Ablation-resistant modified glycosyl carbon fiber composite material and preparation method thereof

Abstract

The invention belongs to the technical field of ablation-resistant polymer-based composite materials, and particularly relates to an ablation-resistant modified sugar-based carbon fiber composite material and a preparation method thereof.The preparation method comprises the following steps that S1, carbon black filler particles are subjected to surface modification treatment; s2, preparing a glycosyl dipping solution; s3, impregnating the carbon fiber preform in a glycosyl impregnation solution in a vacuum environment, and performing pressure maintaining treatment to obtain a pre-impregnated carbon fiber preform; s4, performing gelatinization treatment on sweet water of the pre-impregnated carbon fiber preform in a vacuum drying oven to obtain a gelatinized carbon fiber preform; s5, performing two-stage low-temperature stabilization treatment on the gelatinized carbon fiber preform in a vacuum drying oven to obtain a stabilized carbon fiber preform; and step S6, performing high-temperature normal-pressure carbonization treatment on the stabilized carbon fiber preform in a protective atmosphere to obtain the ablation-resistant modified glycosyl carbon fiber composite material.

Description

Technical Field

[0001] The present invention belongs to the technical field of ablation-resistant polymer-based composite materials, and in particular relates to an ablation-resistant modified sugar-based carbon fiber composite material and a preparation method thereof. Background Art

[0002] Affected by the aerodynamic thermal effect, rockets, satellites, spacecraft and space shuttles often need to withstand thermal loads such as high temperature, strong scouring, and high heat flux during flight. In order to ensure the normal operation of aerospace vehicles, high-temperature resistant thermal protection materials are required to protect the integrity of the internal structure of the aircraft. As one of the most mature thermal protection measures currently used, the ablative thermal protection system has been widely used in the aerospace field. Its working principle is to remove heat through the pyrolysis of the heat protection layer material, thereby maintaining the normal ambient temperature and structural stability of the aircraft.

[0003] Among many ablative materials, polymer-based thermal protection materials have become one of the ideal ablative materials that meet long-term thermal protection needs due to their low density, low cost, excellent thermal protection performance and other characteristics. With the continuous development of aerospace technology, traditional ordinary resin-based thermal protection materials have limited protection effects in increasingly harsh heat flow environments. The current mainstream ablative polymer substrate is phenolic resin, which has complex preparation steps and poor high-temperature ablation resistance. Although the thermal protection performance of phenolic resin-based composite materials can be further improved by modifying inorganic fillers, the addition of inorganic fillers will have a negative impact on the bulk strength of the resin matrix and easily cause defects such as microcracks in the composite material.

[0004] Therefore, how to provide a polymer substrate that is low-cost, easy to prepare, environmentally friendly, and compatible with inorganic particles and resistant to high-temperature ablation is a technical problem that urgently needs to be solved in the art.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0006] The embodiments of the present disclosure at least provide an ablation-resistant modified sugar-based carbon fiber composite material and a preparation method thereof.

[0007] In a first aspect, the disclosed embodiment provides a method for preparing an ablation-resistant modified sugar-based carbon fiber composite material, comprising the following steps: step S1, surface modification of carbon black filler particles, namely, mixing carbon black powder with a saturated aqueous solution of ammonium persulfate under an ultrasonic environment, stirring in a water bath, and washing with deionized water until neutral to obtain modified carbon black particles, which are dried for later use; step S2, preparing a sugar-based impregnation solution, namely, mixing N-N'methylenebisacrylamide and deionized water, adding a sugar source after the solution is completely dissolved, and then adding acrylamide and modified carbon black particles in sequence after the solution is dissolved, and mixing well. The steps of step S3 are as follows: the carbon fiber preform is impregnated with the sugar-based impregnation solution under vacuum and subjected to pressure treatment to obtain a pre-impregnated carbon fiber preform; the pre-impregnated carbon fiber preform is subjected to a gelling treatment of sugar water in a vacuum drying oven to obtain a gelled carbon fiber preform; the gelled carbon fiber preform is subjected to a two-stage low-temperature stabilization treatment in a vacuum drying oven to obtain a stabilized carbon fiber preform; and the stabilized carbon fiber preform is subjected to a high-temperature and normal-pressure carbonization treatment in a protective atmosphere to obtain an ablation-resistant modified sugar-based carbon fiber composite material.

[0008] In an optional embodiment, the mass ratio of the carbon black powder to the ammonium persulfate aqueous solution in step S1 is 1:20-1:30.

[0009] In an optional embodiment, the heating temperature of the water bath in step S1 is 25-40° C. and the stirring time is 10-12 h.

[0010] In an optional embodiment, the sugar source in step S2 includes any one or more combinations of glucose, sucrose and fructose.

[0011] In an optional embodiment, the mass ratio of N-N'methylenebisacrylamide, sugar source and deionized water in step S2 is (0.7-1): (130-170): 100; and the amount of modified carbon black particles added is 1%-3% of the mass of the sugar-based impregnation solution.

[0012] In an optional embodiment, the carbon fiber preform in step S3 includes any one or more combinations of carbon fibers having carbon felt, 2.5D needle-punched structure, web structure and fiber woven structure.

[0013] In an optional embodiment, the time for the immersion and pressure holding in step S3 is 12-20 hours.

[0014] In an optional embodiment, the temperature of the gelation treatment in step S4 is 60-70° C. and the time is 8-10 h.

[0015] In an optional embodiment, the temperature of the first stage of stabilization treatment in step S5 is 100-140°C, and the insulation treatment time is 12-16 hours; the temperature of the second stage is 180-200°C, and the insulation treatment time is 6-10 hours.

[0016] In a second aspect, an embodiment of the present disclosure also provides an ablation-resistant modified sugar-based carbon fiber composite material prepared by the method described above, wherein the residual weight rate of the ablation-resistant modified sugar-based carbon fiber composite material is not less than 85% after being heated to 1200°C under an inert atmosphere.

[0017] The beneficial effect of the present invention is that the ablation-resistant modified sugar-based carbon fiber composite material and its preparation method combine inorganic carbon black particle filler with green, environmentally friendly and easily accessible biomass sugar source as an ablation-resistant substrate. On the one hand, a water-soluble gel curing process is used for the sugar source, and no organic solvent is required. The impregnation curing process is environmentally friendly and convenient. A low-temperature stabilization treatment process is added after curing to remove solvent water in advance to prevent the substrate from cracking due to rapid dehydration and decomposition when the material is used in a high-temperature environment. At the same time, the small molecule sugar source undergoes a condensation reaction to form a stable long-chain structure, thereby increasing the residual carbon rate of the sugar source and effectively improving the ablation resistance of the polymer substrate. On the other hand, hydrophilically modified carbon black particles are added to enhance the interface bonding between the sugar source substrate and the carbonized layer formed during high-temperature use, thereby improving the density and integrity of the carbonized layer and improving the ablation resistance of the sugar-based carbon fiber composite material.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A physical picture of the sugar-based carbon fiber composite material prepared in Example 1 provided in the embodiments of the present disclosure; Figure 2This is a surface SEM image of the sugar-based carbon fiber composite material prepared in Example 1 provided in the embodiments of the present disclosure; Figure 3 A physical picture of the sugar-based carbon fiber composite material obtained in Example 1 provided in the embodiments of the present disclosure after oxyacetylene ablation; Figure 4 SEM images of different positions on the surface of the sugar-based carbon fiber composite material obtained in Example 1 provided in the embodiments of the present disclosure after oxyacetylene ablation; Figure 5 The actual picture (a) of the sugar aqueous solution after adding the modified carbon black and the actual picture (b) of the sugar aqueous solution after adding the unmodified carbon black provided in Example 1 of the present disclosure; Figure 6 This is a diagram of glucose precipitation in Comparative Example 2 provided in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0024] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0025] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0026] The commonly used ablation-resistant polymer substrate in the market is phenolic resin, which is produced by the condensation of phenolic compounds and aldehyde compounds. It requires the additional addition of a curing agent. At the same time, the steps are complicated and the ablation-resistant effect cannot meet the current high-temperature environment requirements.

[0027] The defects existing in the above solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure for the above problems below should be the contributions made by the inventor to the present disclosure during the disclosure process.

[0028] The disclosed embodiment provides a method for preparing an ablation-resistant modified sugar-based carbon fiber composite material, comprising the following steps: step S1, surface modification treatment of carbon black filler particles, namely, mixing carbon black powder with a saturated ammonium persulfate aqueous solution under an ultrasonic environment, stirring in a water bath, and washing with deionized water until neutral to obtain modified carbon black particles, which are dried for later use; step S2, preparing a sugar-based impregnation solution, namely, mixing N-N'methylenebisacrylamide and deionized water, adding a sugar source after the mixture is completely dissolved, and then adding acrylamide and modified carbon black particles in sequence after the mixture is dissolved, mixing evenly, to obtain a sugar-based impregnation solution. to the sugar-based impregnation solution; step S3, impregnating the carbon fiber preform in the sugar-based impregnation solution under a vacuum environment and maintaining pressure to obtain a pre-impregnated carbon fiber preform; step S4, gelling the pre-impregnated carbon fiber preform with sugar water in a vacuum drying oven to obtain a gelled carbon fiber preform; step S5, performing a two-stage low-temperature stabilization treatment on the gelled carbon fiber preform in a vacuum drying oven to obtain a stabilized carbon fiber preform; step S6, performing a high-temperature and normal-pressure carbonization treatment on the stabilized carbon fiber preform under a protective atmosphere to obtain an ablation-resistant modified sugar-based carbon fiber composite material.

[0029] In some embodiments, specifically, the mass ratio of the carbon black powder to the ammonium persulfate aqueous solution in step S1 is 1:20-1:30.

[0030] In some embodiments, specifically, the heating temperature of the water bath in step S1 is 25-40° C.; and the stirring time is 10-12 h.

[0031] In some embodiments, specifically, the sugar source in step S2 includes any one or more combinations of glucose, sucrose and fructose.

[0032] In some embodiments, specifically, the mass ratio of N-N'methylenebisacrylamide, sugar source and deionized water in step S2 is (0.7-1): (130-170): 100; and the amount of modified carbon black particles added is 1%-3% of the mass of the sugar-based impregnation solution.

[0033] In some embodiments, specifically, the carbon fiber preform in step S3 includes any one or more combinations of carbon fibers having carbon felt, 2.5D needle-punched structure, web structure, and fiber woven structure.

[0034] In some embodiments, specifically, the time of immersion and pressure holding in step S3 is 12-20 hours.

[0035] In some embodiments, specifically, the temperature of the gelation treatment in step S4 is 60-70° C. and the time is 8-10 hours.

[0036] In some embodiments, specifically, the temperature of the first stage of stabilization treatment in step S5 is 100-140° C., and the insulation treatment time is 12-16 hours; the temperature of the second stage is 180-200° C., and the insulation treatment time is 6-10 hours.

[0037] The disclosed embodiments also provide an ablation-resistant modified sugar-based carbon fiber composite material prepared by the method described above, wherein the residual weight rate of the ablation-resistant modified sugar-based carbon fiber composite material is not less than 85% after being heated to 1200° C. under an inert atmosphere.

[0038] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] Example 1: The preparation method of this example is as follows: Pretreatment of carbon black inorganic filler: Mix carbon black and saturated ammonium persulfate solution in a mass ratio of 1:21, ultrasonically disperse for 40 min, and then place in a 35°C water bath and stir for 12 h. Wash with deionized water several times until the solution is neutral, then vacuum dry the carbon black for later use.

[0040] Preparation of sugar-based impregnation solution: Add 1% of N-N'methylenebisacrylamide by weight of deionized water to deionized water, and after it is dissolved, add 1.5% of glucose by weight of deionized water and stir until it is completely dissolved. Then add 20% of acrylamide by weight of the solution and 2% of carbon black by weight of the solution in sequence and stir evenly.

[0041] Impregnation: The carbon fiber preform is impregnated under vacuum conditions and the pressure is maintained for 20 hours.

[0042] Gelation treatment: The impregnated carbon fiber parts were treated in a vacuum drying oven at 70 °C for 10 h to complete the gelation.

[0043] Stabilization treatment: The gelled carbon fiber parts were dried in a vacuum drying oven at 140 °C for 12 h, and then dried at 180 °C for 6 h to complete the stabilization treatment.

[0044] Specifically, the modified sugar-based carbon fiber composite material can be obtained by repeating the impregnation-gelation-stabilization process three times. The physical picture and SEM picture are shown in Figure 1 and Figure 2 As shown, it can be seen that the surface of the composite material obtained in Example 1 is dense and smooth, and the carbon black particles inside are evenly dispersed inside the sugar matrix; Figure 3 This is a physical picture of Example 1 after being ablated at 2000°C for 30 seconds with oxyacetylene. It can be seen that the composite material still maintains its original appearance after high-temperature ablation. The grayish-white area in the center is the sugar carbon formed by the carbonization of the sugar matrix at high temperature. The formation of the carbon layer helps to improve the material's resistance to thermal erosion. Figure 4 This is the SEM image of the unimaged area of ​​the surface after ablation of Example 1. It can be seen that the carbon fibers are not exposed after ablation, and the matrix still evenly wraps the internal carbon fibers, which indicates that the composite material prepared by the present invention exhibits good ablation resistance.

[0045] Comparative Example 1 This comparative example is similar to Example 1, except that the carbon black is not surface modified. When the unmodified carbon black is added to the sugar solution, the solution viscosity increases rapidly and becomes a paste with poor fluidity. Figure 5 As shown, it is difficult to complete the subsequent impregnation work.

[0046] Comparative Example 2 This comparative example is similar to Example 1, except that the concentration of sugar source to water is 2:1. Too high a proportion of sugar source increases the viscosity of the solution. During the long vacuum impregnation process, the evaporation of water causes sugar precipitation, such as Figure 6 As shown, white solid glucose powder has begun to appear at the bottom of the container, thus affecting the impregnation process.

[0047] In summary, the ablation-resistant modified sugar-based carbon fiber composite material and its preparation method combine inorganic carbon black particle filler with green, environmentally friendly and easily accessible biomass sugar source as an ablation-resistant substrate. On the one hand, a water-soluble gel curing process is used for the sugar source, which does not require an organic solvent. The impregnation curing process is environmentally friendly and convenient. A low-temperature stabilization treatment process is added after curing to remove solvent water in advance to prevent the substrate from cracking due to rapid dehydration and decomposition when the material is used in a high-temperature environment. At the same time, the small molecule sugar source undergoes a condensation reaction to form a stable long-chain structure, thereby increasing the residual carbon rate of the sugar source and effectively improving the ablation resistance of the polymer substrate. On the other hand, hydrophilically modified carbon black particles are added to enhance the interface bonding between the sugar source substrate and the carbonized layer formed during high-temperature use, thereby improving the density and integrity of the carbonized layer and improving the ablation resistance of the sugar-based carbon fiber composite material.

[0048] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing an ablation-resistant modified sugar-based carbon fiber composite material, characterized in that: The steps include: Step S1, surface modification of carbon black filler particles, that is, mixing carbon black powder with a saturated ammonium persulfate aqueous solution under an ultrasonic environment, stirring in a water bath, washing with deionized water until neutral to obtain modified carbon black particles, and drying for later use; Step S2, preparing a sugar-based impregnation solution, that is, mixing N-N'-methylenebisacrylamide and deionized water, adding a sugar source after the mixture is completely dissolved, and then sequentially adding acrylamide and modified carbon black particles after the mixture is dissolved, and mixing them evenly to obtain a sugar-based impregnation solution; Step S3, impregnating the carbon fiber preform in a sugar-based impregnation solution under a vacuum environment and maintaining pressure to obtain a pre-impregnated carbon fiber preform; Step S4, subjecting the pre-impregnated carbon fiber preform to a gelling treatment with sugar water in a vacuum drying oven to obtain a gelled carbon fiber preform; Step S5, subjecting the gelled carbon fiber preform to a two-stage low-temperature stabilization treatment in a vacuum drying oven to obtain a stabilized carbon fiber preform; Step S6, subjecting the stabilized carbon fiber preform to a high-temperature, normal-pressure carbonization treatment in a protective atmosphere to obtain an ablation-resistant modified sugar-based carbon fiber composite material.

2. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S1 The mass ratio of the carbon black powder to the ammonium persulfate aqueous solution is 1:20-1:

30.

3. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S1 The heating temperature of the water bath is 25-40℃; The stirring time is 10-12h.

4. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S2 The sugar source includes any one or more combinations of glucose, sucrose and fructose.

5. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S2 The mass ratio of the N-N'methylenebisacrylamide, the sugar source and the deionized water is (0.7-1): (130-170): 100; and The added amount of the modified carbon black particles is 1%-3% of the mass of the sugar-based impregnation solution.

6. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S3 The carbon fiber preform comprises any one or more combinations of carbon fibers of carbon felt, 2.5D needle-punched structure, web structure and fiber braided structure.

7. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S3, in step S3 The dipping and pressure-maintaining time is 12-20 hours.

8. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S4 The gelation treatment is carried out at a temperature of 60-70° C. and for a time of 8-10 hours.

9. The method for preparing the ablation-resistant modified sugar-based carbon fiber composite material according to claim 1, characterized in that: In step S5 The temperature of the first stage of stabilization treatment is 100-140°C, and the duration of heat preservation treatment is 12-16h; The temperature of the second stage is 180-200°C, and the insulation treatment time is 6-10h.

10. An ablation-resistant modified sugar-based carbon fiber composite material prepared by the method according to any one of claims 1 to 9, characterized in that: The ablation-resistant modified sugar-based carbon fiber composite material has a residual weight rate of not less than 85% after being heated to 1200° C. in an inert atmosphere.

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