A high heat-resistant polyamide material and preparation method thereof
By preparing the functionalization of base monomers 1,3-bis[(pentafluorobenzyl)oxy]benzene and 4-aminophenol, combining with PAA precursor and solution casting process, adjusting the monomer molar ratio, a high heat resistance polyamide film was successfully prepared, solving the limitations of existing polyamide materials in terms of thermal expansion coefficient and heat resistance, achieving near-zero expansion and high heat resistance, and being suitable for optical devices and precision circuits and other fields.
Patent Information
- Application Number
- CN202410463947.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-17
- Publication Date
- 2025-08-26
- Estimated Expiration
- 2044-04-17
AI Technical Summary
Existing polyamide materials have limitations in reducing the coefficient of thermal expansion (CTE) to impart high heat resistance, especially in the fields of optics, precision circuits and flexible displays, which cannot meet the requirements of light weight and flexible folding.
The base monomer 1,3-bis[(pentafluorobenzyl)oxy]benzene was prepared by Williamson ether synthesis method, and functionalized with 4-aminophenol. Combined with PAA precursor and solution casting process, a high heat resistance polyamide film was prepared by a two-step method, and the molar ratio of rigid 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]benzene]bis(oxy)aniline and flexible 4,4'-diaminodiphenylamine monomer was adjusted to form a polyamide film.
It realizes near-zero expansion, high heat resistance and excellent mechanical properties of polyamide films, and can accurately control CTE parameters, which is suitable for structural stability requirements of high-precision instruments.
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of composite materials, and more particularly to a preparation method and application of a high-heat-resistant polyamide material. Background Art
[0002] Real-world applications for ultra-high-precision instruments, including optical devices, precision circuits, flexible displays, and aircraft components, place even stricter demands on structural dimensional stability, namely near-zero thermal expansion (-2ppm / K ≤ CTE ≤ 2ppm / K). Commercial materials with ultra-low thermal expansion are primarily inorganic or metal, such as silicon dioxide and AlMoV alloys. However, these materials cannot meet the lightweight and flexible requirements of advanced electronic instruments.
[0003] Polyamides (PAs) are gaining popularity in the current electronics market. Compared to traditional polymers such as polyethylene (PE) and polyethylene terephthalate (PET), PAs can achieve lower thermal expansion (CTE ≤ 5 ppm / K). However, current research on reducing CTE to impart high heat resistance to PAs focuses on four strategies: (a) incorporation of nanoparticles with ultralow (or even negative) thermal expansion; (b) cross-linking, including monomers with multifunctional groups or cross-linking chemicals; (c) increasing the drawing ratio or temperature; and (d) designing novel rigid backbones. However, most of these approaches have significant limitations, reflected in (i) the destructive aggregation of most nanoparticles, (ii) the limited selection of cross-linkable polymer matrices with reactive groups (e.g., -OH and -NH-), and (iii) unsuitable stretchable processing due to the presence of partial inorganic layers and the overall fabrication of flexible devices. By designing the structure of rigid heterocyclic monomers, PA films can be endowed with high heat resistance and low thermal expansion. Thanks to the inherent rigidity of the rods and tightly packed polymer chains, CTE values can be reduced to 3–15 ppm / K. However, there are few studies on the controllable regulation of near-zero expansion of PI films, which is more meaningful for long-term service in applications such as optical devices and precision instruments. Summary of the Invention
[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a high heat-resistant polyamide material.
[0005] The purpose of the present invention is achieved through the following technical solution: A method for preparing a high heat-resistant polyamide material comprises the following steps.
[0006] S1. The base monomer 1,3-bis[(pentafluorobenzyl)oxy]benzene was synthesized by Williamson ether synthesis between the alkyl bromide of 2,3,4,5,6-pentafluorobenzyl bromide and the alkoxy group of resorcinol;
[0007] S2. The base monomer 1,3-bis[(pentafluorobenzyl)oxy]benzene was functionalized with 4-aminophenol to synthesize 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]benzene]bis(oxy)aniline;
[0008] S3. A two-step method was used to prepare high heat-resistant polyamide films using PAA precursor and solution casting process.
[0009] Specifically, in step S1, a mixture of 2.20 g of resorcinol, 0.53 g of 18-crown-6, and 6.34 mL of 2,3,4,5,6-pentafluorobenzyl bromide was dissolved in 100 mL of anhydrous acetone and stirred for 1 h to form a homogeneous solution.
[0010] Specifically, 5.80 g of finely ground K 2 CO 3 was added to the above homogeneous solution in step S1, and the mixture was stirred at room temperature under nitrogen atmosphere for 96 h.
[0011] Further, in step S1, the solvent was removed under reduced pressure, and the solid was taken up in CH2Cl2 and partitioned between water (50 mL, twice) and 1 M aqueous potassium chloride solution (50 mL, twice).
[0012] Furthermore, in step S1, the organic layer was dried over anhydrous MgSO4.
[0013] Furthermore, in step S1, the solution is filtered and the solvent is removed under reduced pressure.
[0014] Specifically, in step S2, 2 g of 1,3-bis[(pentafluorobenzyl)oxy]benzene, 1.39 g of 4-aminophenol, 1.76 g of potassium carbonate, 0.30 g of 18-crown-6, and 150 mL of acetonitrile were added under nitrogen flow and stirred for reaction, wherein acetonitrile was used as a solvent.
[0015] Furthermore, the reaction temperature in step S2 is 50°C.
[0016] Furthermore, in step S2, the reaction is carried out for 48 hours.
[0017] Furthermore, the completion of the reaction was monitored by thin layer chromatography (TLC) in step S2.
[0018] Specifically, in step S3, equimolar amounts (20 mmol) of diamine and dianhydride were used to synthesize a PAA solution.
[0019] Specifically, in step S3 , the diamines used are 4,4′-diaminodiphenylamine and 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline.
[0020] Specifically, in step S3, the molar ratio of 4,4'-diaminodiphenylamine to 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline was 4 / 6, i.e., 8 mmol of 4,4'-diaminodiphenylamine and 12 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline were used. All other PAA solutions (4,4'-diaminodiphenylamine / 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline = 10 / 0, 9 / 1, 8.5 / 1.5, 8 / 2, 7 / 3, 6 / 4, 5 / 5, 4.5 / 5.5, 3 / 7, and 0 / 10) were successfully synthesized using the same process.
[0021] Specifically, in step S3, diamine was dissolved in 82.01 g of N,N-dimethylacetamide and stirred until the mixture was uniform.
[0022] Furthermore, in step S3, 20 mmol of pyromellitic dianhydride was slowly poured into the above solution at 0°C and stirred for 10 hours to obtain a PAA solution.
[0023] Furthermore, N2 protection is used in step S3.
[0024] Specifically, in step S3, the PAA solution is filtered and cast onto a clean ultra-flat glass plate.
[0025] Further, in step S3, it was placed in a vacuum oven and a gradient temperature program was adopted (80°C for 5 hours, 150°C for 2 hours, 200°C for 1 hour, 250°C for 1 hour, and 300°C for 1 hour).
[0026] Furthermore, after being immersed in hot water in step S3, the polyamide film is automatically peeled off from the glass plate and stored in a dry state.
[0027] The beneficial effects of the present invention are:
[0028] (1) Compared with the use of only flexible 4,4'-diaminodiphenylamine monomer, the introduction of rigid, symmetrical and spatially almost coplanar 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline monomer and flexible 4,4'-diaminodiphenylamine synergistically reacted with pyromellitic dianhydride to form a polyamide film, which can simultaneously achieve near-zero expansion, high heat resistance and optimal mechanical properties of the polyamide film.
[0029] (2) The CTE parameters of polyamide films can be precisely controlled by adjusting the molar ratio between the rigid 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline and the flexible 4,4′-diaminodiphenylamine monomers. DETAILED DESCRIPTION
[0030] The technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the following.
[0031] Example 1
[0032] A method for preparing a high heat-resistant polyamide material comprises the following steps:
[0033] S1. A mixture of 2.20 g of resorcinol, 0.53 g of 18-crown-6, and 6.34 mL of 2,3,4,5,6-pentafluorobenzyl bromide was dissolved in 100 mL of anhydrous acetone and stirred for 1 hour until a homogeneous solution formed. 5.80 g of finely ground KCO was added to the homogeneous solution, and the mixture was stirred at room temperature under a nitrogen atmosphere for 96 hours. The solvent was removed under reduced pressure, and the solid was taken up in CHCl and partitioned between water (50 mL, twice) and 1 M aqueous potassium chloride (50 mL, twice). The organic layer was dried over anhydrous MgSO. The solution was filtered, and the solvent was removed under reduced pressure.
[0034] S2. Under a nitrogen stream, 2 g of 1,3-bis[(pentafluorobenzyl)oxy]benzene, 1.39 g of 4-aminophenol, 1.76 g of potassium carbonate, 0.30 g of 18-crown-6, and 150 mL of acetonitrile were added and stirred for reaction. Acetonitrile was used as the solvent. The reaction temperature was 50°C and the reaction was allowed to proceed for 48 hours. The completion of the reaction was monitored by thin-layer chromatography (TLC).
[0035] S3. Dissolve 18 mmol of 4,4'-diaminodiphenylamine and 2 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly pour 20 mmol of pyromellitic dianhydride into the above solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process. The PAA solution was filtered and cast onto a clean ultra-flat glass plate. This was placed in a vacuum oven and heated using a gradient temperature program (80°C for 5 hours, 150°C for 2 hours, 200°C for 1 hour, 250°C for 1 hour, and 300°C for 1 hour). After soaking in hot water, the polyamide film was automatically peeled from the glass plate and stored dry.
[0036] Example 2
[0037] Dissolve 16 mmol of 4,4'-diaminodiphenylamine and 4 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0038] Example 3
[0039] Dissolve 14 mmol of 4,4'-diaminodiphenylamine and 6 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0040] Example 4
[0041] Dissolve 12 mmol of 4,4'-diaminodiphenylamine and 8 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0042] Example 5
[0043] Dissolve 10 mmol of 4,4'-diaminodiphenylamine and 10 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0044] Example 6
[0045] Dissolve 8 mmol of 4,4'-diaminodiphenylamine and 12 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0046] Example 7
[0047] Dissolve 6 mmol of 4,4'-diaminodiphenylamine and 14 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0048] Example 8
[0049] Dissolve 4 mmol of 4,4'-diaminodiphenylamine and 16 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0050] Example 9
[0051] Dissolve 2 mmol of 4,4'-diaminodiphenylamine and 18 mmol of 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0052] Comparative Example 1
[0053] A method for preparing a high heat-resistant polyamide material comprises the following steps:
[0054] Dissolve 20 mmol of 4,4'-diaminodiphenylamine in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0055] Comparative Example 2
[0056] Dissolve 20 mmol of 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline in 82.01 g of N,N-dimethylacetamide and stir until homogeneous. Slowly add 20 mmol of pyromellitic dianhydride to the solution at 0°C and stir for 10 hours to obtain a PAA solution. N2 protection was used during this process.
[0057] Table 1 Examples and Comparative Examples
[0058]
[0059] Table 2 Performance of Examples and Comparative Examples
[0060]
[0061] Intrinsic near-zero thermal expansion polyamide films have been carefully designed using 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline. Taking into account its inherent rigidity, symmetry, and nearly coplanar structure, the polyamide films exhibit improved thermal stability and mechanical properties, namely near-zero thermal expansion, high heat resistance, and high mechanical strength. Furthermore, the CTE parameters of the polyamide films can be precisely controlled by adjusting the molar ratio of the rigid 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline and the flexible 4,4'-diaminodiphenylamine monomers. According to the heat stability test results of Comparative Examples 1 and 2 and Examples in Table 2, it can be seen that with the increase of the content of rigid 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline, the initial storage modulus of the polyamide film continues to increase, indicating that its introduction is beneficial to improving the rigidity of the entire molecular chain. As the entire polymer chain becomes more rigid, resulting in T g However, the copolymerization method will also lead to T g The value decreases because the regularity of the polymer chain decreases. Therefore, T g The overall trend of the value is to first decrease and then increase. The above results fully demonstrate that the prepared poly (pyrazine - co-ether) -imide film has excellent thermal properties. In addition, according to the comparison of the CTE values of Comparative Examples 1, 2 and the embodiment in Table 2, as the rigid part increases, the thermal expansion coefficient of the polyamide film gradually decreases, which is mainly attributed to the higher crystallinity and tighter molecular stacking caused by the hydrogen bond interaction in the PAA state. Comparing the mechanical properties of Comparative Examples 1, 2 and the embodiment in Table 2, the addition of the rigid part significantly improves the mechanical properties of the polyamide film, especially in terms of breaking strength and initial modulus, the polyamide chain has a higher degree of crystallinity, the molecular stacking is tighter, and the mechanical properties are improved. Therefore, only using rigid 4,4'-[1,3-bis [(2,3,5,6-tetrafluorobenzyl) oxy] benzene] bis (oxy) aniline or flexible 4,4'-diaminodiphenylamine monomers to prepare polyamide films cannot achieve the effect of the present invention.
[0062] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.
Claims
1. A method for preparing a high heat-resistant polyamide material, characterized in that: The steps include: S1. The base monomer 1,3-bis[(pentafluorobenzyl)oxy]benzene was synthesized by Williamson ether synthesis between the alkyl bromide of 2,3,4,5,6-pentafluorobenzyl bromide and the alkoxy group of resorcinol; S2. Functionalization of the base monomer 1,3-bis[(pentafluorobenzyl)oxy]benzene with 4-aminophenol to synthesize 4,4′-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]benzene]bis(oxy)aniline; S3. Preparation of highly heat-resistant polyamide films using a two-step process using a PAA precursor and solution casting process. In step S3, a PAA solution is synthesized using equimolar amounts of a diamine and a dianhydride. In step S3, the diamines used are 4,4'-diaminodiphenylamine and 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline; and the molar ratio of 4,4'-diaminodiphenylamine to 4,4'-[1,3-bis[(2,3,5,6-tetrafluorobenzyl)oxy]phenyl]bis(oxy)aniline is 4 / 6. In step S3, pyromellitic dianhydride is used as the dianhydride; the diamine is dissolved in N,N-dimethylacetamide and stirred until uniform; pyromellitic dianhydride is slowly poured into the above solution at 0°C and stirred for 10 hours to obtain a PAA solution, and the above PAA solution is filtered and cast onto a clean ultra-flat glass plate.
2. The method for preparing a high heat-resistant polyamide material according to claim 1, wherein: In step S1, a mixture of resorcinol, 18-crown-6, and 2,3,4,5,6-pentafluorobenzyl bromide was dissolved in anhydrous acetone and stirred for 1 h to form a homogeneous solution.
3. The method for preparing a high heat-resistant polyamide material according to claim 2, characterized in that: In step S1, finely ground K2CO3 was added to the above homogeneous solution, and the mixture was stirred at room temperature under nitrogen atmosphere for 96 h.
4. The method for preparing a high heat-resistant polyamide material according to claim 3, characterized in that: In step S1 the solid was taken up in CH2Cl2; the organic layer was dried over anhydrous MgSO4; the solution was filtered and the solvent was removed under reduced pressure.
5. The method for preparing a high heat-resistant polyamide material according to claim 1, characterized in that: In step S2, 1,3-bis[(pentafluorobenzyl)oxy]benzene, 4-aminophenol, potassium carbonate, 18-crown-6, and acetonitrile were added under a nitrogen flow and stirred for reaction, wherein acetonitrile was used as a solvent; the reaction temperature was 50 °C, and the reaction was carried out for 48 h.
6. The method for preparing a high heat-resistant polyamide material according to claim 5, characterized in that: The completion of the reaction was followed by thin layer chromatography (TLC) in step S2.
7. The method for preparing a high heat-resistant polyamide material according to claim 1, characterized in that: In step S3, N2 protection is used; the film is placed in a vacuum oven and a gradient temperature increase program is used; after being soaked in hot water, the polyamide film is automatically peeled off from the glass plate and dried and stored.
8. A high heat-resistant polyamide material, characterized in that: The polyamide material is prepared by the method according to any one of claims 1 to 7.