Glass fiber reinforced epoxy resin composite material and preparation method thereof

Abstract

The invention discloses a glass fiber reinforced epoxy resin composite material and a preparation method thereof, and relates to the technical field of composite materials, and the preparation method comprises the following steps: carrying out organic solvent immersion treatment, cleaning and drying on glass fibers to obtain pretreated glass fibers; respectively carrying out phytic acid modification treatment on the pretreated glass fibers and hollow alumina microspheres; performing plasma surface treatment on the glass fibers and the hollow aluminum oxide microspheres subjected to the phytic acid modification treatment; mixing and dispersing epoxy resin, a curing agent, the glass fibers subjected to plasma surface treatment and the hollow aluminum oxide microspheres according to a preset mass ratio; carrying out vacuum degassing on the mixture; and injecting the degassed mixture into a mold for step-by-step curing. The preparation method has the beneficial effects that active groups are introduced to the surfaces of the glass fibers through phytic acid treatment, the number of the active groups is further increased by combining plasma surface treatment, and the interface bonding capacity of the glass fibers and an epoxy resin matrix is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a glass fiber reinforced epoxy resin composite material and a preparation method thereof. Background Art

[0002] As an important type of engineering material, polymer composites are widely used in aerospace, automobile, power electronics and other fields. Epoxy resin has attracted much attention due to its excellent mechanical properties, bonding properties, chemical stability, electrical insulation and molding processability. In the fiber-reinforced resin molding process, filament winding, compression molding, hand lay-up, pultrusion, resin transfer molding (RTM) and other technologies have become mature. However, the inherent defects of epoxy resin after curing, such as poor toughness, low impact strength, and poor flame retardancy, restrict its application in high-end fields. Especially in terms of the interface performance of composite materials, due to the smooth surface of glass fiber and the lack of active groups, the interface bonding between it and epoxy resin is weak, making it difficult to give full play to the reinforcing and toughening effect of glass fiber.

[0003] In the prior art, the surface modification of materials mainly includes two categories: physical modification and chemical modification. Although chemical modification methods such as chemical etching and chemical surface grafting can significantly improve the surface roughness and interface shear strength, they are prone to surface corrosion and defects, and require a large amount of chemical reagents, and are less environmentally friendly. Although physical modification methods such as surface coating, plasma modification, high-energy radiation, ultrasonic impregnation and other processes can improve the interface performance to a certain extent, the process parameters such as gas type, processing time, and discharge power have a significant impact on the mechanical and electrical properties of the composite material. In addition, the traditional flame retardants synthesized by chemical synthesis are generally used in the prior art, and their manufacturing and use processes have negative impacts on the environment. Summary of the invention

[0004] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0005] Therefore, an object of the present invention is to provide a glass fiber reinforced epoxy resin composite material and a preparation method thereof, which can solve the problems mentioned in the background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a glass fiber reinforced epoxy resin composite material and a preparation method thereof, which comprises subjecting the glass fiber to an organic solvent impregnation treatment, washing and drying to obtain pretreated glass fiber;

[0007] The pretreated glass fibers and hollow alumina microspheres are respectively subjected to phytic acid modification treatment;

[0008] performing plasma surface treatment on the glass fiber and hollow alumina microspheres after the phytic acid modification treatment;

[0009] Mixing and dispersing the epoxy resin, the curing agent, the glass fiber surface-treated by the plasma, and the hollow alumina microspheres according to a preset mass ratio;

[0010] Degassing the mixture under vacuum;

[0011] The degassed mixture is injected into a mold for step-curing.

[0012] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the organic solvent impregnation treatment comprises: impregnating the glass fiber in acetone;

[0013] The cleaning comprises: using deionized water to clean the impregnated glass fiber;

[0014] The drying includes: drying the cleaned glass fibers at a preset temperature.

[0015] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the phytic acid modification treatment comprises: placing the pretreated glass fiber and the hollow alumina microspheres in a phytic acid solution with a mass fraction of w1 respectively; soaking for t1h at a temperature of T1°C; wherein:

[0016] 30≤w1≤50;

[0017] 25≤T1≤50;

[0018] 3≤t1≤12.

[0019] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the parameters of the plasma surface treatment meet the following requirements: gas pressure is P1Pa; high voltage output voltage is V1kV; frequency is f1kHz; discharge power is W1W; treatment time is t2s; wherein:

[0020] 0≤P1≤100;

[0021] 3≤V1≤7;

[0022] 50±1=f1;

[0023] 0≤W1≤100;

[0024] 600≤t2≤900.

[0025] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the preset mass ratio satisfies: the mass fraction of epoxy resin in the matrix material is 100, the mass fraction of the curing agent is w2, the mass fraction of the hollow alumina microspheres is w3, and the mass fraction of the glass fiber is w4; wherein:

[0026] 15≤w2≤35;

[0027] 0.2≤w3≤10;

[0028] 20≤w4≤50.

[0029] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and its preparation method of the present invention, the particle size range of the hollow alumina microspheres is d1-d2 mm; the true density is ρ1-ρ2 g / cm 3 ;in:

[0030] 0.4≤d1≤d2≤1.2;

[0031] 0.38≤ρ1≤ρ2≤0.42.

[0032] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the vacuum degassing comprises: performing vacuum degassing treatment at a pressure of P2kPa and a temperature of T2°C; the degassing time is t3min; wherein:

[0033] 1.5≤P2≤2.5;

[0034] 30≤T2≤50;

[0035] 30≤t3≤60.

[0036] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the step-by-step curing comprises: first curing: applying pressure P3MPa at temperature T3 for curing time t4h; second curing: curing at temperature T4 for curing time t5h; wherein:

[0037] 60 = T3;

[0038] 0.3≤P3≤1;

[0039] 1≤t4≤2;

[0040] 140≤T4≤170;

[0041] 2≤t5≤4.

[0042] As a preferred embodiment of the glass fiber reinforced epoxy resin composite material and the preparation method thereof of the present invention, the epoxy resin is E44 epoxy resin; and the curing agent is an amine curing agent modified by aliphatic amine.

[0043] The beneficial effects of the present invention are as follows: the present invention introduces active groups on the surface of glass fiber through phytic acid treatment, and further increases the number of active groups in combination with plasma surface treatment, thereby significantly improving the interfacial bonding ability between glass fiber and epoxy resin matrix, and the presence of phytic acid effectively weakens the etching damage to the surface of glass fiber caused by plasma treatment, thereby avoiding the degradation of mechanical properties due to surface defects; secondly, the introduced hollow alumina microspheres form a good interfacial bonding with the matrix material after phytic acid treatment, which not only achieves the lightweight of the material, but also improves the structural stability and insulation performance of the material; thirdly, the coke layer formed by phytic acid on the surface of the material and the alumina smoke generated by the high-temperature decomposition of alumina form a dual protective effect, and the synergistic effect of blocking oxygen and combustible gases significantly improves the flame retardant properties of the composite material; finally, the preparation process of the present invention does not require a complicated chemical treatment process, thereby avoiding the use of a large amount of chemical reagents in traditional chemical modification methods, and has the characteristics of being environmentally friendly and easy to operate, and is more suitable for industrial production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 The present invention is a process flow chart of the modified glass fiber reinforced epoxy resin composite material.

[0046] Figure 2 This is a SEM image of the modified glass fiber reinforced epoxy resin composite material of the present invention.

[0047] Figure 3 This is a SEM image of the modified glass fiber reinforced epoxy resin composite material of the present invention.

[0048] Figure 4 This is a SEM image of the modified glass fiber reinforced epoxy resin composite material of the present invention.

[0049] Figure 5 This is a SEM image of the modified glass fiber reinforced epoxy resin composite material of the present invention.

[0050] Figure 6 This is a SEM image of the modified glass fiber reinforced epoxy resin composite material of the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0052] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0053] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0054] Example 1

[0055] Reference Figure 1 , which is the first embodiment of the present invention, provides a glass fiber reinforced epoxy resin composite material and a preparation method thereof, and the specific steps are as follows:

[0056] 1. Raw material selection and pretreatment:

[0057] The short glass fiber with a length of 3 mm was impregnated with acetone for 24 hours. After the impregnation, it was taken out and washed with deionized water, and then placed in a vacuum drying oven and dried at a temperature of 60°C for 12 hours for use. The average diameter of the glass fiber used was in the range of d1=2.0μm to d2=8.0μm, and had a substantially circular cross-section.

[0058] 2. Phytic acid modification treatment:

[0059] Prepare a phytic acid solution with a mass fraction of 50%. Mix the pretreated glass fiber and the 3 The hollow alumina microspheres were placed in phytic acid solution and soaked at 40°C for 8 hours. After soaking, they were taken out and dried for later use.

[0060] 3. Plasma surface treatment:

[0061] The phytic acid-modified glass fibers and hollow alumina microspheres were fixed on the clean and flat surface of the glass substrate. The surface modification treatment was carried out in an air environment using a plasma brush as a high-voltage electrode. The treatment parameters were:

[0062] (1) High voltage output voltage: 7kV;

[0063] (2) Frequency: 50kHz;

[0064] (3) Discharge power: 80W;

[0065] (4) Plasma brush moving speed: 1 mm / s;

[0066] (5) Processing time: 900s;

[0067] 4.Material ratio and mixing:

[0068] Prepare the ingredients according to the following mass ratio:

[0069] (1) Epoxy resin (E44): 100 parts;

[0070] (2) Curing agent (593): 20 parts;

[0071] (3) Hollow alumina microspheres: 6 parts;

[0072] (4) Glass fiber: 30 parts;

[0073] The above components were placed in a shear disperser for mixing, the stirring speed was set to 1500 rpm, the stirring time was 10 min, and a uniform mixing system was obtained.

[0074] 5. Vacuum degassing:

[0075] Place the mixed system in a vacuum degassing oven for degassing:

[0076] (1) Negative pressure: 2.5 kPa;

[0077] (2) Temperature: 30°C;

[0078] (3) Degassing time: 40 min;

[0079] 6. Curing and molding:

[0080] The degassed mixture is injected into a stainless steel mold that has been cleaned with alcohol and coated with a thermosetting epoxy resin high temperature resistant release agent. The curing process is divided into two steps:

[0081] First curing: curing at 60℃ with 1MPa pressure for 2h;

[0082] Second curing: raise the temperature to 170°C and maintain for 4 hours.

[0083] The composite material prepared by the above process has a microscopic morphology such as Figure 2As shown in the SEM image, it can be observed that the surface of the glass fiber treated with phytic acid and plasma is moderately rough, and the interface with the epoxy resin matrix is ​​tightly bonded, without obvious interface detachment. The hollow alumina microspheres are evenly distributed and well bonded with the matrix material interface, forming a stable composite structure.

[0084] The process parameters in this embodiment are properly coordinated, which not only ensures a sufficient number of interfacial active groups, but also avoids surface damage caused by excessive treatment. The synergistic effect of phytic acid pretreatment and plasma treatment significantly improves the interfacial bonding strength; at the same time, the introduction of hollow alumina microspheres achieves a lightweight design of the material and forms a synergistic flame retardant effect with phytic acid.

[0085] Example 2

[0086] This embodiment provides a method for preparing a glass fiber reinforced epoxy resin composite material, which is basically the same as the process route of Example 1, and mainly adjusts the following process parameters:

[0087] 1. Phytic acid modification treatment:

[0088] Prepare a phytic acid solution with a mass fraction of 40%. Pre-treated glass fiber and a particle size of 35-45 μm and a true density of 0.38-0.42 g / cm 3 The hollow alumina microspheres were placed in phytic acid solution and soaked at 40°C for 6 hours. After soaking, they were taken out and dried for later use.

[0089] 2. Plasma surface treatment:

[0090] The processing parameters are adjusted as follows:

[0091] (1) High voltage output voltage: 7kV;

[0092] (2) Frequency: 50kHz;

[0093] (3) Discharge power: 80W;

[0094] (4) Plasma brush moving speed: 1 mm / s;

[0095] (5) Processing time: 720 seconds.

[0096] 3.Material ratio and mixing:

[0097] Adjust the ratio to:

[0098] (1) Epoxy resin (E44): 100 parts;

[0099] (2) Curing agent (593): 20 parts;

[0100] (3) Hollow alumina microspheres: 4 parts;

[0101] (4) Glass fiber: 30 parts.

[0102] The mixing process parameters are adjusted to:

[0103] (1) Stirring speed: 1000 rpm;

[0104] (2) Stirring time: 8 minutes.

[0105] 4. Vacuum degassing:

[0106] The degassing parameters were adjusted to:

[0107] (1) Negative pressure: 2.0 kPa;

[0108] (2) Temperature: 30°C;

[0109] (3) Degassing time: 40 minutes.

[0110] 5. Curing and molding:

[0111] The curing process parameters are adjusted to:

[0112] First curing: Apply 0.8MPa pressure at 60℃ for 1h;

[0113] Second curing: raise the temperature to 160°C and maintain for 2 hours.

[0114] The composite material prepared by the above process has a microscopic morphology such as Figure 3 Compared with Example 1, this example forms a more uniform phytic acid modified layer on the glass fiber surface by adjusting the concentration of the phytic acid solution and the treatment time. It can be observed from the scanning electron microscope that the shorter plasma treatment time reduces the etching effect on the fiber surface, the fiber surface roughness is moderate, and the interface bonding with the matrix material is still good.

[0115] The amount of hollow alumina microspheres used is reduced, but the distribution is still uniform, and the interface with the matrix material is well bonded. The reduction in stirring speed and the shortening of time effectively avoid the damage to the glass fiber caused by high-speed shearing and maintain the integrity of the fiber. The lower curing pressure and shorter curing time reduce the generation of internal stress while ensuring that the material is fully cured.

[0116] This embodiment reduces energy consumption and improves production efficiency by optimizing process parameters while ensuring material performance, making it more suitable for industrial production. At the same time, the reduction in the amount of hollow alumina microspheres also helps to further reduce material costs.

[0117] Example 3

[0118] This embodiment provides a method for preparing a glass fiber reinforced epoxy resin composite material, which is basically the same as the process route of Example 1, and mainly adjusts the following process parameters and ratios:

[0119] 1. Phytic acid modification treatment:

[0120] Prepare a phytic acid solution with a mass fraction of 30%. Mix the pretreated glass fiber and the 3 The hollow alumina microspheres were placed in a phytic acid solution and soaked for 4 hours at a temperature of 30°C. After soaking, they were taken out and dried for later use. This example reduces the concentration of the phytic acid solution and the treatment temperature, and shortens the soaking time to explore the modification effect under the minimum treatment conditions.

[0121] 2. Plasma surface treatment:

[0122] The processing parameters are adjusted as follows:

[0123] (1) High voltage output voltage: 7kV;

[0124] (2) Frequency: 50kHz;

[0125] (3) Discharge power: 80W;

[0126] (4) Plasma brush moving speed: 1 mm / s;

[0127] (5) Processing time: 600s.

[0128] This embodiment further shortens the plasma treatment time to reduce the risk of excessive surface modification.

[0129] 3.Material ratio and mixing:

[0130] Adjust the ratio to:

[0131] (1) Epoxy resin (E44): 100 parts;

[0132] (2) Curing agent (593): 20 parts;

[0133] (3) Hollow alumina microspheres: 2 parts;

[0134] (4) Glass fiber: 30 parts.

[0135] The mixing process parameters are adjusted to:

[0136] (1) Stirring speed: 800 rpm;

[0137] (2) Stirring time: 5 min.

[0138] This embodiment significantly reduces the amount of hollow alumina microspheres added and adopts milder mixing conditions.

[0139] 4. Vacuum degassing:

[0140] The degassing parameters were adjusted to:

[0141] (1) Negative pressure: 1.5 kPa;

[0142] (2) Temperature: 30°C;

[0143] (3) Degassing time: 40 minutes.

[0144] 5. Curing and molding:

[0145] The curing process parameters are adjusted to:

[0146] First curing: Apply 0.8MPa pressure at 60℃ for 1h;

[0147] Second curing: raise the temperature to 150°C and maintain for 2 hours.

[0148] The composite material prepared by the above process has a microscopic morphology such as Figure 4 As shown in the SEM images, it can be observed that despite the use of a lower concentration of phytic acid solution and a shorter treatment time, a continuous modified layer is still formed on the glass fiber surface. The shorter plasma treatment time makes the fiber surface moderately rough and the fiber integrity is good.

[0149] Although the amount of hollow alumina microspheres added is reduced to a minimum, uniform dispersion can still be achieved at a lower stirring speed. The lower curing temperature and pressure effectively reduce the generation of thermal stress, and the internal structure of the material is uniform without obvious defects.

[0150] This example further reduces energy consumption and costs by exploring the lowest process parameter conditions while ensuring the basic performance of the material. The experimental results show that even under relatively mild treatment conditions, the synergistic effect of phytic acid modification and plasma treatment can still effectively improve the interface bonding performance, and a small amount of hollow alumina microspheres still has a significant functional effect.

[0151] Comparative Example 1

[0152] A method for preparing a glass fiber reinforced epoxy resin composite material, wherein the specific process is the same as that of Example 2, except that no plasma surface treatment is performed.

[0153] After the phytic acid modification treatment is completed, the material proportioning and mixing steps are directly performed. Other process parameters are consistent with those in Example 2.

[0154] The composite material prepared by the above process has a microscopic morphology such as Figure 5 As shown. It can be observed from the scanning electron microscope image that the glass fiber surface is only modified by phytic acid, and the number of surface active groups is limited, resulting in the fiber and the epoxy resin matrix The interface bonding is not tight enough. Local interface detachment can be found in multiple observation areas, and micro cracks and interface gaps appear in some areas. The surface of the glass fiber is relatively smooth and lacks sufficient mechanical interlocking structure, which significantly reduces the interfacial bonding strength of the composite material. Although the hollow alumina microspheres still maintain good dispersibility in the matrix, their bonding strength with the matrix is ​​significantly lower than that of Example 2, which may lead to problems such as stress concentration and micro-stratification in practical applications.

[0155] By comparison with Example 2, it can be found that the lack of plasma treatment process will cause the interface bonding performance of the composite material to decrease significantly. Phytic acid modification alone cannot provide enough surface active groups, and the mechanical interlocking effect is weakened, which in turn affects the stress transfer efficiency, and ultimately leads to a decrease in the overall mechanical properties of the material. This comparison result fully demonstrates the important role of plasma treatment in improving the interface bonding performance, and its synergistic effect with phytic acid modification has an irreplaceable effect on improving the performance of the composite material.

[0156] Comparative Example 2

[0157] A method for preparing a glass fiber reinforced epoxy resin composite material, wherein the specific process is the same as that of Example 2, except that the plasma treatment time is shortened to 300 seconds. Other process parameters are the same as those of Example 2.

[0158] The composite material prepared by the above process has a microscopic morphology such as Figure 6 As shown. It can be observed from the scanning electron microscope that after the shortened plasma treatment, only a slight rough morphology appears on the surface of the glass fiber, and the introduction of the surface active groups is insufficient. Although the phytic acid modification provides preliminary interfacial activity, the ideal mechanical interlocking structure cannot be formed due to the insufficient plasma treatment time, resulting in the interfacial bonding strength between the fiber and the epoxy resin matrix being lower than that in Example 2. The bonding condition between the hollow alumina microspheres and the matrix material is also affected accordingly, and the interface bonding is not dense enough.

[0159] Compared with Example 2, the shorter plasma treatment time improved the interface performance to a certain extent, but the effect was obviously insufficient, indicating that the plasma treatment needs to reach a sufficient time threshold to achieve the best modification effect. This result shows that the plasma treatment time is one of the key parameters affecting the interface performance of composite materials.

[0160] Comparative Example 3

[0161] A method for preparing a glass fiber reinforced epoxy resin composite material, the specific process is the same as that of Example 3, the only difference is that the hollow alumina microspheres are not added, and the other process parameters are consistent with those of Example 3. The specific ratio is:

[0162] (1) Epoxy resin (E44): 100 parts;

[0163] (2) Curing agent (593): 20 parts;

[0164] (3) Glass fiber: 30 parts.

[0165] Table 1 Composite material performance test results

[0166] Performance Indicators Test Method unit Example 3 Comparative Example 3 Flame retardant grade Flame retardant properties none V-0 V-1 Limiting oxygen index Limiting oxygen index 29.5 26.5 Tensile Strength GB / T1040.2-2006 MPa 179.5 153.1

[0167] By comparing the performance test data, it can be seen that without adding hollow alumina microspheres, the flame retardant grade of the material is reduced from V-0 to V-1, the limiting oxygen index is reduced from 29.5 to 26.5, and the tensile strength is reduced from 179.5MPa to 153.1MPa. These data show that the addition of hollow alumina microspheres significantly improves the flame retardant properties of the composite material and also enhances the mechanical properties of the material.

[0168] Comparative Example 4

[0169] A method for preparing a glass fiber reinforced epoxy resin composite material, wherein the specific process is the same as that of Example 3, except that the glass fiber and the hollow alumina microspheres are not immersed in a phytic acid solution, and the other process parameters are consistent with those of Example 3.

[0170] Table 2 Composite material performance test results

[0171] Performance Indicators Test Method unit Example 3 Comparative Example 4 Flame retardant grade Flame retardant properties none V-0 V-1 Limiting oxygen index Limiting oxygen index 29.5 25.3 Tensile Strength GB / T1040.2-2006 MPa 179.5 162.8

[0172] By comparing the performance test data, it can be seen that without phytic acid modification, the flame retardant grade of the material is reduced from V-0 to V-1, the limiting oxygen index is reduced from 29.5 to 25.3, and the tensile strength is reduced from 179.5MPa to 162.8MPa. These data show that phytic acid modification not only improves the flame retardant properties of the material, but also improves the mechanical properties of the material by improving the interface bonding state.

[0173] Comparative Example 5

[0174] A method for preparing a glass fiber reinforced epoxy resin composite material, wherein the specific process is the same as that of Example 3, except that the plasma treatment process is not performed, and other process parameters are consistent with those of Example 3.

[0175] Table 3 Composite material performance test results

[0176] Performance Indicators Test Method unit Example 3 Comparative Example 5 Flame retardant grade Flame retardant properties none V-0 V-0 Limiting oxygen index Limiting oxygen index 29.5 28.8 Tensile Strength GB / T1040.2-2006 MPa 179.5 150.4

[0177] Through the comparison of performance test data, it can be seen that without plasma treatment, although the material maintains the flame retardant grade of V-0, the limiting oxygen index slightly decreases from 29.5 to 28.8, and the tensile strength significantly decreases from 179.5MPa to 150.4MPa. These data show that plasma treatment has little effect on the flame retardant properties of the material, but plays an important role in improving the mechanical properties of the material.

[0178] Comparative Example 6

[0179] A method for preparing a glass fiber reinforced epoxy resin composite material, the specific process is the same as that of Example 3, except that the glass fiber is not soaked in a phytic acid solution and hollow alumina microspheres are not added, and other process parameters are consistent with those of Example 3. The specific ratio is:

[0180] (1) Epoxy resin (E44): 100 parts;

[0181] (2) Curing agent (593): 20 parts;

[0182] (3) Glass fiber: 30 parts.

[0183] Table 4 Composite material performance test results

[0184] Performance Indicators Test Method unit Example 3 Comparative Example 6 Flame retardant grade Flame retardant properties none V-0 NR Limiting oxygen index Limiting oxygen index 29.5 22.1 Tensile Strength GB / T1040.2-2006 MPa 179.5 129.1

[0185] By comparing the performance test data, it can be seen that without phytic acid modification and without adding hollow alumina microspheres, the flame retardant grade of the material is reduced from V-0 to NR, the limiting oxygen index is significantly reduced from 29.5 to 22.1, and the tensile strength is greatly reduced from 179.5MPa to 129.1MPa. These data show that the synergistic effect of phytic acid modification and hollow alumina microspheres has a significant effect on improving the flame retardant and mechanical properties of the material.

[0186] Example 4

[0187] This example is a detailed analysis and description of the performance test of the composite materials prepared in Examples 1-3 and Comparative Examples 1-6.

[0188] Table 5 Composite material performance test results

[0189]

[0190] From the comparison of the performance data of Examples 1-3, it can be seen that as the plasma treatment time increases from 600s to 1200s, the limiting oxygen index of the composite material gradually increases from 28.9 to 29.5, and the tensile strength increases from 165.3MPa to 179.5MPa; Comparative Example 1 does not perform plasma treatment at all, resulting in the flame retardant grade being reduced to V-1, the limiting oxygen index being reduced to 24.8, and the tensile strength being reduced to 135.6MPa; Comparative Example 2 only uses a treatment time of 300s, with a flame retardant grade of V-1, a limiting oxygen index of 25.6, and a tensile strength of 145.2MPa, indicating that insufficient treatment time will limit the performance improvement effect.

[0191] Comparative Example 4 shows that the cancellation of phytic acid modification will cause the flame retardant grade to drop from V-0 to V-1, the limiting oxygen index to drop to 25.3, and the tensile strength to drop to 162.8MPa; the data of Comparative Example 6 show that when both phytic acid modification and hollow alumina microspheres are lacking, the material properties deteriorate significantly, the flame retardant grade drops to NR, the limiting oxygen index drops to 22.1, and the tensile strength drops to 129.1MPa.

[0192] In Comparative Example 3, no hollow alumina microspheres were added, resulting in the flame retardancy grade being reduced to V-1, the limiting oxygen index being reduced to 26.5, and the tensile strength being reduced to 153.1 MPa; the performance data of Example 3 verified the important role of the addition of hollow alumina microspheres in improving the flame retardancy and mechanical properties of the material.

[0193] Example 3 uses a plasma treatment time of 1200 s, combined with phytic acid modification and the addition of hollow alumina microspheres, to obtain the optimal performance combination: the flame retardant grade reaches V-0, the limiting oxygen index reaches 29.5, and the tensile strength reaches 179.5 MPa.

[0194] These test results show that the synergistic effect of the three modification methods, namely, plasma treatment to optimize surface conditions, phytic acid modification to strengthen interface bonding, and hollow alumina microspheres to provide reinforcement and flame retardant effects, significantly improved the comprehensive performance of the composite material. Among them, the optimization of plasma treatment time, the interface reinforcement effect of phytic acid modification, and the addition ratio of hollow alumina microspheres are all key factors affecting the final performance.

[0195] In summary, the present invention introduces active groups on the surface of glass fiber through phytic acid treatment, and further increases the number of active groups in combination with plasma surface treatment, thereby significantly improving the interfacial bonding ability between glass fiber and epoxy resin matrix, and the presence of phytic acid effectively weakens the etching damage to the glass fiber surface caused by plasma treatment, thereby avoiding the degradation of mechanical properties due to surface defects; secondly, the introduced hollow alumina microspheres form a good interfacial bonding with the matrix material after phytic acid treatment, which not only achieves the lightweight of the material, but also improves the structural stability and insulation performance of the material; thirdly, the coke layer formed by phytic acid on the surface of the material and the alumina smoke generated by the high-temperature decomposition of alumina form a dual protective effect, which significantly improves the flame retardant properties of the composite material by the synergistic effect of blocking oxygen and combustible gases; finally, the preparation process of the present invention does not require a complicated chemical treatment process, thereby avoiding the use of a large amount of chemical reagents in traditional chemical modification methods, and is environmentally friendly and easy to operate, and is more suitable for industrial production applications.

[0196] It is important to note that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A glass fiber reinforced epoxy resin composite material and a preparation method thereof, characterized in that: include, The glass fiber is impregnated with an organic solvent, cleaned and dried to obtain pretreated glass fiber; The pretreated glass fibers and hollow alumina microspheres are respectively subjected to phytic acid modification treatment; performing plasma surface treatment on the glass fiber and hollow alumina microspheres after the phytic acid modification treatment; Mixing and dispersing the epoxy resin, the curing agent, the glass fiber surface-treated by the plasma, and the hollow alumina microspheres according to a preset mass ratio; Degassing the mixture under vacuum; The degassed mixture is injected into a mold for step-curing.

2. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 1, characterized in that: The organic solvent impregnation treatment comprises: impregnating the glass fiber in acetone; The cleaning comprises: using deionized water to clean the impregnated glass fiber; The drying includes: drying the cleaned glass fibers at a preset temperature.

3. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 1, characterized in that: The phytic acid modification treatment comprises: placing the pretreated glass fiber and hollow alumina microspheres in a phytic acid solution with a mass fraction of w1 respectively; soaking for t1h at a temperature of T1°C; wherein: 30≤w1≤50； 25≤T1≤50； 3≤t1≤12。 4. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 3, characterized in that: The parameters of the plasma surface treatment are as follows: gas pressure is P1Pa; high voltage output voltage is V1kV; frequency is f1kHz; discharge power is W1W; treatment time is t2s; wherein: 0≤P1≤100； 3≤V1≤7； 50±1＝f1； 0≤W1≤100； 600≤t2≤900。 5. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 1, characterized in that: The preset mass ratio satisfies: the mass fraction of epoxy resin in the matrix material is 100, the mass fraction of curing agent is w2, the mass fraction of hollow alumina microspheres is w3, and the mass fraction of glass fiber is w4; wherein: 15≤w2≤35； 0.2≤w3≤10； 20≤w4≤50。 6. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 1, characterized in that: The particle size range of the hollow alumina microspheres is d1-d2 mm; the true density is ρ1-ρ2 g / cm 3 ;in: 0.4≤d1≤d2≤1.2; 0.38≤ρ1≤ρ2≤0.

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7. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 6, characterized in that: The vacuum degassing comprises: performing vacuum degassing treatment at a pressure of P2kPa and a temperature of T2°C; the degassing time is t3min; wherein: 1.5≤P2≤2.5； 30≤T2≤50； 30≤t3≤60。 8. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 7, characterized in that: The step-by-step curing includes: first curing: applying pressure P3MPa at temperature T3°C for curing time t4h; second curing: curing at temperature T4°C for curing time t5h; wherein: 60＝T3； 0.3≤P3≤1； 1≤t4≤2； 140≤T4≤170； 2≤t5≤4。 9. The glass fiber reinforced epoxy resin composite material and the preparation method thereof according to claim 5, characterized in that: The epoxy resin is E44 epoxy resin; the curing agent is an amine curing agent modified by aliphatic amine.

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