A photocatalyzed polyimide microsphere and its preparation method

Abstract

This invention provides a photo-acid-generating catalyzed polyimide microsphere and its preparation method. The preparation method of the photo-acid-generating polyimide microsphere includes the following steps: fully dissolving an amino compound, an aldehyde compound, and a photoacid-generating agent in an organic solvent; then carrying out a photo-reaction under an ultraviolet light source, followed by drying to obtain polyimide microspheres. This invention offers a simple method, uses inexpensive and readily available raw materials, resulting in low cost; the obtained polyimide microspheres have good morphology and are easily controlled, making them suitable for industrial production.

Description

Technical Field

[0001] This invention relates to a method for preparing organic functional microspheres, specifically to a photocatalyzed polyimide microsphere and its preparation method. Background Technology

[0002] In addition to possessing the basic properties of imides, such as excellent mechanical properties, heat resistance, and electrical insulation, polyimide microspheres also have the characteristics of large specific surface area, excellent surface adsorption performance, and controllable structure, which will have wide application value in fields such as carrying various drugs, synthesizing bioactive compounds, and fine chemicals.

[0003] Polyimide microspheres possess excellent properties such as high temperature resistance and solvent resistance. Although polyimide microspheres have broad development prospects, current laboratory research methods for preparing polyimide microspheres still have various drawbacks and problems, such as cumbersome preparation steps, large solvent consumption, difficulty in controlling morphology, easy collapse, and high cost. Therefore, further research and efforts are needed. In the literature Zihua Chen, Yi Jiang, Lu Chen, Wei Huang, Xiang Li, Xiaojuan Li and Xikui Liu. Solvothermal synthesis of polyazomethine microspheres by Pickeringemulsion templates and their transformation into complex microtubes and anisotropic hollow spheres enabled by dynamicimine chemistry. Polymer Journal (2013) 45, 1087–1093, polyimide microspheres were prepared using a solvothermal method, which has a long reaction time, strict reaction conditions, and high cost.

[0004] Therefore, researching, developing, and improving the process methods for preparing polyimide microspheres to make them simple, low-cost, with good morphology, easy to control, and suitable for industrial production is an important problem to be solved. Summary of the Invention

[0005] To address the problems of cumbersome preparation methods, high costs, poor morphology, and difficulty in controlling polyimide microspheres in existing technologies, this invention provides a photocatalyzed acid-generating polyimide microsphere and its preparation method. The method of this invention is simple, uses inexpensive and readily available raw materials, and has low cost; the resulting polyimide microspheres have good morphology and are easy to control, making them suitable for industrial production.

[0006] The technical solution of the present invention is as follows:

[0007] A photocatalyzed polyimide microsphere, wherein the polyimide microsphere has a particle size of 500 nm-1200 nm.

[0008] The above-mentioned method for preparing polyimide microspheres catalyzed by photo-acid production includes the following steps:

[0009] Amino compounds, aldehyde compounds, and photoacid-generating agents are fully dissolved in an organic solvent; then, a photoreaction is carried out under an ultraviolet light source, and after drying, polyimide microspheres are obtained.

[0010] According to a preferred embodiment of the present invention, the amino compound is selected from one or more combinations of 3,3'-dimethoxybenzidine, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-tris(2'-(4'-aminophenyl)acetylene)benzene, or N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine. 3,3'-dimethoxybenzidine, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-tris(2'-(4'-aminophenyl)acetylene)benzene, and N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine respectively have the structures shown in Formulas 1, 2, 3, and 4.

[0011]

[0012] According to a preferred embodiment of the present invention, the aldehyde compound is selected from one or more combinations of m-phenyltricarbonaldehyde, terephthalaldehyde, 2,5-dimethoxybenzene-1,4-dicarbonaldehyde, 4,4'-biphenyldicarbonaldehyde, or 4,4',4”-[benzene-1,3,5-triyltris(acetylene-2,1-diyl)]triphenylformaldehyde. m-phenyltricarbonaldehyde, terephthalaldehyde, 2,5-dimethoxybenzene-1,4-dicarbonaldehyde, 4,4'-biphenyldicarbonaldehyde, or 4,4',4”-[benzene-1,3,5-triyltris(acetylene-2,1-diyl)]triphenylformaldehyde respectively have the structures shown in formulas 5, 6, 7, 8, and 9.

[0013]

[0014] According to a preferred embodiment of the present invention, the molar ratio of the amino group in the amino compound to the aldehyde group in the aldehyde compound is 3:1 to 1:3, preferably 1:1.

[0015] According to a preferred embodiment of the present invention, the photoacid generator is selected from one or more combinations of 2-(2-((((propylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile (acid generator PAG 103), 2-(2-((((octylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile (acid generator PAG 108), N-hydroxynaphthalimide trifluoromethanesulfonic acid, N-hydroxysuccinimide sulfonic acid, or N-hydroxyphthalimide p-toluenesulfonate. 2-(2-(((propylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile, 2-(2-(((octylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile, N-hydroxynaphthalimide trifluoromethanesulfonic acid, N-hydroxysuccinimide sulfonic acid, and N-hydroxyphthalimide p-toluenesulfonate have structures as shown in Formulas I, II, III, IV, and V, respectively;

[0016]

[0017] According to a preferred embodiment of the present invention, the photoacid-generating agent is 2%-30% of the total mass of the amino compound and the aldehyde compound, preferably 9-11%.

[0018] According to the present invention, the organic solvent is preferably selected from one or more combinations of toluene, trimethylbenzene, o-dichlorobenzene, tetrahydrofuran, propylene glycol methyl ether acetate, acetone, n-butanol, dichloromethane, or acetylacetone; preferably, the organic solvent is a combination of n-butanol and acetone.

[0019] According to a preferred embodiment of the present invention, the molar ratio of the amino compound to the volume ratio of the organic solvent is 0.01-1 mol / L, more preferably 0.05-0.1 mol / L, and even more preferably 0.08 mol / L.

[0020] According to a preferred embodiment of the present invention, the ultraviolet light source has a wavelength of 248nm-405nm and a light intensity of 1-30mJ / cm. 2 .

[0021] According to a preferred embodiment of the present invention, the photoreaction temperature is room temperature, and the photoreaction time is 2 min to 200 min, preferably 24 to 30 min.

[0022] The technical features and beneficial effects of this invention are as follows:

[0023] 1. The photoacid-generating agent of this invention decomposes under ultraviolet light to form a sulfonic acid-based photocatalyst, which catalyzes the Schiff base reaction of amino and aldehyde compounds. Under the influence of different solvents and the structure of the reactants themselves, they polymerize into polyimide microspheres with uniform particle size. This invention uses a photoacid-generating agent as a polymerization catalyst, which is highly efficient, fast in reaction rate, and has a short preparation cycle; the preparation process is simple, the raw materials are inexpensive and readily available, the solvent consumption is small, the cost is low, and it is environmentally friendly; the resulting microspheres have good morphology and are easy to control, making them suitable for industrial production.

[0024] 2. The polyimide microspheres obtained by the method of this invention have uniform and controllable particle size; after dispersion in solution, the resulting dispersion exhibits good stability. The polyimide microspheres themselves are relatively stable and do not easily decompose under strong acid or alkali environments. They can be used to carry metal-modified drugs or as carriers for metal catalysts, showing broad application prospects.

[0025] 3. In the preparation method of this invention, the selection of solvent type, amino compound type, aldehyde compound type, ratio of amino and aldehyde compounds, selection of photoacid-generating agent type, and light conditions all affect the formation or particle size of polyimide microspheres. If the above conditions are not suitable, polyimide microspheres will not be obtained. Attached Figure Description

[0026] Figure 1 The image shown is a transmission electron microscope (TEM) image of the imine microspheres prepared in Example 1 of this invention; the scale bar is 2 μm.

[0027] Figure 2 This is a scanning electron microscope image of the imine microspheres prepared in Example 1 of the present invention.

[0028] Figure 3 This is a scanning electron microscope image of the imine microspheres prepared in Example 1 of the present invention.

[0029] Figure 4 This is a particle size distribution diagram of the imine microspheres prepared in Example 1 of the present invention.

[0030] Figure 5 This is a scanning electron microscope image of the imine microspheres prepared in Example 2 of the present invention.

[0031] Figure 6 This is a particle size distribution diagram of the imine microspheres prepared in Example 2 of the present invention.

[0032] Figure 7 This is a scanning electron microscope image of the imine microspheres prepared in Example 3 of the present invention.

[0033] Figure 8 This is a scanning electron microscope image of the imine microspheres prepared in Example 4 of the present invention.

[0034] Figure 9This is a scanning electron microscope image of the imine microspheres prepared in Example 5 of the present invention.

[0035] Figure 10 This is a scanning electron microscope image of the imine microspheres prepared in Example 6 of the present invention.

[0036] Figure 11 This is a scanning electron microscope image of the imine microspheres prepared in Comparative Example 1 of this invention.

[0037] Figure 12 This is a scanning electron microscope image of the imine microspheres prepared in Comparative Example 2 of this invention. Detailed Implementation

[0038] The present invention will be further described below through specific embodiments, but is not limited thereto.

[0039] Unless otherwise specified, the experimental methods described in the examples are conventional methods; the reagents and materials used are commercially available unless otherwise specified.

[0040] Example 1

[0041] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0042] Under light-protected conditions, 0.0004 mol of the amino compound 1,3,5-tris(4-aminophenyl)benzene, 0.0006 mol of the aldehyde compound 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, and 0.026 g (0.00008 mol) of the photoacid-producing agent N-hydroxyphthalimide p-toluenesulfonate were fully dissolved in a 5 mL mixture of the organic solvents n-butanol and acetone (volume ratio 1:1); then, under ultraviolet light (wavelength 254 nm, light intensity 20 mJ / cm²), the mixture was dissolved in a 5 mL mixture of the organic solvents n-butanol and acetone (volume ratio 1:1). 2 The mixture was subjected to room temperature light irradiation for 0.4 h and then dried to obtain polyimide microspheres.

[0043] The transmission image of the polyimide microspheres prepared in this embodiment is as follows: Figure 1 As shown, SEM Figure 2 and Figure 3 As shown, the particle size distribution diagram is as follows: Figure 4 As shown, the particle size is uniform and concentrated, and the average particle size is 873.3 nm after Gaussian fitting.

[0044] Example 2

[0045] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0046] Under light-protected conditions, 0.0004 mol of the amino compound 1,3,5-tris(4-aminophenyl)benzene, 0.0006 mol of the aldehyde compound 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, and 0.025 g (0.00007 mol) of the photoacid-producing agent N-hydroxynaphthalimide trifluoromethanesulfonic acid were fully dissolved in a 5 mL mixture of the organic solvents n-butanol and acetone (volume ratio 1:1); then, under an ultraviolet light source (wavelength 254 nm, light intensity 20 mJ / cm²), the following solutions were prepared: 2 The mixture was subjected to room temperature light irradiation for 0.5 h and then dried to obtain polyimide microspheres.

[0047] SEM images of the polyimide microspheres prepared in this embodiment are shown below. Figure 5 As shown, the particle size distribution diagram is as follows: Figure 6 As shown, the particle size is uniform and concentrated, and the average particle size is 785.1 nm after Gaussian fitting.

[0048] Example 3

[0049] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0050] Under light-protected conditions, 0.0004 mol of the amino compound 1,3,5-tris(4-aminophenyl)benzene, 0.0006 mol of the aldehyde compound 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, and 0.025 g (0.00007 mol) of the photoacid-producing agent N-hydroxynaphthalimide trifluoromethanesulfonic acid were fully dissolved in 5 mL of the organic solvent acetone; then, under an ultraviolet light source (wavelength 365 nm, light intensity 20 mJ / cm²), the solution was dissolved in acetone. 2 The mixture was subjected to room temperature light irradiation for 0.5 h and then dried to obtain polyimide microspheres.

[0051] The SEM image of the product obtained in this embodiment is as follows: Figure 7 As shown, a microsphere structure was obtained, but the morphology of the microspheres was not very good.

[0052] Example 4

[0053] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0054] Under light-protected conditions, a mixture of 0.001 mol of the amino compound 1,3,5-tris(4-aminophenyl)benzene, 0.001 mol of the aldehyde compounds terephthalaldehyde and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (molar ratio of the two compounds being 1:1), and 0.050 g (0.00014 mol) of the photoacid-producing agent N-hydroxynaphthalimide trifluoromethanesulfonic acid were thoroughly dissolved in 10 mL of the organic solvent dichloromethane; then, under an ultraviolet light source (wavelength 365 nm, light intensity 5 mJ / cm²), the mixture was dissolved in 10 mL of dichloromethane. 2 The mixture was subjected to room temperature light irradiation for 1 hour and then dried to obtain polyimide microspheres.

[0055] The SEM image of the product obtained in this embodiment is as follows: Figure 8 As shown, a microsphere structure was obtained, but the microsphere morphology was poor, the particle size was uneven, and the adhesion was heavy.

[0056] Example 5

[0057] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0058] Under light-protected conditions, 0.001 mol of a mixture of the amino compound 3,3'-dimethoxybenzidine and 1,3,5-tris(4-aminophenyl)benzene (molar ratio 1:1), 0.001 mol of a mixture of the aldehyde compound terephthalaldehyde and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (molar ratio 1:1), and 0.045 g (0.00023 mol) of the photoacid-producing agent N-hydroxysuccinimide sulfonic acid were fully dissolved in 10 mL of a mixed organic solvent of dichloromethane and n-butanol (volume ratio 3:7); then, under an ultraviolet light source (wavelength 365 nm, light intensity 5 mJ / cm²), the following solutions were prepared: 2 The mixture was subjected to room temperature light irradiation for 1 hour and then dried to obtain polyimide microspheres.

[0059] The SEM image of the product obtained in this embodiment is as follows: Figure 9 As shown, a microsphere structure was obtained, but the microsphere morphology was poor and the particle size was not uniform.

[0060] Example 6

[0061] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0062] Under light-protected conditions, 0.001 mol of a mixture of the amino compound 3,3'-dimethoxybenzidine and 1,3,5-tris(4-aminophenyl)benzene (molar ratio 1:1), 0.001 mol of a mixture of the aldehyde compound terephthalaldehyde and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (molar ratio 1:1), and 0.065 g (0.00024 mol) of the photoacid-producing agent N-hydroxysuccinimide sulfonic acid and N-hydroxynaphthalimide trifluoromethanesulfonic acid (molar ratio 1:1) were fully dissolved in 10 mL of a mixed organic solvent of dichloromethane and n-butanol (volume ratio 1:1); then, under ultraviolet light (wavelength 365 nm, light intensity 5 mJ / cm²), the mixture was dissolved in water. 2 The mixture was subjected to room temperature light irradiation for 1 hour and then dried to obtain polyimide microspheres.

[0063] The SEM image of the product obtained in this embodiment is as follows: Figure 10 As shown, a microsphere structure was obtained, but the microsphere morphology was poor and the particle size was not uniform.

[0064] Comparative Example 1

[0065] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0066] Under light-protected conditions, 0.0003 mol of the amino compound diethylenediamine, 0.0003 mol of the aldehyde compound terephthalaldehyde, and 0.007 g (0.00002 mol) of the photoacid-producing agent 2-(2-(((propylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile were fully dissolved in 5 mL of the organic solvent tetrahydrofuran; then, under an ultraviolet light source (wavelength 365 nm, light intensity 5 mJ / cm²), the solution was dissolved in 5 mL of the solution. 2 The product was obtained by reacting under light at room temperature for 0.5 h and then drying.

[0067] The SEM image of the product obtained in this embodiment is as follows: Figure 11 As shown, no microsphere structure was obtained.

[0068] Comparative Example 2

[0069] A method for preparing photo-acid-generating polyimide microspheres includes the following steps:

[0070] Under light-protected conditions, 0.001 mol of the amino compound 3,3'-dimethoxybenzidine, 0.001 mol of the aldehyde compound 2,2'-bipyridine-5,5'-dicarboxaldehyde, and 0.045 g (0.0001 mol) of the photoacid-producing agent 2-(2-(((octylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile were fully dissolved in 10 mL of the organic solvent acetone; then, under an ultraviolet light source (wavelength 405 nm, light intensity 14.2 mJ / cm²), the solution was dissolved in acetone. 2 The product was obtained by reacting under light at room temperature for 1 hour and then drying.

[0071] The SEM image of the product obtained in this embodiment is as follows: Figure 12 As shown, no microsphere structure was formed.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing photo-acid-generating polyimide microspheres, comprising the following steps: Amino compounds, aldehyde compounds, and photoacid-generating agents are fully dissolved in an organic solvent; then, a photoreaction is carried out under an ultraviolet light source, followed by drying to obtain polyimide microspheres; The amino compound is selected from one or more of 3,3'-dimethoxybenzidine, 1,3,5-tris(4-aminophenyl)benzene, 1,3,5-tris(2'-(4''-aminophenyl)acetylene)benzene, or N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine; the aldehyde compound is selected from one or more of m-phenyltricarboxaldehyde, terephthalaldehyde, 2,5-dimethoxybenzene-1,4-dicarboxaldehyde, 4,4'-biphenyldicarboxaldehyde, or 4,4',4''-[benzene-1,3,5-triyltris(acetylene-2,1-diyl)]tribenzaldehyde; the ultraviolet light source has a wavelength of 248nm-405nm and a light intensity of 1-30mJ / cm². 2 .

2. The method for preparing photo-acid-generating polyimide microspheres according to claim 1, characterized in that, The molar ratio of the amino group in amino compounds to the aldehyde group in aldehyde compounds is 3:1 to 1:

3.

3. The method for preparing photo-acid-generating polyimide microspheres according to claim 1, characterized in that, The photoacid generator is selected from one or more combinations of 2-(2-(((propylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile (acid generator PAG103), 2-(2-(((octylsulfonyl)oxy)imino)thiophene-3(2H)-ylidene)-2-(o-tolyl)acetonitrile (acid generator PAG 108), N-hydroxynaphthalimide trifluoromethanesulfonic acid, N-hydroxysuccinimide sulfonic acid, or N-hydroxyphthalimide p-toluenesulfonate.

4. The method for preparing photo-acid-generating polyimide microspheres according to claim 1, characterized in that, Photoacid generators comprise 2%-30% of the total mass of amino and aldehyde compounds.

5. The method for preparing photo-acid-generating polyimide microspheres according to claim 4, characterized in that, Photoacid generators comprise 9-11% of the total mass of amino and aldehyde compounds.

6. The method for preparing polyimide microspheres catalyzed by photo-acid production according to claim 1, characterized in that, The organic solvent is selected from one or more combinations of toluene, trimethylbenzene, o-dichlorobenzene, tetrahydrofuran, propylene glycol methyl ether acetate, acetone, n-butanol, dichloromethane, or acetylacetone.

7. The method for preparing photo-acid-generating polyimide microspheres according to claim 6, characterized in that, The organic solvent is a combination of n-butanol and acetone.

8. The method for preparing polyimide microspheres catalyzed by photo-acid production according to claim 1, characterized in that, The molar ratio of the amino compound to the volume ratio of the organic solvent is 0.01-1 mol / L.

9. The method for preparing photo-acid-generating polyimide microspheres according to claim 8, characterized in that, The molar ratio of the amino compound to the volume ratio of the organic solvent is 0.05-0.1 mol / L.

10. The method for preparing photo-acid-generating polyimide microspheres according to claim 1, characterized in that, The photoreaction temperature was room temperature, and the photoreaction time was 2 min to 200 min.

11. The method for preparing photo-acid-generating polyimide microspheres according to claim 10, characterized in that, The photoreaction time is 24-30 minutes.

12. A polyimide microsphere catalyzed by photo-acidification obtained by any one of claims 1-11, characterized in that, The polyimide microspheres have a particle size of 500nm-1200nm.

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