CN113354527A - Method for degrading polyimide material by microwave - Google Patents
Method for degrading polyimide material by microwave Download PDFInfo
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- CN113354527A CN113354527A CN202110673743.5A CN202110673743A CN113354527A CN 113354527 A CN113354527 A CN 113354527A CN 202110673743 A CN202110673743 A CN 202110673743A CN 113354527 A CN113354527 A CN 113354527A
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Abstract
The invention belongs to the field of recycling of waste high polymer materials, and particularly relates to a method for degrading a polyimide material by microwaves. The invention prepares polyimide waste, solvent and catalyst into a degradation system, and places the degradation system in a microwave reactor for degradation reaction. Filtering after degradation is finished, and adding deionized water to wash a filter cake to obtain aromatic diamine; the solvent is evaporated from the washing liquid, hydrochloric acid is added to precipitate the aromatic o-phthalic acid, and the aromatic o-phthalic acid is obtained after filtration and drying. The invention selectively breaks imide bonds under the microwave condition by using an alkaline catalyst to obtain pyromellitic acid and 2, 2' -diaminodiphenyl ether. The invention has the advantages of low recovery cost, mild reaction condition, normal-pressure degradation and easy separation to obtain products with high added value.
Description
Technical Field
The invention belongs to the field of recycling of waste high polymer materials, and particularly relates to a method for degrading a polyimide material by microwaves.
Background
Polyimide is mainly prepared from aromatic diamine and aromatic dianhydride, and is one of organic high polymer materials with the best comprehensive performance. The nano-composite material can be used for a long time within the temperature range of-200-300 ℃, has excellent wear resistance, chemical corrosion resistance, electrical insulation and the like, and is widely applied to the fields of aviation, aerospace, microelectronics, nano-scale, liquid crystal, separation membranes, laser and the like. Meanwhile, the use of polyimide in large quantities leads to the continuous increase of waste resources, and the recycling of polyimide is also concerned widely.
At present, most polyimide materials are recycled in a high-pressure reaction kettle and a hydrothermal reaction kettle, so that the problems that the reaction dynamic state cannot be observed in real time, the mass transfer is slow, the temperature of a lining of the reaction kettle cannot be accurately measured and the like are caused. The microwave reactor has the advantages of high heating speed, uniform heating, strong heating permeability, simple operation and the like. The microwave reactor is used for converting the polyimide waste into a high value-added product, so that the resource waste can be reduced, the environmental pollution is avoided, and a new method is provided for preparing the aromatic diamine and the aromatic o-phthalic tetracarboxylic acid.
Disclosure of Invention
The invention provides a method for degrading polyimide materials by microwaves, aiming at solving the technical problem of recycling polyimide, and the method is simple to operate and mild in condition and can convert polyimide wastes into high value-added products.
In order to realize the purpose, the invention is realized by the following technical scheme:
a method for degrading polyimide materials by microwaves comprises the following steps: preparing a reaction system from a polyimide material, a solvent and a catalyst, and placing the reaction system in a microwave reactor for heating reaction; after the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain aromatic diamine; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate the aromatic pyromellitic acid, filtering and drying to obtain the aromatic pyromellitic acid.
Further, the catalyst is NaOH, KOH, LiOH, RbOH, CsOH、(CH3)4NOH、(CH3CH2)4NOH、CH3CH2·N(CH3)3OH、Na2CO3、K2CO3Any one of them. The invention selectively breaks the imide bond in the polyimide by using the alkaline catalyst, and the catalyst has better catalytic action on selective breaking of the amide bond.
Further, the solvent is water or a mixed solution of water and an organic reagent, wherein the mass ratio of the water to the organic reagent is 1: 1-10. The alkaline catalyst has good dissolving effect in water, active groups required by the degradation of the polyimide are dissociated, and the degradation products can be dissolved in the water, so that the reaction process and the subsequent product separation can be accelerated; the organic solvent is used for improving the wettability of the reaction system and the polyimide material, and simultaneously can maintain the reaction temperature.
Further, the organic reagent is any one of acetone, chloroform, pyridine, propanol, butanol, isopropanol, N-methylpyrrolidone, N '-dimethylformamide, N' -dimethylacetamide, tetrahydrofuran, and m-cresol. The solvent selected by the scheme has better swelling effect and reaction performance on polyimide.
Furthermore, the mass ratio of the polyimide material to the reaction system is 1: 1-100; the mass fraction of the catalyst is 1-10%. When the mass ratio of the polyimide material to the reaction system is too large, the solvent cannot fully swell the polyimide material, which is not beneficial to the catalytic action of the catalyst; when the mass ratio of the polyimide material to the reaction system is too small, the amount of the solvent used is large, and the economy is not good. When the mass fraction of the catalyst is less than 1%, the concentration of the catalyst is low, which is not beneficial to the reaction; when the mass fraction of the catalyst is more than 10%, the catalyst is excessive, which is not beneficial to the separation of subsequent products and also causes unnecessary waste.
Further, the power of the microwave reactor is 100-800W, and the reaction time is 1 min-12 h. When the power of the microwave reactor is lower than 100W, the degradation reaction basically does not occur; when the microwave reactor power is higher than 800W, side reactions occur. When the reaction time is less than 1min, the degradation reaction is insufficient; when the reaction time is more than 12 hours, the reaction effect is not obviously improved.
Further, the polyimide to be recycled has the following structure:
wherein Ar is1The structure comprises the following structures:
Ar2the structure comprises the following structures:
compared with the prior art, the invention has the following beneficial effects:
(1) the invention has high degradation efficiency, can be carried out under normal pressure, and has shorter time required by a higher pressure degradation method;
(2) the degradation product is easy to separate, and the reaction solvent is easy to separate and recover;
(3) the invention can selectively break imide bonds and recover products with high added values, and the reaction mechanism is as follows:
drawings
FIG. 1 is a nuclear magnetic resonance carbon spectrum of pyromellitic acid monomer;
FIG. 2 is a carbon NMR spectrum of 4, 4' -diaminodiphenyl ether;
FIG. 3 is a nuclear magnetic resonance carbon spectrum of 4, 4' -diaminodiphenylmethane;
FIG. 4 is a NMR carbon spectrum of p-phenylenediamine.
Detailed Description
The following examples are given in the detailed description and the specific operation on the premise of the technical solutions of the present invention, but do not limit the protection scope of the patent of the present invention, and all technical solutions obtained by using equivalent alternatives or equivalent variations should fall within the protection scope of the present invention.
Example 1
Preparing water and N, N' -dimethylformamide into a mixed solution according to the mass ratio of 1:1, preparing the mixed solution and NaOH into a reaction system according to the mass fraction of 10% of a catalyst, mixing a polyimide material and the reaction system according to the mass ratio of 1:100, placing the mixture in a microwave reactor, and reacting for 4 hours at 100W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate aromatic pyromellitic acid, filtering and drying to obtain pyromellitic acid.
FIG. 1 is a nuclear magnetic resonance carbon spectrum of a recovered pyromellitic acid monomer; FIG. 2 is a carbon nuclear magnetic resonance spectrum of 4, 4' -diaminodiphenyl ether monomer. It can be seen from fig. 1 and 2 that the recovered pyromellitic acid and 4, 4' -diaminodiphenyl ether are high in purity and hardly have any impurity peak.
Example 2
Preparing water and m-cresol into a mixed solution according to the mass ratio of 1:5, preparing the mixed solution and CsOH into a reaction system according to the mass fraction of 5% of a catalyst, mixing a polyimide material and the reaction system according to the mass ratio of 1:50, placing the mixture in a microwave reactor, and reacting for 2 hours at 400W. After the reaction is finished, cooling to room temperature, filtering, adding deionized water to wash a filter cake to obtain 4,4 '-diaminodiphenylmethane, wherein the nuclear magnetic resonance carbon spectrum of the 4, 4' -diaminodiphenylmethane is shown in figure 3; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the biphenyltetracarboxylic acid.
Example 3
Preparing water and N-methyl pyrrolidone into a mixed solution according to the mass ratio of 1:10, preparing the mixed solution and RbOH according to the mass fraction of 1% of a catalyst into a reaction system, mixing a polyimide material and the reaction system according to the mass ratio of 1:10, placing the mixture into a microwave reactor, and reacting for 1min at 500W. After the reaction is finished, cooling to room temperature, filtering, adding deionized water to wash a filter cake to obtain p-phenylenediamine, wherein the nuclear magnetic resonance carbon spectrum of the p-phenylenediamine is shown in figure 4; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the benzophenone tetracarboxylic acid.
Example 4
Preparing water and butanol into a mixed solution according to the mass ratio of 1:7, and mixing the mixed solution with Na2CO3Preparing a reaction system according to 10% of the mass fraction of the catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:1, placing the mixture into a microwave reactor, and reacting for 12 hours at 800W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenylmethane; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain diphenyl ether tetracarboxylic acid.
Example 5
Preparing water and pyridine into a mixed solution according to the mass ratio of 1:4, and mixing the mixed solution with K2CO3Preparing a reaction system according to the mass fraction of 8% of the catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:40, placing the mixture in a microwave reactor, and reacting for 10 hours at 800W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the biphenyltetracarboxylic acid.
Example 6
Preparing water and acetone into a mixed solution according to the mass ratio of 1:2, and mixing the mixed solution with (CH)3)4Preparing a reaction system from NOH according to the mass fraction of 2% of the catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:20, placing the mixture in a microwave reactor, and reacting for 8 hours at 200W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain diphenyl ether tetracarboxylic acid.
Example 7
Mixing water and CPreparing alcohol into a mixed solution according to the mass ratio of 1:3, and mixing the mixed solution with CH3CH2·N(CH3)3Preparing a reaction system from OH according to the mass fraction of 3% of a catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:30, placing the mixture in a microwave reactor, and reacting for 11 hours at 300W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain diphenyl ether tetracarboxylic acid.
Example 8
Preparing water and chloroform into a mixed solution according to the mass ratio of 1:6, and mixing the mixed solution with K2CO3Preparing a reaction system according to 4% of the mass fraction of the catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:60, placing the mixture in a microwave reactor, and reacting for 6 hours under 600W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the benzophenone tetracarboxylic acid.
Example 9
Preparing water and N, N' -dimethylacetamide into a mixed solution according to the mass ratio of 1:8, and mixing the mixed solution with (CH)3CH2)4Preparing a reaction system from NOH according to 9% of the mass fraction of the catalyst, mixing the polyimide material and the reaction system according to the mass ratio of 1:80, placing the mixture in a microwave reactor, and reacting for 8 hours at 650W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate pyromellitic acid, filtering and drying to obtain pyromellitic acid.
Example 10
Preparing water and tetrahydrofuran into a mixed solution according to the mass ratio of 1:9, preparing the mixed solution and CsOH into a reaction system according to the mass fraction of 9% of a catalyst, mixing a polyimide material and the reaction system according to the mass ratio of 1:90, placing the mixture in a microwave reactor, and reacting for 9 hours at 350W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the biphenyltetracarboxylic acid.
Example 11
Preparing a mixed solution from water and isopropanol in a mass ratio of 1:5, preparing a reaction system from the mixed solution and RbOH according to 5% of the mass of the catalyst, mixing a polyimide material and the reaction system in a mass ratio of 1:50, placing the mixture in a microwave reactor, and reacting for 5 hours at 500W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate pyromellitic acid, filtering and drying to obtain pyromellitic acid.
Example 12
Preparing water and NaOH into a reaction system according to the mass fraction of 10% of a catalyst, mixing a polyimide material and the reaction system according to the mass ratio of 1:10, placing the mixture into a microwave reactor, and reacting for 1h under 400W. After the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain 4, 4' -diaminodiphenyl ether; evaporating the solvent in the filtrate, adding hydrochloric acid to precipitate out pyromellitic acid, filtering and drying to obtain the biphenyltetracarboxylic acid.
Claims (8)
1. A method for degrading polyimide materials by microwaves is characterized by comprising the following steps: preparing a reaction system from a polyimide material, a solvent and a catalyst, and placing the reaction system in a microwave reactor for heating reaction; after the reaction is finished, cooling to room temperature, filtering, and adding deionized water to wash a filter cake to obtain aromatic diamine; evaporating the organic solvent in the filtrate, adding hydrochloric acid to precipitate the aromatic pyromellitic acid, filtering and drying to obtain the aromatic pyromellitic acid.
2. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the solvent is water or a mixed solution of water and an organic reagent, wherein the mass ratio of the water to the organic reagent is 1: 1-10.
3. The method for microwave degradation of polyimide materials according to claim 2, wherein the method comprises the following steps: the organic reagent is any one of acetone, chloroform, pyridine, propanol, butanol, isopropanol, N-methylpyrrolidone, N '-dimethylformamide, N' -dimethylacetamide, tetrahydrofuran and m-cresol.
4. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the catalyst is NaOH, KOH, LiOH, RbOH, CsOH, (CH)3)4NOH、(CH3CH2)4NOH、CH3CH2·N(CH3)3OH、Na2CO3、K2CO3Any one of them.
5. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the mass ratio of the polyimide material to the reaction system is 1: 1-100.
6. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the mass fraction of the catalyst is 1-10%.
7. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the power of the microwave reactor is 100-800W, and the reaction time is 1 min-12 h.
8. The method for microwave degradation of polyimide materials according to claim 1, wherein the method comprises the following steps: the structure of the polyimide material to be degraded is as follows:
wherein Ar is1The structure comprises the following structures:
Ar2the structure comprises the following structures:
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116284994A (en) * | 2023-04-12 | 2023-06-23 | 四川大学 | Recovery method of waste high polymer material containing ester group/amide bond/imide bond |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1324789A (en) * | 2001-06-26 | 2001-12-05 | 中国科学院长春应用化学研究所 | Polyimide hydrolyzing recovery process |
| CN103553906A (en) * | 2013-11-05 | 2014-02-05 | 上海固创化工新材料有限公司 | Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water |
| CN104844819A (en) * | 2015-05-06 | 2015-08-19 | 无锡顺铉新材料有限公司 | Modified polyimide film and modified polyimide precursor composite film waste material recovery processing method |
| CN105017560A (en) * | 2015-05-06 | 2015-11-04 | 无锡顺铉新材料有限公司 | Waste recovery processing method for modified polyimide precursor composition film |
| CN109503614A (en) * | 2018-12-04 | 2019-03-22 | 宏威高新材料有限公司 | A method of recycling polyimides waste |
| CN111073035A (en) * | 2019-12-12 | 2020-04-28 | 江苏奥神新材料股份有限公司 | Method for rapidly degrading and recycling polyimide material |
| WO2021091420A1 (en) * | 2019-11-07 | 2021-05-14 | Федеральное государственное бюджетное учреждение науки Институт проблем химической физики Российской Академии наук (ФГБУН ИПХФ РАН) | Method for processing polyimide materials |
-
2021
- 2021-06-17 CN CN202110673743.5A patent/CN113354527A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1324789A (en) * | 2001-06-26 | 2001-12-05 | 中国科学院长春应用化学研究所 | Polyimide hydrolyzing recovery process |
| CN103553906A (en) * | 2013-11-05 | 2014-02-05 | 上海固创化工新材料有限公司 | Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water |
| CN104844819A (en) * | 2015-05-06 | 2015-08-19 | 无锡顺铉新材料有限公司 | Modified polyimide film and modified polyimide precursor composite film waste material recovery processing method |
| CN105017560A (en) * | 2015-05-06 | 2015-11-04 | 无锡顺铉新材料有限公司 | Waste recovery processing method for modified polyimide precursor composition film |
| CN109503614A (en) * | 2018-12-04 | 2019-03-22 | 宏威高新材料有限公司 | A method of recycling polyimides waste |
| WO2021091420A1 (en) * | 2019-11-07 | 2021-05-14 | Федеральное государственное бюджетное учреждение науки Институт проблем химической физики Российской Академии наук (ФГБУН ИПХФ РАН) | Method for processing polyimide materials |
| CN111073035A (en) * | 2019-12-12 | 2020-04-28 | 江苏奥神新材料股份有限公司 | Method for rapidly degrading and recycling polyimide material |
Non-Patent Citations (1)
| Title |
|---|
| TETSUO HONMA: "Hydrolysis kinetics of PMDA/ODA polyimide for monomer recovery using sodium hydroxide in high-temperature water", THE JOURNAL OF SUPERCRITICAL FLUIDS, vol. 166, pages 330 - 332 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116284994A (en) * | 2023-04-12 | 2023-06-23 | 四川大学 | Recovery method of waste high polymer material containing ester group/amide bond/imide bond |
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