Carboxymethyl cellulose encapsulated and modified aramid fiber reinforced polymer-based composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of composite materials, and particularly relates to a carboxymethyl cellulose encapsulated and modified aramid fiber reinforced polymer-based composite material as well as a preparation method and application thereof. The surface-modified aramid fiber is obtained by utilizing hydrogen bond combination between hydroxyl and carboxyl of carboxymethyl cellulose and the aramid fiber and coating the surface of the aramid fiber with the carboxymethyl cellulose coating, and the roughness of the fiber surface is remarkably improved. According to the carboxymethyl cellulose packaging modification method, the interface bonding between the aramid fiber and the polymer matrix can be effectively improved, then the mechanical performance, ablation resistance and scouring resistance of the composite material are improved, and the carboxymethyl cellulose packaging modification method has good application prospects in the fields of aerospace, transportation tools, energy equipment and the like.

Description

Technical Field

[0001] The present invention belongs to the field of composite materials, and particularly relates to an aramid fiber reinforced polymer matrix composite material encapsulated and modified with carboxymethyl cellulose, and a preparation method and use thereof. Background Art

[0002] Due to its high strength, high modulus, acid and alkali resistance, chemical reagent resistance, fatigue resistance, high temperature resistance, light weight, high wear resistance, etc., aramid fiber is widely used in the fields of aerospace, military defense, transportation, electronic communication, tire rubber, safety protection, sports and leisure, environmental protection, etc. However, the aramid molecular chain segments are highly regular, and there are few active groups on the fiber surface, making it difficult to react chemically or interact with other atoms or groups. As a result, aramid has strong hydrophobicity and poor surface wettability. At the same time, the fiber has high crystallinity and a smooth surface, resulting in weak interfacial bonding force and affecting its bonding performance with the matrix. Therefore, in order to fully utilize the excellent properties of aramid fiber and improve the interfacial bonding performance of aramid reinforced composites, the surface of aramid fiber must be modified.

[0003] Ethylene propylene diene monomer (EPDM) has a small relative density and has properties such as ozone resistance, weather resistance, heat resistance, and chemical stability, and has been widely used in thermal insulation layer materials. Due to the poor polarity of EPDM itself, the interfacial bonding strength between it and the fiber is poor. During the ablation process, the interface will become a weak area and is extremely vulnerable to oxygen erosion, resulting in material failure. For this reason, researchers have tried to modify the fiber to improve the interfacial bonding strength and enhance the ablation resistance of EPDM-based composites. For example, Zhang (Polymer Degradation and Stability, 2023, 217: 110510) et al. designed a vinyl-containing polycarbosilane surface-modified aramid fiber reinforced EPDM, which greatly reduced the linear ablation rate of the material. The strong interfacial bonding made the carbonized layer more solid and firm, and was expected to enhance the anti-erosion ability of the material during the ablation process. However, this type of surface modification method requires multiple-step treatment, and such chemical treatment may damage the surface of the fiber, causing larger defects and thus reducing the mechanical properties of the fiber. Therefore, developing a convenient and green and sustainable aramid fiber surface modification method while improving the mechanical properties and ablation properties of aramid fiber reinforced polymer matrix composites has become a research hotspot. Summary of the Invention

[0004] Aiming at the problems of the prior art, to simultaneously improve the mechanical properties and ablation resistance of aramid fiber reinforced ethylene propylene diene monomer composites. The present invention provides an aramid fiber reinforced polymer matrix composite material encapsulated and modified with carboxymethyl cellulose, and a preparation method and use thereof.

[0005] A surface-modified aramid fiber reinforced polymer matrix composite, which is composed of surface-modified aramid fibers and a polymer matrix; the weight ratio of the surface-modified aramid fibers to the polymer matrix is (1-20):100; the surface-modified aramid fibers are prepared by dispersing aramid fibers in an aqueous carboxymethyl cellulose solution so that carboxymethyl cellulose covers the aramid fibers; in the aqueous carboxymethyl cellulose solution, the feeding mass ratio of carboxymethyl cellulose to aramid fibers is 1-10:20.

[0006] Preferably, in the aqueous carboxymethyl cellulose solution, the feeding mass ratio of carboxymethyl cellulose to aramid fibers is 3.75:20.

[0007] Preferably, the polymer matrix is made from raw materials including the following parts by weight:

[0008] 80-150 parts of polyolefin rubber,

[0009] 0.1-20 parts of activator,

[0010] 0.1-20 parts of softener,

[0011] 0.1-20 parts of vulcanizing agent,

[0012] 0.1-20 parts of reinforcing agent.

[0013] Preferably, the polyolefin rubber is selected from at least one of ethylene propylene diene monomer rubber, polyethylene rubber, and polybutene rubber;

[0014] and / or, the activator is selected from at least one of zinc oxide, magnesium oxide, and lead oxide;

[0015] and / or, the softener is selected from at least one of phthalate, phosphate ester, and stearic acid;

[0016] and / or, the vulcanizing agent is selected from at least one of benzophenone peroxide, dicumyl peroxide, and sulfur;

[0017] and / or, the reinforcing agent is selected from silica.

[0018] Preferably, the mass fraction of the aqueous carboxymethyl cellulose solution is 0.25-2%.

[0019] Preferably, the preparation method of the surface-modified aramid fibers includes the following steps: impregnating the aramid fibers without sizing agent or desized aramid fibers in the aqueous carboxymethyl cellulose solution, stirring and filtering, and drying to obtain.

[0020] Preferably, the impregnation time is 1-10 min; the drying temperature is 80-150 °C, and the drying time is 1-5 h.

[0021] Preferably, the steps of the desizing treatment include: impregnating the aramid fiber in a volatile organic solvent, and obtaining the desized aramid fiber after ultrasonic treatment.

[0022] Preferably, the volatile organic solvent is selected from acetone; the time of the ultrasonic treatment is 1-5 h.

[0023] The present invention also provides a method for preparing the above-mentioned surface-modified aramid fiber-reinforced polymer matrix composite material, including the following steps:

[0024] a. Reacting polyolefin rubber with an activator, a softener, a vulcanizing agent, a reinforcing agent, and the surface-modified aramid fiber, adjusting the roll gap, and passing thinly to obtain a mixed rubber;

[0025] b. The mixed rubber is obtained after vulcanization.

[0026] Preferably, in step a, the roll gap is adjusted to 0.1-1 mm; the thin pass is 1-10 times;

[0027] And / or, in step b, the vulcanization temperature is 100-200 °C, and the vulcanization time is 10-60 min.

[0028] The present invention also provides the use of the above-mentioned surface-modified aramid fiber-reinforced polymer matrix composite material for preparing and / or as an ablation-resistant material.

[0029] By coating a carboxymethyl cellulose coating on the surface of the aramid fiber, the present invention obtains carboxymethyl cellulose-encapsulated aramid fiber, whose roughness is significantly increased and the interfacial bonding performance is significantly improved; the prepared aramid fiber-reinforced polymer matrix composite material can effectively improve the interfacial bonding ability and mechanical properties between the aramid fiber and ethylene propylene diene monomer rubber, and has good ablation and erosion resistance performance, and can be applied to fields such as aerospace, military defense, transportation, electronic communication, tire rubber, etc.

[0030] Obviously, based on the above content of the present invention, according to the common general knowledge and conventional means in the art, without departing from the above basic technical idea of the present invention, various other forms of modifications, substitutions or changes can be made.

[0031] The above content of the present invention will be further described in detail below through specific embodiments in the form of examples. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention. Description of the Drawings

[0032] Figure 1The surface morphologies of aramid fibers before and after being treated with carboxymethyl cellulose solution. (a - e) Scanning electron microscopy at high magnification was used to observe the microstructure of the samples; (f - h) Scanning electron microscopy at low magnification was used to observe the microstructure of the samples; (i - k) Atomic force microscopy was used to observe the samples.

[0033] Figure 2 To verify the CMC content formed on the surface of aramid fibers by thermogravimetric analysis and X - ray photoelectron spectroscopy. (a) Thermogravimetric curve of carboxymethyl cellulose - encapsulated aramid fibers in the nitrogen range; (b) Elemental analysis.

[0034] Figure 3 The H - extraction force and tensile strength of rubber composites prepared from aramid fibers encapsulated with different concentrations of carboxymethyl cellulose.

[0035] Figure 4 To observe the tensile fracture surface by scanning electron microscopy.

[0036] Figure 5 To conduct ablation tests on rubber composites before and after the interfacial modification of aramid fibers. (a) Plasma ablation test diagram; (b) Variation of ablation rate with CMC concentration; (c - e) Macroscopic ablation morphology.

[0037] Figure 6 The morphology of the carbon layer formed after ablation. (a - c) Cross - sectional electron microscopy of the center of the carbon layer after ablation, where the upper surface is the ablation surface. (d - f) are local magnified images inside the carbon layer. Specific Embodiments

[0038] In the following examples and experimental examples, the reagents and raw materials not specifically described are all commercially available products.

[0039] Example 1 Preparation of Aramid Fibers Modified by Carboxymethyl Cellulose Encapsulation

[0040] Step 1: Weigh 20 g of chopped aramid fibers (aramid 1414, Inner Mongolia Synthetic Chemical Industry Research Institute) and put them into a 500 - ml beaker, add 500 ml of acetone, take them out after ultrasonic treatment for 3 h, and repeatedly wash them in deionized water to obtain desized aramid fibers, denoted as RAF.

[0041] Step 2: Place 500 ml of deionized water in a beaker and weigh carboxymethyl cellulose (Aladdin, molecular weight is 250,000) at mass fractions of 0.25, 0.5, 0.75 and 1%, and stir for 30 minutes until the carboxymethyl cellulose (CMC) is completely dissolved in the deionized water. Weigh 20 g of de-sizing chopped fibers and dissolve them in the prepared CMC aqueous solution, stir for 3 minutes, filter out, place on a tray, and treat in an oven at 110°C for 3 hours to remove excess solvent to obtain carboxymethyl cellulose encapsulated modified aramid fibers, which are recorded as AF / 0.25CMC, AF / 0.5CMC, AF / 0.75CMC and AF / 1CMC, respectively.

[0042] Example 2 Preparation of carboxymethyl cellulose encapsulated modified aramid fiber reinforced polymer matrix composite material

[0043] 100g of ethylene propylene diene monomer rubber (EPDM) (Jilin Petrochemical Brand 4050) was put into an open mixing mill for mixing. After the rubber material was rolled, 5g of zinc oxide, 0.5g of stearic acid, 1.5g of DCP, 10g of SiO2, 20g of modified chopped aramid fiber and 0.5g of sulfur were added in sequence. After mixing evenly, the mixture was passed through the mill for 6 times. The roller spacing was adjusted to 0.4mm to obtain the mixed rubber. The mixture was placed for 8h and the vulcanization conditions were 160℃ for 30min and the pressure was 10MPa to obtain EPDM / AF / 0.25CMC, EPDM / AF / 0.5CMC, EPDM / AF / 0.75CMC and EPDM / AF / 1CMC respectively.

[0044] The comparative examples provide the control samples used in the experiments:

[0045] Comparative Example 1 Desizing of Aramid Fiber (RAF)

[0046] Prepare according to step 1 of Example 1 to obtain the compound.

[0047] Comparative Example 2 Aramid fiber reinforced polymer matrix composite material (EPDM / RAF) without carboxymethyl cellulose encapsulation

[0048] The method of Example 2 is used to prepare the rubber mixture, except that the prepared rubber mixture and the aramid fiber not encapsulated with carboxymethyl cellulose are vulcanized to obtain the obtained product.

[0049] The technical solution of the present invention is further illustrated by experiments below.

[0050] Experimental Example 1 Surface morphology analysis of carboxymethyl cellulose encapsulated modified aramid fiber

[0051] The AF / 0.25CMC, AF / 0.5CMC, AF / 0.75CMC, AF / 1CMC and RAF samples used in this experimental example were prepared according to the methods of Example 1 and Comparative Example 1.

[0052] I. Experimental method

[0053] Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to scan and observe the microstructure of aramid fibers before and after treatment with carboxymethyl cellulose solution, and to study the effect of different CMC concentrations on the surface microstructure of aramid fibers.

[0054] Scanning electron microscopy (SEM): The surface structure and morphology of aramid fibers were observed through a field emission scanning electron microscope (Apreo S, Thermo Scientific, USA). The working voltage was 15 kV.

[0055] Atomic force microscopy (AFM): An atomic force microscope (Smart SPM, AIST-NT, USA) was used to measure the surface topography of the fibers in the tapping mode, and the test size was 2 μm × 2 μm.

[0056] II. Experimental results

[0057] As Figure 1 (a, f) shows, the surface of the RAF fibers without treatment with CMC solution is very smooth, with only a small amount of attached particles and grooves. The attached particles are very likely the sizing agent or contaminants remaining on the fiber surface. CMC contains abundant hydroxyl groups, has strong hydrogen bonding and excellent film-forming properties, and will form a film adhering to the surface of aramid fibers after the solution volatilizes. As Figure 1 (b - e)(g - h) shows, after treatment with CMC solution, a gelatinous film appears on the surface of aramid fibers, and with the increase of CMC concentration, more and more thin films adhere to the surface, and a large number of wrinkles are formed. When the content reaches 0.75%, a large number of horizontal overlaps are formed between aramid fibers by the film formed by CMC, and it is difficult to separate spontaneously, showing strong bundling properties. A large number of wrinkles can increase the roughness of the fibers, increase the specific surface area of the fibers, improve the interfacial mechanical riveting effect between the fibers and the rubber, and thus improve the interfacial bonding performance of the composite material. The change in surface roughness can be more clearly observed in the AFM images of aramid fibers Figure 1 (i, j, k). An attached film was observed on the surface of AF / 0.25CMC, and with the increase of CMC concentration, the surface roughness increased significantly. A large number of protrusions and wrinkles appeared on the surface of AF / 0.75CMC. The results show that the surface roughness of aramid fibers encapsulated with carboxymethyl cellulose increases significantly, improving its interfacial bonding performance.

[0058] Experimental Example 2 Component Analysis of Aramid Fibers Encapsulated and Modified with Carboxymethyl Cellulose

[0059] The AF / 0.25CMC, AF / 0.5CMC, AF / 0.75CMC, AF / 1CMC, and RAF samples used in this experimental example were prepared according to the methods of Example 1 and Comparative Example 1.

[0060] I. Experimental Method

[0061] Thermogravimetry (TGA) and X-ray photoelectron spectroscopy (XPS) were used to verify the CMC content formed on the surface of aramid fibers.

[0062] TGA: The temperature range was 50 - 800 °C, the heating rate was 10 °C / min, and it was carried out under a nitrogen atmosphere.

[0063] XPS: The surface elements of RAF and aramid fibers encapsulated with carboxymethyl cellulose were qualitatively and quantitatively analyzed using an X-ray photoelectron spectrometer. The test used an AI Kα X-ray source with 1 keV, and the emission current was 0.6 μA.

[0064] II. Experimental Method

[0065] As Figure 2 (a) shows, from the thermogravimetric analysis curve (TGA) of RAF, it can be seen that the maximum weight loss reached 50% at 520 - 600 °C, mainly due to partial decarboxylation of aramid fibers and alkane decomposition. After treatment with CMC, different pyrolysis rules were shown. A slight thermal degradation occurred at 268 °C, which was attributed to the removal of a large number of hydroxyl groups in CMC. And with the increase in CMC concentration, the weight loss at this temperature was greater, and the curve shifted downward. After complete pyrolysis, the residual weight of RAF at 800 °C was 37.6%, while the residual weight increased to 41.3% with the increase in CMC concentration, which also indicated that the film formed on the fiber surface increased with the increase in CMC concentration. Further, the characteristic parameters obtained from TGA and XPS are shown in Table 1. From the analysis results of XPS ( Figure 2 b), the C element content remained at 76%, while the O content of AF / 1CMC increased to 17.05%, and the O / C ratio increased from 0.206 of RAF to 0.223, which further proved that a rich CMC coating was constructed on the surface of aramid fibers.

[0066] Table 1 Element Analysis and Residual Weight Changes

[0067]

[0068] Experimental Example 3 H Extraction Force and Tensile Strength of Aramid Fibers Encapsulated and Modified with Carboxymethyl Cellulose

[0069] The EPDM / AF / 0.25CMC, EPDM / AF / 0.5CMC, EPDM / AF / 0.75CMC, EPDM / AF / 1CMC, and EPDM / RAF samples used in this experimental example were prepared according to the methods of Example 2 and Comparative Example 2.

[0070] I. Experimental Methods

[0071] H Pull-out Experiment: Referring to GB / T 2942-2009, the prepared H extraction specimens of aramid fiber / rubber were tested for H extraction force on a universal tensile testing machine at a tensile rate of 100 mm / min. Each group had no less than 8 test specimens, and the results were averaged. The preparation method of the pull-out spline was as follows: The mixed rubber was cut into strips with a width of 11 mm and a length of 220 mm according to the H extraction mold. Referring to GB / T 2942-2009, the cut splines were placed in the mold cavity, and the aramid fiber encapsulated with carboxymethyl cellulose was placed between the mold grooves and buried between the upper and lower mold rubber strips. The vulcanization conditions were vulcanization at 160°C for 30 min to obtain the product.

[0072] Tensile Test: According to the standard GB / T 528–1998, the test was carried out on a mechanical testing machine at a rate of 200 mm / min. The preparation method of the tensile spline was as follows: The prepared mixed rubber was cut into thin sheets with a size of 20*10 cm, stacked in a mold with a thickness of 2 mm, and vulcanized at 160°C for 30 min to obtain a rubber composite material reinforced with short aramid fibers. Tensile splines were cut on a stamping machine according to the size of Type 3 of the rubber tensile test spline GB / T528–1998 standard.

[0073] Scanning Electron Microscope SEM: The surface structural morphology of the aramid fiber and the morphology after the composite material was damaged were observed through a field emission scanning electron microscope (Apreo S, Thermo Scientific, USA). The working voltage was 15 kV.

[0074] II. Experimental Results

[0075] The H extraction force and tensile strength of the rubber composite materials prepared from aramid fibers encapsulated with different concentrations of carboxymethyl cellulose are as Figure 3As shown in Table 2. It can be seen that the H extraction force and tensile strength of EPDM / RAF are 7.3 N and 7.86 MPa respectively. After being treated with CMC, both the H extraction force and tensile strength gradually increase with the increase of CMC concentration. The tensile strength reaches the maximum value of 10.27 MPa when the CMC content is 0.25%, while the H extraction force keeps increasing to 10.61 N. When the CMC content is 0.75%, the H extraction force is the largest, which is 26% higher than that of RAF, and the tensile strength is increased by 31%. This is because CMC also contains unsaturated active double bonds, which can participate in the vulcanization reaction of EPDM. At the same time, the abundant hydroxyl groups in CMC can form a large number of hydrogen bonds on the surface of aramid fibers, thus forming a bridging effect between EPDM and aramid fibers, improving the interfacial bonding between the two. In addition, a large number of wrinkles and protrusions formed by the CMC film itself also effectively improve the interfacial mechanical riveting effect between the fiber and the rubber, thus significantly improving the mechanical properties. It shows that coating the CMC coating on the surface of aramid fibers can effectively enhance the interfacial bonding and mechanical properties with EPDM rubber.

[0076] Table 2 Tensile strength and H pull-out force

[0077]

[0078] The cross-sectional morphology after stretching is as Figure 4 shown. A large number of holes are observed in the cross-section of EPDM / RAF, which are caused by fiber pull-out, and the diameter of the holes is small and comparable to the fiber size. It can also be observed from the magnified electron microscope that there is no residual rubber on the surface of RAF, indicating the poor interfacial bonding ability between the two. After being treated with CMC, the morphology has changed significantly. In EPDM / AF / 0.25CMC, a large number of fibers even remain in the matrix, and the fibers in the cross-section are even pulled apart and damaged to form a large number of single filaments. With the increase of concentration, a large amount of matrix remains on the surface of the fibers in EPDM / AF / 0.75CMC. It shows that the "bridging" and "mechanical riveting" effects formed by CMC between aramid fibers and EPDM improve the interfacial bonding between the two, so that more matrix is brought out during the stretching process, improving the mechanical properties of the composite material.

[0079] Experimental Example 4 Ablation performance analysis of rubber composites prepared from aramid fibers encapsulated and modified with carboxymethyl cellulose

[0080] The samples of EPDM / AF / 0.25CMC, EPDM / AF / 0.5CMC, EPDM / AF / 0.75CMC, EPDM / AF / 1CMC and EPDM / RAF used in this experimental example were prepared according to the methods of Example 2 and Comparative Example 2.

[0081] I. Experimental method

[0082] Using a plasma ablation machine with a heat flux of 1.5 MW / m 2 , an ablation time of 20 s, and a surface temperature of 2100 °C during testing, the rubber composites before and after the interfacial modification of aramid fibers were tested ( Figure 5 a). The preparation method of the ablation spline is as follows: The prepared mixed rubber is cut into thin slices with a diameter less than 35 mm and stacked in a mold with a diameter of 35 mm and a thickness of 10 mm, and vulcanized at 160 °C for 30 min to obtain a short aramid fiber-reinforced rubber composite material.

[0083] II. Experimental Results

[0084] From the ablation rate ( Figure 5 b) and Table 3, combined with Figure 5 (c - e), it can be seen that the Rl and Rm of EPDM / RAF are 0.1336 g / s and 0.0956 mm / s respectively. After treating aramid fibers with CMC, both the mass ablation rate and the linear ablation rate are significantly improved, indicating that the improvement of the interfacial bonding between aramid fibers and EPDM is beneficial to the improvement of ablation performance. Among them, the ablation rate of EPDM / AF / 0.5CMC is reduced to the lowest 0.0976 g / s and 0.0820 mm / s. The mass ablation rate and the linear ablation rate are reduced by 27% and 14% respectively compared with EPDM / RAF. It shows that the rubber composite material prepared from aramid fibers encapsulated with carboxymethyl cellulose helps the bonding of the carbon layer between the matrix and the fibers through the improvement of interfacial bonding, thereby improving the heat insulation effect of the carbon layer. In addition, the increase in interfacial bonding improves the ablation performance of the composite material by slowing down the damage of the matrix caused by the scouring effect of the gas flow.

[0085] Table 3 Variation of ablation rate with CMC concentration

[0086]

[0087]

[0088] The morphology of the carbon layer formed after ablation is as shown in Figure 6 . The upper part is the ablation surface. It can be seen that for EPDM / RAF, the contour of the fibers in the formed carbon layer is clearly visible, and serious delamination occurs between the ablation surface and the inside of the carbon layer, and the fiber's solidifying effect on the carbon layer is not effectively exerted. On the contrary, in the composite system with good interfacial bonding, no fiber detachment from the carbon layer is found, and the aramid fibers have formed an integral carbon layer structure with the cracked carbon of EPDM, which helps to improve the erosion resistance of the carbon layer, thereby blocking the transfer of heat flux along the inside, and further effectively improving the ablation resistance performance of the composite material.

[0089] In summary, for the aramid fiber encapsulated and modified with carboxymethyl cellulose prepared by the present invention, the surface roughness is significantly increased and the interfacial bonding performance is significantly improved; the prepared aramid fiber reinforced polymer matrix composite material can effectively enhance the interfacial bonding ability and mechanical properties between the aramid fiber and ethylene propylene diene monomer rubber, and has good ablation resistance and erosion resistance, and can be used for preparing ablation-resistant materials, having very good application prospects.

Claims

1. A surface-modified aramid fiber-reinforced polymer matrix composite material, characterized in that, It is composed of surface-modified aramid fibers and a polymer matrix; the weight ratio of the surface-modified aramid fibers to the polymer matrix is (1-20):100; the surface-modified aramid fibers are prepared by dispersing aramid fibers in an aqueous carboxymethyl cellulose solution so that carboxymethyl cellulose covers the aramid fibers; in the aqueous carboxymethyl cellulose solution, the feeding mass ratio of carboxymethyl cellulose to aramid fibers is 1-10:

20.

2. The surface-modified aramid fiber-reinforced polymer matrix composite material according to claim 1, wherein The polymer matrix is made from raw materials including the following parts by weight: 80-150 parts of polyolefin rubber, 0.1-20 parts of activator, 0.1-20 parts of softener, 0.1-20 parts of vulcanizing agent, 0.1-20 parts of reinforcing agent.

3. The surface-modified aramid fiber reinforced polymer matrix composite material according to claim 2, characterized in that, The polyolefin rubber is selected from at least one of ethylene propylene diene monomer rubber, polyethylene rubber, and polybutene rubber; and / or, the activator is selected from at least one of zinc oxide, magnesium oxide, and lead oxide; and / or, the softener is selected from at least one of phthalate, phosphate ester, and stearic acid; and / or, the vulcanizing agent is selected from at least one of benzophenone peroxide, dicumyl peroxide, and sulfur; and / or, the reinforcing agent is selected from silica.

4. The surface-modified aramid fiber-reinforced polymer matrix composite material according to claim 1, characterized in that: The mass fraction of the aqueous carboxymethyl cellulose solution is 0.25-2%.

5. The surface-modified aramid fiber reinforced polymer matrix composite material according to claim 1, wherein The preparation method of the surface-modified aramid fibers includes the following steps: impregnating the unsized aramid fibers or the desized aramid fibers in the aqueous carboxymethyl cellulose solution, stirring, filtering, and drying to obtain the surface-modified aramid fibers.

6. The surface-modified aramid fiber-reinforced polymer matrix composite material according to claim 5, wherein, The desizing treatment step includes: impregnating the aramid fibers in a volatile organic solvent and subjecting them to ultrasonic treatment to obtain the desized aramid fibers.

7. The preparation method of the surface-modified aramid fiber reinforced polymer matrix composite material according to any one of claims 1-6, characterized in that, It includes the following steps: a. Reacting the polyolefin rubber with the activator, softener, vulcanizing agent, reinforcing agent, and surface-modified aramid fibers, adjusting the roll gap, and passing through thinly to obtain a mixed rubber; b. The mixed rubber is obtained after vulcanization.

8. Use of the surface-modified aramid fiber-reinforced polymer matrix composite material according to any one of claims 1-6 for the preparation and / or as an ablation-resistant material.

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