High-toughness polyetherketoneketone polymer and preparation method thereof

Abstract

The invention discloses a high-toughness polyetherketoneketone polymer and a preparation method thereof, and belongs to the technical field of macromolecular special engineering plastics. The high-toughness polyether ketone ketone polymer is obtained by reacting diphenyl ether, paraphthaloyl chloride, a compound 1 and anhydrous aluminum trichloride according to a molar ratio of 1: a: (1-a): (3-5), the value of a is 0.5-0.9, and the compound 1 is isophthaloyl chloride with a flexible polyether side chain. According to the high-toughness PEKK polymer disclosed by the invention, a flexible polyether side chain is introduced into a rigid polymer main chain, so that compared with a traditional PEKK polymer molecule with a pure rigid structure, the high-toughness PEKK polymer shows better flexibility, and harmony and unification of strength, rigidity and flexibility are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer special engineering plastics, and in particular relates to a high-toughness polyetherketoneketone polymer and a preparation method thereof. Background Art

[0002] Advanced materials are an important material basis for the development of science and technology. High-performance resin-based composite materials have become one of the developing high-tech materials due to their light weight, high specific strength, high specific modulus, high temperature resistance and strong performance designability. Their application in industries such as aerospace has also shown unique advantages and potential. At present, common high-performance resin matrices can generally be divided into two categories: thermoplastic and thermosetting resins. Typical high-performance thermoplastic resins include thermoplastic polyimide, polyamide, polyether sulfone, liquid crystal polyester, polyaryletherketone, etc. Among them, polyaryletherketone (PEAK) special engineering plastics have excellent mechanical and physical properties. Compared with other high-temperature resistant plastics, PEAK is currently the variety with the highest heat resistance and the best comprehensive performance among special engineering plastics, with a long-term heat resistance of more than 250 ℃. In addition, PEAK also has excellent self-lubrication, flame retardancy and chemical resistance. PEAK's excellent comprehensive performance makes it widely used in the automotive industry, aerospace, electronic information, transportation pipelines and other fields.

[0003] PEAK can be divided into polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and so on according to the monomer sequence of its main chain. In recent years, PEKK has great research value and application prospects due to its higher mechanical and high temperature resistance. PEKK and its composite materials are polymers with 2 ketone bonds and 1 ether bond repeating units in the main chain structure, which are different from PEEK and surpass PEEK. Among them, the three benzene rings in the smallest repeating unit composed of 2 ketone bonds and 1 ether bond form a super large π bond. This structural feature makes PEKK the leader among all high-performance thermoplastic polymer materials. It has excellent mechanical properties, solvent resistance and chemical corrosion resistance, radiation resistance and flame retardancy, etc. These characteristics make it particularly suitable for use as a resin matrix and super engineering plastics for high-performance composite materials.

[0004] The PEKK preparation processes reported so far are mainly divided into two types: nucleophilic substitution and electrophilic substitution. Among them, the side reactions of nucleophilic substitution, such as branching and cross-linking, are easier to control, but the reaction conditions are harsh (usually required to be carried out at a temperature of >300 °C), and the synthesis process is complicated, the monomer is expensive, and the production cost is high, which restricts the wide application of this method. The conditions of electrophilic substitution are relatively mild and the raw materials are cheaper, but there are also disadvantages such as many side reactions, large catalyst dosage, and cumbersome post-treatment process. At present, the common electrophilic substitution polymerization process is mostly based on diphenyl ether and p- / isophthaloyl chloride as copolymer monomers, Lewis acid / base as catalyst, and condensation reaction at low temperature to room temperature (CN106800649B, CN109608627B, CN109608626B, CN109593183B, CN107973902B). Therefore, it is of great practical significance to develop new structural PEKK polymers with high performance and their preparation processes through molecular design. Summary of the invention

[0005] Technical problems solved: In view of the above technical problems, the present invention provides a high-toughness polyetherketoneketone polymer and a preparation method thereof, which can effectively solve the above-mentioned nucleophilic substitution branching, cross-linking and other reaction conditions are harsh (usually need to be carried out at a temperature of >300°C), and the synthesis process is complicated, the monomer is expensive, and the production cost is high, which restricts the wide application of this method; and the electrophilic substitution has many side reactions, a large amount of catalyst, and a cumbersome post-treatment process.

[0006] Technical solution: In the first aspect, the present invention provides a high-toughness polyetherketoneketone polymer, and the general structural formula of the high-toughness polyetherketoneketone polymer is as follows: , When the carbonyl group at the far right of the structural formula is in the para position, X is H; when the carbonyl group at the far right of the structural formula is in the meta position, X is O (CH 2 CH 2 O) m H, m is an integer from 10 to 100; n is an integer from 10 to 10000.

[0007] In a second aspect, the present invention provides a method for preparing the high-toughness polyetherketoneketone polymer described in the first aspect, wherein the high-toughness polyetherketoneketone polymer is obtained by reacting diphenyl ether, terephthaloyl chloride, compound 1 and anhydrous aluminum chloride in a molar ratio of 1:a:(1-a):(3~5), wherein a is 0.5~0.9, and the compound 1 is isophthaloyl chloride with a flexible polyether side chain.

[0008] Preferably, the general structural formula of the compound 1 is as follows: , Here, m is an integer from 10 to 100.

[0009] Furthermore, the compound 1 is prepared by a reaction type known in the art. The specific process is as follows: Step 1, placing 3,5-dimethylphenol and a catalyst in a high pressure reactor, introducing ethylene oxide at 120-140° C., and reacting for 1-3 hours to obtain compound 2; The catalyst is sodium hydride, sodium methoxide or sodium tert-butoxide; The molar ratio of 3,5-dimethylphenol, catalyst and ethylene oxide is 1:(0.01-0.1):m; Step 2, compound 2 and potassium permanganate are dissolved in a mixture of pyridine and water in a volume ratio of 1:1, reacted at 90-110° C. for 6-10 hours, filtered, and the filtrate is adjusted to acidity with dilute hydrochloric acid, and the precipitated solid is filtered, washed with water, and dried to obtain compound 3; The molar ratio of the compound 2 to potassium permanganate is 1:(2-4); Step 3, dissolving compound 3, pyridine and thionyl chloride in tetrahydrofuran, reacting at room temperature for 2 to 4 hours, and removing the solvent by distillation under reduced pressure to obtain compound 1; The molar ratio of the compound 3, pyridine and thionyl chloride is 1: (0.01-0.1): (2-4); The synthetic route of compound 1 is as follows: .

[0010] Preferably, the specific process of the preparation method of the high-toughness polyetherketoneketone polymer is as follows: S1. Mix diphenyl ether, anhydrous aluminum chloride and an organic solvent in a reaction kettle, cool the reaction system to -10~-30 °C, and bubble with inert gas for 0.5~1.5 h to obtain solution A; S2, dissolving the mixture of terephthaloyl chloride and compound 1 in an organic solvent to obtain a solution B; S3. Slowly add solution B to solution A under the protection of inert gas. The addition should be completed within 1 to 3 hours. Maintain the reaction at a low temperature of -10 to -30 °C for 8 to 16 hours, then heat the temperature to room temperature and continue the reaction for 8 to 16 hours. S4. Filter and remove the organic solvent, wash the obtained solid with a mixture of HCl aqueous solution and ethanol for 3 to 5 times, then wash with water for 1 to 3 times, and obtain a PEKK polymer after drying; wherein the volume percentage concentration of the HCl aqueous solution is 5 to 20%, and the volume ratio of the HCl aqueous solution to the ethanol is 1:0.2 to 0.5.

[0011] Furthermore, the organic solvent is any one of dichloromethane, dichloroethane, chloroform, and o-dichlorobenzene.

[0012] Furthermore, the inert gas is nitrogen or argon.

[0013] Beneficial effects: The high-toughness PEKK polymer of the present invention introduces flexible polyether side chains into the rigid polymer main chain, and exhibits better flexibility than the traditional purely rigid structured PEKK polymer molecules, thereby achieving a harmonious unity of strength, rigidity and flexibility. DETAILED DESCRIPTION

[0014] The present invention is described in detail below in conjunction with specific embodiments: The materials used in the examples are all commercially available products. All chemical reagents (analytical grade) used for the synthesis of PEKK polymers were purchased from Anage Technology Co., Ltd., and organic solvents (analytical grade) were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0015] Synthesis Example 1 0.1 mol of 3,5-dimethylphenol and 1 mmol of sodium hydride were placed in a high-pressure reactor, and 1 mol of ethylene oxide was introduced at 120°C for 1 hour to obtain compound 2; 0.1 mol of compound 2 and 0.2 mol of potassium permanganate were dissolved in 200 mL of a mixture of pyridine and water in a volume ratio of 1:1, reacted at 90°C for 6 hours, filtered, and the filtrate was adjusted to acidity with dilute hydrochloric acid. The precipitated solid was filtered, washed with water, and dried to obtain compound 3; 0.1 mol of compound 3, 1 mmol of pyridine and 0.2 mol of dichlorothionyl were dissolved in 200 mL of tetrahydrofuran, reacted at room temperature for 2 hours, and the solvent was removed by distillation under reduced pressure to obtain compound 1 (m=10); 0.2 mol of diphenyl ether, 0.6 mol of anhydrous aluminum chloride and 800 g of dichloroethane were mixed in a reactor, the reaction system was cooled to -10 °C, and nitrogen was bubbled for 0.5 h to obtain solution A; 0.18 mol of terephthaloyl chloride and 0.02 mol of compound 1 (m = 10) were dissolved in 400 g of dichloroethane to obtain solution B; solution B was slowly added dropwise to solution A under nitrogen protection for 1 h, the reaction was maintained at low temperature for 8 h, and then the reaction was continued at room temperature for 8 h; the organic solvent was filtered out, and the obtained solid was washed 3 times with a mixed solution of 5% by volume HCl aqueous solution and ethanol in a volume ratio of 1:0.2, and then washed once with water, and dried to obtain PEKK polymer 1 (m = 10, the molar ratio of terephthaloyl chloride to compound 1 is 9:1).

[0016] Synthesis Example 2 0.1 mol of 3,5-dimethylphenol and 1 mmol of sodium methoxide were placed in a high-pressure reactor, and 5 mol of ethylene oxide was introduced at 130°C for 2 hours to obtain compound 2; 0.1 mol of compound 2 and 0.3 mol of potassium permanganate were dissolved in 200 mL of a mixture of pyridine and water in a volume ratio of 1:1, reacted at 100°C for 8 hours, filtered, and the filtrate was adjusted to acidity with dilute hydrochloric acid. The precipitated solid was filtered, washed with water, and dried to obtain compound 3; 0.1 mol of compound 3, 5 mmol of pyridine and 0.3 mol of dichlorothionyl were dissolved in 200 mL of tetrahydrofuran, reacted at room temperature for 3 hours, and the solvent was removed by distillation under reduced pressure to obtain compound 1 (m=50); 0.2 mol of diphenyl ether, 0.7 mol of anhydrous aluminum chloride and 800 g of dichloroethane were mixed in a reactor, the system was cooled to -20 °C, and nitrogen was bubbled for 1 h to obtain solution A; 0.16 mol of terephthaloyl chloride and 0.04 mol of compound 1 (m=50) were dissolved in 400 g of dichloroethane to obtain solution B; solution B was slowly added dropwise to solution A under nitrogen protection for 2 h, the reaction was maintained at low temperature for 12 h, and then the reaction was continued at room temperature for 12 h; the organic solvent was filtered out, and the obtained solid was washed 4 times with a mixed solution of 10% by volume HCl aqueous solution and ethanol in a volume ratio of 1:0.3, and then washed twice with water, and PEKK polymer 2 (m=50, the molar ratio of terephthaloyl chloride to compound 1 is 8:2) was obtained after drying.

[0017] Synthesis Example 3 0.1 mol of 3,5-dimethylphenol and 0.01 mol of sodium tert-butoxide were placed in a high-pressure reactor, and 5 mol of ethylene oxide was introduced at 140°C for 3 hours to obtain compound 2; 0.1 mol of compound 2 and 0.4 mol of potassium permanganate were dissolved in 200 mL of a mixture of pyridine and water in a volume ratio of 1:1, and reacted at 110°C for 10 hours, followed by filtration, and the filtrate was adjusted to acidity with dilute hydrochloric acid, and the precipitated solid was filtered, washed with water, and dried to obtain compound 3; 0.1 mol of compound 3, 10 mmol of pyridine and 0.4 mol of dichlorothionyl were dissolved in 200 mL of tetrahydrofuran, reacted at room temperature for 4 hours, and the solvent was removed by distillation under reduced pressure to obtain compound 1 (m=50); 0.2 mol of diphenyl ether, 0.8 mol of anhydrous aluminum chloride and 800 g of chloroform were mixed in a reactor, the system was cooled to -20 °C, and argon was bubbled for 1 h to obtain solution A; 0.14 mol of terephthaloyl chloride and 0.06 mol of compound 1 (m = 50) were dissolved in 400 g of chloroform to obtain solution B; solution B was slowly added dropwise to solution A under argon protection for 2 h, the reaction was maintained at low temperature for 12 h, and then the reaction was continued at room temperature for 12 h; the organic solvent was filtered out, and the obtained solid was washed 4 times with a mixed solution of 15% by volume HCl aqueous solution and ethanol in a volume ratio of 1:0.4, and then washed twice with water, and PEKK polymer 3 (m = 50, the molar ratio of terephthaloyl chloride to compound 1 is 7:3) was obtained after drying.

[0018] Synthesis Example 4 0.1 mol of 3,5-dimethylphenol and 0.01 mol of sodium tert-butoxide were placed in a high-pressure reactor, and 10 mol of ethylene oxide was introduced at 140°C for 3 hours to obtain compound 2; 0.1 mol of compound 2 and 0.4 mol of potassium permanganate were dissolved in 200 mL of a mixture of pyridine and water in a volume ratio of 1:1, reacted at 110°C for 10 hours, filtered, and the filtrate was adjusted to acidity with dilute hydrochloric acid. The precipitated solid was filtered, washed with water, and dried to obtain compound 3; 0.1 mol of compound 3, 10 mmol of pyridine and 0.4 mol of dichlorothionyl were dissolved in 200 mL of tetrahydrofuran, reacted at room temperature for 4 hours, and the solvent was removed by distillation under reduced pressure to obtain compound 1 (m=100); 0.2 mol of diphenyl ether, 0.9 mol of anhydrous aluminum chloride and 800 g of o-dichlorobenzene were mixed in a reactor, the system was cooled to -30 °C, and argon was bubbled for 1.5 h to obtain solution A; 0.12 mol of terephthaloyl chloride and 0.08 mol of compound 1 (m=100) were dissolved in 400 g of o-dichlorobenzene to obtain solution B; solution B was slowly added dropwise to solution A under argon protection for 3 h, the reaction was maintained at low temperature for 16 h, and then the reaction was continued at room temperature for 16 h; the organic solvent was filtered out, and the obtained solid was washed 5 times with a mixed solution of 20% by volume HCl aqueous solution and ethanol in a volume ratio of 1:0.5, and then washed 3 times with water, and the PEKK polymer 4 (m=100, the molar ratio of terephthaloyl chloride to compound 1 is 6:4) was obtained after drying.

[0019] Comparative Example 1 The compound 1 in Synthesis Example 4 was replaced by isophthaloyl chloride, and the remaining steps were the same as those in Synthesis Example 4 to obtain a comparative PEKK polymer 1 (the molar ratio of terephthaloyl chloride to isophthaloyl chloride was 6:4).

[0020] Comparative Example 2 Commercially available conventional PEKK polymer powder was used as comparative polymer 2 (the molar ratio of terephthaloyl chloride to isophthaloyl chloride was 6:4).

[0021] Application Example 1 The glass transition temperature (Tg) and melting temperature (Tm) of PEKK polymer were obtained by differential scanning calorimetry (DSC). Test of polymer mechanical properties: The polymer powder was pressed into thin sheets by a flat hot press, and the mold temperature of the flat hot press was set to 400 °C. The tensile and bending properties of the materials were tested in accordance with the national standards GB / T 1040-2018 "Determination of tensile properties of plastics" and GB / T 9341-2008 "Determination of bending properties of plastics".

[0022] The test results are shown in Table 1 below: Table 1 Comparison of properties of different PEKK polymers , It can be seen that compared with the traditional PEKK polymer molecules with pure rigid structure (comparative PEKK polymer 1 and comparative PEKK polymer 2), the polymers prepared by the present invention (PEKK polymer 1~PEKK polymer 4) introduce flexible polyether side chains into the rigid polymer main chain, so the polymers show lower glass transition temperature and melting temperature. The polymers prepared by the present invention show relatively slightly lower tensile strength, tensile modulus, bending strength and bending modulus, and at the same time show a significantly higher elongation at break than the control sample, indicating that they have better flexibility. The more flexible polyether side chains the polymer molecules carry, the longer the polyether side chains, the greater the elongation at break and the better the flexibility. In summary, the PEKK polymers prepared by the present invention show better flexibility and achieve a harmonious unity of strength, rigidity and flexibility.

[0023] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-toughness polyetherketoneketone polymer, characterized in that: The general structural formula of the high-toughness polyetherketoneketone polymer is as follows: ， Among them, when the carbonyl group at the far right of the structural formula is in the para position, X is H; when the carbonyl group at the far right of the structural formula is in the meta position, X is O (CH2CH2O) m H, m is an integer from 10 to 100; n is an integer from 10 to 10000.

2. A method for preparing the high-toughness polyetherketoneketone polymer according to claim 1, characterized in that: The high-toughness polyetherketoneketone polymer is obtained by reacting diphenyl ether, terephthaloyl chloride, compound 1 and anhydrous aluminum chloride in a molar ratio of 1:a:(1-a):(3-5), wherein the value of a is 0.5-0.9, and the compound 1 is isophthaloyl chloride with a flexible polyether side chain.

3. The preparation method according to claim 2, characterized in that: The general structural formula of the compound 1 is as follows: ， Here, m is an integer from 10 to 100.

4. The preparation method according to claim 2, characterized in that: The specific process is as follows: S1. Mix diphenyl ether, anhydrous aluminum chloride and an organic solvent in a reaction kettle, cool the reaction system to -10~-30 °C, and bubble with inert gas for 0.5~1.5 h to obtain solution A; S2, dissolving the mixture of terephthaloyl chloride and compound 1 in an organic solvent to obtain a solution B; S3. Slowly add solution B to solution A under the protection of inert gas, and complete the addition within 1 to 3 hours. Maintain the reaction at -10 to -30 °C for 8 to 16 hours, and then heat to room temperature to continue the reaction for 8 to 16 hours. S4. Filter and remove the organic solvent, wash the obtained solid with a mixture of HCl aqueous solution and ethanol for 3 to 5 times, then wash with water for 1 to 3 times, and obtain a PEKK polymer after drying; wherein the volume percentage concentration of the HCl aqueous solution is 5 to 20%, and the volume ratio of the HCl aqueous solution to the ethanol is 1:0.2 to 0.

5.

5. The preparation method according to claim 4, characterized in that: The organic solvent is any one of dichloromethane, dichloroethane, chloroform and o-dichlorobenzene.

6. The preparation method according to claim 4, characterized in that: The inert gas is nitrogen or argon.

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