High-modulus and high-toughness carbon fiber vacuum infusion epoxy resin and preparation method thereof

Abstract

The invention discloses high-modulus and high-toughness carbon fiber vacuum infusion epoxy resin and a preparation method thereof, and belongs to the field of high-molecular compound compositions. Raw materials of the carbon fiber vacuum infusion epoxy resin comprise a resin component, a curing agent component and a pre-impregnated carbon fiber felt, the resin component comprises bisphenol A epoxy resin, alkali metal silicate mixture modified silicon dioxide, a defoaming agent and a dispersing agent, and the curing agent component comprises a curing agent and a curing accelerator. The carbon fiber vacuum infusion epoxy resin is good in dielectric property and high in breakdown voltage, the breakdown voltage of the carbon fiber vacuum infusion epoxy resin is tested according to the method in GB / T1408.1-2016, and the breakdown voltage ranges from 31.2 kV to 32.2 kV.

Description

Technical Field

[0001] The present invention relates to a high-modulus and high-toughness carbon fiber vacuum-infused epoxy resin and a preparation method thereof, belonging to the field of polymer compound compositions. Background Art

[0002] The Vacuum Infusion Molding Process (VIMP) is a new composite material molding process, which is mainly applicable to composite material products with high molding quality requirements, small batches, and large sizes, such as wind turbine blades, ship hulls, etc. Compared with the early hand lay-up molding process, spray molding process, compression molding process, and transfer molding process, VIMP has greatly improved in production efficiency, environmental protection, product quality, and raw material utilization rate. Therefore, it has been successfully applied in the fields of aerospace, shipbuilding, military, and civil industries abroad.

[0003] The working principle of the vacuum infusion molding process is mainly to lay a vacuum bag and fiber reinforcement material on a single-sided rigid mold, then use vacuum to exhaust the gas in the mold, and under negative pressure conditions, utilize the fluidity of the resin to achieve the penetration and impregnation of the fiber reinforcement material in the mold. Finally, it is cured and formed under certain conditions. The core goal of vacuum infusion is to remove bubbles. However, when the viscosity of the epoxy resin is high, it is difficult to fully infiltrate the fibers or complex structures even under high vacuum. If the vacuum degree is insufficient or the degassing is not thorough, the residual bubbles will cause an increase in the porosity inside the product, resulting in a decrease in its mechanical strength, electrical performance, and thermal stability.

[0004] In order to reduce the generation of bubbles during the production process, a resin with a lower viscosity can be selected as the main component. Bisphenol F type epoxy resin is widely used in the fields of vacuum infusion, wind power blades, etc. due to its advantages such as low viscosity and high wettability. After curing, the crosslinking density of bisphenol F type epoxy resin is higher, which improves the solvent resistance and corrosion resistance, but also leads to brittle materials and poor impact resistance. In addition, the synthesis process of bisphenol F is complex, the domestic production technology level is low, and the high dependence on imports results in high raw material costs (about 2-3 times that of bisphenol A). Bisphenol A type has stronger advantages in fatigue resistance, high temperature resistance, and processing performance. Therefore, considering the comprehensive cost and performance, it is a better choice to select the more common bisphenol A type epoxy resin.

[0005] Bisphenol A epoxy resin can improve the performance defects caused by vacuum infusion by adding a certain amount of silica. Silica can reduce the viscosity of bisphenol A epoxy resin, improve its fluidity, reduce the generation of bubbles during processing, make it easier to process, and at the same time avoid the decrease in glass transition temperature caused by the viscosity reduction and avoid the loss of resin in terms of heat resistance. However, it is found in the experiment that after adding silica, the electrical properties of the material decline, which will cause local electric field distortion and a decrease in breakdown voltage, thereby affecting the insulation reliability of the material. At the same time, the fracture toughness of the material will also decrease. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects existing in the prior art. By preparing alkali metal silicate mixture-modified silica and mixing it with bisphenol A epoxy resin, while reducing its viscosity and improving fluidity, the electrical properties of the material are ensured. At the same time, combined with the pre-impregnation step of carbon fiber felt, the toughness of the material is improved.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions: A high-modulus and high-toughness carbon fiber vacuum infusion epoxy resin, the raw materials of the carbon fiber vacuum infusion epoxy resin include a resin component, a curing agent component, and a pre-impregnated carbon fiber felt. The resin component includes bisphenol A epoxy resin, alkali metal silicate mixture-modified silica, an antifoaming agent, and a dispersant. The curing agent component includes a curing agent and a curing accelerator.

[0008] The following is a further improvement of the above technical solution: The mass ratio of bisphenol A epoxy resin, alkali metal silicate mixture-modified silica, antifoaming agent, and dispersant in the resin component is 850-1150:70-80:2.7-3.3:4.5-5.5; The antifoaming agent is an organosilicon antifoaming agent, and the model is BYK-077; The dispersant is a polyurethane dispersant, and the model is EFKA-4010; The mass ratio of the curing agent and the curing accelerator in the curing agent component is 4.5-5.5:1; The curing agent is phthalic anhydride; The curing agent accelerator is 2-methylimidazole; The mass ratio of the resin component, the curing agent component, and the pre-impregnated carbon fiber felt is 85-115:12-14:60-70.

[0009] The preparation method of the alkali metal silicate mixture-modified silica is as follows: Lithium silicate, barium silicate, and deionized water are mixed and dissolved to obtain a mixed solution of alkali metal silicate. Then, silicon dioxide and the mixed solution of alkali metal silicate are mixed, the temperature is controlled at 67 - 69 °C, and stirring is carried out for 5.5 - 6.5 h. After stirring is completed, filtration is carried out, and the filtered solid is calcined at 630 - 670 °C for 60 - 90 min. After calcination is completed, it is cooled to room temperature, and then it is mixed with a benzyltriethylammonium chloride solution. The temperature is controlled at 49 - 53 °C, and stirring is carried out for 70 - 80 min. After stirring is completed, it is filtered and dried to obtain silicon dioxide modified with a mixture of alkali metal silicates; The mass ratio of the lithium silicate, barium silicate, and deionized water is 4.5 - 5.5:8 - 12:175 - 225; The mass ratio of the silicon dioxide and the mixed solution of alkali metal silicate is 9 - 11:55; The particle size of the silicon dioxide is 10 - 20 μm; The mass ratio of the filtered solid to the benzyltriethylammonium chloride solution is 2:10 - 12; The concentration of the benzyltriethylammonium chloride solution is 7.0 - 8.0 wt%;

[0010] The preparation method of the pre - impregnated carbon fiber felt is as follows: The carbon fiber felt, polyethylene glycol, deionized water, nano - silicon dioxide, and potassium lauryl polyoxyethylene ether phosphate are mixed, and ultrasonic treatment is carried out at 50 - 70 kHz for 12 - 20 min. After ultrasonic treatment is completed, stirring is carried out for 25 - 35 min. After stirring is completed, the carbon fiber felt is dried in vacuum to obtain the pre - impregnated carbon fiber felt; The mass ratio of the carbon fiber felt, polyethylene glycol, deionized water, nano - silicon dioxide, and potassium lauryl polyoxyethylene ether phosphate is 45 - 55:85 - 115:125 - 175:6.5 - 7.5:4.5 - 5.5; The thickness of the carbon fiber felt is 1.1 - 1.3 mm; The particle size of the nano - silicon dioxide is 10 nm, and the specific surface area is 295 m 2 / g.

[0011] The preparation method of the carbon fiber vacuum - infused epoxy resin is as follows: Mix bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant evenly to obtain a resin component. Mix the curing agent and curing accelerator evenly to obtain a curing agent component. Mix the resin component and the curing agent component evenly to obtain the resin to be vacuum infused. After laying the carbon fiber felt in the mold, control the vacuum degree to 1 - 3 Pa, pour the resin to be vacuum infused into the mold, then control the temperature to 30 - 35 °C, control the pressure applied to the mold to 7.3 - 7.7 MPa, and let it stand. The standing time is 140 - 160 min. After standing, a high-modulus and high-toughness carbon fiber vacuum-infused epoxy resin is obtained.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The carbon fiber vacuum-infused epoxy resin of the present invention has excellent tensile properties. According to the method in GB / T31293-2014, test its tensile strength, tensile elastic modulus, and elongation at break. The tensile strength is 668 - 672 MPa, the tensile elastic modulus is 112 - 115 GPa, and the elongation at break is 15.2 - 16.1%; The carbon fiber vacuum-infused epoxy resin of the present invention has excellent compressive properties. According to the method in GB / T31293-2014, test its compressive strength and compressive modulus. The compressive strength is 712 - 721 MPa, and the compressive modulus is 103 - 107 GPa; The carbon fiber vacuum-infused epoxy resin of the present invention has excellent flexural properties. According to the method in GB / T31293-2014, test its flexural strength and flexural modulus. The flexural strength is 1152 - 1213 MPa, and the flexural modulus is 178 - 184 GPa; The carbon fiber vacuum-infused epoxy resin of the present invention has excellent shrinkage resistance. According to the method in GB / T31293-2014, test its volume shrinkage rate. The volume shrinkage rate is 1.3 - 1.5%; The carbon fiber vacuum-infused epoxy resin of the present invention has a high interlaminar fracture toughness. According to the method in HB7718.1-2002, test its interlaminar fracture toughness. The interlaminar fracture toughness is 1.81 - 1.84 kJ / m 2 ; The carbon fiber vacuum-infused epoxy resin of the present invention has good dielectric properties and a high breakdown voltage. According to the method in GB / T1408.1-2016, test its breakdown voltage. The breakdown voltage is 31.2 - 32.2 kV. Detailed implementation mode Example 1

[0013] A high-modulus and high-toughness carbon fiber vacuum infusion epoxy resin, whose raw materials include a resin component, a curing agent component, and a pre-impregnated carbon fiber felt. The resin component includes bisphenol A epoxy resin, alkali metal silicate mixture-modified silica, an antifoaming agent, and a dispersant. The curing agent component includes a curing agent and a curing accelerator; In the resin component, the mass ratio of bisphenol A epoxy resin, alkali metal silicate mixture-modified silica, antifoaming agent, and dispersant is 1000:75:3:5; The antifoaming agent is an organosilicon antifoaming agent, and the model is BYK-077; The dispersant is a polyurethane dispersant, and the model is EFKA-4010; In the curing agent component, the mass ratio of the curing agent to the curing accelerator is 5:1; The curing agent is phthalic anhydride; The curing agent accelerator is 2-methylimidazole; The mass ratio of the resin component, the curing agent component, and the pre-impregnated carbon fiber felt is 100:13:65.

[0014] The preparation method of the alkali metal silicate mixture-modified silica is as follows: Mix lithium silicate, barium silicate, and deionized water and dissolve them to obtain an alkali metal silicate mixed solution. Then mix silica and the alkali metal silicate mixed solution, control the temperature at 68 °C, stir for 6 h, filter after stirring is completed, calcine the filtered solid at 650 °C for 75 min, cool to room temperature after calcination is completed, and then mix it with a benzyltriethylammonium chloride solution, control the temperature at 51 °C, stir for 75 min, and after stirring is completed, filter and dry to obtain the alkali metal silicate mixture-modified silica; The mass ratio of lithium silicate, barium silicate, and deionized water is 5:10:200; The mass ratio of silica and the alkali metal silicate mixed solution is 10:55; The particle size of the silica is 15 μm; The mass ratio of the filtered solid to the benzyltriethylammonium chloride solution is 2:11; The concentration of the benzyltriethylammonium chloride solution is 7.5 wt%.

[0015] The preparation method of the pre-impregnated carbon fiber felt is as follows: Mix carbon fiber felt, polyethylene glycol, deionized water, nano-silica, and potassium lauryl polyoxyethylene ether phosphate, and perform ultrasonic treatment at 60 kHz for 15 minutes. After ultrasonic treatment, stir for 30 minutes. After stirring, vacuum dry the carbon fiber felt to obtain a pre-impregnated carbon fiber felt; The mass ratio of the carbon fiber felt, polyethylene glycol, deionized water, nano-silica, and potassium lauryl polyoxyethylene ether phosphate is 50:100:150:7:5; The thickness of the carbon fiber felt is 1.2 mm; The particle size of the nano-silica is 10 nm, and the specific surface area is 295 m 2 / g.

[0016] The preparation method of the carbon fiber vacuum infusion epoxy resin is as follows: Mix bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant evenly to obtain a resin component. Mix the curing agent and curing accelerator evenly to obtain a curing agent component. Mix the resin component and the curing agent component evenly to obtain the resin to be vacuum infused. After laying the carbon fiber felt in the mold, control the vacuum degree to 2 Pa, infuse the resin to be vacuum infused into the mold, then control the temperature to 32 °C, control the pressure applied to the mold to 7.5 MPa, and let it stand for 150 minutes. After standing, obtain a high-modulus and high-toughness carbon fiber vacuum infusion epoxy resin. Example 2

[0017] A high-modulus and high-toughness carbon fiber vacuum infusion epoxy resin, the raw materials of which include a resin component, a curing agent component, and a pre-impregnated carbon fiber felt. The resin component includes bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant. The curing agent component includes a curing agent and a curing accelerator; The mass ratio of bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant in the resin component is 850:70:2.7:4.5; The defoamer is a silicone defoamer, and the model is BYK-077; The dispersant is a polyurethane dispersant, and the model is EFKA-4010; The mass ratio of the curing agent and the curing accelerator in the curing agent component is 4.5:1; The curing agent is phthalic anhydride; The curing agent accelerator is 2-methylimidazole; The mass ratio of the resin component, the curing agent component, and the pre-impregnated carbon fiber felt is 85:12:60.

[0018] The preparation method of the alkali metal silicate mixture modified silica is as follows: Lithium silicate, barium silicate and deionized water are mixed and dissolved to obtain an alkali metal silicate mixed solution. Then, silica and the alkali metal silicate mixed solution are mixed, the temperature is controlled at 67 °C, and stirring is carried out for 6.5 h. After stirring is completed, filtration is carried out. The filtered solid is calcined at 630 °C for 60 min. After calcination is completed, it is cooled to room temperature, and then it is mixed with a benzyltriethylammonium chloride solution. The temperature is controlled at 49 °C, and stirring is carried out for 80 min. After stirring is completed, it is filtered and dried to obtain the alkali metal silicate mixture modified silica; The mass ratio of lithium silicate, barium silicate and deionized water is 4.5:8:175; The mass ratio of silica and the alkali metal silicate mixed solution is 9:55; The particle size of the silica is 10 μm; The mass ratio of the filtered solid to the benzyltriethylammonium chloride solution is 2:10; The concentration of the benzyltriethylammonium chloride solution is 8.0 wt%.

[0019] The preparation method of the pre-impregnated carbon fiber felt is as follows: Carbon fiber felt, polyethylene glycol, deionized water, nano-silica and potassium lauryl polyoxyethylene ether phosphate are mixed, and ultrasonic treatment is carried out at 50 kHz for 20 min. After ultrasonic treatment is completed, stirring is carried out for 25 min. After stirring is completed, the carbon fiber felt is vacuum dried to obtain the pre-impregnated carbon fiber felt; The mass ratio of the carbon fiber felt, polyethylene glycol, deionized water, nano-silica and potassium lauryl polyoxyethylene ether phosphate is 45:85:125:6.5:4.5; The thickness of the carbon fiber felt is 1.1 mm; The particle size of the nano-silica is 10 nm, and the specific surface area is 295 m 2 / g.

[0020] The preparation method of the carbon fiber vacuum infused with epoxy resin is as follows: Mix bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant evenly to obtain the resin component. Mix the curing agent and curing accelerator evenly to obtain the curing agent component. Mix the resin component and the curing agent component evenly to obtain the resin to be vacuum infused. After laying the carbon fiber felt in the mold, control the vacuum degree to 1 Pa, pour the resin to be vacuum infused into the mold, then control the temperature to 30 °C, control the pressure applied to the mold to 7.3 MPa, and let it stand. The standing time is 160 min. After standing, a high modulus and high toughness carbon fiber vacuum infused epoxy resin is obtained. Example 3

[0021] A high modulus and high toughness carbon fiber vacuum infused epoxy resin, whose raw materials include a resin component, a curing agent component, and a pre-impregnated carbon fiber felt. The resin component includes bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant. The curing agent component includes a curing agent and a curing accelerator. The mass ratio of bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer, and dispersant in the resin component is 1150:80:3.3:5.5. The defoamer is a silicone defoamer, and the model is BYK-077. The dispersant is a polyurethane dispersant, and the model is EFKA-4010. The mass ratio of the curing agent and the curing accelerator in the curing agent component is 5.5:1. The curing agent is phthalic anhydride. The curing agent accelerator is 2-methylimidazole. The mass ratio of the resin component, the curing agent component, and the pre-impregnated carbon fiber felt is 115:14:70.

[0022] The preparation method of the alkali metal silicate mixture modified silica is as follows: Mix lithium silicate, barium silicate, and deionized water to dissolve, obtaining an alkali metal silicate mixed solution. Then mix silica and the alkali metal silicate mixed solution, control the temperature to 69 °C, and stir. The stirring time is 5.5 h. After stirring, filter, and calcine the filtered solid at 670 °C for 90 min. After calcination, cool to room temperature, and then mix it with benzyltriethylammonium chloride solution, control the temperature to 53 °C, and stir. The stirring time is 70 min. After stirring, filter and dry to obtain the alkali metal silicate mixture modified silica. The mass ratio of lithium silicate, barium silicate, and deionized water is 5.5:12:225. The mass ratio of silica and the alkali metal silicate mixed solution is 11:55. The particle size of the silica is 20 μm; The mass ratio of the solid after filtration to the benzyltriethylammonium chloride solution is 2:12; The concentration of the benzyltriethylammonium chloride solution is 7.0 wt%.

[0023] The preparation method of the pre-impregnated carbon fiber felt is as follows: Mix the carbon fiber felt, polyethylene glycol, deionized water, nano-silica, and potassium lauryl polyoxyethylene ether phosphate, perform ultrasonic treatment at 70 kHz for 12 min, stir after ultrasonic treatment for 35 min, and after stirring, vacuum-dry the carbon fiber felt to obtain the pre-impregnated carbon fiber felt; The mass ratio of the carbon fiber felt, polyethylene glycol, deionized water, nano-silica, and potassium lauryl polyoxyethylene ether phosphate is 55:115:175:7.5:5.5; The thickness of the carbon fiber felt is 1.3 mm; The particle size of the nano-silica is 10 nm, and the specific surface area is 295 m 2 / g.

[0024] The preparation method of the carbon fiber vacuum-infused epoxy resin is as follows: Mix bisphenol A epoxy resin, alkali metal silicate mixture-modified silica, defoaming agent, and dispersant evenly to obtain the resin component, mix the curing agent and curing accelerator evenly to obtain the curing agent component, mix the resin component and the curing agent component evenly to obtain the resin to be vacuum-infused. After laying the carbon fiber felt in the mold, control the vacuum degree to 3 Pa, pour the resin to be vacuum-infused into the mold, then control the temperature to 35 °C, control the pressure applied to the mold to 7.7 MPa, and let it stand for 140 min. After standing, obtain a high-modulus and high-toughness carbon fiber vacuum-infused epoxy resin.

[0025] Comparative Example 1 Different from Example 1, in the resin component, without changing the dosage, untreated silica is used instead of alkali metal silicate mixture-modified silica, and the other steps are the same to prepare the carbon fiber vacuum-infused epoxy resin; The particle size of the silica is 15 μm.

[0026] Comparative Example 2 Different from Example 1, without changing the usage amount, untreated carbon fiber felt is used instead of the pre-impregnated carbon fiber felt as the raw material, and the other steps are the same to prepare the carbon fiber vacuum-infused epoxy resin; The thickness of the carbon fiber felt is 1.2 mm.

[0027] Tensile Property Test of Test Example 1 The carbon fiber vacuum-infused epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their tensile strength, tensile elastic modulus, and elongation at break according to the method in GB / T 31293-2014, and the results are shown in Table 1.

[0028] Table 1

[0029] In Examples 1-3, by preparing alkali metal silicate mixture-modified silica, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, the tensile properties of the material can be improved, and the tensile strength, tensile elastic modulus, and elongation at break are all relatively high. In Comparative Example 1, using untreated silica instead of alkali metal silicate mixture-modified silica will cause a significant decrease in the tensile properties of the material, and the degrees of decrease in tensile strength, tensile elastic modulus, and elongation at break are all relatively high. In Comparative Example 2, using untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material will cause a certain degree of decrease in the tensile properties of the material, and the tensile strength, tensile elastic modulus, and elongation at break all decrease to a certain extent.

[0030] Compressive Property Test of Test Example 2 The carbon fiber vacuum-infused epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their compressive strength and compressive modulus according to the method in GB / T 31293-2014, and the results are shown in Table 2.

[0031] Table 2

[0032] In Examples 1-3, by preparing alkali metal silicate mixture-modified silica, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, the compressive properties of the material can be improved, and the compressive strength and compressive modulus are both relatively high. In Comparative Example 1, using untreated silica instead of alkali metal silicate mixture-modified silica will cause a significant decrease in the compressive properties of the material, and the degrees of decrease in compressive strength and compressive modulus are both relatively high. In Comparative Example 2, using untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material will cause a certain degree of decrease in the compressive properties of the material, and the compressive strength and compressive modulus both decrease to a certain extent.

[0033] Flexural Property Test of Test Example 3 The carbon fiber vacuum-injected epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their flexural strength and flexural modulus according to the method in GB / T 31293-2014, and the results are shown in Table 3.

[0034] Table 3

[0035] By preparing alkali metal silicate mixture-modified silica in Examples 1-3, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, the flexural properties of the material can be improved, and both the flexural strength and flexural modulus are relatively high. In Comparative Example 1, using untreated silica instead of alkali metal silicate mixture-modified silica will cause a significant decrease in the flexural properties of the material, and both the flexural strength and flexural modulus decrease to a relatively high extent. In Comparative Example 2, using untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material will cause a certain degree of decrease in the flexural properties of the material, and both the flexural strength and flexural modulus decrease to a certain extent.

[0036] Test Example 4 Shrinkage Property Test The carbon fiber vacuum-injected epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their volume shrinkage rate according to the method in GB / T 31293-2014, and the results are shown in Table 4.

[0037] Table 4

[0038] By preparing alkali metal silicate mixture-modified silica in Examples 1-3, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, the shrinkage resistance of the material can be improved, and the volume shrinkage rate is low. In Comparative Example 1, using untreated silica instead of alkali metal silicate mixture-modified silica will cause a certain degree of decrease in the shrinkage resistance of the material, and the volume shrinkage rate increases to a certain extent. In Comparative Example 2, using untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material will cause a significant decrease in the shrinkage resistance of the material, and the volume shrinkage rate increases more severely.

[0039] Test Example 5 Interlaminar Fracture Toughness Test The carbon fiber vacuum-injected epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their interlaminar fracture toughness according to the method in HB7718.1-2002, and the results are shown in Table 5.

[0040] Table 5

[0041] Examples 1-3 modified silica by preparing an alkali metal silicate mixture, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, which can improve the interlaminar fracture toughness of the material.

[0042] Comparative Example 1 used untreated silica instead of the alkali metal silicate mixture to modify silica, which led to a certain degree of decrease in the interlaminar fracture toughness of the material; Comparative Example 2 used untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material, which led to a more serious decrease in the interlaminar fracture toughness of the material.

[0043] Test Example 6 Dielectric Property Test The carbon fiber vacuum-infused epoxy resins prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their breakdown voltage according to the method in GB / T 1408.1-2016, and the results are shown in Table 6.

[0044] Table 6

[0045] Examples 1-3 modified silica by preparing an alkali metal silicate mixture, mixing it with bisphenol A epoxy resin, and combining the pre-impregnation step of carbon fiber felt, which can improve the dielectric properties of the material and has a high breakdown voltage.

[0046] Comparative Example 1 used untreated silica instead of the alkali metal silicate mixture to modify silica, which led to a more serious decrease in the dielectric properties of the material and a significant decrease in the breakdown voltage; Comparative Example 2 used untreated carbon fiber felt instead of pre-impregnated carbon fiber felt as the raw material, which led to a certain degree of decrease in the dielectric properties of the material and a slightly lower breakdown voltage.

Claims

1. A high modulus and high toughness carbon fiber vacuum infused epoxy resin, characterized in that: The raw materials of carbon fiber vacuum infusion epoxy resin include resin component, curing agent component and pre-impregnated carbon fiber felt, wherein the resin component includes bisphenol A type epoxy resin, alkali metal silicate mixture modified silica, defoamer and dispersant, and the curing agent component includes curing agent and curing accelerator; The preparation method of the alkali metal silicate mixture modified silicon dioxide is: Mix and dissolve lithium silicate, barium silicate and deionized water to obtain an alkali metal silicate mixed solution, then mix and stir silicon dioxide and the alkali metal silicate mixed solution and filter, calcine the filtered solid, cool to room temperature, mix and stir with benzyltriethylammonium chloride solution, filter and dry to obtain alkali metal silicate mixture modified silicon dioxide; The preparation method of the pre-impregnated carbon fiber felt is: The carbon fiber felt, polyethylene glycol, deionized water, nano-silica and potassium dodecyl polyoxyethylene ether phosphate are mixed and ultrasonicated, and then stirred. Finally, the carbon fiber felt is vacuum dried to obtain a pre-impregnated carbon fiber felt.

2. The high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: The mass ratio of bisphenol A epoxy resin, alkali metal silicate mixture modified silica, defoamer and dispersant in the resin component is 850-1150:70-80:2.7-3.3:4.5-5.5; The defoamer is a silicone defoamer, model BYK-077; The dispersant is a polyurethane dispersant, model EFKA-4010; The mass ratio of curing agent to curing accelerator in the curing agent component is 4.5-5.5:1; The curing agent is phthalic anhydride; The curing agent accelerator is 2-methylimidazole; The mass ratio of the resin component, the curing agent component and the pre-impregnated carbon fiber felt is 85-115:12-14:60-70.

3. The high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: In the preparation method of the alkali metal silicate mixture modified silicon dioxide, after the silicon dioxide and the alkali metal silicate mixed solution are mixed, the stirring method is to control the temperature to 67-69° C. and stir for 5.5-6.5 hours; The filtered solid is calcined at 630-670°C for 60-90 minutes. The filtered solid is calcined, cooled to room temperature, and then mixed with benzyltriethylammonium chloride solution and stirred at a temperature of 49-53° C. for 70-80 minutes.

4. The high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: In the preparation method of the alkali metal silicate mixture modified silicon dioxide, the mass ratio of lithium silicate, barium silicate and deionized water is 4.5-5.5:8-12:175-225; The mass ratio of the silicon dioxide and alkali metal silicate mixed solution is 9-11:55; The particle size of the silicon dioxide is 10-20 μm; The mass ratio of the filtered solid to the benzyltriethylammonium chloride solution is 2:10-12; The concentration of the benzyltriethylammonium chloride solution is 7.0-8.0 wt %.

5. The high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: In the preparation method of the pre-impregnated carbon fiber felt, the carbon fiber felt, polyethylene glycol, deionized water, nano-silica, and potassium dodecyl polyoxyethylene ether phosphate are mixed, and then ultrasonicated at 50-70 kHz for 12-20 minutes, and the stirring time after the ultrasonication is completed is 25-35 minutes.

6. The high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: In the preparation method of the pre-impregnated carbon fiber felt, the mass ratio of the carbon fiber felt, polyethylene glycol, deionized water, nano-silicon dioxide, and potassium dodecyl polyoxyethylene ether phosphate is 45-55:85-115:125-175:6.5-7.5:4.5-5.5; The thickness of the carbon fiber felt is 1.1-1.3 mm; The particle size of the nano-silicon dioxide is 10 nm and the specific surface area is 295 m 2 / g.

7. The method for preparing a high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 1, characterized in that: The preparation method comprises the following steps: uniformly mixing bisphenol A epoxy resin, alkali metal silicate mixture modified silicon dioxide, defoamer and dispersant to obtain a resin component; uniformly mixing a curing agent and a curing accelerator to obtain a curing agent component; uniformly mixing the resin component and the curing agent component to obtain a vacuum infusion resin; laying carbon fiber felt in a mold, controlling a certain vacuum degree to infuse the vacuum infusion resin into the mold, and then controlling a certain temperature and pressure to allow the mold to stand; after the standing is completed, a high modulus and high toughness carbon fiber vacuum infusion epoxy resin is obtained.

8. The method for preparing high modulus and high toughness carbon fiber vacuum infused epoxy resin according to claim 7, characterized in that: After laying the carbon fiber felt in the mold, the vacuum degree needs to be controlled at 1-3Pa, and the resin to be vacuum infused is poured into the mold. After pouring into the mold, the temperature needs to be controlled at 30-35°C, and the pressure applied to the mold is controlled at 7.3-7.7MPa. Let it stand for 140-160min.

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