High-strength fluorine-containing polyimide and preparation method thereof
By synthesizing high-strength fluorinated polyimide, the problem of high dielectric constant in existing materials has been solved, resulting in a material with low dielectric constant, low water absorption and high mechanical strength, suitable for aerospace, automotive and other fields.
Patent Information
- Application Number
- CN202511172264.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2025-10-28
AI Technical Summary
Existing materials have high dielectric constants and dielectric losses, making it difficult to meet the needs of aerospace, automotive and other fields for high-strength transparent materials.
A high-strength fluorinated polyimide preparation method was adopted, using raw materials such as 4,4-hexafluoroisopropylphthalic anhydride, 4,4'-diaminodiphenyl ether, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine to synthesize polyimide through specific steps.
The prepared high-strength fluorinated polyimide material maintains high mechanical strength and light transmittance while significantly reducing dielectric constant and water absorption, improving the material's toughness and processability, making it suitable for applications requiring high bending and impact resistance.
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Figure CN120842572A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a fluorinated polyimide and its preparation method, belonging to the technical field of fluorinated polyimide. Background Technology
[0002] Polyimide (PI) is a class of high-molecular polymers with repeating imide units. Due to its excellent comprehensive properties, it is hailed as "one of the most promising engineering plastics of the 21st century." Benefiting from its superior structural characteristics, it has been widely used in high-tech fields such as aerospace, microelectronics, automotive, machinery, optoelectronics, and separation membranes. Fluorinated polyimide (FPI), in particular, introduces fluorine atoms or fluorine-containing groups into its molecular structure. The introduction of fluorine atoms gives FPI unique advantages. Fluorine-containing groups (-CF3, -C(CF3)3, etc.) have a strong electron-withdrawing effect, effectively reducing the electron cloud density on the attached carbon atoms. Especially when connected to aromatic rings, it weakens the ability of aromatic rings to act as electron donors or acceptors. Furthermore, fluorine-containing groups have greater steric hindrance. When introduced into the polyimide molecular chain structure, they significantly increase the free volume of the molecular chain, making it more difficult for the molecular chains to stack tightly, effectively reducing the dielectric constant and dielectric loss of the material.
[0003] Therefore, developing a high-strength fluorinated polyimide has significant scientific and practical value. This high-strength fluorinated polyimide retains the inherent optical transparency, low dielectric constant, low water absorption, and excellent thermal stability of fluorinated polyimides, while significantly improving the material's mechanical strength and toughness. These unique and superior properties give the material a significant advantage in industries such as aerospace, automotive, and portable electronic devices that require transparency, high strength, and are highly weight-sensitive. Summary of the Invention
[0004] To address the problem of high dielectric constant and dielectric loss in existing materials, this invention proposes a high-strength fluorinated polyimide and its preparation method.
[0005] The technical solution adopted by the present invention to solve the above problems is as follows: The high-strength fluorinated polyimide of the present invention includes a solvent, 4,4-hexafluoroisopropylphthalic anhydride, the 4,4'-diaminodiphenyl ether, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine.
[0006] Furthermore, the solvent is composed of one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
[0007] The steps of the method for preparing high-strength fluorinated polyimide according to the present invention include: Step 1: Place N,N-dimethylacetamide into a reaction vessel, stir, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection. Step 2: Add 4,4'-diaminodiphenyl ether to the reaction vessel, stir and let it dissolve completely; Step 3: Dissolve 4,4-hexafluoroisopropylphthalic anhydride in ultra-dry N,N-dimethylacetamide, and drop the solution into the reaction vessel using a partial pressure dropping funnel, while mixing and stirring. Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA). Step 5: Transfer PAA to a vacuum environment for complete imidization to obtain polyimide.
[0008] Furthermore, in step 1, 10 mL of N,N-dimethylacetamide was measured and placed into a reaction vessel, and the stirring speed was 200 rpm.
[0009] Furthermore, in step 2, 2.21 g of 4,4'-diaminodiphenyl ether was weighed and added to the reaction vessel, and the mixture was stirred for 15 min.
[0010] Furthermore, in step 3, 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and 30 mL of ultra-dry N,N-dimethylacetamide were weighed out and mixed for 12 h.
[0011] Furthermore, in step 5, the vacuum temperature is 180℃ and the processing time is 4 hours.
[0012] The beneficial effects of this invention are as follows: The fluorinated polyimide prepared by this invention maintains high mechanical strength and exhibits excellent resistance to bending, impact, and tearing, while also possessing superior light transmittance and a low dielectric constant. The introduction of the hexafluoroisopropyl group, a large-volume, strongly electron-withdrawing group, significantly increases the free volume and reduces intermolecular interactions, thereby improving solubility and lowering the dielectric constant and water absorption. ODA (4,4'-diaminodiphenyl ether) provides flexibility to the ether bonds, contributing to improved toughness and processability of the material, while maintaining the aromatic rigidity of the main chain. Furthermore, the preparation process of this invention is simple and easy to implement, showing promising prospects for industrial application and potential for large-scale preparation and application. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of Example 1; Figure 2 This is a schematic diagram of Embodiment 2; Figure 3 This is a schematic diagram of Example 3.
[0014] Example Example 1: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 30 parts of N,N-dimethylacetamide, 2.21 parts of 4,4'-diaminodiphenyl ether, and 4.4 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0015] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide into a reaction vessel, stir at 200 rpm, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection.
[0016] Step 2: Weigh 2.21 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0017] Step 3: Weigh 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0018] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0019] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0020] Example 2: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 30 parts of N,N-dimethylformamide, 2.21 parts of 4,4'-diaminodiphenyl ether, and 4.4 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0021] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylformamide into a reaction vessel, stir at 200 rpm, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection.
[0022] Step 2: Weigh 2.21 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0023] Step 3: Weigh 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of N,N-dimethylformamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0024] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0025] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0026] Example 3: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 30 parts of dimethyl sulfoxide, 2.21 parts of 4,4'-diaminodiphenyl ether, and 4.4 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0027] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of dimethyl sulfoxide into a reaction vessel, stir at 200 rpm, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection.
[0028] Step 2: Weigh 2.21 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0029] Step 3: Weigh 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of dimethyl sulfoxide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0030] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0031] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0032] Example 4: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 30 parts of N,N-dimethylacetamide, 2.21 parts of 4,4'-diaminodiphenyl ether, and 5.5 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0033] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide into a reaction vessel, stir at 200 rpm, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection.
[0034] Step 2: Weigh 2.21 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0035] Step 3: Weigh 5.5 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0036] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0037] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0038] Example 5: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 30 parts of N,N-dimethylacetamide, 3.31 parts of 4,4'-diaminodiphenyl ether, and 4.4 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0039] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of DMAc into a reaction vessel, stir at 200 rpm, transfer the reaction vessel to an ice-water bath, and purge with nitrogen for protection.
[0040] Step 2: Weigh 3.31 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0041] Step 3: Weigh 3.31 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of ultra-dry DMAc. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0042] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0043] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0044] Example 6: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 40 parts of N,N-dimethylacetamide, 2.50 parts of 4,4'-diaminodiphenyl ether, and 4.4 parts of 4,4-hexafluoroisopropylphthalic anhydride.
[0045] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide and place it in a reaction vessel. Stir at 200 rpm and purge with nitrogen for protection.
[0046] Step 2: Weigh 2.50 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0047] Step 3: Weigh 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0048] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0049] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0050] Comparative Example Comparative Example 1: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 40 parts of N,N-dimethylacetamide, 2.50 parts of 4,4'-diaminodiphenyl ether, and 3.6 parts of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride.
[0051] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide and place it in a reaction vessel. Stir at 200 rpm and purge with nitrogen for protection.
[0052] Step 2: Weigh 2.50 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0053] Step 3: Weigh 3.6 g of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0054] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0055] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0056] Comparative Example 2: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 40 parts of N,N-dimethylacetamide, 2.50 parts of 4,4'-diaminodiphenyl ether, and 3.2 parts of 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine.
[0057] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide and place it in a reaction vessel. Stir at 200 rpm and purge with nitrogen for protection.
[0058] Step 2: Weigh 2.50 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0059] Step 3: Weigh 3.2 g of 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0060] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0061] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0062] Comparative Example 3: This embodiment discloses a high-strength fluorinated polyimide and its preparation method, which is composed of the following components by weight: 40 parts of N,N-dimethylacetamide, 2.50 parts of 4,4'-diaminodiphenyl ether, and 5.6 parts of 1,4-bis(trifluoromethyl)phenyl-2,5-diamine.
[0063] This embodiment discloses a high-strength fluorinated polyimide and its preparation method, including the following steps: Step 1: Measure 10 mL of N,N-dimethylacetamide and place it in a reaction vessel. Stir at 200 rpm and purge with nitrogen for protection.
[0064] Step 2: Weigh 2.50 g of 4,4'-diaminodiphenyl ether and add it to the reaction vessel. Stir for 15 min to dissolve completely.
[0065] Step 3: Weigh 5.6 g of 1,4-bis(trifluoromethyl)phenyl-2,5-diamine and dissolve it in 30 mL of N,N-dimethylacetamide. Use a partial pressure dropping funnel to drop the solution into the reaction vessel and mix and stir for 12 h.
[0066] Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA).
[0067] Step 5: Transfer PAA to a vacuum environment and treat it at 180°C for 4 hours to fully imidize it, thereby obtaining polyimide.
[0068] The high-strength fluorinated polyimide of this invention has broad application prospects, especially in fields requiring high bending and impact resistance as well as high light transmittance, such as high-speed rail head cover mesh, flexible cover materials, high-performance transparent electronic packaging, and optical thin films. In this invention, the introduction of hexafluoroisopropyl groups effectively increases the free volume and reduces intermolecular interactions. The introduction of ether bonds with a certain degree of flexibility helps improve the toughness and processability of the material while ensuring the aromatic rigidity of the main chain. Future improvements include further optimizing the transparent preparation steps, enhancing light transmittance, and exploring multifunctional applications to meet the needs of different fields.
[0069] The performance of a high-strength fluorinated polyimide obtained in Examples 1 to 6 and their proportions 1 to 3 was tested, and the results are shown in the table below:
[0070] This invention provides a novel preparation process for high-strength fluorinated polyimides, expanding the application fields of fluorinated polyimide materials. In Example 1, N,N-dimethylacetamide is used as a solvent because its low polarity contributes to reaction uniformity and reduces the possibility of side reactions. Meanwhile, in Examples 1-6, the introduction of hexafluoroisopropyl, a large-volume, strongly electron-withdrawing group, significantly increases the free volume and reduces intermolecular interactions, thereby improving solubility and reducing dielectric constant and water absorption. ODA (4,4'-diaminodiphenyl ether) provides the flexibility of the ether bond, helping to improve the toughness and processability of the material while maintaining the aromatic rigidity of the main chain. In Comparative Examples 1-3, the altered structure of the fluorinated monomer also has a certain impact on the light transmittance and mechanical properties of the material. Furthermore, the introduction of more aromatic rings or biphenyl structures is beneficial for the close packing and orientation of molecular chains, which has a certain influence on the mechanical properties of the material.
[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.
Claims
1. A high-strength polyimide, characterized in that, The polyimide comprises a solvent, 4,4-hexafluoroisopropylphthalic anhydride, the 4,4'-diaminodiphenyl ether, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine.
2. The high-strength polyimide according to claim 1, characterized in that, The solvent is composed of one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
3. A method for preparing high-strength polyimide, characterized in that, The specific steps include: Step 1: Place N,N-dimethylacetamide into a reaction vessel, stir, transfer the reaction vessel to an ice-water bath, and purge with nitrogen gas for protection. Step 2: Add 4,4'-diaminodiphenyl ether to the reaction vessel, stir and let it dissolve completely; Step 3: Dissolve 4,4-hexafluoroisopropylphthalic anhydride in ultra-dry N,N-dimethylacetamide, and drop the solution into the reaction vessel using a partial pressure dropping funnel, while mixing and stirring. Step 4: After the reaction is complete, the solution is transferred to a vacuum device, and the solvent is removed by evaporation to obtain polyamic acid (PAA). Step 5: Transfer PAA to a vacuum environment for complete imidization to obtain polyimide.
4. The method for preparing high-strength polyimide according to claim 3, characterized in that, In step 1, 10 mL of N,N-dimethylacetamide was measured and placed into a reaction vessel, and the stirring speed was 200 rpm.
5. The method for preparing high-strength polyimide according to claim 3, characterized in that, In step 2, 2.21 g of 4,4'-diaminodiphenyl ether was weighed and added to the reaction vessel, and the mixture was stirred for 15 min.
6. The method for preparing a high-strength polyimide body according to claim 3, characterized in that, In step 3, 4.4 g of 4,4-hexafluoroisopropylphthalic anhydride and 30 mL of ultra-dry N,N-dimethylacetamide were weighed out and mixed for 12 h.
7. The method for preparing high-strength polyimide according to claim 3, characterized in that, In step 5, the vacuum temperature is 180℃ and the processing time is 4 hours.