Butyl acrylate-based polymeric dispersant for polyimide foam as well as preparation method and application of butyl acrylate-based polymeric dispersant

Abstract

The invention relates to the technical field of high polymer materials, in particular to a butyl acrylate-based high polymer dispersant for polyimide foam as well as a preparation method and application of the butyl acrylate-based high polymer dispersant. The dispersing agent is prepared from butyl acrylate (BA), methyl methacrylate (MIMA), polyethylene glycol monomethyl ether acrylate (PEG400MEA), hydroxyethyl methylacrylate (HEMA) and functional monomers through free radical polymerization reaction, wherein the mass percent of each monomer is as follows: 20%-40% of BA, 10%-25% of MMA, 35%-60% of PEG400MEA, 3%-10% of HEMA and 1%-5% of functional monomers. The functional monomer is one or more of acrylic acid, methacrylic acid, sodium p-styrene sulphonate or N-hydroxymethyl acrylamide. In the preparation process, peroxide or an azo substance initiator is adopted, and free radical reaction is carried out under the protection of inert gas. The dispersant belongs to anionic macromolecules, the weight-average molecular weight is 5000-50000, and the molecular weight dispersion coefficient (PDI 1.2-2.5).

Description

A butyl acrylate-based polymeric dispersant for polyimide foam, its preparation method and application Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a butyl acrylate-based polymeric dispersant for polyimide foam, its preparation method, and its application. Background Technology

[0002] Polyimide foam is a high-performance polymeric foam material with excellent thermal stability, mechanical properties, and insulation properties, making it widely applicable in aerospace, electronics, and automotive fields. To further improve the performance of polyimide foam, nanofillers, such as nano-silica and nano-alumina, are often added. These nanofillers possess unique properties such as small size effect and surface effect, which can significantly improve the mechanical, thermal, and flame-retardant properties of polyimide foam. However, due to their large specific surface area and high surface energy, nanofillers are prone to agglomeration, leading to uneven dispersion within the polyimide matrix and thus affecting the performance improvement of the polyimide foam. To solve the problem of nanofiller agglomeration, dispersants are needed. However, ordinary dispersants may interact with the polyimide matrix, affecting the original properties of the polyimide foam, such as reducing foam strength and thermal stability.

[0003] Therefore, it is of great significance to develop a dispersant that can effectively disperse nanofillers without affecting the performance of polyimide foam, or even improve the performance of polyimide foam.

[0004] Chinese invention patent CN202310515522.4 discloses a method for preparing polyimide / silica nanocomposite fiber materials. This method synthesizes SiO2 nanospheres via a sol-gel method, mixes them with a polyamic acid (PAA) solution, electrospins them, and then performs high-temperature imidization treatment to obtain a continuous PI / SiO2 composite fiber material. This material has good flexibility and strong insulation properties, but its filler dispersion process relies on mechanical stirring and centrifugation. Chinese invention patent CN202510648112.6 proposes a method for preparing polyimide / titanium dioxide composite hollow nanofiber aerogels. It employs coaxial electrospinning combined with hydrolysis-freeze-drying processes to achieve a hollow structure and high specific surface area, and achieves antibacterial function by loading TiO2. However, the introduction of the inorganic phase in this method still depends on subsequent impregnation and hydrolysis processes, resulting in uneven distribution, weak interfacial bonding, and complex processes, and it is difficult to apply to the filler dispersion requirements in foam systems. Chinese invention patent CN106751832A discloses a thermally insulating composite film and its preparation method. This technology involves doping a polyimide matrix with 10-70 VOL% hollow glass microspheres to produce a composite film with low thermal conductivity, ranging from 0.15-0.3 W / (m·K), exhibiting excellent thermal insulation performance. This method effectively reduces the overall thermal conductivity of the material by introducing low thermal conductivity micron-sized hollow fillers, making it suitable for applications requiring lightweight thermal insulation materials in flexible electronics and aerospace lighting. Summary of the Invention

[0005] To address the aforementioned technical problems in the prior art, this invention provides a butyl acrylate-based polymeric dispersant for polyimide foam, its preparation method, and its application. Specifically, this is achieved through the following technical solution: A method for preparing a butyl acrylate-based polymeric dispersant for polyimide foam, comprising the following steps: (1) mixing polyethylene glycol monomethyl ether acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, and functional monomers in proportion, and adding a polymerization inhibitor to obtain a monomer mixture; (2) subjecting the monomer mixture obtained in step (1) to a controlled free radical polymerization reaction with an initiator solution under inert gas protection; (3) after the reaction is completed, precipitating, washing, and drying the product to obtain the polymeric dispersant.

[0006] Furthermore, the functional monomer is selected from any one or more of acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide, hydroxyethyl acrylate, glycidyl methacrylate, sodium styrene sulfonate, vinylpyrrolidone, and N-vinylcaprolactam, mixed in any proportion.

[0007] Furthermore, in step (1), the polymerization inhibitor is selected from any one or more of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, and phenothiazine, mixed in any proportion, and the amount used is 0.01-0.1% of the total weight of the monomers.

[0008] Furthermore, the mass ratio of each component in the monomer mixture is as follows: polyethylene glycol monomethyl ether acrylate: 20-50%, butyl acrylate: 10-40%, methyl methacrylate: 10-30%, hydroxyethyl methacrylate: 5-20%, and functional monomer: 1-15%.

[0009] Furthermore, the initiator in step (2) is selected from any one or more of azobisisobutyronitrile, azobisisovalerate, azobisisoheptanenitrile, benzoyl peroxide, diisopropyl peroxide, ammonium persulfate, and potassium persulfate, and is mixed in any proportion, with the amount being 0.1-1.0% of the total weight of the monomers.

[0010] Furthermore, in step (2), the reaction temperature is 60-80℃ and the reaction time is 4-12 hours.

[0011] A butyl acrylate-based polymeric dispersant for polyimide foam is prepared by the above-mentioned method. The prepared dispersant is an anionic polymeric dispersant with a weight-average molecular weight of 5000-50000.

[0012] The application of the butyl acrylate-based polymeric dispersant in the dispersion of polyimide foam fillers.

[0013] Furthermore, the polyimide foam filler dispersion is specifically achieved by mixing the polymeric dispersant with the filler and then adding it to the polyimide foam preparation system to obtain a uniformly dispersed polyimide foam material.

[0014] Furthermore, the filler is selected from any one or more of silica, hollow glass microspheres, calcium carbonate, alumina, boron nitride, carbon fiber, and glass fiber, mixed in any proportion, and the filler particle size is 0.05-5μm.

[0015] Furthermore, the amount of the polymeric dispersant is 0.5-5% of the filler weight.

[0016] A uniformly dispersed polyimide foam material is prepared by dispersing fillers using the aforementioned polymeric dispersant.

[0017] Furthermore, the uniformity of the packing material's dispersion is more than 30% higher than that of the control sample without added dispersant.

[0018] Furthermore, in step (1), the polymerization inhibitor is selected from any one or more of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, and phenothiazine, mixed in any proportion, and the amount used is 0.01-0.1% of the total weight of the monomers.

[0019] Compared with the prior art, the technical effects of the present invention are reflected in: (1) excellent compatibility: the present invention uses butyl acrylate as the main hydrophobic monomer, whose structure has good chemical compatibility with the polyimide matrix, which can effectively improve the interfacial bonding between the dispersant and the matrix and avoid phase separation.

[0020] (2) Good thermal stability: By rationally designing the molecular structure and introducing rigid monomers such as methyl methacrylate, the thermal decomposition temperature of the dispersant is improved, and it can still maintain a stable dispersion effect at 200-300℃.

[0021] (3) Adjustable molecular structure: By adjusting the ratio of each monomer, the present invention can precisely control the molecular weight and distribution of the dispersant to meet different application requirements.

[0022] (4) Excellent dispersibility: The dispersant molecules of the present invention can form a stable adsorption layer on the surface of the filler, effectively preventing the filler from agglomerating. Detailed Implementation

[0023] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description made.

[0024] Example 1 A polymeric dispersant based on butyl acrylate is copolymerized from the following monomers in weight percentages: butyl acrylate (BA): 30%, methyl methacrylate (MMA): 15%, polyethylene glycol monomethyl ether acrylate (PEG400MEA): 50%, hydroxyethyl methacrylate (HEMA): 5%. The preparation method includes the following steps: (1) Weigh each monomer according to the above proportions, add 0.01% hydroquinone as a polymerization inhibitor, and mix evenly to obtain a monomer mixture; (2) Place the monomer mixture in a three-necked flask, purge with nitrogen for 15 minutes to remove oxygen, add AIBN initiator (0.5% of the total weight of monomers), and react at 70°C for 8 hours; (3) After the reaction is completed, pour the product into methanol to precipitate, filter and wash 3 times, and vacuum dry to obtain a white powdery polymeric dispersant with a molecular weight of 8500 and a PDI of 1.8.

[0025] Example 2: A butyl acrylate-based polymeric dispersant, copolymerized from the following monomers in weight percentages: butyl acrylate (BA): 25%, methyl methacrylate (MMA): 20%, polyethylene glycol monomethyl ether acrylate (PEG400MEA): 45%, hydroxyethyl methacrylate (HEMA): 7%, acrylic acid (AA): 3%. The preparation method is the same as in Example 1, with a reaction temperature of 75°C and a reaction time of 6 hours, yielding a polymeric dispersant with a molecular weight of 6200 and a PDI of 1.6.

[0026] Example 3: A butyl acrylate-based polymeric dispersant, copolymerized from the following monomers by weight percentage: butyl acrylate (BA): 35%, methyl methacrylate (MMA): 12%, polyethylene glycol monomethyl ether acrylate (PEG400MEA): 48%, hydroxyethyl methacrylate (HEMA): 3%, N-hydroxymethylacrylamide (NMA): 2%. The preparation method is the same as in Example 1, with a reaction temperature of 65°C and a reaction time of 10 hours, yielding a polymeric dispersant with a molecular weight of 12000 and a PDI of 2.1.

[0027] Comparative Example 1 used commercially available polyvinylpyrrolidone (PVPK30) as a dispersant with a molecular weight of approximately 50,000.

[0028] Comparative Example 2 used polyethylene glycol (PEG400) as a dispersant.

[0029] Application Example 1: The polymeric dispersant prepared in Example 1 was used to disperse silica filler in polyimide foam: 100 parts of silica (particle size 50 nm) and 2 parts of dispersant were dispersed in a ball mill, 0.5 mm zirconia beads were added, and the mixture was ball-milled for 30 minutes to obtain a pre-dispersed filler; 2) 100 parts of polyimide precursor volume solution, 20 parts of crosslinking agent 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), and 5 parts of the above pre-dispersed filler were added to a mold; 3) The mixture was foamed and cured at 250°C for 4 hours to obtain polyimide foam material.

[0030] Application Example 2: The polymeric dispersant prepared in Example 2 was used to disperse hollow glass microspheres in polyimide foam: 1) Hollow glass microspheres (particle size 5 μm, density 0.15 g / cm³) were dispersed. 3 1) Mix 100 parts with 3 parts of dispersant and ultrasonically disperse for 30 minutes; 2) Prepare foam material by mixing polyimide precursor solution, crosslinking agent and the above dispersion system according to conventional process.

[0031] Application Example 3: The polymeric dispersant prepared in Example 3 was used to disperse the composite filler in polyimide foam: 1) 50 parts of silica, 50 parts of hollow glass microspheres and 4 parts of dispersant were mixed; 2) The material was prepared according to the conventional polyimide foam preparation process.

[0032] Comparative Application Example 1 uses the PVP dispersant of Comparative Example 1, with other conditions the same as in Application Example 1.

[0033] Comparative Application Example 2 uses the PEG dispersant from Comparative Example 2, with other conditions the same as in Application Example 1.

[0034] Performance Testing and Results 1. Basic Performance Testing of Dispersants The basic performance of the polymeric dispersants prepared in Examples 1-3 was tested:

[0035] 2. Dispersion stability test: Add 0.5%-5% dispersant to disperse silica, place at 60℃ for 30 days, and observe the dispersion state of the filler.

[0036] 2. Polyimide Foam Performance Testing: Performance tests were conducted on the polyimide foams prepared in the application examples and comparative application examples.

[0037] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.

Claims

1. A method for preparing a butyl acrylate-based polymeric dispersant for polyimide foam, characterized in that, Specifically, the steps are as follows: (1) Polyethylene glycol monomethyl ether acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl methacrylate and functional monomers are mixed in proportion, and a polymerization inhibitor is added to obtain a monomer mixture; (2) The monomer mixture obtained in step (1) is subjected to a controlled free radical polymerization reaction with an initiator solution under inert gas protection; (3) After the reaction is completed, the product is precipitated, washed and dried to obtain a polymeric dispersant.

2. The preparation method according to claim 1, characterized in that, The functional monomers are selected from any one or more of acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-hydroxymethylacrylamide, hydroxyethyl acrylate, glycidyl methacrylate, sodium styrene sulfonate, vinylpyrrolidone, and N-vinylcaprolactam, mixed in any proportion.

3. The preparation method according to claim 1, characterized in that, In step (1), the polymerization inhibitor is selected from any one or more of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, and phenothiazine, mixed in any proportion, and the amount used is 0.01-0.1% of the total weight of the monomers.

4. The preparation method according to claim 1, characterized in that, The mass ratio of each component in the monomer mixture is as follows: polyethylene glycol monomethyl ether acrylate: 20-50%, butyl acrylate: 10-40%, methyl methacrylate: 10-30%, hydroxyethyl methacrylate: 5-20%, and functional monomers: 1-15%.

5. The preparation method according to claim 1, characterized in that, The initiator in step (2) is selected from any one or more of azobisisobutyronitrile, azobisisovalerate, azobisisoheptanenitrile, benzoyl peroxide, diisopropyl peroxide, ammonium persulfate, and potassium persulfate, and is mixed in any proportion, with the amount being 0.1-1.0% of the total weight of the monomers.

6. The preparation method according to claim 1, characterized in that, The reaction temperature in step (2) is 60-80℃ and the reaction time is 4-12 hours.

7. A butyl acrylate-based polymeric dispersant for polyimide foam, characterized in that, The dispersant prepared by the preparation method described in claim 1 is an anionic polymeric dispersant with a weight-average molecular weight of 5000-50000.

8. The application of the butyl acrylate-based polymeric dispersant according to claim 7 in the dispersion of polyimide foam fillers.

9. The application according to claim 8, characterized in that, The polyimide foam filler dispersion is specifically achieved by mixing the polymeric dispersant with the filler and then adding it to the polyimide foam preparation system to obtain a uniformly dispersed polyimide foam material.

10. A uniformly dispersed polyimide foam material, characterized in that, The filler was prepared by dispersing the polymeric dispersant according to claim 7.

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