generally polyetherketoneketone (PEKK). When the aromatic ether is 4,4'-diphenoxybenzophenone, the resulting product is PEKEKK. Generally, PEKEKK is mainly prepared using 4,4'-diphenoxybenzophenone (EKE) and terephthaloyl chloride. Patent CN121270876A discloses a method using acyl chloride, solvent, Lewis base, diphenyl ether, and Lewis acid as raw materials. The diphenyl ether used in this method has six aromatic hydrogen sites, including four ortho-hydrogens and two para-hydrogens. If the acyl chloride selectively attacks the para-hydrogen of the diphenyl ether, a linear, straight-chain polymer will be successfully formed, such as... Figure 1 As shown in structure a; if the acyl chloride attacks the ortho-hydrogen of the diphenyl ether, two types of side reaction pathways will occur ( Figure 1 In this context, 'b' refers to a collective term for two types of intermediates in the ortho-acylation reaction system, including two structures: b1 and b2: the first type ( Figure 1 In b1), after ortho-acylation, the remaining para-hydrogen in the diphenyl ether molecule can continue to participate in the acylation reaction, and the molecular chain continues to grow, only disrupting the regularity of the polymer molecular chain; the second type ( Figure 1 In step b2), the ortho-acylated product undergoes further intramolecular cyclization, generating an unstable thallium alcohol end group structure. This end group no longer participates in the polymerization reaction, causing chain termination. Furthermore, this thallium alcohol functional group is prone to subsequent reactions upon heating, forming free radicals. These free radicals attack other polymer chains, initiating side reactions such as branching and crosslinking, thus deteriorating the polymer's melt processing properties. Although formic acid washing can reduce the hydroxyl groups on the thallium alcohol group back to thallium groups, making it less likely for the thallium groups to release free radicals at high temperatures, in a high-temperature, aerobic environment, the thallium groups can easily revert back to thallium alcohol groups.

[0005] Electrophilic substitution also presents the problem of branched structure. During electrophilic polymerization, excess Lewis acid catalysts or reactions at high temperatures can easily further activate the aromatic rings on the already formed polymer chains, initiating intermolecular Friedel-Crafts acylation reactions and forming branched or even cross-linked structures. These branched structures exhibit characteristic absorption peaks in the UV-Vis spectrum around 490–520 nm, and this absorption value reflects the degree of branching in PEKK. The presence of branched structures significantly affects the melt rheological behavior and thermal stability of PEKK.

[0006] Electrophilic substitution also presents gelation problems. While the addition of the Lewis base in a Lewis acid / Lewis base co-catalyzed system can suppress side reactions of the tonol to some extent, a gel-like substance easily forms on the reactor wall during polymerization. This not only affects heat transfer efficiency but also prevents proper stirring in the later stages of the reaction, making post-processing difficult. Furthermore, the PEKK product obtained after decomplexation in this method has a low bulk density, posing challenges for subsequent storage and melt extrusion granulation.

[0007] Existing technologies also include first reacting terephthaloyl chloride with diphenyl ether to prepare 1,4-bis(4-phenoxybenzoyl)benzene (EKKE) prepolymer monomers, then refining to remove ortho-byproducts, and using EKKE as a raw material to continue polymerization with iso- / terephthaloyl chloride to prepare PEKK. Due to the large steric hindrance of EKKE, the formation of a terephthaloyl alcohol structure is impossible when using EKKE as a raw material to prepare PEKK. However, due to the use of a large amount of aluminum trichloride, branched structures may still be generated in the later stages of the reaction. In addition, US Patent 9023468B2 discloses a method for preparing near-spherical PEKK powder using EKKE as a raw material, dichloromethane as a solvent, and benzoic acid as a dispersant, which is suitable for selective laser sintering (SLS) additive manufacturing processes. However, the dispersant used in this method generally forms a complex with Lewis acid, thus consuming too much Lewis acid. On the other hand, the dispersant is generally a small molecule substance, and if it cannot be completely removed from the prepared polymer after polymerization, it may have an adverse effect on the thermal stability of the polymer. Furthermore, this method also uses a large amount of aluminum trichloride and reacts at room temperature, yet it still cannot avoid the formation of branched structures, such as... Figure 3 As shown, depending on the reactants, it exhibits high UV absorption values ​​at 490 nm and 520 nm, respectively. Figure 3 The branched structure shown can also have an adverse effect on the thermal stability of the polymer. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the existing technology in the preparation of PAEK (polyaryletherketone) by electrophilic substitution, which is difficult to control by side reactions. The invention provides a polyaryletherketone and a process for preparing polyaryletherketone by electrophilic substitution, which effectively controls the side reactions of alcohol end groups and branching structures in the preparation of PAEK by electrophilic substitution without significantly increasing production costs, and at the same time obtains PAEK products with suitable packing density and good processing performance.

[0009] The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: mixing an aryl ether monomer with two active hydrogens, an aromatic acyl chloride monomer, and a solvent; adding a Lewis acid catalyst at -15 to 5°C to obtain a reaction system; heating the system to 10 to 20°C for reaction; cooling the reaction solution after the reaction is completed; and obtaining polyarylether ketones after post-treatment. The aryl ether monomer with two active hydrogens is 1,4-bis(4-phenoxybenzoyl)benzene (EKKE) or 4,4'-diphenoxybenzophenone (EKE); preferably 1,4-bis(4-phenoxybenzoyl)benzene. Using EKKE as the aryl ether monomer effectively utilizes the para-active hydrogens of the two terminal phenoxy groups in its molecular structure to participate in chain propagation reactions. Simultaneously, the steric hindrance effect generated by the larger molecular volume of EKKE suppresses ortho-side reactions and the formation of tonol end groups. EKKE and EKE can be prepared in-house or commercially available; as long as the purity meets the requirements, they are ready for use.

[0010] The Lewis acid catalyst is aluminum trichloride, which is added to the mixed system in multiple portions. The aluminum trichloride is anhydrous aluminum trichloride. Anhydrous aluminum trichloride plays a dual role in the reaction system: a portion of it complexes with carbonyl groups in the system (1 mole of carbonyl group complexes 1 mole of anhydrous aluminum trichloride), while the remaining anhydrous aluminum trichloride acts as a catalyst. The molar ratio of the Lewis acid catalyst must satisfy the following condition: (Total molar amount of carbonyl groups + Molar amount of aryl ethers in the reaction system / 2) < Molar amount of Lewis acid catalyst < Total molar amount of carbonyl groups + Molar amount of aryl ethers in the reaction system. When the molar amount of the catalytic Lewis acid is greater than the molar amount of aryl ethers, the amount of catalyst in the system is excessive, making it prone to adsorption. Figure 3 The branching reaction described above can lead to cross-linking, causing the reaction system to form a gel-like substance that cannot be molded or processed. By precisely controlling the total amount of Lewis acid within the above range, sufficient carbonyl complexing capacity and catalytic activity are ensured, while avoiding intermolecular branching and cross-linking side reactions caused by excessive Lewis acid. Figure 3 In the diagram, a and b represent the branched structures resulting from the branching reactions during the synthesis of PEKK and PEKEKK, respectively. The dichloroacetic acid solution of a has a maximum absorption peak at 520 nm, while the dichloroacetic acid solution of b has a maximum absorption peak at 490 nm.

[0011] The aluminum trichloride is added to the mixing system in multiple portions, preferably in 5 to 7 portions, in an even distribution manner, in 3 to 10 portions.

[0012] For example, when the total molar amount of Lewis acid is 0.97 mol, and the reaction system contains 0.2036 mol of EKKE, 0.08 mol of TPC, and 0.12 mol of IPC, the total molar amount of carbonyl groups in the entire reaction system is: 2 carbonyl groups in EKKE × 0.2036 mol + 2 carbonyl groups in TPC × 0.08 mol + 2 carbonyl groups in IPC × 0.12 mol = 0.4072 + 0.16 + 0.24 = 0.8072 mol. The molar amount of aryl ether in the reaction system is 0.2036 mol. Therefore, the lower limit of the amount of Lewis acid used in the reaction system is 0.2036 / 2 + 0.8072 = 0.909 mol. The upper limit of the amount of Lewis acid used in the reaction system is 0.2036 + 0.8072 = 1.0108 mol. According to the above calculation method, the effective amount of catalyst / molar amount of EKKE = (0.97-0.8072) / 0.2036≈0.7996.

[0013] The aromatic acyl chloride monomer is terephthaloyl chloride, isophthaloyl chloride, or a mixture of the two.

[0014] The Lewis acid catalyst is added at -15 to 5°C, and should be added as quickly as possible to reduce the entry of ambient moisture into the reaction system. Simultaneously, care should be taken to minimize the adhesion of aluminum trichloride powder to the inner wall of the reaction apparatus; if it does adhere, it can be washed off using an aprotic solvent. After the addition is complete, the stirring speed of the reaction system should be maintained at 200 to 400 rpm.

[0015] The solvent is dichloromethane or 1,2-dichloroethane. Dichloromethane is preferred. Dichloromethane has a moderate boiling point (about 40°C), good solubility, and low cost, and is easily recovered by distillation during post-processing.

[0016] The system is heated to 10-20°C for reaction, and the reaction ends afterward. The reaction time is generally controlled between 60-180 minutes. Specifically, a temperature of 12-20°C or 10-18°C is effective, with 12-18°C being a more preferred range. This invention mainly controls the polymerization reaction by controlling the amount of Lewis acid catalyst and the reaction temperature to prepare low-defect PEKK products. The maximum temperature of the reaction system is controlled to be no lower than 10°C. Below this temperature, no matter how long the reaction time is extended, the degree of reaction is not high, resulting in more acyl chloride groups being capped. After hydrolysis and complexation, these will become terminal carboxyl groups, which are detrimental to the thermal stability of the final polymer product. The maximum temperature of the reaction system is controlled to be below 20°C. Above this temperature, PEKK is prone to generating substances such as... Figure 3 The branched structure shown indicates that, on the other hand, the reaction solvent is prone to alkylation reactions at temperatures above this level, which affects the stability of the final polymer.

[0017] After the reaction is complete, the resulting reaction solution is cooled in an ice-water bath. The reaction solution is then slowly poured into the ice-water bath to quench it.

[0018] The post-processing includes the following specific operations: solid-liquid separation, solvent distillation, washing of the solid with hot water, and drying. The hot water is used for multiple washes at 60-100℃. Drying can be performed under normal pressure or under vacuum.

[0019] An end-capping agent is added to the mixture before the Lewis acid catalyst is added. The end-capping agent is one or more of electrophilic and nucleophilic end-capping agents. Electrophilic end-capping agents include benzoyl chloride, p-fluorobenzoyl chloride, and p-chlorobenzoyl chloride; nucleophilic end-capping agents include 4-phenoxybenzophenone, 4-phenoxydiphenyl sulfone, and biphenyl. The addition of the end-capping agent effectively controls the molecular weight of the polymer and eliminates residual active end groups, further improving the thermal stability of the product.

[0020] A polyaryletherketone, with the following structural formula: ; Where Ar is simultaneously , or Ar is simultaneously .

[0021] The specific structure is as follows: or .

[0022] The defects or branching in the structure of the prepared polyaryletherketone were characterized by ultraviolet-visible spectroscopy. The prepared polyaryletherketone was treated at 250℃ for 30 min in the presence of air and then prepared into a 1 mg / mL dichloroacetic acid solution. The absorption peak at 455 nm in the ultraviolet-visible spectrum was less than 0.05; the maximum absorption peak at 490~520 nm was less than 0.05.

[0023] The intrinsic viscosity of the polyaryletherketone, measured in 98% concentrated sulfuric acid at 25°C, is 0.8~1.4 dL / g, preferably 0.85~1.10 dL / g.

[0024] The bulk density of the polyaryletherketone is 0.15~0.25 g / mL, preferably 0.18~0.22 g / mL.

[0025] The polyaryletherketones prepared above are processed using conventional polymer molding methods such as injection molding, extrusion, compression molding, and additive manufacturing.

[0026] The anhydrous aluminum trichloride is added to the mixing system in 3 to 10 portions.

[0027] The polyarylether ketones prepared above are used in aerospace, petrochemical, medical and health fields.

[0028] Specifically, the electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In the reaction apparatus, solvent, 1,4-bis(4-phenoxybenzoyl)benzene or 4,4'-diphenoxybenzophenone, TPC and / or IPC are added respectively. The mixture is cooled to -15~5℃, and anhydrous aluminum trichloride is added in 3~10 batches to obtain the reaction system. The system is heated to 10~20℃ for reaction. As the reaction proceeds, the color of the reaction system gradually deepens to dark red, and particulate substances gradually precipitate out. The reaction is continued for 90~150min. After the reaction is completed, the reaction solution is slowly poured into an ice-water bath for quenching and allowed to stand for more than 12h. Then, the aprotic solvent is recovered by distillation, and the solid crude product is collected by filtration. The obtained crude PEKK product is washed multiple times with hot water at 70~85℃ (500mL each time) and dried under vacuum at 115~125℃ for 12~16h to obtain the PEKK product.

[0029] (1) When preparing polyarylether ketones using EKKE, TPC, and IPC as raw materials, the reaction equations are as follows: .

[0030] (2) When polyaryletherketones are prepared using EKE, TPC, and IPC as raw materials, the reaction equations are as follows: .

[0031] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention selects 1,4-bis(4-phenoxybenzoyl)benzene (EKKE) or 4,4'-diphenoxybenzophenone as monomers of aryl ether compounds with two active hydrogens. It utilizes the para-active hydrogens of the two terminal phenoxy groups in its molecular structure to participate in the chain growth reaction. Combined with the steric hindrance effect generated by its large molecular volume, it effectively suppresses the tendency of generating tonol end groups due to ortho-position side reactions during electrophilic substitution polymerization. At the same time, this invention precisely controls the total amount of Lewis acid catalyst, which ensures the full complexation activation and catalytic activity of the carbonyl group, and avoids the intermolecular branching and cross-linking side reactions caused by the further activation of the aromatic ring on the polymer chain by excessive Lewis acid. Thus, a polyaryl ether ketone product with high molecular chain regularity and few defects is obtained. The maximum absorption peaks of this product at 455 nm and 490-520 nm in the ultraviolet-visible spectrum are both less than 0.05, indicating that the tonol end groups and branched structures are effectively controlled.

[0032] (2) By controlling the maximum temperature of the reaction system within the range of 10~20℃, this invention overcomes the problem of insufficient reaction degree at low temperature (below 10℃) and avoids the defects of branched structure formation and alkylation side reaction of reaction solvent at high temperature (above 20℃). Combined with the operation of adding Lewis acid catalyst at low temperature of -15~5℃, the polymerization reaction is carried out stably under mild and controllable conditions. After the reaction is completed, the reaction liquid is cooled in an ice-water bath. The polyaryletherketone product obtained after post-treatment has a suitable bulk density, which effectively improves the problem of storage and melt extrusion granulation difficulties caused by the low bulk density of the product in the prior art, and is conducive to transportation, storage and processing in subsequent industrial production.

[0033] (3) Without significantly increasing production costs, this invention does not require complex and expensive monomer synthesis and refining routes. It can produce polyaryletherketone products with intrinsic viscosity of 0.8~1.4 dL / g simply by optimizing the Lewis acid dosage ratio, reaction temperature range and monomer selection. This product has low defect structure, suitable bulk density and good processing performance. It can be widely used in injection molding, extrusion, compression molding, additive manufacturing and other molding processing methods to meet the application needs of high-end fields such as aerospace, petrochemical, medical and health care for high-performance special engineering plastics. Attached Figure Description

[0034] Figure 1 This diagram illustrates the side reactions of alcohol end groups and the thermal decomposition mechanism of unstable end groups during the polymerization of polyarylether ketones via electrophilic substitution in the prior art.

[0035] Figure 2 This is a schematic diagram illustrating the formation mechanism of intermolecular branching side reactions during the polymerization of polyaryletherketones using the electrophilic substitution method in the prior art.

[0036] Figure 3 This is a schematic diagram of the branched structure generated by the intermolecular branching side reaction during the polymerization of polyaryletherketones using the electrophilic substitution method in the prior art.

[0037] Figure 4 The image shows the transmission infrared spectrum of the polyaryletherketone product from Example 1.

[0038] Figure 5 The polyaryletherketone product of Example 1 1 HNMR spectrum.

[0039] Figure 6 The TGA thermogravimetric analysis spectrum of the polyaryletherketone product in Example 1 is shown.

[0040] Figure 7 The image shows the differential scanning calorimetry (DSC) curve of the polyaryletherketone product in Example 1. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments.

[0042] The reagents used in the following examples and comparative examples are all commercially available products.

[0043] 1,4-Bis(4-phenoxybenzoyl)benzene (EKKE), purity ≥99.8%; 4,4'-diphenoxybenzophenone (EKE), purity ≥99.8%; isophthaloyl chloride (IPC), purity ≥99.5%; terephthaloyl chloride (TPC), purity ≥99.5%; anhydrous aluminum trichloride (AlCl3), purity ≥99.0%; aprotic solvent water content ≤50ppm; benzoic acid, analytical grade; 98wt% concentrated sulfuric acid, analytical grade; dichloroacetic acid (DCAA), analytical grade.

[0044] Example 1 The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 400 mL of dichloromethane, 95.80 g (0.2036 mol) of EKKE, 16.24 g (0.08 mol) of TPC, and 24.36 g (0.12 mol) of IPC (T / I molar ratio = 70:30) were added. The mixture was cooled to -5 °C, and 129.35 g (total 0.97 mol) of anhydrous aluminum trichloride was added rapidly in five batches. After the addition was complete, the aluminum trichloride powder adhering to the reaction flask wall was rinsed with 100 mL of dichloromethane. At this point, the contents of the reaction flask... The solution was orange-red. The stirring speed was controlled at 300 rpm, and the temperature of the reaction system was raised to 15℃. As the reaction proceeded, the color of the reaction system gradually deepened to dark red, and particulate matter gradually precipitated out. After continuing the reaction at 15℃ for 90 min, the reaction solution was slowly poured into an ice-water bath to quench it. After standing for 12 h, dichloromethane was recovered by distillation, and the solid product, namely the crude PEKK product, was collected by filtration. The crude product was washed twice with 80℃ hot water (500 mL each time) and dried under vacuum at 120℃ for 12 h to obtain the PEKK product, which was denoted as PEKK-1.

[0045] like Figure 4As shown in the transmission infrared spectrum of the prepared polyether ketone ketone (PEKK), the PEKK product prepared in this embodiment exhibits all characteristic infrared absorption peaks corresponding to the aromatic ring, aromatic ketone carbonyl, and aromatic ether bond, confirming the successful construction of an alternating ether-ketone aromatic backbone. The coexistence of the carbonyl double peak and the characteristic peaks of the para- and meta-benzene rings in the fingerprint region confirms that the two acyl chloride monomers, TPC and IPC, participate in the polymerization together, forming a random copolymer structure with a 70:30 ratio. The spectrum shows no characteristic absorption of raw materials, solvents, and catalyst impurities, and the peaks are regular with no side reaction impurities, indicating that the copolymerized PEKK product obtained by the electrophilic substitution process of this invention has a structure that matches the designed molecule, high purity, and no obvious degradation or cross-linking side reactions during the polymerization process.

[0046] like Figure 5 As shown, the prepared polyetherketoneketone (PEKK) 1 The 1H NMR spectrum shows that the PEKK product prepared in this embodiment exhibits multiple characteristic aromatic hydrogen peaks only in the aromatic hydrogen chemical shift region of 7.27~8.00 ppm, corresponding to benzene ring hydrogens with different substitution environments on the molecular chain. There are no obvious phenolic hydroxyl or carboxyl impurity hydrogen signals at 11.62 ppm, and no aliphatic hydrogen impurity peaks. The integral ratio matches the number of hydrogen atoms in the theoretical molecular structure, and there are no extra impurity peaks corresponding to the raw material monomers, solvents, and catalysts. This proves that the copolymerized PEKK molecular structure prepared by the electrophilic substitution process of this invention is consistent with the designed framework, with no chain-breaking degradation impurities, no aliphatic residual impurities, sufficient polymerization reaction, and a pure and regular product structure.

[0047] like Figure 6 As shown in the TGA thermogravimetric analysis (TGA) curve of the prepared polyether ketone ketone (PEKK), it can be seen that the residual mass of the PEKK product prepared in this example is still 95% at 579.47℃, and significant thermal weight loss only occurs above 540℃. The curve is stable with no mass loss in the low-temperature to medium-temperature range (40~540℃). This indicates that the copolymer PEKK does not contain volatile impurities such as low-molecular-weight solvents, monomers, and moisture. Moreover, the main chain aromatic ether ketone conjugated structure endows the material with an extremely high thermal decomposition temperature and excellent thermal stability, which can meet the requirements of high-temperature molding and high-temperature service conditions.

[0048] like Figure 7 As shown in the differential scanning calorimetry (DSC) curve of the prepared polyether ketone ketone (PEKK), the DSC curve of the PEKK product prepared in this embodiment clearly shows the glass transition and melting endothermic characteristics. The midpoint temperature of the glass transition is 160.58℃, and the peak temperature of the melting endothermic is 334.17℃. The glass transition step is gentle and there are no impurity peaks, which proves that the product is free of small molecule plasticizing impurities. The melting endothermic peak is regular and single, indicating that the copolymer molecular chain structure is uniform, the material has a high glass transition temperature and a clear melting processing window, and has excellent thermal processing performance.

[0049] Example 2 This embodiment modifies the amount of anhydrous aluminum trichloride based on Example 1, replacing "adding 129.35g (total 0.97mol) of anhydrous aluminum trichloride in five batches" with "adding 130.67g (total 0.98mol) of anhydrous aluminum trichloride in five batches" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-2.

[0050] Example 3 This embodiment modifies the amount of anhydrous aluminum trichloride based on Example 1, replacing "adding 129.35g (total 0.97mol) of anhydrous aluminum trichloride in five batches" with "adding 126.67g (0.95mol) of anhydrous aluminum trichloride in five batches" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-3.

[0051] Example 4 This embodiment modifies the amount of anhydrous aluminum trichloride based on Example 1, replacing "adding 129.35g (total 0.97mol) of anhydrous aluminum trichloride in five batches" with "adding 125.34g (0.94mol) of anhydrous aluminum trichloride in five batches" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-4.

[0052] Example 5 This embodiment modifies the amount of anhydrous aluminum trichloride based on Example 1, replacing "adding 129.35g (total 0.97mol) of anhydrous aluminum trichloride in five batches" with "adding 122.67g (0.92mol) of anhydrous aluminum trichloride in five batches" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-5.

[0053] Example 6 This embodiment modifies the reaction temperature and reaction time based on Example 1, replacing "raising the reaction system temperature to 15℃... and continuing the reaction at 15℃ for 90 min" with "raising the reaction system temperature to 10℃... and continuing the reaction at 10℃ for 150 min". Other conditions remain unchanged, and the resulting PEKK product is denoted as PEKK-6.

[0054] Example 7 This embodiment modifies the reaction temperature and reaction time based on Example 1, replacing "raising the reaction system temperature to 15°C... and continuing the reaction at 15°C for 90 min" with "raising the reaction system temperature to 18°C... and continuing the reaction at 18°C ​​for 90 min". Other conditions remain unchanged, and the resulting PEKK product is denoted as PEKK-7.

[0055] Example 8 This embodiment modifies the reaction temperature and reaction time based on Example 1. The phrase "raise the reaction system temperature to 15°C and continue the reaction at 15°C for 90 min" is replaced with "raise the reaction system temperature to 20°C and continue the reaction at 20°C for 75 min". Other conditions remain unchanged. The resulting PEKK product is denoted as PEKK-8.

[0056] Example 9 This embodiment modifies the molar ratio of TPC to IPC based on Example 1, replacing "16.24g (0.08mol) TPC and 24.36g (0.12mol) IPC (T / I molar ratio = 70:30)" with "24.36g (0.12mol) TPC and 16.24g (0.08mol) IPC (T / I molar ratio = 80:20)" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-9.

[0057] Example 10 This embodiment modifies the molar ratio of TPC to IPC based on Example 1, replacing "16.24g (0.08mol) TPC and 24.36g (0.12mol) IPC (T / I molar ratio = 70:30)" with "8.12g (0.04mol) TPC and 32.48g (0.16mol) IPC (T / I molar ratio = 80:20)" while keeping other conditions unchanged. The resulting PEKK product is denoted as PEKK-10.

[0058] Example 11 The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 400 mL of 1,2-dichloroethane, 95.80 g (0.2036 mol) of EKKE, 16.24 g (0.08 mol) of TPC, and 24.36 g (0.12 mol) of IPC (T / I molar ratio = 70:30) were added. The mixture was cooled to 5 °C, and 129.35 g (total 0.97 mol) of anhydrous aluminum trichloride was added rapidly in five batches. After the addition was complete, the aluminum trichloride powder adhering to the reaction flask wall was rinsed with 100 mL of dichloroethane. At this point, the solution in the reaction flask... The liquid was orange-red. The stirring speed was controlled at 300 rpm, and the temperature of the reaction system was raised to 18℃. As the reaction proceeded, the color of the reaction system gradually deepened to dark red, and particulate matter gradually precipitated out. After continuing the reaction at 18℃ for 90 min, the reaction solution was slowly poured into an ice-water bath to quench it. After standing for 12 h, 1,2-dichloroethane was recovered by distillation, and the solid product, namely the crude PEKK product, was collected by filtration. The crude product was washed twice with 80℃ hot water (500 mL each time) and dried under vacuum at 120℃ for 12 h to obtain the PEKK product, which was designated as PEKK-11.

[0059] Example 12 The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 400 mL of dichloromethane, 74.60 g (0.2036 mol) of EKE, and 40.60 g (0.20 mol) of TPC were added separately. The mixture was cooled to 5 °C, and 102.19 g (total 0.767 mol) of anhydrous aluminum trichloride was added rapidly in five batches. After the addition was complete, the aluminum trichloride powder adhering to the reaction flask wall was rinsed with 100 mL of dichloromethane. At this point, the solution in the reaction flask was orange-red. The stirring speed was controlled at 300 rpm. At pm, the temperature of the reaction system was raised to 15℃. As the reaction proceeded, the color of the reaction system gradually deepened to dark red, and particulate matter gradually precipitated out. After continuing the reaction at 15℃ for 90 min, the reaction solution was slowly poured into an ice-water bath to quench it. After standing for 12 h, dichloromethane was recovered by distillation, and the solid product, namely the crude PEKK product, was collected by filtration. The crude product was washed twice with 80℃ hot water (500 mL each time) and dried under vacuum at 120℃ for 12 h to obtain the PEKEKK product, denoted as PEKEKK-12.

[0060] Example 13 The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In a 1000mL three-necked flask equipped with a mechanical stirrer, 400mL of dichloromethane, 95.80g (0.2036mol) of EKKE, 16.24g (0.08mol) of TPC, and 24.36g (0.12mol) of IPC (T / I molar ratio = 70:30) were added, along with 2.81g (0.02... Using benzoyl chloride (mol) as an electrophilic end-capping agent, the mixture was cooled to 0°C, and 129.35 g (total 0.97 mol) of anhydrous aluminum trichloride was rapidly added in five batches. After the addition was complete, the aluminum trichloride powder adhering to the reaction flask wall was rinsed with 100 mL of dichloromethane. At this time, the solution in the reaction flask was orange-red. The stirring speed was controlled at 300 rpm, and the temperature of the reaction system was raised to 15°C. As the reaction proceeded, the color of the reaction system gradually deepened to dark red, and particulate matter gradually precipitated out. After continuing the reaction at 15°C for 90 min, the reaction solution was slowly poured into an ice-water bath for quenching and allowed to stand for 12 h. Then, the dichloromethane was recovered by distillation, and the solid product, namely the crude PEKK product, was collected by filtration. The crude product was washed twice with 80°C hot water (500 mL each time) and dried under vacuum at 120°C for 12 h to obtain the PEKK product, denoted as PEKK-13.

[0061] Example 14 The electrophilic substitution method for preparing polyarylether ketones of the present invention includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 400 mL of dichloromethane, 74.60 g (0.2036 mol) of EKE, and 40.60 g (0.20 mol) of TPC were added separately. The mixture was cooled to 5 °C, and 106.26 g (total 0.80 mol) of anhydrous aluminum trichloride was added rapidly in five batches. After the addition was complete, the aluminum trichloride powder adhering to the reaction flask wall was rinsed with 100 mL of dichloromethane. At this point, the solution in the reaction flask was orange-red. The stirring speed was controlled at 300 rpm. m, the temperature of the reaction system was raised to 15℃. As the reaction proceeded, the color of the reaction system gradually deepened to dark red, and particulate matter gradually precipitated out. After continuing the reaction at 15℃ for 90 min, the reaction solution was slowly poured into an ice-water bath to quench it. After standing for 12 h, dichloromethane was recovered by distillation, and the solid product, namely the crude PEKK product, was collected by filtration. The crude product was washed twice with 80℃ hot water (500 mL each time) and dried under vacuum at 120℃ for 12 h to obtain the PEKEKK product, denoted as PEKEKK-14.

[0062] Comparative Example 1 A process for preparing polyarylether ketones includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, add 400 mL of dichloromethane and 56.5838 g (0.1203 mol) of EKKE. After cooling the mixture to -20 °C, slowly add 133 g (0.9975 mol) of anhydrous aluminum trichloride, strictly controlling the temperature not to exceed -10 °C during the addition process, and minimizing powder splashing onto the reactor walls. Subsequently, cool the reaction system to -20 °C, add 14.6436 g (0.0721 mol) of IPC and 9.2888 g (0.0458 mol) of TPC (T / I = 70:30, molar ratio), followed by 133 mL of dichloromethane. Add 42.33 g of benzoic acid as a dispersant at -20 °C. Stop external cooling while stirring at 100 rpm, allowing the reaction mixture to naturally warm to room temperature (approximately 22-25 °C). During this period, the color of the reaction mixture gradually changes from yellow to pale orange. When signs of phase separation appeared, the stirring speed was increased to 350 rpm and maintained. After stirring the reaction for 6 h at room temperature, the reaction solution was slowly poured into an ice-water bath to quench it and allowed to stand for 12 h. Subsequently, dichloromethane was recovered by distillation, the solid product was collected by filtration, washed twice with 500 mL of hot water at 80 °C each time, and dried under vacuum at 120 °C for 12 h to obtain the PEKK product, denoted as PEKK-C1.

[0063] Comparative Example 2 (Catalyst in excess) A process for preparing polyarylether ketones includes the following steps: In a 1000 mL three-necked flask equipped with a mechanical stirrer, 400 mL of dichloromethane, 95.80 g (0.2036 mol) of EKKE, 16.24 g (0.08 mol) of TPC, and 24.36 g (0.12 mol) of IPC were added. The mixture was cooled to below -5 °C, and 155.22 g (1.164 mol) of anhydrous aluminum trichloride was added in five batches, with the temperature strictly controlled not to exceed -5 °C during the addition process. After the addition was completed, the flask wall was rinsed with 100 mL of dichloromethane. The stirring speed was controlled at 300 rpm, and the temperature was raised to 15 °C and the reaction was continued for 90 min. The reaction solution was then slowly poured into an ice-water bath to quench the reaction and allowed to stand for 12 h. Subsequently, the dichloromethane was recovered by distillation, the solid product was collected by filtration, washed twice with 500 mL of hot water at 80 °C each time, and dried under vacuum at 120 °C for 12 h to obtain the PEKK product, denoted as PEKK-C2.

[0064] Comparative Example 3 This comparative example modifies the reaction temperature and reaction time based on Example 1. The phrase "raise the reaction system temperature to 15°C and continue the reaction at 15°C for 90 min" is replaced with "raise the reaction system temperature to 5°C and continue the reaction at 5°C for 240 min". Other conditions remain unchanged. The resulting PEKK product is denoted as PEKK-C3.

[0065] Comparative Example 4 This comparative example modifies the reaction temperature and reaction time based on Example 1. The phrase "raise the reaction system temperature to 15°C and continue the reaction at 15°C for 90 min" is replaced with "raise the reaction system temperature to 30°C and continue the reaction at 30°C for 30 min". Other conditions remain unchanged. The resulting PEKK product is denoted as PEKK-C4.

[0066] The basic performance test results of the PEKK prepared in the above examples and comparative examples are shown in Table 1.

[0067] The performance characterization methods are as follows: (1) Intrinsic viscosity test An Ubbelohde viscometer was used to prepare a 0.5 g / L solution with 98% concentrated H₂SO₄ as the solvent. The intrinsic viscosity of the polymer was determined using the four-point method at a constant temperature T = 25 ± 0.1 °C. (In Table 1, 'a' indicates the presence of gel and cannot be tested.) (2) Infrared spectroscopy test Infrared spectroscopy measurements were performed on a PerkinElmer (FTIR) infrared spectrometer. The attenuated total reflectance (ATR) method was used, with wavenumbers ranging from 400 to 4000 cm⁻¹. -1 .

[0068] (3) Thermal transition test The polymer thermal transition test was performed on a Mettler DSC5+ under a nitrogen atmosphere at a heating rate of 10 °C / min. The glass transition temperature (Tg) was taken as the midpoint of the thermal change on the scan curve, and the test range was 50–400 °C.

[0069] (4) Thermal decomposition temperature test The polymer decomposition temperature was tested on a Mettler TGA2 at an air atmosphere with an air flow rate of 40 mL / min and a heating rate of 20 °C / min. The test range was 50–800 °C.

[0070] (5) Ultraviolet spectroscopy test Ultraviolet spectroscopy analysis was performed on an ultraviolet spectrophotometer. 10 mg of PEKK was dissolved in 10 mL of dichloroacetic acid, and its absorbance value at 455 nm was measured.

[0071] (6) Nuclear magnetic resonance analysis Nuclear magnetic resonance (NMR) measurements were performed on a BRUKERAVANCE III 600 with deuterated trifluoroacetic acid and deuterated chloroform as solvents at a temperature of 20 °C and an observation frequency of 600 MHz.

[0072] Table 1 Test Results

Claims

1. A process for preparing polyarylether ketones via electrophilic substitution, characterized in that, Includes the following steps: An aryl ether monomer with two active hydrogens, an aromatic acyl chloride monomer, and a solvent are mixed, and a Lewis acid catalyst is added at -15 to 5°C to obtain a reaction system. The reaction system is then heated to 10 to 20°C for further reaction. After the reaction is completed, the reaction solution is cooled and post-treated to obtain polyaryl ether ketone. The monomer of the aryl ether compound having two active hydrogens is 1,4-bis(4-phenoxybenzoyl)benzene or 4,4'-diphenoxybenzophenone; The Lewis acid is anhydrous aluminum trichloride, and its addition amount satisfies the following relationship: total molar amount of carbonyl groups + molar amount of aryl ether compound monomers in the reaction system / 2 < total molar amount of anhydrous aluminum trichloride < total molar amount of carbonyl groups + molar amount of aryl ether compound monomers in the reaction system.

2. The process for preparing polyarylether ketones by electrophilic substitution according to claim 1, characterized in that, The aromatic acyl chloride monomer is terephthaloyl chloride, isophthaloyl chloride, or a mixture of the two.

3. The process for preparing polyarylether ketones by electrophilic substitution according to claim 1, characterized in that, The solvent is dichloromethane or 1,2-dichloroethane.

4. The process for preparing polyarylether ketones by electrophilic substitution according to claim 1, characterized in that, The anhydrous aluminum trichloride is added to the mixing system in 3 to 10 portions.

5. The process for preparing polyarylether ketones by electrophilic substitution according to claim 1, characterized in that, After the reaction system is heated to 10~20℃, the reaction is maintained at this temperature for 60~180 min.

6. The process for preparing polyarylether ketones by electrophilic substitution according to claim 5, characterized in that, After the reaction is complete, the reaction solution is poured into an ice-water bath to decomplex.

7. The process for preparing polyarylether ketones by electrophilic substitution according to claim 6, characterized in that, The post-processing includes: solid-liquid separation, solvent removal by evaporation, hot water washing, and drying.

8. The process for preparing polyarylether ketones by electrophilic substitution according to any one of claims 1 to 7, characterized in that, It also includes the step of adding a capping agent to the mixture before adding the Lewis acid catalyst; the capping agent is one or more of benzoyl chloride, p-fluorobenzoyl chloride, p-chlorobenzoyl chloride, 4-phenoxybenzophenone, 4-phenoxydiphenyl sulfone, and biphenyl.

9. A polyarylether ketone obtained by the electrophilic substitution method for preparing polyarylether ketones according to any one of claims 1 to 7, characterized in that, The structural formula is: Ar is simultaneously Or Ar is simultaneously .

10. The polyaryletherketone according to claim 9, characterized in that, The polyaryletherketone was treated at 250°C for 30 min in the presence of air and then prepared into a 1 mg / mL dichloroacetic acid solution. The absorption peak at 455 nm in the UV-Vis spectrum was less than 0.05, and the maximum absorption peak at 490~520 nm was less than 0.

05. The intrinsic viscosity measured in 98% concentrated sulfuric acid at 25°C was 0.8~1.4 dL / g. The bulk density is 0.15~0.25 g / mL.

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