A block copolymer toughened polyether ether ketone material and a method of making the same

Abstract

The application provides a kind of toughening polyether ether ketone material based on block copolymer and a preparation method thereof, relates to the technical field of polymer materials, and the method is by accurately controlling the ternary block copolymerization of hydroquinone, 4,4'-difluorobenzophenone and diphenylol, to synthesize the block copolymer PAEK-B with specific sequence structure, then melt blend it with PEEK, effectively improve the toughness of PEEK, improve the mechanical properties, while keeping the original processing temperature unchanged.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polyether ether ketone material toughened by block copolymer and its preparation method. Background Technology

[0002] Polyether ether ketone (PEEK), as a typical representative of semi-crystalline thermoplastic polyarylether ketone (PAEK), has a molecular backbone composed of rigid alternations of benzene rings, ether bonds, and ketone bonds, which endows the material with excellent high temperature resistance (melting point up to 334℃), excellent chemical corrosion resistance, and high mechanical strength, and is widely used in high-end fields such as aerospace and medical devices.

[0003] However, while PEEK's inherent semi-crystalline properties provide high stiffness and strength, they also result in low fracture toughness and elongation at break. This is essentially because the crystalline regions limit the plastic deformation capacity of the molecular chain segments. This brittle characteristic has become a key bottleneck restricting PEEK's application under harsh conditions such as high impact and high fatigue loads. To overcome PEEK's insufficient toughness, existing technologies mainly focus on the following three methods, but all have significant limitations:

[0004] 1. Blending for Toughening: PEEK is melt-blended with elastomers or flexible thermoplastics. The core bottleneck of this method lies in the interfacial compatibility between the two phases. If the compatibility is poor, stress concentration is easily generated at the phase interface, which can become the starting point for material failure, leading to unstable toughening effect or even a decrease in overall mechanical properties. 2. Fiber Composite Reinforcement: Introducing rigid fillers such as carbon fiber (CF) and glass fiber (GF) to improve strength and stiffness. For example, adding 30wt% carbon fiber can double the tensile strength (>200MPa). However, this method sacrifices toughness, usually resulting in a sharp drop in elongation at break to below 2%, and the material exhibits typical brittle fracture behavior, greatly limiting its application in impact-resistant components. 3. Copolymer Modification: Through molecular design, flexible segments or large-volume side groups are introduced into the PEEK backbone to disrupt molecular chain regularity and reduce crystallinity. Although this method can control toughness at the molecular level, it inevitably degrades the material's inherent advantages, such as heat resistance, modulus, and chemical stability. At the same time, changes in molecular structure often require complex adjustments to the corresponding processing technology, which increases the difficulty and cost of industrialization.

[0005] In summary, existing toughening technologies are either limited by phase interface issues, fall into the paradox of "strength equals brittleness," or face a trade-off dilemma in performance. They struggle to achieve a simultaneous and significant improvement in toughness while maintaining the core performance advantages of PEEK, thus failing to meet the increasingly stringent comprehensive requirements of advanced equipment for high-performance structural materials. Therefore, developing a new PEEK material modification strategy that can balance high toughness, high strength, and excellent comprehensive performance has become a key technical problem urgently needing to be solved in this field.

[0006] In view of this, it is necessary to design an improved block copolymer-toughened polyetheretherketone material and its preparation method to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a block copolymer-toughened polyether ether ketone material and its preparation method.

[0008] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a method for preparing a polyetheretherketone (PEEK) material toughened based on a block copolymer, comprising the following steps:

[0009] S1. After mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenyl phenol and alkali metal carbonate evenly, under a protective atmosphere, keep all the reaction raw materials at 150-170℃ for 0.5-2h, then at 210-230℃ for 0.5-2h, and finally at 290-310℃ for 0.5-2h.

[0010] S2. Add 4,4'-difluorobenzophenone and hydroquinone to the reaction system of step S1, and react at 300-320℃ for 1-2 hours to obtain polyaryletherketone block copolymer.

[0011] The total mass of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone is 0.25 to 0.35, and the total molar mass of 4,4'-difluorobenzophenone is 1.01 to 1.05 times the sum of the molar masses of biphenyl sulfone and hydroquinone. The ratio of the total molar mass of biphenyl sulfone to the total molar mass of hydroquinone is 41:59 to 43:57. In step S1, the molar mass of 4,4'-difluorobenzophenone is 1.01 to 1.03 times the molar mass of biphenyl sulfone.

[0012] S3. At 370-390℃, the polyaryletherketone block copolymer obtained in step S2 is blended with polyetheretherketone at a mass ratio of 1:99-99:1 to obtain the polyetheretherketone material.

[0013] Preferably, in step S3, the mass ratio of polyaryletherketone block copolymer to polyetheretherketone is 5:95-50:50.

[0014] Preferably, in step S1, the molar amount of the alkali metal carbonate is 1.1-1.2 times the sum of the molar amounts of biphenyl and hydroquinone.

[0015] Preferably, the alkali metal carbonate is sodium carbonate and / or potassium carbonate.

[0016] Preferably, in step S1, the protective atmosphere is argon gas, and its flow rate is 50-100 mL / min.

[0017] Preferably, the ratio of the total molar amount of biphenyl to the total molar amount of hydroquinone is 42:58.

[0018] In a second aspect, the present invention provides a polyetheretherketone material, the raw materials of which include polyaryletherketone block copolymer and polyetheretherketone.

[0019] The beneficial effects of this invention are:

[0020] 1. Significantly Improved Toughness (Elongation at Break) Without Significantly Sacrificing Strength: This invention precisely controls the composition and structure of the ternary block copolymer PAEK-B. In particular, the introduction of biphenyl disrupts the regularity of the PEEK segments, reducing the crystallinity of the final alloy. Lower crystallinity directly leads to higher elongation at break, thus significantly improving the material's toughness. Compared with existing technologies, this avoids the sharp decrease in elongation at break (often below 2%) caused by fiber composite reinforcement (such as carbon fiber / glass fiber), and also avoids the unstable toughening effect and potential strength loss caused by interfacial stress concentration in blending toughening, achieving the goal of improving toughness.

[0021] 2. Excellent Material Compatibility and Dispersibility: The ether-ether-ketone segments in PAEK-B share the same chemical structural units as PEEK. When the number of repeating units in the ether-ether-ketone segments reaches a certain level, these segments exhibit properties similar to PEEK. By controlling the length of the ether-ether-ketone segments in PAEK-B, excellent compatibility between PAEK-B and the PEEK substrate can be achieved during melt blending. The two polymer segments can dissolve and entangle well, resulting in a strong interfacial bond. Compared to existing technologies, this fundamentally solves the interfacial compatibility problem commonly found in conventional blending toughening methods (adding elastomers or incompatible thermoplastics). It avoids the drawbacks of clear two-phase interfaces, stress concentration, and susceptibility to cracking and debonding caused by incompatibility, ensuring effective transfer of toughening effects and stability of overall material properties. Compared to other polymer alloys or similar ternary random copolymers, the ether-ether-ketone segments in PAEK-B can better integrate with PEEK materials.

[0022] 3. Maintaining key processing characteristics (melting point) consistent with pure PEEK: By precisely adjusting the content of biphenyl in the terpolymer, the melting point (Tm) of PAEK-B can be precisely controlled to keep it consistent with the melting point (334℃) of PEEK. This melting point matching is crucial for the processing of the alloy, mainly reflected in the following aspects: (1) Consistent melting temperature: The alloy material can be processed at the same melting temperature as pure PEEK (such as injection molding and extrusion); (2) Good melt flowability: PAEK-B in the molten state has a similar viscosity to PEEK, mixes evenly, and has good flowability; (3) Existing processing equipment and processes can be used: There is no need to significantly adjust the original PEEK processing temperature, pressure, mold design and other key parameters due to the addition of toughening components, which greatly reduces the threshold and cost of industrial production. This is especially important for the fields where PEEK is widely used (such as the manufacturing of complex medical device parts).

[0023] 4. Crystallinity and Properties Can Be Flexiblely Controlled: The crystallinity of the final material (and the resulting balance of toughness and strength) can be achieved by simply adjusting the blending ratio of PAEK-B to PEEK. Increasing the PAEK-B content decreases the crystallinity of the polyetheretherketone (PEEK) material and increases its toughness; conversely, increasing the PEEK content increases crystallinity and strengthens rigidity. Compared to existing technologies, and the complexity of copolymer modification (where molecular chain adjustments require balancing multiple properties simultaneously) or fiber composites (where changes in ratio have a non-linear effect on toughness and rigidity, and are limited by fiber length / orientation), this method provides a simple, linear, and highly controllable way to customize the comprehensive mechanical properties of PEEK materials (especially the balance between toughness and rigidity).

[0024] 5. Avoidance of Additional Additives and Process Complexity: The core of this method is the melt blending of the base resin (PEEK) and the reinforcing resin (PAEK-B) with a designed structure. This process eliminates the need for incompatible elastomers or inorganic fillers (such as fibers), avoiding filler agglomeration and dispersion problems, and overcoming the difficulties in uniform dispersion and agglomeration associated with adding fibers or powder fillers. Material purity is maintained, and the inherent biocompatibility and chemical resistance of PEEK remain unaffected. The entire modification process is simple and short, requiring only melt blending, without the need for complex coupling agent treatment or multi-step modification processes, making it more suitable for large-scale production and resulting in lower overall costs. Attached Figure Description

[0025] Figure 1 This is the structural formula of the polyaryletherketone block copolymer used in the preparation of polyetheretherketone materials according to the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0028] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] On one hand, the present invention provides a polyetheretherketone material, the raw materials of which include polyaryletherketone block copolymer and polyetheretherketone, with a mass ratio of 1:99-99:1. Preferably, the mass ratio is 5:95-50:50.

[0030] Furthermore, the present invention also provides a method for preparing the above-mentioned polyetheretherketone material, which includes the following steps:

[0031] S1. After mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenyl phenol and alkali metal carbonate evenly, under a protective atmosphere, keep all the reaction raw materials at 150-170℃ for 0.5-2h, then at 210-230℃ for 0.5-2h, and finally at 290-310℃ for 0.5-2h.

[0032] S2. Add 4,4'-difluorobenzophenone and hydroquinone to the reaction system of step S1, and react at 300-320℃ for 1-2 hours to obtain polyarylether ketone block copolymer PAEK-B, the structural formula of which is as follows: Figure 1 As shown in the figure, the ratio of n1 to n2 is the molar ratio of hydroquinone to biphenyl phenol;

[0033] S3. At 370-390℃, PAEK-B obtained in step S2 is blended with polyetheretherketone at a mass ratio of 1:99-99:1 to obtain polyetheretherketone material.

[0034] In some embodiments, in step S1, the molar amount of 4,4'-difluorobenzophenone is 1.01-1.03 times the molar amount of biphenyl hydroquinone.

[0035] In some embodiments, in step S1, the alkali metal carbonate is sodium carbonate and / or potassium carbonate, and the molar amount of the alkali metal carbonate is 1.1-1.2 times the sum of the molar amounts of biphenyl and hydroquinone.

[0036] In some embodiments, in step S1, the protective atmosphere is preferably argon, and when argon is used as the protective gas, its flow rate is 50-100 mL / min.

[0037] In some embodiments, the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone used in steps S1-S2 to the total mass of diphenyl sulfone is 0.25-0.35 (i.e., the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone used in S1 and S2 to the total mass of 4,4'-difluorobenzophenone, hydroquinone, biphenyl sulfone used in S1 and S2 is 0.25-0.35). The ratio of the sum of their masses is 0.25-0.35, and the total molar amount of 4,4'-difluorobenzophenone is 1.01-1.05 times the sum of the molar amounts of biphenyl and hydroquinone, with the ratio of the total molar amount of biphenyl to hydroquinone being 41:59-43:57; in step S1, the molar amount of 4,4'-difluorobenzophenone is 1.01-1.03 times the molar amount of biphenyl. More specifically, the total molar amount of 4,4'-difluorobenzophenone added twice is 1.01-1.05 times the sum of the molar amounts of biphenyl and hydroquinone, and the molar ratio of biphenyl to hydroquinone is 41:59-43:57, preferably 42:58.

[0038] In some embodiments, in step S3, the mass ratio of PAEK-B to polyetheretherketone is 1:99-99:1, preferably 5:95-50:50.

[0039] The following specific embodiments further illustrate the block copolymer-toughened polyetheretherketone (PEEK) material and its preparation method proposed in this invention: Example 1

[0040] This embodiment proposes a method for preparing polyetheretherketone (PEEK) materials toughened based on block copolymers, comprising the following steps:

[0041] S1. Mix 800g of diphenyl sulfone, 0.43mol of 4,4'-difluorobenzophenone, 0.42mol of biphenylhydramine, and 1.11mol of sodium carbonate evenly. Under stirring conditions and an argon atmosphere, keep all reaction materials at 165℃ for 2 hours, then at 215℃ for 2 hours, and finally at 290℃ for 2 hours. The argon flow rate is 50mL / min. It should be noted that the stirring conditions (temperature, stirring method, stirring rate) in this embodiment of the invention can be selected as needed, as long as the purpose of mixing is met. Therefore, no restrictions are imposed here.

[0042] S2. Add 0.59 mol of 4,4'-difluorobenzophenone and 0.58 mol of hydroquinone to the reaction system of step S1, react at 300℃ for 2 h, pour the reaction product into cold water to cool and solidify, pulverize, remove impurities by ethanol reflux treatment and water boiling treatment, and dry to obtain polyarylether ketone block copolymer PAEK-B.

[0043] S3. The PAEK-B obtained in step S2 is blended with polyetheretherketone at a mass ratio of 30:70 and granulated at 370°C to obtain the polyetheretherketone material. Example 2

[0044] This embodiment proposes a method for preparing polyetheretherketone (PEEK) materials toughened based on block copolymers, comprising the following steps:

[0045] S1. Mix 800g of diphenyl sulfone, 0.42mol of 4,4'-difluorobenzophenone, 0.42mol of biphenylhydrazine, 1.0mol of sodium carbonate, and 0.13mol of potassium carbonate evenly. Under stirring conditions and an argon atmosphere, keep all reaction materials at 165℃ for 2 hours, then at 215℃ for 2 hours, and finally at 290℃ for 2 hours. The argon flow rate is 100mL / min. It should be noted that the stirring conditions (temperature, stirring method, stirring rate) of this embodiment can be selected as needed, as long as the purpose of mixing is met. Therefore, no restrictions are imposed here.

[0046] S2. Add 0.59 mol of 4,4'-difluorobenzophenone and 0.58 mol of hydroquinone to the reaction system of step S1, react at 310℃ for 1 h, pour the reaction product into cold water to cool and solidify, pulverize, remove impurities by ethanol reflux treatment and water boiling treatment, and dry to obtain polyarylether ketone block copolymer PAEK-B.

[0047] S3. The PAEK-B obtained in step S2 is blended with polyetheretherketone at a mass ratio of 71.4:28.6 and granulated at 370°C to obtain the polyetheretherketone material. Comparative Example 1

[0048] In this comparative example, pure PEEK resin powder was granulated at 370℃ to obtain PEEK granules. Comparative Example 2

[0049] This comparative example presents a method for preparing PAEK-30 particles, comprising the following steps:

[0050] S1. Mix 800g of diphenyl sulfone, 0.31mol of 4,4'-difluorobenzophenone, 0.30mol of biphenylhydramine, 1.0mol of sodium carbonate, and 0.13mol of potassium carbonate evenly. Under stirring and an argon atmosphere, keep all the reaction materials at 165℃ for 2h, then at 215℃ for 2h, and finally at 290℃ for 2h. The argon flow rate is 50mL / min.

[0051] S2. Add 0.71 mol 4,4'-difluorobenzophenone and 0.70 mol hydroquinone to the reaction system of step S1, react at 310℃ for 1 h, pour the reaction product into cold water to cool and solidify, pulverize, remove impurities by ethanol reflux treatment and water boiling treatment, and dry to obtain PAEK-30.

[0052] S3. Granulate the PAEK-30 obtained in step S2 at 370℃ to obtain PAEK-30 granules. Comparative Example 3

[0053] This comparative example presents a method for preparing polyetheretherketone (PEEK) materials toughened by block copolymers, comprising the following steps:

[0054] S1. Mix 800g of diphenyl sulfone, 1.02mol of 4,4'-difluorobenzophenone, 0.42mol of biphenylhydramine, 0.58mol of hydroquinone, and 1.11mol of sodium carbonate evenly. Under stirring and an argon atmosphere, keep all reaction materials at 165℃ for 2h, then at 215℃ for 2h, then at 290℃ for 2h, and finally at 300℃ for 2h. Pour the reaction product into cold water to cool and solidify, then crush it. Remove impurities by reflux with ethanol and boiling in water, and dry to obtain PAEK-C. The argon flow rate is 50mL / min.

[0055] S2. The PAEK-C obtained in step S1 is blended with polyether ether ketone at a mass ratio of 30:70 and granulated at 370°C to obtain the polyether ether ketone material.

[0056] The properties of the materials obtained in Examples 1 to 2 and Comparative Examples 1 to 3 are shown in Table 1. Comparing the experimental data of Example 1 and Example 2, it can be found that as the PAEK-B content in the polyetheretherketone material increases, the crystallinity of the polyetheretherketone material decreases (from opaque to translucent), the mechanical properties improve, and the toughness improves (elongation at break and impact strength improve). However, the melting point remains at the melting point temperature of PEEK. The results show that the addition of PAEK-B can effectively improve the toughness of the polyetheretherketone material without changing the processing temperature.

[0057] Comparing the experimental data of Comparative Example 1, Example 1, and Example 2, it can be found that as the PAEK-B content in the material increases, the crystallinity of the polyetheretherketone material decreases (from opaque to translucent), the mechanical properties improve, and the toughness improves (elongation at break and impact strength improve). Moreover, the melting point remains at the melting point temperature of PEEK. The results show that the addition of PAEK-B can effectively improve the toughness of polyetheretherketone materials without changing the processing temperature.

[0058] Comparing Comparative Example 1 and Example 2, it can be found that, under the condition that the total amount of biphenyl structure is the same, the polyether ether ketone material prepared by copolymerization first (Example 2) has better mechanical properties and toughness than the material obtained by direct copolymerization (Comparative Example 2), and has the same melting point as PEEK.

[0059] The materials used in Comparative Example 3 and Example 1 were random copolymer PAEK-C & PEEK and block copolymer PAEK-B & PEEK, respectively. The second T of the polyetheretherketone material in Comparative Example 3... g Slightly higher than the second T of the polyetheretherketone material in Example 1 g Meanwhile, the elongation at break of the material in Comparative Example 3 is slightly lower than that of the material in Example 1. This is because the block copolymer contains segments identical to PEEK, and these segments have a certain length. This allows PAEK-B to have better compatibility with PEEK resin, which is manifested in T... g Changes and better elongation at break.

[0060] Table 1. Properties of the materials obtained in Examples 1 to 2 and Comparative Examples 1 to 3

[0061]

[0062] In summary, the block copolymer-toughened polyetheretherketone (PEEK) material and its preparation method proposed in this invention can effectively improve the toughness and mechanical properties of PEEK by adding PAEK-B to PEEK to prepare an alloy, while maintaining the original processing temperature unchanged.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a polyetheretherketone (PEEK) material toughened based on a block copolymer, characterized in that, The process includes the following steps: S1. After uniformly mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenylhydramine, and alkali metal carbonate, under a protective atmosphere, all reactants are kept at 150-170°C for 0.5-2 hours, then at 210-230°C for 0.5-2 hours, and finally at 290-310°C for 0.5-2 hours; S2. [The text abruptly ends here, likely due to an incomplete sentence or missing information.] 4,4'-Difluorobenzophenone and hydroquinone were added to the reaction system, and the reaction was carried out at 300-320°C for 1-2 hours to obtain a polyarylether ketone block copolymer. The ratio of the total mass of 4,4'-difluorobenzophenone to the total mass of hydroquinone and biphenyl sulfone, and the ratio of the total mass of biphenyl sulfone to diphenyl sulfone, was 0.25-0.

35. The total molar amount of 4,4'-difluorobenzophenone was 1.01-1.05 times the total molar amount of biphenyl sulfone and hydroquinone, and the ratio of the total molar amount of biphenyl sulfone to the total molar amount of hydroquinone was 41:59-43:

57. In step S1, the molar amount of 4,4'-difluorobenzophenone was 1.01-1.03 times the molar amount of biphenyl sulfone. In step S3, the reaction was carried out at 370-390°C for step S2. The obtained polyaryletherketone block copolymer was blended with polyetheretherketone at a mass ratio of 1:99-99:1 to obtain a polyetheretherketone material; the polyetheretherketone material has a single melting peak and a melting point of 334±5°C.

2. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of polyaryletherketone block copolymer to polyetheretherketone is 5:95-50:

50.

3. The preparation method according to claim 1, characterized in that, In step S1, the molar amount of the alkali metal carbonate is 1.1-1.2 times the sum of the molar amounts of biphenyl and hydroquinone.

4. The preparation method according to claim 3, characterized in that, The carbonates of alkali metals are sodium carbonate and / or potassium carbonate.

5. The preparation method according to claim 1, characterized in that, In step S1, the protective atmosphere is argon gas, and the flow rate is 50-100 mL / min.

6. The preparation method according to claim 1, characterized in that, The ratio of the total molar amount of biphenyl to the total molar amount of hydroquinone is 42:

58.

7. A polyetheretherketone material prepared by the method according to any one of claims 1-6, characterized in that, Its raw materials include polyaryletherketone block copolymer and polyetheretherketone, and it has a single melting peak with a melting point of 334±5°C.

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