Interface modifier for carbon fiber / vinyl ester composite material and preparation method therefor

Abstract

The present invention provides an interface modifier for a carbon fiber / vinyl ester composite material and a preparation method therefor. Raw materials for the interface modifier include an amine-based monomer and an amide precursor monomer, wherein the molar ratio of the amide precursor monomer to the amine-based monomer is 1:0.8-3; or include a silane coupling agent and a diol, wherein the molar ratio of the silane coupling agent to the diol is 1:0.8-3. The method comprises: step 1. raw material preparation; step 2. experimental device construction; step 3. controlling the reaction temperature and reaction time until no continued generation of a distillate in a reaction system; and step 4. after the reaction system is cooled to room temperature, collecting the required interface modifier. By means of the interface modifier for a carbon fiber / vinyl ester composite material and the preparation method of the present invention, the structure of the interface modifier can be optimized, such that the interface modifier serves as a link between a resin matrix and the surface of a carbon fiber, thereby improving the interface performance therebetween. The method for preparing a modifier can also be simplified, the preparation efficiency is improved, and large-scale preparation is achieved.

Description

An interface modifier for carbon fiber / vinyl ester composite materials and its preparation method Technical Field

[0001] This invention relates to the field of polymer chemistry, and more specifically, to an interface modifier for carbon fiber / vinyl ester composite materials and its preparation method. Background Technology

[0002] The interface, as a crucial component of composite materials, significantly impacts the performance of carbon fiber reinforced materials. While research on the interface between carbon fiber and epoxy resin systems is relatively in-depth and systematic, the poor water resistance and weather resistance of epoxy composites severely limit their application in the shipbuilding and marine industries. Vinyl ester resin, on the other hand, is internationally recognized as a highly corrosion-resistant resin. Its excellent resistance to marine corrosion and low water absorption make it a mainstream resin in shipbuilding and marine engineering. However, current research on the compatibility between carbon fiber and vinyl ester resin is limited, and existing systems exhibit poor compatibility and low interfacial bonding strength between the carbon fiber and vinyl ester resin matrix. This results in low interlaminar shear strength in the prepared composite materials, affecting their overall mechanical properties and long-term durability, failing to meet the long-term service requirements of shipbuilding and marine engineering. Therefore, researching how to optimize modifiers to improve the compatibility and interfacial bonding strength between carbon fiber and vinyl ester is of great significance.

[0003] Currently, common methods for improving the interfacial properties of carbon fiber / vinyl ester composites include: developing carbon fiber sizing agents that match vinyl ester resins, performing surface activation treatment on carbon fiber fabrics, and adding functional additives.

[0004] Specifically, in 2022, patent CN113957718A disclosed a method for preparing an environmentally friendly modified polyurethane vinyl carbon fiber sizing agent. The method first synthesizes a modified polyurethane vinyl sizing agent main sizing material, and then reverse-emulsifies it to obtain the modified polyurethane vinyl carbon fiber sizing agent. Research found that the interlaminar shear strength of the composite material prepared from carbon fiber fabric using this sizing agent increased from 35.6 MPa in the comparative example to a maximum of 98.3 MPa, significantly improving the interfacial properties of the carbon fiber / vinyl ester composite material.

[0005] In 2024, patent CN118407253A disclosed a carbon nanotube-modified vinyl ester carbon fiber sizing agent composition, its preparation method, and its application. This composition includes isocyanate-modified vinyl ester resin prepolymer and carbon nanotubes. The carbon nanotubes in the sizing agent composition can effectively increase the interfacial properties between the carbon fiber and the composite matrix. The isocyanate-modified vinyl ester resin prepolymer can improve the hydrolysis resistance and media corrosion resistance of the composite material, and can co-crosslink and cure with vinyl ester resin, endowing the carbon fiber composite material with excellent mechanical properties and fatigue resistance. Studies have found that the interfacial properties of the carbon fiber vinyl ester composite material prepared using this sizing agent were significantly improved, increasing from 56.7 MPa in the control group to a maximum of 93.5 MPa.

[0006] Patent CN111032747A discloses a composition of an additive for carbon fiber composite materials. The additive has a molecular weight greater than 200 g / mol and contains unsaturated bonds, amino groups and ester linkage groups in its molecular structure. When added to the carbon fiber composite material system, the transverse tensile strength of the composite material is increased from 18.0 MPa to a maximum of 33.1 MPa, showing a significant improvement effect.

[0007] However, the synthesis steps of the polymer or sizing agent molecules required for grafting carbon fiber surfaces in the aforementioned patent documents are quite complex, which has a significant impact on the process of existing composite material systems. Summary of the Invention

[0008] In view of this, the present invention aims to propose an interface modifier for carbon fiber / vinyl ester composite materials and its preparation method, in order to solve the problems of weak interfacial properties, low interlaminar shear strength, poor comprehensive mechanical properties and long-term durability of existing carbon fiber / vinyl ester composite materials, as well as the problem of the complex preparation process of existing sizing agents or additives for carbon fiber / vinyl ester composite materials. This invention optimizes the structure of the interface modifier, giving it characteristics of low viscosity, high functionality, low chain entanglement, good solubility and low surface energy, thereby enabling it to act as a connector between the resin matrix and the carbon fiber surface, improving the interfacial properties between the two. Furthermore, it simplifies the preparation method of the interface modifier, improves the preparation efficiency, reduces the preparation cost, and enables large-scale preparation of the interface modifier.

[0009] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0010] This invention relates to an interface modifier for carbon fiber / vinyl ester composite materials and its preparation method. The raw materials of the interface modifier for carbon fiber / vinyl ester composite materials include an amino monomer and an amide precursor monomer, wherein the molar ratio of the amide precursor monomer to the amino monomer is 1:0.8-3; or the raw materials of the interface modifier include a silane coupling agent and a diol, wherein the molar ratio of the silane coupling agent to the diol is 1:0.8-3.

[0011] Furthermore, the interface modifier is any one or more of the following: linear polysiloxanes containing active hydroxyl groups, hyperbranched polysiloxanes containing active hydroxyl groups, linear polysiloxanes containing epoxy groups, hyperbranched polysiloxanes containing epoxy groups, linear polysiloxanes containing amino groups, hyperbranched polysiloxanes containing amino groups, linear polyamide amines containing amino and amide groups, and hyperbranched polyamide amines containing amino and amide groups.

[0012] Furthermore, the silane coupling agent is a silane coupling agent containing hydroxyl / amino or epoxy groups; the diol is a small molecule diol.

[0013] Furthermore, the amine monomer is a diamine or a triamine; the amide precursor monomer is any one of acid anhydrides, acyl chlorides, or acrylates.

[0014] A method for preparing an interface modifier for carbon fiber / vinyl ester composite materials, the method being applied to the aforementioned interface modifier for carbon fiber / vinyl ester composite materials, the method comprising the following steps:

[0015] Step 1: Raw material preparation: Weigh the raw materials of the interface modifier according to the required proportion and add the weighed raw materials to a three-necked flask;

[0016] Step 2: Set up the experimental setup so that the part of the three-necked flask containing the raw material is submerged in the oil bath for oil bath treatment, and insert the stirrer into the raw material through the inlet of the three-necked flask to stir.

[0017] Step 3: Control the reaction temperature and reaction time dynamically until no more distillate is generated in the reaction system, then stop the reaction.

[0018] Step 4: After the reaction system cools to room temperature, collect the interface modifier polymer in the three-necked flask to obtain the interface modifier for the composite material to be prepared.

[0019] Furthermore, step two includes:

[0020] Step S21: Select the necessary laboratory equipment and set up the required laboratory equipment; the required equipment includes an oil bath, heating device, thermometer or temperature controller, stirrer, support, clamp, heat transfer oil, three-necked flask, and safety equipment.

[0021] Step S22: Submerge the part of the three-necked flask containing the raw material into the oil bath for oil bath treatment;

[0022] Step S23: Insert the stirrer into the raw material through the inlet of the three-necked flask and stir.

[0023] Furthermore, step three includes:

[0024] Step S31: The preset reaction start temperature is T1℃, the reaction time after reaching the reaction start temperature is t1, the reaction heating interval time is t2, the number of temperature increases within each reaction heating interval time is T2℃, and the highest reaction temperature is T3℃.

[0025] Step S32: Using dynamic adjustment, first control the temperature of the heat transfer oil in the oil bath to reach T1℃, and after the reaction t1 hours, increase the temperature by T2℃ every t2 hours until the temperature reaches T3℃, then stop heating;

[0026] Step S33: Continue the reaction at a temperature of T3℃ until no more distillate is generated in the reaction system, then stop the reaction.

[0027] Furthermore, the value range of T1 is 30-60; the value range of t1 is 2-4.

[0028] Furthermore, the value range of t2 is 1-2; the value range of T2 is 5-10.

[0029] Furthermore, in step four, the structural formula of the obtained interface modifier polymer is:

[0030] ,in, .

[0031] Compared with the prior art, the interface modifier and preparation method for carbon fiber / vinyl ester composite materials described in this invention have the following beneficial effects:

[0032] By incorporating the aforementioned interface modifier, its structure can be optimized, resulting in characteristics such as low viscosity, high functionality, minimal chain entanglement, good solubility, and low surface energy. This allows it to act as a connector between the resin matrix and the carbon fiber surface, improving the interfacial properties between the two. Furthermore, the method for preparing the interface modifier described in this application simplifies the preparation process, improves efficiency, reduces costs, and enables large-scale production. Attached Figure Description

[0033] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0034] Figure 1 is a schematic diagram of the polymer structure of the interface modifier containing active groups (i.e., amino / hydroxyl groups);

[0035] Figure 2 is a schematic diagram of the infrared characterization (FT-IR) of the interface modifier polymer containing active amino groups;

[0036] Figure 3 is a schematic diagram of gel permeation chromatography (GPC) of interface modifier polymers containing active amino groups;

[0037] Figure 4 is a schematic diagram of the 1H NMR spectrum of the interface modifier polymer containing active amino groups. Detailed Implementation

[0038] The inventive concepts of this disclosure will be described below using terminology commonly used by those skilled in the art to communicate the essence of their work to others skilled in the art. However, these inventive concepts may be embodied in many different forms and should not be construed as limited to the embodiments described herein.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] In existing technologies, there are problems such as poor compatibility and low interfacial bonding strength between carbon fiber and vinyl ester resin matrix. This results in low interlaminar shear strength in the prepared composite materials, thus affecting the overall mechanical properties and long-term durability of the composites, failing to meet the long-term service requirements in shipbuilding and marine engineering. Furthermore, the existing processes for preparing sizing agents or additives suitable for carbon fiber / vinyl ester resin systems involve complex synthesis steps for the polymer or sizing agent slurry molecules, significantly impacting the existing composite material processing procedures.

[0042] To address the problems of weak interfacial properties, low interlaminar shear strength, poor overall mechanical properties, and poor long-term durability in existing carbon fiber / vinyl ester composite materials, as well as the complex preparation processes of existing sizing agents or additives for carbon fiber / vinyl ester composite materials, this embodiment proposes an interface modifier for carbon fiber / vinyl ester composite materials and its preparation method. The raw materials for the interface modifier include an amino monomer and an amide precursor monomer, with a molar ratio of 1:0.8-3. Alternatively, the raw materials for the interface modifier include a silane coupling agent and a diol, with a molar ratio of 1:0.8-3. The interface modifiers prepared in this application fall into two main categories: hyperbranched polysiloxanes and hyperbranched polyamide amines. Hyperbranched polysiloxanes are prepared from silane coupling agents and diols; hyperbranched polyamide amines are prepared from amino monomers and amide precursor monomers. Specifically, the interface modifiers prepared are any one or more of the following: linear polysiloxanes containing active hydroxyl groups, hyperbranched polysiloxanes containing active hydroxyl groups, linear polysiloxanes containing epoxy groups, hyperbranched polysiloxanes containing epoxy groups, linear polysiloxanes containing amino groups, hyperbranched polysiloxanes containing amino groups, linear polyamide amines containing amino and amide groups, and hyperbranched polyamide amines containing amino and amide groups.

[0043] By incorporating the aforementioned interface modifier, its structure can be optimized, resulting in characteristics such as low viscosity, high functionality, minimal chain entanglement, good solubility, and low surface energy. This allows it to act as a connector between the resin matrix and the carbon fiber surface, improving the interfacial properties between the two. Furthermore, using a polymer containing active functional groups prepared in this application as an interface modifier, and adding it to a vinyl ester resin matrix, can effectively improve the interfacial strength of the carbon fiber / vinyl ester composite material, ensuring the mechanical stability and long-term durability of the composite material's internal structure.

[0044] A method for preparing an interface modifier for carbon fiber / vinyl ester composite materials, the method being applied to the aforementioned interface modifier for carbon fiber / vinyl ester composite materials, the method comprising the following steps:

[0045] Step 1: Raw material preparation: Weigh the raw materials of the interface modifier according to the required proportion and add the weighed raw materials to a three-necked flask;

[0046] Step 2: Set up the experimental setup so that the part of the three-necked flask containing the raw material is submerged in the oil bath for oil bath treatment, and insert the stirrer into the raw material through the inlet of the three-necked flask to stir.

[0047] Step 3: Control the reaction temperature and reaction time dynamically until no more distillate is generated in the reaction system, then stop the reaction.

[0048] Step 4: After the reaction system cools to room temperature, collect the interface modifier polymer in the three-necked flask to obtain the interface modifier for the composite material to be prepared.

[0049] In step one, the silane coupling agent in the raw material of the interface modifier is a silane coupling agent containing hydroxyl / amino or epoxy groups, and the diol in the raw material of the interface modifier is a small molecule diol. The amine monomer is a diamine or triamine; the amide precursor monomer is any one of acid anhydrides, acyl chlorides, or acrylates.

[0050] The method described above simplifies the preparation of interface modifiers, improves their efficiency, reduces costs, and enables large-scale production. Furthermore, since the polymer's properties are relatively stable and less affected by the environment, applying the interface modifier prepared in this application to carbon fiber / vinyl ester composites can not only improve the interfacial strength of the composites, meeting the demands for high-performance composites in the shipbuilding and marine engineering field, but also promote the application and dissemination of carbon fiber / vinyl ester composites in this field.

[0051] Step two includes:

[0052] Step S21: Select the necessary laboratory equipment and assemble it. The required equipment includes an oil bath, a heating device, a thermometer or temperature controller, a stirrer, a support, clamps, thermal oil, a three-necked flask, and safety equipment. Specifically, the heating device includes any one or more of a hot plate and a heating mantle, used to heat the oil bath. The thermal oil includes any one or more of silicone oil or mineral oil. Safety equipment includes any one or more of protective gloves, goggles, and eye protection. The assembly process includes: fixing the oil bath containing thermal oil to the support, placing the heating device below the oil bath, and placing the thermometer or temperature controller inside the oil bath and / or the three-necked flask.

[0053] Step S22: Submerge the part of the three-necked flask containing the raw material into the oil bath for oil bath treatment; wherein, the three-necked flask is connected to the support to facilitate the improvement of the stability of the three-necked flask in the oil bath.

[0054] Step S23: Insert the stirrer into the raw material through the inlet of the three-necked flask to stir it; in order to maintain a uniform oil bath temperature and improve the efficiency of the preparation of the interface modifier.

[0055] By selecting and setting up the experimental setup, and immersing the portion of the three-necked flask containing the raw materials in an oil bath, it is possible to simplify the process of synthesizing polymers for interface modifiers in carbon fiber / vinyl ester composites. This also facilitates the large-scale preparation of interface modifiers. Furthermore, by adding interface modifiers to the vinyl ester resin matrix, the interfacial strength of carbon fiber / vinyl ester composites can be improved without affecting the existing composite material preparation process.

[0056] Step three includes:

[0057] Step S31: The preset reaction start temperature is T1℃, the reaction time after reaching the reaction start temperature is t1, the reaction heating interval time is t2, the number of temperature increases within each reaction heating interval time is T2℃, and the highest reaction temperature is T3℃.

[0058] Step S32: Using dynamic adjustment, first control the temperature of the heat transfer oil in the oil bath to reach T1℃, and after the reaction t1 hours, increase the temperature by T2℃ every t2 hours until the temperature reaches T3℃, then stop heating;

[0059] Step S33: Continue the reaction at a temperature of T3℃ until no more distillate is generated in the reaction system, then stop the reaction; at this time, during the synthesis process, the polymer color gradually darkens as the temperature and the degree of reaction increase.

[0060] Wherein, T1 ranges from 30 to 60; t1 ranges from 2 to 4; t2 ranges from 1 to 2; T3 ranges from 5 to 10; and T3 ranges from 150 to 200. In this embodiment, the specific values ​​of T1, T2, T3, t1, and t2 are set according to requirements. The units for t1 and t2 are both hours. Temperature control can be achieved using a stepped heating method to avoid localized overheating during heating, which could lead to gelation and experimental failure.

[0061] By controlling the temperature during the oil bath process, the rapid and efficient precipitation of polymers can be effectively achieved, and the production cycle of interface modifiers can be effectively reduced, thereby improving the quality of interface modifiers.

[0062] In step four, the structural formula of the obtained interface modifier polymer is:

[0063] ,in, .

[0064] Furthermore, in step four, the composite material is a carbon fiber / vinyl ester composite material. The method for improving the interfacial properties of the composite material includes: weighing a predetermined mass fraction of interfacial modifier from the desired vinyl ester resin matrix, adding the weighed interfacial modifier to the vinyl ester resin matrix, and then, according to the composite material preparation method, combining the vinyl ester resin matrix with the added interfacial modifier with carbon fiber fabric to prepare a carbon fiber / vinyl ester composite material with excellent interfacial properties. The predetermined mass fraction ranges from 2% to 20%. The carbon fiber fabric includes any one or more of the following: polyacrylonitrile-based PAN carbon fiber fabric or pitch-based carbon fiber fabric. The polyacrylonitrile-based PAN carbon fiber fabric categories include any one or more of the following: T300 grade, T700 grade, T800 grade, T1000 grade, M40 grade, M45 grade, M50 grade, and large tow. The vinyl ester resin categories include any one or more of the following: high-strength vinyl ester resin, high-toughness vinyl ester resin, aging-resistant vinyl ester resin, flame-retardant vinyl ester resin, and epoxy resin.

[0065] By optimizing the structure of the interface modifier to include active functional groups and a certain degree of polymerization, and then applying it to carbon fiber / vinyl ester composites, carbon fiber reinforced vinyl ester composite systems with excellent interfacial properties can be effectively prepared. This is beneficial for improving the interfacial properties and overall performance of carbon fiber / vinyl ester composites in the fields of shipbuilding and marine engineering.

[0066] In this embodiment, the interfacial properties of the prepared carbon fiber / vinyl ester composite system will differ when different types of carbon fiber fabrics and vinyl ester resins are selected, as well as when different types and amounts of interfacial modifiers are added. See Examples 1-7 and Comparative Examples 1-2 below for details: Example

[0067] Step 1: First, add the epoxy-containing difunctional silane coupling agent and 1,3-propanediol to a three-necked flask at a molar ratio of 1:0.8.

[0068] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0069] Step 3: Set the initial reaction temperature to 50℃. After reaching this temperature, react for 2 hours. Then increase the temperature by 5℃ every hour until the maximum reaction temperature of 150℃ is reached. At this temperature, react until no more distillate is produced in the system, and then stop the reaction.

[0070] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the epoxy-containing carbon fiber / vinyl ester composite interface modifier.

[0071] The above-mentioned interface modifier was added at 10% by weight of the high-strength vinyl ester resin matrix to prepare T300 grade carbon fiber / vinyl ester composite material. Example

[0072] Step 1: First, add the vinyl-containing difunctional silane coupling agent and diethylene glycol to a three-necked flask in a molar ratio of 1:1.2;

[0073] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0074] Step 3: Set the initial reaction temperature to 60℃, and react for 2 hours after reaching this temperature. Then increase the temperature by 5℃ every hour until the maximum reaction temperature of 130℃ is reached. At this temperature, react until no more distillate is produced in the system, and then stop the reaction.

[0075] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the interface modifier for vinyl-containing carbon fiber / vinyl ester composite materials.

[0076] The above-mentioned interface modifier was added at 5% by weight of the high-toughness vinyl ester resin matrix to prepare T700 grade carbon fiber / vinyl ester composite material. Example

[0077] Step 1: First, add the epoxy-containing trifunctional silane coupling agent and diethylene glycol to a three-necked flask in a molar ratio of 1:1.8;

[0078] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0079] Step 3: Set the initial reaction temperature to 60℃, and react for 2 hours after reaching this temperature. Then increase the temperature by 10℃ every hour until the maximum reaction temperature of 180℃ is reached. At this temperature, react until no more distillate is produced in the system, and then stop the reaction.

[0080] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the epoxy-containing carbon fiber / vinyl ester composite interface modifier.

[0081] The above-mentioned interface modifier was added at 8% by weight of the high-strength vinyl ester resin matrix to prepare T700 grade carbon fiber / vinyl ester composite material. Example

[0082] Step 1: First, add the vinyl-containing trifunctional silane coupling agent and 1,4-butanediol to a three-necked flask in a molar ratio of 1:1.6;

[0083] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0084] Step 3: Set the initial reaction temperature to 60℃, and react for 2 hours after reaching this temperature. Then increase the temperature by 5℃ every hour until the maximum reaction temperature of 130℃ is reached. At this temperature, react until no more distillate is produced in the system, and then stop the reaction.

[0085] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the interface modifier for vinyl-containing carbon fiber / vinyl ester composite materials.

[0086] The above-mentioned interface modifier was added at 5% by weight of the high-strength vinyl ester resin matrix to prepare T700 grade carbon fiber / vinyl ester composite material. Example

[0087] Step 1: First, add the amino-containing difunctional silane coupling agent and 1,3-propanediol to a three-necked flask in a molar ratio of 1:1.2.

[0088] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0089] Step 3: Set the initial reaction temperature to 50℃. After reaching this temperature, react for 1 hour, then increase the temperature by 5℃ every hour until the maximum reaction temperature of 140℃ is reached. At this temperature, react until no more distillate is produced in the system, then stop the reaction.

[0090] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the amino-containing carbon fiber / vinyl ester composite interface modifier.

[0091] The above-mentioned interface modifier was added at 10% by weight of the high-strength vinyl ester resin matrix to prepare carbon fiber / vinyl ester composite material. Example

[0092] Step 1: First, add the amino-containing trifunctional silane coupling agent and 1,3-propanediol to a three-necked flask in a molar ratio of 1:1.8.

[0093] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0094] Step 3: Set the initial reaction temperature to 50℃. After reaching this temperature, react for 1 hour, then increase the temperature by 5℃ every hour until the maximum reaction temperature of 140℃ is reached. At this temperature, react until no more distillate is produced in the system, then stop the reaction.

[0095] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the amino-containing carbon fiber / vinyl ester composite interface modifier.

[0096] The above-mentioned interface modifier was added at 10% by weight of the high-strength vinyl ester resin matrix to prepare large-tow carbon fiber / vinyl ester composite material. Example

[0097] Step 1: First, add methyl acrylate and diethylenetriamine to a three-necked flask in a molar ratio of 1:1.3;

[0098] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0099] Step 3: Set the initial reaction temperature to 50℃. After reaching this temperature, react for 1 hour. Then increase the temperature by 5℃ every hour until the maximum reaction temperature of 140℃ is reached. Stop the reaction after reacting at this temperature for 3 hours.

[0100] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the interface modifier for carbon fiber / vinyl ester composite materials containing amino and amide groups.

[0101] The above-mentioned interface modifier was added at 10% by weight of the high-strength vinyl ester resin matrix to prepare large-tow carbon fiber / vinyl ester composite material. Example

[0102] Step 1: First, add maleic anhydride and diethylenetriamine to a three-necked flask in a molar ratio of 1:1.15;

[0103] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0104] Step 3: Set the initial reaction temperature to 60℃. After reaching this temperature, react for 1 hour, then increase the temperature by 5℃ every hour until the maximum reaction temperature of 150℃ is reached. At this temperature, continue reacting until no more distillate is produced in the system, then stop the reaction.

[0105] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the amino-containing carbon fiber / vinyl ester composite interface modifier.

[0106] The above-mentioned interface modifier was added at 8% by weight of the high-strength vinyl ester resin matrix to prepare T700 grade carbon fiber / vinyl ester composite material. Example

[0107] Step 1: First, add methyl acrylate and ethylenediamine to a three-necked flask in a molar ratio of 1:0.8;

[0108] Step 2: Set up the experimental setup so that the portion of the three-necked flask containing the reactants is submerged in the oil bath, and equip it with a stirrer for stirring;

[0109] Step 3: Set the initial reaction temperature to 50℃. After reaching this temperature, react for 1 hour, then increase the temperature by 5℃ every hour until the maximum reaction temperature of 140℃ is reached. At this temperature, react until no more distillate is produced in the system, then stop the reaction.

[0110] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the amino-containing carbon fiber / vinyl ester composite interface modifier.

[0111] The above-mentioned interface modifier was added at 8% by weight of the high-strength vinyl ester resin matrix to prepare T700 grade carbon fiber / vinyl ester composite material.

[0112] Carbon fiber / vinyl ester composite material was prepared by vacuum infusion process using high-strength vinyl ester resin as matrix and T700 grade carbon fiber fabric as reinforcement phase.

[0113] Carbon fiber / vinyl ester composite material was prepared by vacuum infusion process using high-strength vinyl ester resin as matrix and large-tow carbon fiber fabric as reinforcing phase.

[0114] The specific values ​​of the interlaminar shear strength of the composite materials prepared in Examples 1-9 and Comparative Examples 1-2 are shown in Table 1 below:

[0115] Table 1 Comparison of interlaminar shear strength of different systems

[0116]

[0117] Table 1 shows that by preparing polymers containing different active functional groups to improve the interfacial properties of carbon fiber / vinyl ester composites, and by directly adding them to the vinyl ester resin matrix to prepare modified carbon fiber / vinyl ester composites, not only can their application in the field of shipbuilding and marine engineering be promoted, but the problem of weak interfacial properties of composites can also be solved, thereby improving the interfacial properties of composites. Compared with the interlaminar shear strength of 25.7-34.2 in Comparative Examples 1-2, the interlaminar shear strength of composites prepared using the interfacial modifier prepared in this application is between 41.4-57.5. By comparing the two, it is easy to see that by setting the interfacial modifier in this application, the mechanical stability of the internal structure of the composite material can be greatly improved, thereby improving the quality of the composite material.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An interface modifier for carbon fiber / vinyl ester composite materials, characterized in that, The raw materials of the interface modifier include amine monomers and amide precursor monomers, with a molar ratio of amide precursor monomers to amine monomers of 1:0.8-3; or the raw materials of the interface modifier include silane coupling agents and diols, with a molar ratio of silane coupling agents to diols of 1:0.8-3.

2. The interface modifier for carbon fiber / vinyl ester composite materials according to claim 1, characterized in that, The interface modifier is any one or more of the following: linear polysiloxanes containing active hydroxyl groups, hyperbranched polysiloxanes containing active hydroxyl groups, linear polysiloxanes containing epoxy groups, hyperbranched polysiloxanes containing epoxy groups, linear polysiloxanes containing amino groups, hyperbranched polysiloxanes containing amino groups, linear polyamide amines containing amino and amide groups, and hyperbranched polyamide amines containing amino and amide groups.

3. The interface modifier for carbon fiber / vinyl ester composite materials according to claim 1, characterized in that, The silane coupling agent is a silane coupling agent containing hydroxyl / amino or epoxy groups; the diol is a small molecule diol.

4. The interface modifier for carbon fiber / vinyl ester composite materials according to claim 1, characterized in that, The amine monomer is a diamine or a triamine; the amide precursor monomer is any one of acid anhydrides, acyl chlorides, or acrylates.

5. A method for preparing an interface modifier for carbon fiber / vinyl ester composite materials, characterized in that, The method is applied to an interface modifier for carbon fiber / vinyl ester composite materials according to any one of claims 1-4, and the method includes the following steps: Step 1: Raw material preparation: Weigh the raw materials of the interface modifier according to the required proportion and add the weighed raw materials to a three-necked flask; Step 2: Set up the experimental setup so that the part of the three-necked flask containing the raw material is submerged in the oil bath for oil bath treatment, and insert the stirrer into the raw material through the inlet of the three-necked flask to stir. Step 3: Control the reaction temperature and reaction time dynamically until no more distillate is generated in the reaction system, then stop the reaction. Step 4: After the reaction system cools to room temperature, collect the interface modifier polymer in the three-necked flask to obtain the interface modifier for the composite material to be prepared.

6. The method for preparing an interface modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that, Step two includes: Step S21: Select the necessary laboratory equipment and set up the required laboratory equipment; the required equipment includes an oil bath, heating device, thermometer or temperature controller, stirrer, support, clamp, heat transfer oil, three-necked flask, and safety equipment. Step S22: Submerge the part of the three-necked flask containing the raw material into the oil bath for oil bath treatment; Step S23: Insert the stirrer into the raw material through the inlet of the three-necked flask and stir.

7. The method for preparing an interface modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that, Step three includes: Step S31: The preset reaction start temperature is T1℃, the reaction time after reaching the reaction start temperature is t1, the reaction heating interval time is t2, the number of temperature increases within each reaction heating interval time is T2℃, and the highest reaction temperature is T3℃. Step S32: Using dynamic adjustment, first control the temperature of the heat transfer oil in the oil bath to reach T1℃, and after the reaction t1 hours, increase the temperature by T2℃ every t2 hours until the temperature reaches T3℃, then stop heating; Step S33: Continue the reaction at a temperature of T3℃ until no more distillate is generated in the reaction system, then stop the reaction.

8. The method for preparing an interface modifier for carbon fiber / vinyl ester composite materials according to claim 7, characterized in that, The value of T1 ranges from 30 to 60; the value of t1 ranges from 2 to 4.

9. The method for preparing an interface modifier for carbon fiber / vinyl ester composite materials according to claim 7, characterized in that, The value of t2 is in the range of 1-2; the value of T2 is in the range of 5-10.

10. The method for preparing an interface modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that, In step four, the structural formula of the obtained interface modifier polymer is: ,in, 。

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