Glass fiber-reinforced epoxy resin composite material and preparation method therefor

Abstract

The present invention relates to the technical field of composite materials. Provided are a glass fiber-reinforced epoxy resin composite material and a preparation method therefor. In the present invention, an epoxy silane coupling agent solution is used for performing surface modification on glass fibers. An epoxy silane coupling agent contains a hydrolyzable group and an epoxy group. Silicon hydroxyl generated when the hydrolyzable group is hydrolyzed can be connected to the glass fibers, so as to effectively modify the surfaces of the glass fibers. The epoxy group can react with an epoxy resin matrix, thereby improving the infiltration effect of the epoxy resin on the glass fibers and improving the bonding performance of the interface of the glass fiber-reinforced epoxy resin composite material, and thus improving the mechanical properties of the glass fiber-reinforced epoxy resin composite material. The epoxy resin is cured and modified by using a functional curing agent or nanoparticles, so as to improve the ductility or strength of the epoxy resin, thereby improving the mechanical properties of the prepared glass fiber-reinforced epoxy resin composite material.

Description

Glass fiber reinforced epoxy resin composite material and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on March 11, 2024, with application number 202410268608.6 and invention name “A glass fiber reinforced epoxy resin composite material and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of composite materials, and in particular to a glass fiber reinforced epoxy resin composite material and a preparation method thereof. Background Art

[0003] Glass fiber reinforced epoxy resin composites have excellent mechanical and corrosion resistance properties and good economic benefits, and have been widely used in various fields. Their performance is closely related to the resin matrix, fiber strength and resin-fiber interface. The existing glass fiber surface is inert and has poor impregnation effect with epoxy resin, resulting in poor interfacial bonding performance of glass fiber reinforced epoxy resin composites, which in turn leads to poor mechanical properties of glass fiber reinforced epoxy resin composites. The epoxy resin matrix is ​​relatively fragile and easily degraded under the influence of external environmental factors, forming surface cracks and internal defects, making it easier for external corrosive substances to enter the interior of the composite material, causing fiber degradation. Moreover, with the extension of service time, the decomposition of the epoxy resin matrix and glass fiber intensifies, and the weak interface area between the glass fiber and epoxy resin matrix increases, resulting in interfacial debonding, which in turn leads to poor mechanical properties of glass fiber reinforced epoxy resin composites.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide a glass fiber reinforced epoxy resin composite material and a preparation method thereof. The glass fiber reinforced epoxy resin composite material provided by the present invention has excellent mechanical properties.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a glass fiber reinforced epoxy resin composite material, comprising the following steps:

[0008] (1) immersing the glass fiber in an epoxy silane coupling agent solution for surface modification to obtain a surface-modified glass fiber;

[0009] (2) mixing an epoxy resin with a functional curing agent to obtain a modified epoxy resin system; the functional curing agent comprises one of a phenalkamine curing agent and an alicyclic amine curing agent;

[0010] Alternatively, epoxy resin, nanoparticles, and polyamide curing agent are mixed to obtain a modified epoxy resin system;

[0011] (3) mixing the surface-modified glass fiber obtained in step (1) with the modified epoxy resin system obtained in step (2) and curing the mixture to obtain a glass fiber reinforced epoxy resin composite material.

[0012] Preferably, the mass concentration of the epoxy silane coupling agent solution in step (1) is 2-4%.

[0013] Preferably, the pH value of the epoxy silane coupling agent solution in step (1) is 4-6.

[0014] Preferably, the preparation method of the epoxy silane coupling agent solution in step (1) is: mixing the epoxy silane coupling agent, ethanol, water and acetic acid to carry out a hydrolysis reaction to obtain the epoxy silane coupling agent solution.

[0015] Preferably, the surface modification time in step (1) is 0.5 to 1 h.

[0016] Preferably, in step (2), the mass ratio of epoxy resin to functional curing agent is 2:(1-1.2).

[0017] Preferably, the nanoparticles in step (2) include one or both of nano-titanium dioxide and nano-silicon dioxide.

[0018] Preferably, the amount of the nanoparticles added in step (2) is 2 to 12 wt % of the polyamide curing agent.

[0019] Preferably, the amount of the nanoparticles added in step (2) is 2 to 6 wt % of the polyamide curing agent.

[0020] Preferably, in step (2), the mass ratio of epoxy resin to polyamide curing agent is 1:(0.8-1.2).

[0021] Preferably, in step (3), the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is 4:(2.6-6).

[0022] Preferably, in step (3), the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is 4:(3-5).

[0023] Preferably, the curing temperature in step (3) is 20 to 30° C., and the curing time is 12 to 24 hours.

[0024] The present invention provides a glass fiber reinforced epoxy resin composite material prepared by the preparation method described in the above technical solution, comprising a modified epoxy resin matrix and modified glass fibers dispersed in the modified epoxy resin matrix;

[0025] Alternatively, the invention comprises a modified epoxy resin matrix and modified glass fibers and nanoparticles dispersed in the modified epoxy resin matrix.

[0026] The present invention provides a preparation method of a glass fiber reinforced epoxy resin composite material, comprising the following steps: (1) immersing glass fiber in an epoxy silane coupling agent solution for surface modification to obtain surface-modified glass fiber; (2) mixing epoxy resin with a functional curing agent to obtain a modified epoxy resin system; the functional curing agent comprises one of a phenolic amine curing agent and an alicyclic amine curing agent; or, mixing epoxy resin, nanoparticles and a polyamide curing agent to obtain a modified epoxy resin system; and (3) mixing the surface-modified glass fiber obtained in step (1) with the modified epoxy resin system obtained in step (2) and curing the mixture to obtain a glass fiber reinforced epoxy resin composite material. The present invention adopts an epoxy silane coupling agent solution to modify the surface of glass fiber. The epoxy silane coupling agent contains a hydrolyzable group and an epoxy group. The silanol groups generated after the hydrolyzable group is hydrolyzed can be connected with the glass fiber to effectively modify the fiber surface. The epoxy group can react with the epoxy resin matrix to improve the impregnation effect of the epoxy resin and the glass fiber, improve the bonding performance of the interface of the glass fiber reinforced epoxy resin composite material, and further improve the mechanical properties of the glass fiber reinforced epoxy resin composite material. Functional curing agent or nanoparticles are used to perform curing modification on the epoxy resin to improve the ductility or strength of the epoxy resin, and further improve the mechanical properties of the prepared glass fiber reinforced epoxy resin composite material. The results of the examples show that the elastic modulus of the glass fiber reinforced epoxy resin composite material prepared by using the functional curing agent alicyclic amine can reach 12GPa, the tensile strength can reach 125MPa, and the ultimate strain can reach 1.06%; the elastic modulus of the glass fiber reinforced epoxy resin composite material prepared by using the functional curing agent phenolic amine can reach 11GPa, the tensile strength can reach 125MPa, and the ultimate strain can reach 1.24%; the elastic modulus of the glass fiber reinforced epoxy resin composite material prepared by using the polyamide curing agent with added nanomaterials can reach 7GPa, the tensile strength can reach 99MPa, and the ultimate strain can reach 1.89%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a tensile stress-strain curve diagram of the resin matrix prepared in Examples 1 to 3 of the present invention and Comparative Example 1;

[0028] FIG2 is a tensile stress-strain curve of the glass fiber reinforced epoxy resin composite materials prepared in Examples 1 to 3 of the present invention and Comparative Example 2;

[0029] Figure 3 shows the static contact angles of surface-modified glass fibers obtained with different surface modification times. DETAILED DESCRIPTION

[0030] The present invention provides a method for preparing a glass fiber reinforced epoxy resin composite material, comprising the following steps:

[0031] (1) immersing the glass fiber in an epoxy silane coupling agent solution for surface modification to obtain a surface-modified glass fiber;

[0032] (2) mixing an epoxy resin with a functional curing agent to obtain a modified epoxy resin system; the functional curing agent comprises one of a phenalkamine curing agent and an alicyclic amine curing agent;

[0033] Alternatively, epoxy resin, nanoparticles, and polyamide curing agent are mixed to obtain a modified epoxy resin system;

[0034] (3) mixing the surface-modified glass fiber obtained in step (1) with the modified epoxy resin system obtained in step (2) and curing the mixture to obtain a glass fiber reinforced epoxy resin composite material.

[0035] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0036] The present invention immerses glass fiber in an epoxy silane coupling agent solution to perform surface modification, thereby obtaining surface-modified glass fiber.

[0037] In the present invention, the diameter of the glass fiber is preferably 5 to 30 μm, more preferably 7 to 15 μm. The present invention limits the size of the glass fiber to ensure that the prepared glass fiber reinforced epoxy resin composite material has better mechanical properties.

[0038] In the present invention, the glass fiber is preferably pretreated before use; the pretreatment includes acetone immersion, deionized water washing and drying in sequence.

[0039] In the present invention, the acetone immersion time is preferably 12 to 24 hours. The present invention removes colloid and impurities from the glass fiber surface through acetone immersion. In the present invention, the drying temperature is preferably 40 to 70°C, and the drying time is preferably 12 to 24 hours. The present invention does not specifically limit the drying equipment; any drying equipment known in the art can be used. In an embodiment of the present invention, the drying equipment is preferably a constant temperature drying oven.

[0040] In the present invention, the mass concentration of the epoxy silane coupling agent solution is preferably 2-4%, more preferably 2-3%. In the present invention, the pH value of the epoxy silane coupling agent solution is preferably 4-6, more preferably 4-5. In the present invention, limiting the mass concentration and pH value of the epoxy silane coupling agent solution to the above ranges is conducive to more complete hydrolysis of the silane coupling agent.

[0041] In the present invention, the epoxy silane coupling agent in the epoxy silane coupling agent solution is preferably silane coupling agent KH560 (γ-glycidyloxypropyltrimethoxysilane). In the present invention, the epoxy silane coupling agent contains hydrolyzable groups and epoxy groups. The silanol groups generated by hydrolysis of the hydrolyzable groups can connect with the glass fibers to effectively modify the fiber surface. The epoxy groups contained in the epoxy silane coupling agent can react with the resin matrix to improve the wetting effect of the resin and the glass fibers.

[0042] In the present invention, the epoxy silane coupling agent solution is preferably prepared by mixing an epoxy silane coupling agent, ethanol, water and acetic acid and performing a hydrolysis reaction to obtain the epoxy silane coupling agent solution.

[0043] In the present invention, the water is preferably deionized water; the mass ratio of ethanol to water is preferably 1: (0.5-1.5), more preferably 1: 1. The present invention limits the mass ratio of ethanol to water to the above range, which is conducive to more complete hydrolysis of the silane coupling agent.

[0044] The present invention has no particular limitation on the amount of acetic acid used, as long as the pH value of the epoxy silane coupling agent solution is within the above range.

[0045] In the present invention, the epoxy silane coupling agent, ethanol, water and acetic acid are preferably mixed as follows: first, ethanol and water are mixed to obtain a mixed solution, then the epoxy silane coupling agent is added, and finally, acetic acid is added to adjust the pH value.

[0046] In the present invention, the hydrolysis reaction time is preferably 20 to 40 minutes, more preferably 30 minutes; the hydrolysis reaction temperature is preferably 20 to 30°C; and the hydrolysis reaction is preferably carried out under stirring. The present invention does not specifically limit the stirring method and rate; stirring methods and rates familiar to those skilled in the art can be used. By limiting the hydrolysis reaction time to the above range, the present invention can achieve more complete hydrolysis of the silane coupling agent.

[0047] In the present invention, the reaction during the hydrolysis reaction is as shown in Formula I:

[0048] In the formula I, X is a hydrolyzable group OCH3, Y is an epoxy functional group, and R is a methyl group.

[0049] In the present invention, the surface modification time is preferably 0.5 to 1 hour, more preferably 0.8 hours; the surface modification temperature is preferably 20 to 30°C. In the present invention, the hydrolyzable groups in the epoxysilane coupling agent, upon hydrolysis, produce silanol groups that can bond with the glass fiber, effectively modifying the fiber surface. By limiting the surface modification time and temperature, the present invention ensures more complete surface modification of the glass fiber.

[0050] After the surface modification is completed, the present invention preferably performs drying on the surface-modified product to obtain the surface-modified glass fiber.

[0051] In the present invention, the drying temperature is preferably 40 to 70° C. and the drying time is preferably 12 to 24 hours. The present invention limits the drying temperature and time to better remove moisture and ethanol from the surface-modified glass fiber.

[0052] In one technical solution of the present invention, the present invention mixes an epoxy resin with a functional curing agent to obtain a modified epoxy resin system; the functional curing agent includes one of a phenalkamine curing agent and an alicyclic amine curing agent.

[0053] In the present invention, the epoxy resin is preferably epoxy resin E51. In the present invention, the mass ratio of the epoxy resin to the functional curing agent is preferably 2:(1-1.2), more preferably 2:1.1.

[0054] In the present invention, the mixing time of the epoxy resin and the functional curing agent is preferably 5 to 15 minutes, more preferably 10 to 15 minutes. In the present invention, the mixing is preferably carried out under stirring conditions. In the present invention, the stirring rate is preferably 1000 to 3000 rpm, more preferably 1500 to 2000 rpm. The present invention has no special limitation on the stirring method, and a stirring method familiar to those skilled in the art can be used. In the present invention, the stirring method is preferably mechanical stirring. The present invention has no special limitation on the stirring equipment, and a stirring equipment familiar to those skilled in the art can be used. In an embodiment of the present invention, the stirring equipment is preferably a mechanical stirrer.

[0055] In another technical solution of the present invention, the present invention mixes epoxy resin, nanoparticles and polyamide curing agent to obtain a modified epoxy resin system.

[0056] In the present invention, the epoxy resin is preferably epoxy resin E51.

[0057] In the present invention, the nanoparticles preferably include one or both of nano-titanium dioxide and nano-silicon dioxide, more preferably nano-titanium dioxide and nano-silicon dioxide. In the present invention, the mass ratio of the nano-titanium dioxide to nano-silicon dioxide is preferably (1-5):(1-5), more preferably (1-3):(1-3).

[0058] In the present invention, the amount of the nanoparticles added is preferably 2-6 wt % of the polyamide solidification. By limiting the amount of nanoparticles added, the present invention allows the nanomaterials to be more fully and evenly dispersed in the resin, avoiding agglomeration and further improving the mechanical properties of the resin matrix.

[0059] In the present invention, the mass ratio of the epoxy resin to the polyamide curing agent is preferably 1: (0.8-1.2), more preferably 1: 1. In the present invention, the polyamide curing agent is preferably polyamide curing agent 650.

[0060] In the present invention, the epoxy resin, nanoparticles, and polyamide curing agent are preferably mixed by first mixing the nanoparticles with the epoxy resin and then mixing with the polyamide curing agent. In the present invention, the nanoparticles are preferably mixed with the epoxy resin for 10 to 20 minutes, more preferably 15 to 20 minutes. In the present invention, the nanoparticles are then mixed with the polyamide curing agent for 10 to 20 minutes, more preferably 15 to 20 minutes. In the present invention, the mixing is preferably performed under stirring. In the present invention, the stirring rate is preferably 1000 to 2000 rpm, more preferably 1500 to 2000 rpm.

[0061] After obtaining the surface-modified glass fiber and the modified epoxy resin system, the present invention mixes the surface-modified glass fiber and the modified epoxy resin system and then solidifies them to obtain a glass fiber reinforced epoxy resin composite material.

[0062] In the present invention, the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is preferably 4:(2.6-6), more preferably 4:(3-5), and most preferably 4:4. By limiting the mass ratio of the modified epoxy resin system to the surface-modified glass fiber, the present invention ensures that the resulting glass fiber-reinforced epoxy resin composite material has better mechanical properties.

[0063] In the present invention, the modified epoxy resin system is preferably mixed with the surface-modified glass fiber and then molded and cured.

[0064] The present invention has no particular limitation on the molding method, and any method known in the art for preparing and molding glass fiber reinforced epoxy resin composite materials can be used. In the present invention, the method for preparing and molding the glass fiber reinforced epoxy resin composite materials is preferably a manual layup method.

[0065] In the present invention, the curing temperature is preferably 20 to 30° C.; the curing time is preferably 12 to 24 hours, more preferably 15 to 20 hours.

[0066] In the present invention, the curing is preferably followed by placing the film in a cool, dry place. In the present invention, the placing time is preferably 5 to 7 days, more preferably 6 days. The present invention limits the placing time to ensure more complete curing.

[0067] The present invention adopts an epoxy silane coupling agent solution to modify the surface of glass fiber. The epoxy silane coupling agent contains a hydrolyzable group and an epoxy group. The silanol groups generated after the hydrolyzable group is hydrolyzed can be connected with the glass fiber to effectively modify the fiber surface. The epoxy group can react with the epoxy resin matrix to improve the impregnation effect of the epoxy resin and the glass fiber, improve the bonding performance of the interface of the glass fiber reinforced epoxy resin composite material, and further improve the mechanical properties of the glass fiber reinforced epoxy resin composite material. Functional curing agent or nanoparticles are used to perform curing modification on the epoxy resin to improve the ductility or strength of the epoxy resin, and further improve the mechanical properties of the prepared glass fiber reinforced epoxy resin composite material.

[0068] The present invention also provides a glass fiber reinforced epoxy resin composite material prepared by the preparation method described in the above technical solution, comprising a modified epoxy resin matrix and modified glass fibers dispersed in the modified epoxy resin matrix;

[0069] Alternatively, the invention comprises a modified epoxy resin matrix and modified glass fibers and nanoparticles dispersed in the modified epoxy resin matrix.

[0070] The glass fiber reinforced epoxy resin composite material prepared by the present invention has good mechanical properties. Among them, the glass fiber reinforced epoxy resin composite material prepared by using a functional curing agent alicyclic amine has an elastic modulus of up to 12 GPa, a tensile strength of up to 125 MPa, and an ultimate strain of up to 1.06%; the glass fiber reinforced epoxy resin composite material prepared by using a functional curing agent phenalkamine has an elastic modulus of up to 11 GPa, a tensile strength of up to 125 MPa, and an ultimate strain of up to 1.24%; and the glass fiber reinforced epoxy resin composite material prepared by using nanomaterials and polyamide curing agents has an elastic modulus of up to 7 GPa, a tensile strength of up to 99 MPa, and an ultimate strain of up to 1.89%.

[0071] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0072] Example 1

[0073] A method for preparing a glass fiber reinforced epoxy resin composite material comprises the following steps:

[0074] (1) After the glass fiber was immersed in an acetone solution for 24 hours, it was washed with deionized water and dried in a constant temperature drying oven at 40°C for 24 hours. Then, it was immersed in a 2% mass concentration of epoxy silane coupling agent KH560 solution for 1 hour for surface modification, and then dried in a constant temperature drying oven at 50°C for 24 hours to obtain a surface-modified glass fiber;

[0075] The preparation method of the epoxy silane coupling agent solution with a mass concentration of 2% is as follows: 2g of silane coupling agent KH560 is added to a mixture of 49g of deionized water and 49g of anhydrous ethanol (the mass ratio of deionized water to anhydrous ethanol is 1:1), an appropriate amount of acetic acid is added to adjust the pH value to 4, and the mixture is stirred at room temperature with a magnetic stirrer for 30 minutes to obtain a 2% mass concentration of epoxy silane coupling agent KH560 solution.

[0076] (2) 2 g of titanium dioxide, 2 g of silicon dioxide and 100 g of epoxy resin E51 were mixed, stirred at 2000 r / min for 15 min using a mechanical stirrer, and then mixed with 100 g of polyamide curing agent 650 and stirred for another 15 min to obtain a modified epoxy resin E51 system; the mass ratio of the epoxy resin E51 to the polyamide curing agent 650 was 1:1; the amount of the nanoparticles added was preferably 4% of the polyamide;

[0077] (3) The surface-modified glass fiber obtained in step (1) is mixed with the modified epoxy resin E51 system obtained in step (2) (the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is 6:4), and then a glass fiber reinforced epoxy resin composite material is prepared and molded by a manual laying method, cured at 24° C. for 24 hours, and allowed to stand for 6 days to obtain a glass fiber reinforced epoxy resin composite material, which is recorded as PA650-Md-GFs.

[0078] Example 2

[0079] A method for preparing a glass fiber reinforced epoxy resin composite material comprises the following steps:

[0080] (1) After the glass fiber was immersed in an acetone solution for 24 hours, it was washed with deionized water and dried in a constant temperature drying oven at 40°C for 24 hours. Then, it was immersed in a 2% mass concentration of epoxy silane coupling agent KH560 solution for 1 hour for surface modification, and then dried in a constant temperature drying oven at 50°C for 24 hours to obtain a surface-modified glass fiber;

[0081] The preparation method of the epoxy silane coupling agent solution with a mass concentration of 2% is as follows: 2g of silane coupling agent KH560 is added to a mixture of 49g of deionized water and 49g of anhydrous ethanol (the mass ratio of deionized water to anhydrous ethanol is 1:1), an appropriate amount of acetic acid is added to adjust the pH value to 4-5, and stirring is carried out at room temperature using a magnetic stirrer for 30 minutes to obtain a 2% mass concentration of epoxy silane coupling agent KH560 solution.

[0082] (2) 40 g of phenalkamine curing agent (labeled JH-5553, produced by Hangzhou Wuhuigang Adhesive Co., Ltd.) was added to 80 g of epoxy resin E51 (the mass ratio of epoxy resin E51 to phenalkamine curing agent was 1:2), and stirred at 2000 r / min for 5 min using a mechanical stirrer to obtain a modified epoxy resin E51 system;

[0083] (3) The surface-modified glass fiber obtained in step (1) was mixed with the modified epoxy resin E51 system obtained in step (2) (the mass ratio of the modified epoxy resin system to the surface-modified glass fiber was 6:4), and then a glass fiber reinforced epoxy resin composite material was prepared and molded by a manual laying method, cured at 24° C. for 12 h, and allowed to stand for 6 days to obtain a glass fiber reinforced epoxy resin composite material, which was recorded as PAA-GFs.

[0084] Example 3

[0085] The difference between Example 3 and Example 2 is that the phenolic amine curing agent in step 2) is replaced with an alicyclic amine curing agent (labeled JH-5516, produced by Hangzhou Wuhuigang Adhesive Co., Ltd.) to obtain a modified epoxy resin E51 system. The rest is the same as Example 2 to obtain a glass fiber reinforced epoxy resin composite material, which is recorded as AA-GFs.

[0086] Comparative Example 1

[0087] A method for preparing an epoxy resin matrix comprises the following steps: mixing 100 g of epoxy resin E51 and 100 g of polyamide curing agent 650, stirring at 2000 r / min for 15 min using a mechanical stirrer, and curing at room temperature for 24 h to obtain a modified epoxy resin E51 matrix, which is recorded as PA650.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that the surface modification by impregnation with an epoxy silane coupling agent in step 1) is omitted; the addition of nanoparticles in step 2) is omitted. Otherwise, the same as in Example 1 is used to obtain a glass fiber reinforced epoxy resin composite material, which is recorded as PA650-GFs.

[0090] The modified epoxy resin E51 matrix obtained by curing the modified epoxy resin E51 system obtained in step 2) of Example 1 for 24 hours was designated PA650-Md; the modified epoxy resin E51 matrix obtained by curing the modified epoxy resin E51 system obtained in step 2) of Examples 2-3 for 12 hours was designated PAA and AA, respectively. The present invention conducted tensile tests on the cured epoxy resin E51 matrices of Examples 1-3 and Comparative Example 1, and the tensile stress-strain curves are shown in Figure 1. As can be seen from the figure, compared to Comparative Example 1, the tensile strength of the epoxy resin E51 matrix cured with the nanomaterial-added polyamide in Example 1 was not significantly improved, but the ultimate strain was increased, resulting in improved ductility. The ductility of the epoxy resins cured with phenolic amines and alicyclic amines in Examples 1 and 2 decreased, but the elastic modulus and tensile strength were improved.

[0091] The glass fiber reinforced epoxy resin composites prepared in Examples 1 to 3 and Comparative Example 2 were subjected to tensile tests, and the tensile stress-strain curves are shown in Figure 2. As can be seen from the figure, compared to Comparative Example 2, the glass fiber reinforced epoxy resin composite material prepared in Example 1 using nanomaterial-filled polyamide-cured epoxy resin and modified glass fiber exhibits improved elastic modulus and tensile strength, while maintaining good ultimate strain. The composite material prepared using alicyclic amine and phenalkamine-cured epoxy resin and modified glass fiber exhibits reduced ultimate strain, but significantly improved elastic modulus and tensile strength.

[0092] Contact angle tests were conducted on surface-modified glass fibers produced with different surface modification times. The static contact angles with epoxy resin are shown in Figure 3. As shown in the figure, the contact angle can be used to quantitatively characterize the wetting effect between the resin and the fiber. The longer the impregnation time, the smaller the contact angle, indicating better wetting.

[0093] It can be seen from the above comparative examples and embodiments that the present invention uses an epoxy silane coupling agent solution to modify the surface of glass fiber and uses a functional curing agent or nanoparticles to cure and modify the epoxy resin, which can improve the ductility or strength of the epoxy resin and thereby improve the mechanical properties of the obtained glass fiber reinforced epoxy resin composite material.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a glass fiber reinforced epoxy resin composite material, comprising the following steps: (1) immersing the glass fiber in an epoxy silane coupling agent solution for surface modification to obtain a surface-modified glass fiber; (2) mixing an epoxy resin with a functional curing agent to obtain a modified epoxy resin system; the functional curing agent comprises one of a phenalkamine curing agent and an alicyclic amine curing agent; Alternatively, epoxy resin, nanoparticles, and polyamide curing agent are mixed to obtain a modified epoxy resin system; (3) mixing the surface-modified glass fiber obtained in step (1) with the modified epoxy resin system obtained in step (2) and curing the mixture to obtain a glass fiber reinforced epoxy resin composite material. There is no order in which steps (1) and (2) are performed.

2. The preparation method according to claim 1, characterized in that The mass concentration of the epoxy silane coupling agent solution in step (1) is 2-4%.

3. The preparation method according to claim 1 or 2, characterized in that The pH value of the epoxysilane coupling agent solution in step (1) is 4-6.

4. The preparation method according to claim 3, characterized in that The preparation method of the epoxy silane coupling agent solution in the step (1) is: mixing the epoxy silane coupling agent, ethanol, water and acetic acid to carry out a hydrolysis reaction to obtain the epoxy silane coupling agent solution.

5. The preparation method according to claim 1, characterized in that The surface modification time in step (1) is 0.5 to 1 hour.

6. The preparation method according to claim 1, characterized in that In the step (2), the mass ratio of the epoxy resin to the functional curing agent is 2:(1-1.2).

7. The preparation method according to claim 1, characterized in that The nanoparticles in step (2) include one or both of nano-titanium dioxide and nano-silicon dioxide.

8. The preparation method according to claim 1 or 7, characterized in that The amount of the nanoparticles added in step (2) is 2 to 12 wt % of the polyamide curing agent.

9. The preparation method according to claim 8, characterized in that The amount of the nanoparticles added in step (2) is 2 to 6 wt % of the polyamide curing agent.

10. The preparation method according to claim 1, characterized in that The mass ratio of the epoxy resin to the polyamide curing agent in the step (2) is 1: (0.8-1.2).

11. The preparation method according to claim 1, characterized in that In the step (3), the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is 4:(2.6-6).

12. The preparation method according to claim 11, characterized in that In the step (3), the mass ratio of the modified epoxy resin system to the surface-modified glass fiber is 4:(3-5).

13. The preparation method according to claim 1, characterized in that The curing temperature in step (3) is 20 to 30° C., and the curing time is 12 to 24 hours.

14. A glass fiber reinforced epoxy resin composite material prepared by the preparation method according to any one of claims 1 to 13, comprising a modified epoxy resin matrix and modified glass fibers dispersed in the modified epoxy resin matrix; Alternatively, the invention comprises a modified epoxy resin matrix and modified glass fibers and nanoparticles dispersed in the modified epoxy resin matrix.

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