CN112266611B - Functionalized polyimide composite microsphere and preparation method thereof - Google Patents
Functionalized polyimide composite microsphere and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a functionalized polyimide composite microsphere and a preparation method thereof, wherein the preparation method comprises the steps of preparing polyamide acid microsphere, pretreatment of the polyamide acid microsphere, functionalization of the polyamide acid microsphere and preparation of the functional polyimide microsphere; the method utilizes the advantages of more surface active groups and easiness in surface modification of polyamide acid microspheres which are precursors of polyimide, and takes hydrogen bonds and electrostatic adsorption force as bonding energy to realize the coating of functional materials such as heat conducting filler, electric conducting filler, photocatalytic filler and the like on the surfaces of the polyamide acid microspheres, and finally successfully prepares the functional polyimide microspheres through thermal imidization. The preparation method designed by the invention can realize the coating of the polyimide microspheres by various functional materials, widens the application field of polyimide composite microspheres, has universality, simple process route, low cost and easy mass production.
Description
Technical Field
The invention belongs to the technical field of electronic packaging materials, and particularly relates to a functionalized polyimide composite microsphere and a preparation method thereof.
Background
Polyimide has excellent high and low temperature resistance, mechanical performance, chemical stability, excellent dielectric performance and other excellent performance, and may be used widely in aviation, microelectronic, liquid crystal display and other fields. However, with the rapid development of downstream applications, polyimide has failed to meet specific performance requirements in industrial applications, such as electrical conductivity, thermal conductivity, electromagnetic shielding properties, and the like. The introduction of functional particles into polyimide matrices is a common strategy for achieving functionalization. Meanwhile, in order to improve efficiency, designing a specific microstructure is a hot spot of attention in recent years. The functionalized polyimide microspheres gradually draw attention due to the characteristics of convenience in use, functional diversity and the like.
Because most of the surfaces of the thermosetting polyimide microspheres are imide groups and have no active groups, the special structure enables the polyimide microspheres to have larger rigidity and excellent chemical stability, so that the surface modification of the polyimide microspheres is difficult, few relevant reports on the surface modification of the thermosetting polyimide microspheres are provided, and the thermosetting polyimide microspheres are difficult to be coated by heat conducting materials, electric conducting materials, photocatalytic materials and the like. In addition, in the prior art, the modification of the polymer microsphere is mostly aimed at coating a certain functional material, and the polymer microsphere has no universality. Therefore, there is an urgent need for a method for simply and effectively preparing polyimide composite microspheres coated with functional materials, which has universality and can be applied to various functional materials.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a functionalized polyimide composite microsphere.
The invention provides a preparation method of a functionalized polyimide composite microsphere, which aims to overcome the defect that polyimide in the prior art is difficult to modify.
In order to solve the technical problem of the invention, the technical scheme adopted is a functionalized polyimide composite microsphere, the particle size of the functionalized polyimide composite microsphere is 0.5-10 mu m, the functionalized polyimide composite microsphere is formed by compounding polyimide microsphere and functional material according to the mass ratio of 100 (1-40), and the functional material is uniformly coated on the surface of the polyimide microsphere.
Further improvement as functionalized polyimide composite microspheres:
preferably, the functional material is one or a combination of two or more of graphene oxide, silicon dioxide, titanium dioxide, aluminum oxide, ferric oxide, boron nitride, graphene nanoplatelets and nano silver.
Preferably, the binding force between the functional material and the polyimide microsphere is electrostatic adsorption force and hydrogen bonding effect.
In order to solve another technical problem of the invention, the adopted technical scheme is a preparation method of the functionalized polyimide composite microsphere, which comprises the following steps:
s1, preparing polyamide acid microspheres: mixing an organic solvent and polyamide acid in a mass ratio of (2-12): 1 to obtain a mixed solution, stirring the mixed solution at 20-50 ℃ for 1-3 hours, transferring the mixed solution into a constant temperature and humidity box with humidity of 80-98% and temperature of 25-50 ℃ for reaction for 8-24 hours, collecting a product, centrifugally washing the product with deionized water, and drying to obtain polyamide acid microspheres;
s2, pretreatment of polyamide acid microspheres: adding water-soluble polymer into water to prepare water-soluble polymer solution with the concentration of 0.01-0.06g/ml, adding 100 parts by mass of polyamide acid microspheres prepared in the step S1 into the water-soluble polymer water solution according to the adding mass ratio of 1 (100-200), performing ultrasonic dispersion to completely infiltrate the microspheres, stirring for 0.5-1h, and performing centrifugal separation to obtain modified polyamide acid microspheres;
s3, functionalization of polyamide acid microspheres: weighing 1-40 parts by mass of functional material, adding the functional material into an aqueous solution with the pH value of 3-7, uniformly stirring, adding the modified polyamide acid microspheres prepared in the step S2, stirring for 5-30min after mixing, centrifugally washing with deionized water, and drying to obtain the functional polyamide acid composite microspheres;
s4, preparing functional polyimide microspheres: and (3) placing the functionalized polyamide acid composite microsphere prepared in the step (S3) at 50-90 ℃ for 2-4 hours, heating to 180-220 ℃ at the speed of 1-10 ℃/min, preserving heat for 1-3 hours, heating to 280-300 ℃ at the heating speed of 1-10 ℃/min, and preserving heat for 1-2 hours to obtain the functionalized polyimide composite microsphere.
As a further improvement of the preparation method of the functionalized polyimide composite microsphere:
preferably, the organic solvent in the step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, cyclohexane and chloroform.
Preferably, the water-soluble polymer in step S2 is one of polyvinylpyrrolidone, polyvinyl alcohol, polyurethane, polyethylene glycol, and dopamine hydrochloride.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention solves the problems of few thermosetting polyimide surface active groups and difficult surface modification and functional coating, utilizes the characteristic that polyimide precursors, namely the surfaces of polyamide acid, are easy to modify, realizes the coating of the polyamide acid microsphere by the functional material through modifying the polyamide acid microsphere, and further realizes the coating of the polyimide by the functional material through a thermal imidization process, and provides a preparation method of the polyimide microsphere coated by the functional material.
(2) The concentration and the pH value of the water-soluble polymer solution of the polyamide acid microsphere are regulated, so that a plurality of binding forces such as hydrogen bonds, electrostatic adsorption force and the like exist between the polyamide acid microsphere and the functional material, and the coating of the functional material on polyimide is realized.
(3) The preparation method of the functionalized polyimide composite microsphere is simple and feasible, has low cost, is environment-friendly and reliable, and has universality.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) picture of a graphene oxide coated polyimide microsphere;
FIG. 2 is a Scanning Electron Microscope (SEM) image of an alumina coated polyimide microsphere;
FIG. 3 is a Scanning Electron Microscope (SEM) image of 30wt% titanium dioxide coated polyimide microspheres;
FIG. 4 is a Scanning Electron Microscope (SEM) image of 15wt% titanium dioxide coated polyimide microspheres;
FIG. 5 is a Scanning Electron Microscope (SEM) picture of a 20wt% titanium dioxide coated polyimide microsphere;
fig. 6 is a graph showing the degradation curve and degradation effect of rhodamine B photocatalytic degradation of the titanium dioxide coated polyimide microspheres.
Detailed Description
The present invention will be further described in detail with reference to the drawings and examples, wherein all other examples, which are obtained by a person skilled in the art without making any inventive effort, are included in the scope of the present invention.
The technical scheme of the invention is further described below with reference to specific examples:
example 1
The preparation method of the functionalized polyimide composite material comprises the following steps:
(1) Preparation of polyamide acid microsphere
Weighing 20g of polyamide acid with the solid content of 18wt%, adding the polyamide acid into 100ml of N, N-dimethylformamide solution, stirring for 2 hours, then transferring the mixture into a constant temperature and humidity box with the humidity of 98% and the temperature of 30 ℃ for 16 hours, collecting a product, centrifugally washing the product with deionized water, and drying the product to obtain polyamide acid microspheres;
(2) Modification of polyamic acid microspheres
First, 1g of polyamic acid microsphere powder was added to 200ml of an aqueous solution of polyvinyl alcohol (0.04 g/ml), and uniformly dispersed by ultrasonic treatment for 1 hour. And centrifuging out the polyamide acid microsphere to obtain the polyamide acid microsphere coated with a layer of polyvinyl alcohol.
(3) Preparation of graphene oxide coated polyamide acid microsphere
After ultrasonic treatment, the microspheres obtained in (2) are dispersed in 200ml of deionized water and mixed with 100ml of 1mg/ml graphene oxide solution. And (3) stirring the mixed solution for 1h, and washing the precipitate with deionized water to obtain the graphene oxide coated polyamide acid microspheres.
(4) Preparation of functional polyimide microsphere by thermal imidization method
And (3) drying the functionalized polyamide acid composite microsphere prepared in the step (2) at 60 ℃ for 2 hours, then putting the microsphere into a muffle furnace for heating, heating to 200 ℃ at a heating rate of 5 ℃/min, preserving heat for 1 hour, heating to 300 ℃ at a heating rate of 5 ℃/min, and preserving heat for 1 hour to obtain the graphene oxide coated polyimide composite microsphere.
As shown in fig. 1, after the graphene oxide is coated, the surface of the polyimide microsphere with the original smooth surface is wrinkled, and meanwhile, the graphene oxide coating is relatively uniform.
Example 2
(1) Preparation of polyamide acid microsphere
Weighing 20g of polyamide acid with the solid content of 18wt%, adding the polyamide acid into 100ml of N, N-dimethylformamide solution, stirring for 2 hours, then transferring the mixture into a constant temperature and humidity box with the humidity of 98% and the temperature of 30 ℃ for 16 hours, collecting a product, centrifugally washing the product with deionized water, and drying the product to obtain polyamide acid microspheres;
(2) Preparation of polyamide acid microsphere coated by aluminum oxide
Firstly, 1g of polyamide acid microsphere powder is added into 500ml of aqueous solution with pH of 4, and uniformly dispersed for 1h through ultrasonic treatment. Then 0.3g of aluminum oxide powder is weighed and dispersed into aqueous solution with pH of 4 by ultrasonic, after stirring the two solutions for 1h, the precipitate is washed with deionized water for 3 times, and the polyamide acid microsphere coated by aluminum oxide is obtained.
(3) Preparation of functional polyimide microsphere by thermal imidization method
And (3) drying the functionalized polyamide acid composite microsphere prepared in the step (2) at 60 ℃ for 2 hours, then placing the microsphere into a muffle furnace for heating, heating to 200 ℃ at a heating rate of 5 ℃/min, preserving heat for 1 hour, heating to 300 ℃ at a heating rate of 5 ℃/min, and preserving heat for 1 hour to obtain the polyimide composite microsphere coated with aluminum oxide.
As shown in FIG. 2, the result of scanning electron microscope of the polyimide composite microsphere prepared above shows that a plurality of granular aluminum oxide appears on the surface of the polyimide microsphere, which indicates that the aluminum oxide is successfully adsorbed on the surface of the PI microsphere through electrostatic adsorption.
Example 3
The preparation method is the same as in example 2, except that the pH value of the aqueous solution in step (2) is 5, and the functional material is titanium dioxide, so as to prepare the polyimide composite microsphere coated with titanium dioxide.
The polyimide composite microsphere prepared above is subjected to a scanning electron microscope, and the result is shown in figure 3.
Example 4
The production method was the same as in example 3 except that the mass of titanium dioxide in step (2) was 0.15g as a comparative example to example 3.
The polyimide composite microsphere prepared above is subjected to a scanning electron microscope, and the result is shown in fig. 4.
Example 5
The production method was the same as in example 3 except that the mass of titanium dioxide in step (2) was 0.2g as a comparative example to example 3.
The polyimide composite microsphere prepared above is subjected to a scanning electron microscope, and the result is shown in fig. 5.
As can be seen from fig. 3, 4 and 5, the nanoscale titanium dioxide is successfully adsorbed on the surface of the polyimide microsphere through electrostatic adsorption, and the adsorption amount can be controlled by controlling the addition amount of the titanium dioxide.
The blank polyimide microspheres, the 15wt% titanium dioxide coated polyimide microspheres prepared in example 4 and the 30wt% titanium dioxide coated polyimide microspheres prepared in example 3 are respectively added into rhodamine B solution with the same concentration, the change of the concentration of rhodamine B in the solution with time is tested, and a degradation curve is shown in fig. 6 (a), and the degradation effect pair is shown in fig. 6 (B); as can be seen from fig. 6, after the titanium dioxide is loaded, the polyimide composite microsphere has the performance of degrading rhodamine B by photocatalysis, and meanwhile, the degradation efficiency is improved along with the increase of the titanium dioxide loading.
Those skilled in the art will appreciate that the foregoing is merely a few, but not all, embodiments of the invention. It should be noted that many variations and modifications can be made by those skilled in the art, and all variations and modifications which do not depart from the scope of the invention as defined in the appended claims are intended to be protected.
Claims (4)
1. The preparation method of the functional polyimide composite microsphere is characterized in that the particle size of the functional polyimide composite microsphere is 0.5-10 mu m, the functional polyimide composite microsphere is formed by compounding thermosetting polyimide microsphere and functional material according to the mass ratio of 100 (1-40), the functional material is uniformly coated on the surface of the polyimide microsphere, and the binding force between the functional material and the polyimide microsphere is electrostatic adsorption force and hydrogen bonding effect;
the preparation method comprises the following steps:
s1, preparing polyamide acid microspheres: mixing an organic solvent and polyamide acid in a mass ratio of (2-12): 1 to obtain a mixed solution, stirring the mixed solution at 20-50 ℃ for 1-3 hours, transferring the mixed solution into a constant temperature and humidity box with humidity of 80-98% and temperature of 25-50 ℃ for reaction for 8-24 hours, collecting a product, centrifugally washing the product with deionized water, and drying to obtain polyamide acid microspheres;
s2, pretreatment of polyamide acid microspheres: adding a water-soluble polymer into water to prepare a water-soluble polymer solution with the concentration of 0.01-0.06g/ml, adding 100 parts by mass of polyamide acid microspheres prepared in the step S1 into the water-soluble polymer water solution according to the adding mass ratio of 1 (100-200), performing ultrasonic dispersion to completely infiltrate the microspheres, stirring for 0.5-1h, and performing centrifugal separation to obtain modified polyamide acid microspheres;
s3, functionalization of polyamide acid microspheres: weighing 1-40 parts by mass of functional material, adding the functional material into an aqueous solution with the pH value of 3-7, uniformly stirring, adding the modified polyamide acid microspheres prepared in the step S2, stirring for 5-30min after mixing, centrifugally washing with deionized water, and drying to obtain the functional polyamide acid composite microspheres;
s4, preparing functional polyimide microspheres: and (3) placing the functionalized polyamide acid composite microsphere prepared in the step (S3) at 50-90 ℃ for 2-4 hours, heating to 180-220 ℃ at a heating rate of 1-10 ℃/min, preserving heat for 1-3 hours, heating to 280-300 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 1-2 hours to obtain the functionalized polyimide composite microsphere.
2. The method for preparing the functionalized polyimide composite microsphere according to claim 1, wherein the functional material is one or a combination of two or more of graphene oxide, silicon dioxide, titanium dioxide, aluminum oxide, ferroferric oxide, boron nitride, graphene nanoplatelets and nano silver.
3. The method for preparing functionalized polyimide composite microspheres according to claim 1, wherein the organic solvent in the step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, cyclohexane and chloroform.
4. The method for preparing functionalized polyimide composite microspheres according to claim 1, wherein the water-soluble polymer in the step S2 is one of polyvinylpyrrolidone, polyvinyl alcohol, polyurethane and polyethylene glycol.
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| CN113956658B (en) * | 2021-10-21 | 2024-01-30 | 北京宇程科技有限公司 | Polyimide/titanium dioxide composite microsphere and preparation method thereof |
| CN114457325B (en) * | 2021-12-30 | 2023-12-08 | 安徽中科元贞科技有限责任公司 | Nickel layer thickness control method for nickel-plated high polymer microspheres |
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| CN103570946A (en) * | 2013-11-19 | 2014-02-12 | 武汉理工大学 | Preparation method of polyimide microsphere |
| CN104587919A (en) * | 2014-12-07 | 2015-05-06 | 北京化工大学 | Preparation method for core-shell type polyimide@metal/metal oxide/metal sulfide composite microballoons |
| CN111454451A (en) * | 2019-01-22 | 2020-07-28 | 东莞东阳光科研发有限公司 | Preparation method of polyimide microspheres |
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| CN103570946A (en) * | 2013-11-19 | 2014-02-12 | 武汉理工大学 | Preparation method of polyimide microsphere |
| CN104587919A (en) * | 2014-12-07 | 2015-05-06 | 北京化工大学 | Preparation method for core-shell type polyimide@metal/metal oxide/metal sulfide composite microballoons |
| CN111454451A (en) * | 2019-01-22 | 2020-07-28 | 东莞东阳光科研发有限公司 | Preparation method of polyimide microspheres |
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