A polyaryletherketone composite material and a method for preparing the same

Abstract

The application provides a polyaryletherketone composite material and a preparation method thereof, and relates to the technical field of polymer composite materials.The method comprises the following steps: S1, mixing carbon nanotubes and PAEK-B resin without fluorine in the end groups, and then melt granulating to obtain carbon nanotube masterbatch; S2, mixing the carbon nanotube masterbatch prepared in the step S1 with polyether ether ketone resin without fluorine in the end groups, and then feeding into an extruder, and adding carbon fibers through the feeding assembly of the mixing section of the extruder, and then melt granulating to obtain the polyaryletherketone composite material.In the above technical scheme, through the two-step process of "masterbatch preparation-secondary melting", the CNTs are further broken and dispersed under the action of strong shearing, a three-dimensional isotropic conductive network is formed, the direction dependence of the conductive performance is significantly reduced, and the high stability and spatial consistency of the surface resistivity of the composite material are realized.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a polyaryletherketone composite material and its preparation method. Background Technology

[0002] Polyetheretherketone (PEEK) is a high-performance specialty engineering plastic widely used in high-end fields. However, its extremely high insulation properties can easily lead to static electricity buildup, posing safety risks. Therefore, it is crucial to develop composite materials that combine the excellent bulk properties of PEEK with reliable antistatic functions.

[0003] Carbon nanotubes (CNTs) are considered ideal fillers for achieving this goal, but the dispersion and bonding of CNTs in a PEEK matrix faces three key challenges: 1. The poor interfacial compatibility caused by the low surface energy of PEEK and the high surface energy of CNTs makes CNTs difficult to disperse and prone to agglomeration; 2. The high melt viscosity of PEEK limits its shear dispersion effect during processing, further hindering uniform dispersion; 3. When low molecular weight PEEK is selected to improve processability, a contradiction arises—it has more end groups, lower surface energy (poorer compatibility), and higher crystallinity, making it easier to repel CNTs to the grain boundaries and enrich them during crystallization, thus destroying the uniformity of dispersion.

[0004] Existing improved methods that involve preparing high-concentration masterbatches and then diluting them have limited effectiveness when applied to PEEK / CNT systems because they cannot overcome the aforementioned fundamental contradictions. This results in composite materials exhibiting problems such as unstable electrical conductivity, significant anisotropy, and substantial mechanical losses.

[0005] In view of this, it is necessary to design an improved polyaryletherketone composite material and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a polyaryletherketone composite material and its preparation method.

[0007] To achieve the above-mentioned objective, in a first aspect, the present invention provides a method for preparing a polyaryletherketone composite material, comprising the following steps:

[0008] S1. Carbon nanotubes and PAEK-B resin are mixed and melt-granulated to obtain carbon nanotube masterbatch; the PAEK-B resin is a PAEK resin with fluorine-free end groups, which is obtained by copolymerization of 4,4'-difluorobenzophenone, hydroquinone, diphenyl sulfone, and biphenylol.

[0009] S2. The carbon nanotube masterbatch obtained in step S1 is mixed with polyether ether ketone resin with fluorine-free end groups and fed into an extruder. Carbon fibers are added through the feeding component of the mixing section of the extruder, and polyarylether ketone composite material is obtained by melt granulation.

[0010] The amount of carbon nanotube masterbatch added is 10-20% of the total mass of carbon nanotube masterbatch, fluorine-free end-group polyetheretherketone resin, and carbon fiber, and the amount of carbon fiber added is 5-10% of the total mass of carbon nanotube masterbatch, fluorine-free end-group polyetheretherketone resin, and carbon fiber.

[0011] Preferably, in step S1, the PAEK-B resin is prepared according to the following steps:

[0012] S11. After mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenyl hydroquinone and sodium carbonate evenly, gradually heat all the reaction raw materials under a protective atmosphere.

[0013] S12. Add 4,4'-difluorobenzophenone and hydroquinone to the reaction system of step S1, and react to obtain polyaryletherketone block copolymer;

[0014] S13. Add a fluorine-free end-capping agent to the polyaryletherketone block copolymer obtained in step S2 to seal it, and obtain PAEK-B resin.

[0015] Preferably, in step S11, the molar amount of 4,4'-difluorobenzophenone is 1.03 times the molar amount of biphenyl, and the molar amount of carbonate is 1.1-1.2 times the sum of the molar amounts of biphenyl and hydroquinone.

[0016] Preferably, in steps S11-S12, the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl to the total mass of diphenyl sulfone is 0.33; the total molar amount of 4,4'-difluorobenzophenone added twice is 1.05 times the total molar amount of biphenyl and hydroquinone, and the molar ratio of biphenyl to hydroquinone is 42:58.

[0017] Preferably, in step S13, the fluorine-free end-capping agent is one of 4-hydroxybenzophenone, a potassium salt or a sodium salt of 4-hydroxybenzophenone.

[0018] Preferably, the heating process in step S11 is carried out as follows: first, it is kept at 170°C for 1 hour, then at 230°C for 1 hour, and finally at 310°C for 1 hour.

[0019] Preferably, in step S1, the temperature of melt granulation is 370-400℃.

[0020] Preferably, in step S2, the temperature of melt granulation is 370-400℃.

[0021] Preferably, in step S12, the reaction temperature is 320°C and the reaction time is 2 hours.

[0022] Secondly, the present invention provides a polyaryletherketone composite material, wherein the polyaryletherketone composite material has a tensile strength ≥200MPa, a modulus >19.0GPa, and a surface resistivity of 10. 4 -10 9 Ω.

[0023] The beneficial effects of this invention are:

[0024] 1. Addressing the issue that traditional PEEK and PAEK molecules often have fluorinated phenyl groups at the ends of their molecular chains, whose extremely low surface energy weakens the interfacial interaction with carbon nanotubes, this invention modifies the end groups from fluorinated phenyl to phenyl groups. This eliminates the negative impact of fluorine at its source, significantly enhancing the interfacial bonding between the resin matrix and carbon nanotubes. This effect is particularly pronounced when the molecular weight of the matrix resin is relatively low and the end groups constitute a higher proportion of the molecular chain, providing a molecular-level foundation for constructing a robust interface.

[0025] 2. A novel approach is taken to utilize low-crystallinity PAEK-B resin containing a biphenyl structure as both a pre-dispersion medium and an interfacial compatibilizer for carbon nanotubes. First, leveraging its similarly optimized benzene-terminated structure, it forms a strong interaction with carbon nanotubes during the masterbatch preparation stage, achieving primary uniform dispersion of the carbon nanotubes. Subsequently, this PAEK-B / carbon nanotube functional masterbatch is blended with the host resin. During this process, PAEK-B plays a highly efficient bridging and compatibilizing role at the two-phase interface, ensuring that the carbon nanotubes in the composite material remain in a stable dispersed state.

[0026] 3. After being coated onto the surface of carbon nanotubes, low-crystallinity PAEK-B forms a flexible polymer interface layer. When the composite material cools and crystallizes after processing, the highly crystalline PAEK-B matrix undergoes significant volume shrinkage. At this time, the flexible PAEK-B interface layer can effectively buffer and absorb this crystallization shrinkage stress, thereby significantly reducing the tendency for carbon nanotubes to detach from the resin matrix due to the difference in crystallization behavior between the two phases. This reduces the interface defect density of the composite material and improves its mechanical integrity and reliability.

[0027] 4. Through a two-step process of "masterbatch preparation - secondary melt blending," carbon nanotubes undergo two high-shear dispersion processes using a screw. Compared to direct blending of carbon nanotube powder and matrix resin, this process enables more effective breakage and dispersion of carbon nanotubes, producing a large number of smaller, randomly oriented carbon nanotube fragments. These fragments are more likely to form a three-dimensional interpenetrating, isotropic conductive network in the matrix, rather than a highly oriented linear pathway along the shear direction. This significantly reduces the dependence of the composite material's conductivity on the processing direction and location, ultimately achieving high stability and spatial consistency of the composite material's surface resistivity. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments.

[0029] 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 text, while other details that are not closely related to the present invention are omitted.

[0030] 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.

[0031] This invention provides a method for preparing polyaryletherketone composite materials, comprising the following steps:

[0032] S1. Carbon nanotubes and PAEK-B are mixed and melt-granulated to obtain carbon nanotube masterbatch;

[0033] S2. The carbon nanotube masterbatch obtained in step S1 is mixed with polyether ether ketone (PEEK-B) resin with fluorine-free end groups and fed into an extruder. Carbon fibers are added through the feeding component of the mixing section of the extruder, and the mixture is melt-granulated to obtain polyarylether ketone composite material.

[0034] In step S1, PAEK-B is specifically a fluorine-free PAEK resin with biphenyl end groups, and the mass ratio of carbon nanotubes to PAEK-B resin in the carbon nanotube masterbatch is 15:85-20:80.

[0035] The preparation method of PAEK-B resin is as follows:

[0036] S11. After mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenyl hydroquinone and sodium carbonate evenly, gradually heat all the reaction raw materials under a protective atmosphere.

[0037] S12. Add 4,4'-difluorobenzophenone and hydroquinone to the reaction system of step S1, and react to obtain polyaryletherketone block copolymer;

[0038] S13. Add a fluorine-free end-capping agent to the polyaryletherketone block copolymer obtained in step S2 to seal it, and obtain PAEK-B resin.

[0039] Specifically, in step S11, the molar amount of 4,4'-difluorobenzophenone is 1.03 times the molar amount of biphenylacetone; the molar amount of carbonate is 1.1-1.2 times the sum of the molar amounts of biphenylacetone and hydroquinone. The protective atmosphere in this step is preferably argon. Preferably, the heating process in step S11 is carried out as follows: first, a constant temperature of 170°C for 1 hour, then a constant temperature of 230°C for 1 hour, and finally a constant temperature of 310°C for 1 hour.

[0040] More specifically, in steps S11-S12, the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone used to the total mass of diphenyl sulfone used is 0.33 (i.e., the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone used in S11 and S12 to the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, biphenyl sulfone used in S11 and S12 is 0.33). The total molar amount of 4,4'-difluorobenzophenone added in the two steps is 1.05 times the total molar amount of biphenyl sulfone and hydroquinone, and the molar ratio of biphenyl sulfone to hydroquinone is 42:58. In step S13, the fluorine-free end-capping agent is one of 4-hydroxybenzophenone, sodium salt of 4-hydroxybenzophenone, or potassium salt of 4-hydroxybenzophenone, and the total molar amount of the end-capping agent is 0.02-0.11 times the sum of the molar amounts of biphenyl and hydroquinone.

[0041] In steps S1 and S2, the temperature for melt granulation is 370-400℃.

[0042] In some embodiments, in step S2, the amount of carbon nanotube masterbatch added is 10-20% of the total mass of all materials in this step, and the amount of carbon fiber added is 5-10% of the total mass of all materials in this step. Specifically, to avoid the influence of impurities such as water in the raw materials on the preparation process, the carbon fiber, carbon nanotubes, PAEK-B, and PEEK-B resin need to be dried at 140-200°C for 2-5 hours before use. It should be noted that PEEK-B can be synthesized according to existing technology, or it can be obtained by end-capping the PAEK-B in this invention to achieve fluorine-free treatment of the end groups. The choice can be made according to the needs in practical applications, and therefore will not be described in detail here.

[0043] The polyaryletherketone composite material and its preparation method provided by the present invention will be further described below with reference to specific embodiments:

[0044] Example 1

[0045] This embodiment provides a polyaryletherketone composite material and its preparation method, including the following steps:

[0046] S1. Mix 0.65 kg of diphenyl sulfone, 0.4326 mol of 4,4'-difluorobenzophenone, 0.42 mol of biphenylol, and 1.15 mol of sodium carbonate evenly. Under argon protection, keep all reaction materials at 170°C for 1 h, then at 230°C for 1 h, and finally at 310°C for 1 h. Add 0.6174 mol of 4,4'-difluorobenzophenone and 0.58 mol of hydroquinone to the above reaction system, and react at 320°C for 2 h to obtain polyaryletherketone block copolymer. At 320°C, add 0.02 mol of sodium salt of 4-hydroxybenzophenone to the above polyaryletherketone block copolymer for end capping. Wash and dry the prepared PAEK-B resin for later use.

[0047] S2. Carbon fibers (purchased from Guangzhou Carbon Composite Materials Co., Ltd., model H2550-12K), carbon nanotubes (purchased from Shandong Dazhan Nanomaterials Co., Ltd., model GT-300), PAEK-B resin powder, and PEEK-B resin powder were dried at 150℃ for 3 hours. 4 kg of carbon nanotubes and 16 kg of PAEK-B resin powder were added to a mechanical mixer and mechanically stirred for 2 hours. The mixed powder was then granulated through a twin-screw extruder to obtain CNT masterbatch at a granulation temperature of 390℃.

[0048] S3. The above CNT masterbatch is thoroughly mixed with 70kg of PEEK-B resin powder, and then fed into a twin-screw extruder. 10kg of carbon fiber is uniformly added through the feeding component of the extruder mixing section, and granulation is carried out at 380℃ to obtain polyaryletherketone composite material particles.

[0049] Example 2

[0050] The only difference between Example 2 and Example 1 is that in step S1, the sodium salt of 4-hydroxybenzophenone is replaced with 4-hydroxybenzophenone, and the amount used is different from that in Example 1, specifically 0.11 mol. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0051] Example 3

[0052] The only difference between Example 3 and Example 1 is that the amount of each raw material used in steps S2-S3 is different from that in Example 1. Specifically, it is 2 kg of carbon nanotubes, 8 kg of PAEK-B resin powder, and 80 kg of PEEK-B resin powder. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0053] Example 4

[0054] The only difference between Example 4 and Example 1 is that the amount of each raw material used in steps S2-S3 is different from that in Example 1. Specifically, it is 3 kg of carbon nanotubes, 17 kg of PAEK-B resin powder, 75 kg of PEEK-B resin powder, and 5 kg of carbon fiber. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0055] Comparative Example 1

[0056] The only difference between Comparative Example 1 and Example 1 is that the sodium salt of 4-hydroxybenzophenone, which is used as a capping agent in step S1, is not added. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0057] Comparative Example 2

[0058] The only difference between Comparative Example 2 and Example 1 is that carbon fiber is not added in step S3, and the mass of PEEK-B resin powder is 80 kg. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0059] Comparative Example 3

[0060] The only difference between Comparative Example 3 and Example 1 is that the raw material quality in step S2 is different from that in Example 1, specifically 6 kg of carbon nanotubes and 14 kg of PAEK-B resin powder. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0061] Comparative Example 4

[0062] The only difference between Comparative Example 4 and Example 1 is that the PEEK-B resin powder in step S3 is replaced with an equal amount of fluorine-terminated (i.e., 4,4'-difluorobenzophenone-terminated) PEEK resin powder. The other experimental parameters are the same as those in Example 1, and will not be repeated here.

[0063] The properties of the polyaryletherketone composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1. The data in the table show that the surface resistance of the composite material increases significantly as the amount of carbon nanotubes decreases. This is because carbon nanotubes are an important material for constructing a micro-conductive network. The mechanical properties of the composite material also decrease significantly as the amount of carbon fiber added decreases, indicating that it makes a great contribution to the mechanical properties of the composite material.

[0064] Furthermore, the composite materials in Comparative Examples 1 to 4 did not perform as well as those in the Example. This is because: in Comparative Example 1, the polyaryletherketone used to prepare the masterbatch was end-capped with 4,4'-difluorobenzophenone, with fluorine atoms at the end groups. This resulted in relatively poor bonding with carbon nanotubes, leading to decreased dispersion of the carbon nanotubes and reduced microcircuit overlap, thus increasing the surface resistivity of the material. Carbon fibers act as a skeleton in this invention, improving the material's mechanical strength and building large (relative to carbon nanotubes) conductive pathways within the material. Comparative Example 2 did not add carbon fibers, resulting in lower conductivity and mechanical properties compared to Example 1. In Comparative Example 3, the increased amount of carbon nanotubes led to filler agglomeration. Microscopically, this agglomeration hindered the uniform overlap of the conductive network, causing a decrease in conductivity; macroscopically, it formed structural defects, causing stress concentration and damaging mechanical properties. Therefore, its performance indicators were all lower than those of Example 1.

[0065] By comparing the surface resistance of the products of Example 1 and Comparative Example 4, it can be found that both have excellent conductivity. This is due to the good dispersion of carbon nanotubes in the composite material caused by PAEK-B and the masterbatch preparation process. However, the tensile strength of Comparative Example 4 is slightly lower than that of Example 1. This is because the bonding force between traditional PEEK and carbon fiber is not as good as that of PEEK-B.

[0066] Table 1. Performance results of polyaryletherketone composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 4

[0067]

[0068] 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 polyaryletherketone composite material, characterized in that, Includes the following steps: S1. Carbon nanotubes and PAEK-B resin are mixed and then melt-granulated to obtain carbon nanotube masterbatch; the PAEK-B resin is a PAEK resin with fluorine-free end groups, which is prepared according to the following steps: S11. After mixing diphenyl sulfone, 4,4'-difluorobenzophenone, biphenyl hydroquinone and sodium carbonate evenly, gradually heat all the reaction raw materials under a protective atmosphere. S12. Add 4,4'-difluorobenzophenone and hydroquinone to the reaction system of step S1, and react to obtain polyaryletherketone block copolymer; S13. Add a fluorine-free end-capping agent to the polyaryletherketone block copolymer obtained in step S2 to end-cap, and obtain PAEK-B resin with fluorine-free end groups. The mass ratio of the carbon nanotubes to the PAEK-B resin is 15:85-20:80; In steps S11-S12, the ratio of the sum of the masses of 4,4'-difluorobenzophenone, hydroquinone, and biphenyl sulfone used to the total mass of the four components used is 0.33; the total molar amount of 4,4'-difluorobenzophenone added in the two steps is 1.05 times the total molar amount of biphenyl sulfone and hydroquinone, and the molar ratio of biphenyl sulfone to hydroquinone is 42:58; S2. The carbon nanotube masterbatch obtained in step S1 is mixed with polyether ether ketone resin with fluorine-free end groups and fed into an extruder. Carbon fibers are added through the feeding component of the mixing section of the extruder, and polyarylether ketone composite material is obtained by melt granulation. The amount of carbon nanotube masterbatch added is 10-20% of the total mass of carbon nanotube masterbatch, fluorine-free end-group polyetheretherketone resin, and carbon fiber, and the amount of carbon fiber added is 5-10% of the total mass of carbon nanotube masterbatch, fluorine-free end-group polyetheretherketone resin, and carbon fiber.

2. The preparation method according to claim 1, characterized in that, In step S11, the molar amount of 4,4'-difluorobenzophenone is 1.03 times the molar amount of biphenyl, and the molar amount of sodium carbonate is 1.1-1.2 times the sum of the molar amounts of biphenyl and hydroquinone.

3. The preparation method according to claim 1, characterized in that, In step S13, the fluorine-free end-capping agent is one of 4-hydroxybenzophenone, a potassium salt or a sodium salt of 4-hydroxybenzophenone.

4. The preparation method according to claim 1, characterized in that, The heating process in step S11 is carried out as follows: first, it is kept at 170℃ for 1 hour, then at 230℃ for 1 hour, and finally at 310℃ for 1 hour.

5. The preparation method according to claim 1, characterized in that, In step S1, the temperature for melt granulation is 370-400℃.

6. The preparation method according to claim 1, characterized in that, In step S2, the temperature for melt granulation is 370-400℃.

7. The preparation method according to claim 1, characterized in that, In step S12, the reaction temperature is 320℃ and the reaction time is 2h.

8. A polyaryletherketone composite material prepared by the method according to any one of claims 1-7, characterized in that, The polyaryletherketone composite material has a tensile strength ≥200MPa, a modulus >19.0GPa, and a surface resistivity of 10. 4 -10 9 Ω.

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