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

Abstract

The invention provides an interface modifier for a carbon fiber / vinyl ester composite material and a preparation method, the interface modifier comprises the following raw materials: an amido monomer and an amide precursor monomer, and the molar ratio of the amide precursor monomer to the amido monomer is 1: (0.8-3); or the silane coupling agent and the dihydric alcohol are included, and the molar ratio of the silane coupling agent to the dihydric alcohol is 1: (0.8-3). The method comprises the following steps: step 1, preparing raw materials; 2, building an experimental device; step 3, controlling the reaction temperature and the reaction time until no distillate is continuously generated in the reaction system; step 4, after the reaction system is cooled to room temperature, collecting to obtain the required interface modifier; according to the interface modifier for the carbon fiber / vinyl ester composite material and the preparation method, the structure of the interface modifier can be optimized, so that the interface modifier plays a connecting role between a resin matrix and the surface of the carbon fiber, and the interface performance between the resin matrix and the surface of the carbon fiber is improved. The preparation method of the modifier can be simplified, the preparation efficiency is improved, and large-scale preparation is realized.

Description

Technical Field

[0001] The present invention relates to the field of polymer chemistry, and in particular, to an interfacial modifier for a carbon fiber / vinyl ester composite material and a preparation method thereof. Background Art

[0002] The interface, as an important part of composite materials, has an important impact on the performance of carbon fiber reinforced materials. At present, the interface research on carbon fiber and epoxy resin systems is relatively in-depth and systematic. However, due to the poor water resistance and weather resistance of epoxy composites, their applications in the ship and ocean fields are greatly restricted. Vinyl ester resin is an internationally recognized highly corrosion-resistant resin, and its excellent marine corrosion resistance and low water absorption characteristics also make it the mainstream resin in the ship and ocean engineering fields. However, at present, there is little research on the compatibility between carbon fiber and vinyl ester resin at home and abroad. There are problems such as poor compatibility and low interfacial bonding strength between the existing carbon fiber and vinyl ester resin matrix. The interlaminar shear strength of the prepared composite products is low, which in turn affects the comprehensive mechanical properties and long-term durability of the composites and cannot meet the long-term use requirements in ship and ocean engineering. Therefore, it is of great significance to study how to optimize the modifier to improve the compatibility and interfacial bonding strength between carbon fiber and vinyl ester.

[0003] At present, the common methods to improve the interfacial properties of carbon fiber / vinyl ester composites include: developing a sizing agent for carbon fiber that matches vinyl ester resin, surface activation treatment of carbon fiber fabric, adding functional additives, etc.

[0004] Specifically, in 2022, Patent CN113957718A disclosed a preparation method of an environmentally friendly modified polyurethane vinyl carbon fiber sizing agent. First, the main slurry of the modified polyurethane vinyl sizing agent was synthesized, and then it was inversely emulsified to obtain the modified polyurethane vinyl carbon fiber sizing agent. It was found that the interlaminar shear strength of the composite material prepared from the carbon fiber fabric using this sizing agent was 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, a sizing agent composition for carbon nanotube-modified vinyl carbon fiber, its preparation method and application were disclosed in Patent CN118407253A, which includes an isocyanate-modified vinyl resin prepolymer and carbon nanotubes. The carbon nanotubes in the sizing agent composition can effectively improve the interfacial properties between the carbon fiber and the composite matrix. The isocyanate-modified vinyl resin prepolymer can enhance the hydrolysis resistance and corrosion resistance of the composite material in media, and can co-crosslink and cure with vinyl ester resin, endowing the carbon fiber composite material with excellent mechanical properties and fatigue resistance. It was found that the interfacial properties of the carbon fiber vinyl ester composite prepared with this sizing agent were improved from 56.7 MPa of the control group to a maximum of 93.5 MPa, with a significant improvement effect.

[0006] Patent CN111032747A disclosed 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-linked groups in its molecular structure. After adding it to the carbon fiber composite material system, the transverse tensile strength of the composite material was improved from 18.0 MPa to a maximum of 33.1 MPa, with a significant improvement effect.

[0007] However, in the above patent documents, the synthesis steps of the polymers or sizing agent slurries required for grafting on the carbon fiber surface are relatively complex, which has a great impact on the process of the existing composite material system. Summary of the Invention

[0008] In view of this, the present invention aims to provide an interfacial modifier for carbon fiber / vinyl ester composite materials and its preparation method to solve the problems existing in the prior art, such as the weak interfacial properties, low interlaminar shear strength, poor comprehensive mechanical properties and long-term durability of existing carbon fiber / vinyl ester composite materials, and the relatively complex preparation process of sizing agents or additives for existing carbon fiber / vinyl ester composite materials. By doing so, it is possible to optimize the structure of the interfacial modifier to make it have the characteristics of low viscosity, high functionality, few chain entanglements, good solubility and low surface energy, so as to play a connecting role between the resin matrix and the carbon fiber surface and improve the interfacial properties between the two. In addition, it can also simplify the preparation method of the interfacial modifier, improve the preparation efficiency of the interfacial modifier, reduce the preparation cost, and realize the large-scale preparation of the interfacial modifier.

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

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

[0011] Furthermore, the interfacial modifier is any one or more of linear polysiloxane with active hydroxyl groups, hyperbranched polysiloxane with active hydroxyl groups, linear polysiloxane with epoxy groups, hyperbranched polysiloxane with epoxy groups, linear polysiloxane with amino groups, hyperbranched polysiloxane with amino groups, linear polyamidoamine with amino and amide groups, and hyperbranched polyamidoamine with 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 amino monomer is a diamine or a triamine; the amide precursor monomer is any one of acid anhydrides, acyl chlorides, and acrylate esters.

[0014] A preparation method of an interfacial modifier for carbon fiber / vinyl ester composite materials. The method is applied to the interfacial modifier for carbon fiber / vinyl ester composite materials described above, and the method includes the following steps:

[0015] Step 1. Raw material preparation: Weigh the raw materials of the interfacial modifier according to the required ratio, and add the weighed raw materials into a three-necked flask.

[0016] Step 2. Set up the experimental device, immerse the part of the three-necked flask containing the raw materials in an oil bath pan for oil bath treatment, and insert a stirrer into the raw materials through the inlet of the three-necked flask to stir.

[0017] Step 3. In a dynamically adjusted manner, control the reaction temperature and reaction time until no more distillate is generated in the reaction system, and then stop the reaction.

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

[0019] Furthermore, Step 2 includes:

[0020] Step S21: Select the required laboratory devices and set them up; among them, the required devices include an oil bath pan, a heating device, a thermometer or a temperature controller, a stirrer, a bracket, a clamp, heat transfer oil, a three-necked flask, and safety equipment.

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

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

[0023] Furthermore, Step 3 includes:

[0024] Step S31: Preset the initial reaction temperature as T1 °C, the reaction time after reaching the initial reaction temperature as t1, the reaction temperature increase interval time as t2, the temperature increase degree within each reaction temperature increase interval time as T2 °C, and the highest reaction temperature as T3 °C;

[0025] Step S32: In a dynamically adjusted manner, first control the temperature of the heat transfer oil in the oil bath pot to reach T1 °C, and after reacting for t1 hours, increase the temperature by T2 °C every t2 hours until the temperature reaches T3 °C, then stop heating;

[0026] Step S33: At the temperature of T3 °C, continue the reaction 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 4, the structural formula of the prepared interfacial modifier polymer is:

[0030] .

[0031] Compared with the prior art, the interfacial modifier for carbon fiber / vinyl ester composite material and its preparation method of the present invention have the following beneficial effects:

[0032] Through the setting of the interfacial modifier, the structure of the interfacial modifier can be optimized, making it have the characteristics of low viscosity, high functionality, less chain entanglement, good solubility, and low surface energy. Furthermore, it can play a connecting role between the resin matrix and the carbon fiber surface, improving the interfacial performance between the two. In addition, through the setting of the method for preparing the interfacial modifier in this application, the preparation method of the interfacial modifier can be simplified, the preparation efficiency of the interfacial modifier can be improved, the preparation cost can be reduced, and the large-scale preparation of the interfacial modifier can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0034] Figure 1 Schematic diagram of the polymer structure of the interfacial modifier containing reactive groups (i.e., amino / hydroxyl groups);

[0035] Figure 2 Schematic diagram of the infrared characterization (FT-IR) of the polymer of the interfacial modifier containing reactive amino groups;

[0036] Figure 3 Schematic diagram of the gel permeation chromatography (GPC) of the polymer of the interfacial modifier containing reactive amino groups;

[0037] Figure 4 Schematic diagram of the nuclear magnetic resonance hydrogen spectrum (1H NMR) of the polymer of the interfacial modifier containing reactive amino groups. Detailed implementation manners

[0038] Hereinafter, the inventive concepts of the present disclosure will be described using the terms that those skilled in the art would typically use to convey the substance of their work to other skilled persons in the art. However, these inventive concepts may be embodied in many different forms and thus should not be construed as limited to the embodiments described herein.

[0039] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

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

[0041] In the prior art, there are problems such as poor compatibility and low interfacial bonding strength between carbon fibers and vinyl ester resin matrices. The interlaminar shear strength of the prepared composite products is low, which in turn affects the comprehensive mechanical properties and long-term durability of the composites and cannot meet the long-term use requirements in ship and ocean engineering. Moreover, in the existing processes for preparing sizing agents or additives applicable to carbon fiber / vinyl ester resin systems, there are problems that the synthesis steps of polymer or sizing agent slurry molecules are relatively complex and have a great impact on the process of the existing composite material systems.

[0042] In order to solve the problems existing in the existing carbon fiber / vinyl ester composites in the prior art, such as weak interfacial properties, low interlaminar shear strength, poor comprehensive mechanical properties and long-term durability, and the complex preparation process of sizing agents or additives used in the existing carbon fiber / vinyl ester composites; this embodiment proposes an interfacial modifier for carbon fiber / vinyl ester composites and a preparation method. The raw materials of the interfacial modifier for carbon fiber / vinyl ester composites include amino monomers and amide precursor monomers, and the molar ratio of amide precursor monomers to amino monomers is 1:0.8 - 3. Or the raw materials of the interfacial modifier include silane coupling agents and diols, and the molar ratio of silane coupling agents to diols is 1:0.8 - 3. Among them, the types of interfacial modifiers prepared in this application include two categories: hyperbranched polysiloxanes and hyperbranched polyamidoamines; silane coupling agents and diols are used to prepare hyperbranched polysiloxanes; amino monomers and amide precursor monomers are used to prepare hyperbranched polyamidoamines. Specifically, the types of interfacial modifiers prepared are any one or more of 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 polyamidoamines containing amino and amide groups, and hyperbranched polyamidoamines containing amino and amide groups.

[0043] Through the setting of the interfacial modifier, the structure of the interfacial modifier can be optimized, making it have the characteristics of low viscosity, high functionality, few chain entanglements, good solubility and low surface energy. Furthermore, it can play a connecting role between the resin matrix and the carbon fiber surface, enhancing the interfacial properties between the two. In addition, by using a type of polymer containing active functional groups in the structure prepared in this application as the interfacial modifier and adding it to the vinyl ester resin matrix, the interfacial strength of the carbon fiber / vinyl ester composite can be effectively improved, ensuring the mechanical stability and long-term durability of the internal structure of the composite material.

[0044] A preparation method of an interfacial modifier for carbon fiber / vinyl ester composites, which is applied to the interfacial modifier for carbon fiber / vinyl ester composites described above. The method includes the following steps:

[0045] Step 1: Raw material preparation: Weigh the raw materials of the interfacial modifier according to the required ratio, and add the weighed raw materials into a three-necked flask.

[0046] Step 2: Set up the experimental device, immerse the part of the three-necked flask containing the raw materials in an oil bath pan for oil bath treatment, and extend the stirrer into the raw materials through the inlet of the three-necked flask to stir.

[0047] Step 3: Control the reaction temperature and reaction time in a dynamic adjustment manner until no more distillate is generated in the reaction system, and then stop the reaction;

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

[0049] Among them, in Step 1, the silane coupling agent in the raw materials of the interfacial modifier is a silane coupling agent containing hydroxyl / amino or epoxy groups, and the diol in the raw materials of the interfacial modifier is a small molecule diol. The amine monomer is a diamine or a triamine; the amide precursor monomer is any one of acid anhydrides, acyl chlorides, and acrylate esters.

[0050] Through the setting of the above method, the preparation method of the interfacial modifier can be simplified, the preparation efficiency of the interfacial modifier can be improved, the preparation cost can be reduced, and the large-scale preparation of the interfacial modifier can be realized. In addition, since the polymer has relatively stable properties and is less affected by the environment, therefore, applying the interfacial modifier prepared in this application to carbon fiber / vinyl ester composites can not only improve the interfacial strength of the composites and meet the requirements of the ship and ocean engineering fields for high-performance composites, but also play a promoting role in the application and popularization of carbon fiber / vinyl ester composites in the ship and ocean engineering fields.

[0051] Step 2 includes:

[0052] Step S21: Select the required laboratory equipment and set up the required laboratory equipment; among them, the required equipment includes an oil bath, a heating device, a thermometer or a temperature controller, a stirrer, a bracket, a clamp, a heat transfer oil, a three-necked flask, and safety equipment. Specifically, the heating device includes any one or more of an electric hot plate and a heating mantle, and is used to realize the heating treatment of the oil bath. The heat transfer oil includes any one or more of silicone oil and mineral oil. The safety equipment includes any one or more of protective gloves, goggles, and safety glasses. The process of setting up the experimental equipment includes: fixing the oil bath containing the heat transfer oil on the bracket, setting the heating device under the oil bath, and setting the thermometer or the temperature controller in the oil bath and / or the three-necked flask.

[0053] Step S22: Immerse the part of the three-necked flask containing the raw materials in the oil bath for oil bath treatment; among them, the three-necked flask is connected to the bracket to facilitate improving the stability of the three-necked flask in the oil bath.

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

[0055] By selecting and setting up the experimental device and immersing the part of the three-necked flask containing the raw materials in the oil bath, it is possible to simplify the process of synthesizing the interfacial modifier polymer for carbon fiber / vinyl ester composites and facilitate the large-scale preparation of the interfacial modifier. Moreover, by adding the interfacial modifier to the vinyl ester resin matrix, the interfacial strength of the carbon fiber / vinyl ester composite can be improved without affecting the existing composite preparation process.

[0056] Step three includes:

[0057] Step S31: Preset the initial reaction temperature as T1 °C, the reaction time after reaching the initial reaction temperature as t1, the reaction temperature rising interval time as t2, the temperature rise degree within each reaction temperature rising interval time as T2 °C, and the highest reaction temperature as T3 °C.

[0058] Step S32: In a dynamically adjusted manner, first control the temperature of the heat transfer oil in the oil bath pot to reach T1 °C, and after reacting for t1 hours, increase the temperature by T2 °C every t2 hours until the temperature reaches T3 °C, then stop heating;

[0059] Step S33: At the temperature of T3 °C, continue the reaction until no more distillate is generated in the reaction system, then stop the reaction; At this time, during the synthesis process, as the temperature and the reaction degree increase, the color of the polymer gradually becomes darker.

[0060] Among them, the value range of T1 is 30 - 60; the value range of t1 is 2 - 4; the value range of t2 is 1 - 2; the value range of T2 is 5 - 10; the value range of T3 is 150 - 200. In this embodiment, the specific values of T1, T2, T3, t1, and t2 are set according to requirements. And the units of t1 and t2 are both hours. The temperature control can be carried out in a stepwise temperature rising manner. This is used to avoid local overheating during the heating process and gelation, which may lead to the failure of the experiment.

[0061] By controlling the temperature during the oil bath process, it is possible to effectively achieve the rapid and efficient precipitation of the polymer, and effectively reduce the production cycle of the interfacial modifier and improve the quality of the interfacial modifier.

[0062] In step four, the structural formula of the prepared interfacial modifier polymer is:

[0063] .

[0064] In addition, in Step 4, the composite material is a carbon fiber / vinyl ester composite material. The methods for improving the interfacial properties of the composite material include: weighing an interfacial modifier with a preset mass fraction of the required vinyl ester resin matrix, adding the weighed interfacial modifier to the vinyl ester resin matrix, and then, according to the preparation method of the composite material, compounding the vinyl ester resin matrix added with the interfacial modifier with a carbon fiber fabric to prepare a carbon fiber / vinyl ester composite material with excellent interfacial properties. Among them, the value range of the preset mass fraction is 2% - 20%. The types of carbon fiber fabrics include any one or more of polyacrylonitrile-based PAN carbon fiber fabrics or pitch-based carbon fiber fabrics. The categories of polyacrylonitrile-based PAN carbon fiber fabrics include any one or more of T300 grade, T700 grade, T800 grade, T1000 grade, M40 grade, M45 grade, M50 grade, and large tow. The types of vinyl ester resins include any one or more of high-strength vinyl ester resins, high-toughness vinyl ester resins, anti-aging vinyl ester resins, flame-retardant vinyl ester resins, and epoxy resins.

[0065] By optimizing the structure of the interfacial modifier to make it contain active functional groups and a certain degree of polymerization and applying it to the carbon fiber / vinyl ester composite material, a carbon fiber-reinforced vinyl ester composite material system with excellent interfacial properties can be effectively prepared. Furthermore, it is beneficial to improve the interfacial properties and comprehensive service performance of the carbon fiber / vinyl ester composite material in the field of ship and ocean engineering.

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

[0067] Example 1:

[0068] Step 1: First, add a difunctional silane coupling agent containing epoxy groups and 1,3-propanediol to a three-necked flask at a molar ratio of 1:0.8;

[0069] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants is immersed in the oil bath, and equip a stirrer for stirring;

[0070] Step 3: Set the initial reaction temperature to 50°C, react for 2 hours after reaching this temperature, then raise the temperature by 5°C every 1 hour until the maximum reaction temperature of 150°C, and react at this temperature until no more distillate is generated in the system, then stop the reaction;

[0071] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain the interfacial modifier for carbon fiber / vinyl ester composite materials containing epoxy groups.

[0072] The above interfacial modifier was added at 10% by weight fraction of the high-strength vinyl ester resin matrix to prepare a T300-grade carbon fiber / vinyl ester composite.

[0073] Example 2:

[0074] Step 1: First, a difunctional silane coupling agent containing vinyl and diethylene glycol were added to a three-necked flask at a molar ratio of 1:1.2.

[0075] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants was immersed in the oil bath, and a stirrer was equipped for stirring.

[0076] Step 3: The initial reaction temperature was set at 60 °C. After reaching this temperature, the reaction was carried out for 2 hours, and then the temperature was increased by 5 °C every 1 hour until the highest reaction temperature of 130 °C. The reaction was carried out at this temperature until no more distillate was generated in the system, and then the reaction was stopped.

[0077] Step 4: After the reaction system was cooled to room temperature, the polymer in the three-necked flask was collected to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing vinyl.

[0078] The above interfacial modifier was added at 5% by weight fraction of the high-toughness vinyl ester resin matrix to prepare a T700-grade carbon fiber / vinyl ester composite.

[0079] Example 3:

[0080] Step 1: First, a trifunctional silane coupling agent containing epoxy groups and diethylene glycol were added to a three-necked flask at a molar ratio of 1:1.8.

[0081] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants was immersed in the oil bath, and a stirrer was equipped for stirring.

[0082] Step 3: The initial reaction temperature was set at 60 °C. After reaching this temperature, the reaction was carried out for 2 hours, and then the temperature was increased by 10 °C every 1 hour until the highest reaction temperature of 180 °C. The reaction was carried out at this temperature until no more distillate was generated in the system, and then the reaction was stopped.

[0083] Step 4: After the reaction system was cooled to room temperature, the polymer in the three-necked flask was collected to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing epoxy groups.

[0084] The above interfacial modifier was added at 8% by weight fraction of the high-strength vinyl ester resin matrix to prepare a T700-grade carbon fiber / vinyl ester composite.

[0085] Example 4:

[0086] Step 1: First, add a vinyl-functional trifunctional silane coupling agent and 1,4-butanediol into a three-necked flask at a molar ratio of 1:1.6;

[0087] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants is immersed in an oil bath, and equip a stirrer for stirring;

[0088] Step 3: Set the initial reaction temperature to 60 °C. After reaching this temperature, react for 2 hours, then increase the temperature by 5 °C every 1 hour until the maximum reaction temperature of 130 °C. React at this temperature until no more distillate is generated in the system, and then stop the reaction;

[0089] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing vinyl groups;

[0090] Add the above interfacial modifier at 5% by weight of the high-strength vinyl ester resin matrix to prepare T700-grade carbon fiber / vinyl ester composites.

[0091] Example 5:

[0092] Step 1: First, add an amino-functional difunctional silane coupling agent and 1,3-propanediol into a three-necked flask at a molar ratio of 1:1.2;

[0093] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants is immersed in an oil bath, and equip a stirrer for stirring;

[0094] Step 3: Set the initial reaction temperature to 50 °C. After reaching this temperature, react for 1 hour, then increase the temperature by 5 °C every 1 hour until the maximum reaction temperature of 140 °C. React at this temperature until no more distillate is generated in the system, and 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 an interfacial modifier for carbon fiber / vinyl ester composites containing amino groups;

[0096] Add the above interfacial modifier at 10% by weight of the high-strength vinyl ester resin matrix to prepare carbon fiber / vinyl ester composites.

[0097] Example 6:

[0098] Step 1: First, add an amino-functional trifunctional silane coupling agent and 1,3-propanediol into a three-necked flask at a molar ratio of 1:1.8;

[0099] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants is immersed in an oil bath, and equip a stirrer for stirring;

[0100] Step 3: Set the initial reaction temperature to 50°C. After reaching this temperature, react for 1 hour, then increase the temperature by 5°C every 1 hour until the maximum reaction temperature of 140°C is reached. React at this temperature until no more distillate is produced in the system, then stop the reaction;

[0101] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing amino groups;

[0102] Add the above interfacial modifier at 10% by weight of the high-strength vinyl ester resin matrix to prepare large tow carbon fiber / vinyl ester composites.

[0103] Example 7:

[0104] Step 1: First, add methyl acrylate and diethylenetriamine to a three-necked flask in a molar ratio of 1:1.3;

[0105] Step 2: Set up the experimental apparatus so that the part of the three-necked flask containing the reactants is immersed in the oil bath, and equip a stirrer for stirring;

[0106] Step 3: Set the initial reaction temperature to 50°C. After reaching this temperature, react for 1 hour, then increase the temperature by 5°C every 1 hour until the maximum reaction temperature of 140°C is reached. React at this temperature for 3 hours and then stop the reaction;

[0107] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing amino and amide groups;

[0108] Add the above interfacial modifier at 10% by weight of the high-strength vinyl ester resin matrix to prepare large tow carbon fiber / vinyl ester composites.

[0109] Example 8:

[0110] Step 1: First, add maleic anhydride and diethylenetriamine to a three-necked flask in a molar ratio of 1:1.15;

[0111] Step 2: Set up the experimental apparatus so that the part of the three-necked flask containing the reactants is immersed in the oil bath, and equip a stirrer for stirring;

[0112] Step 3: Set the initial reaction temperature to 60°C. After reaching this temperature, react for 1 hour, then increase the temperature by 5°C every 1 hour until the maximum reaction temperature of 150°C is reached. React at this temperature until no more distillate is produced in the system, then stop the reaction;

[0113] Step 4: After the reaction system cools to room temperature, collect the polymer in the three-necked flask to obtain an interfacial modifier for carbon fiber / vinyl ester composites containing amino groups;

[0114] The above interfacial modifier was added at 8% of the weight fraction of the high-strength vinyl ester resin matrix to prepare a T700 grade carbon fiber / vinyl ester composite material.

[0115] Example 9:

[0116] Step 1: First, methyl acrylate and ethylenediamine were added to a three-necked flask at a molar ratio of 1:0.8.

[0117] Step 2: Set up the experimental device so that the part of the three-necked flask containing the reactants was immersed in the oil bath, and a stirrer was equipped for stirring.

[0118] Step 3: The initial reaction temperature was set at 50 °C. After reaching this temperature, the reaction was carried out for 1 hour, and then the temperature was increased by 5 °C every 1 hour until the highest reaction temperature of 140 °C. The reaction was carried out at this temperature until no more distillate was generated in the system, and then the reaction was stopped.

[0119] Step 4: After the reaction system was cooled to room temperature, the polymer in the three-necked flask was collected to obtain an interfacial modifier for carbon fiber / vinyl ester composite materials containing amino groups.

[0120] The above interfacial modifier was added at 8% of the weight fraction of the high-strength vinyl ester resin matrix to prepare a T700 grade carbon fiber / vinyl ester composite material.

[0121] Comparative Example 1:

[0122] Using high-strength vinyl ester resin as the matrix and T700 grade carbon fiber fabric as the reinforcing phase, a carbon fiber / vinyl ester composite material was prepared by vacuum infusion process.

[0123] Comparative Example 2:

[0124] Using high-strength vinyl ester resin as the matrix and large tow carbon fiber fabric as the reinforcing phase, a carbon fiber / vinyl ester composite material was prepared by vacuum infusion process.

[0125] 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:

[0126] Table 1 Comparison of interlaminar shear strength of different systems

[0127] It can be seen from Table 1 that by preparing polymers containing different active functional groups to improve the interfacial properties of carbon fiber / vinyl ester composites and directly adding them to the vinyl ester resin matrix to prepare the modified carbon fiber / vinyl ester composites, not only can its application in the field of ship and ocean engineering be promoted, but also the problem of weak interfacial properties existing in the composites can be solved, the interfacial properties of the composites can be improved. Different from Comparative Examples 1-2, the interlaminar shear strength is 25.7-34.2; the interlaminar shear strength of the composites prepared with the interfacial modifier prepared in this application is between 41.4 and 57.5. By comparing the two, it is not difficult to see that through the setting of the interfacial modifier in this application, the mechanical stability of the internal structure of the composites to which it is applied can be greatly improved, thereby improving the quality of the composites.

[0128] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

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

2. The interfacial modifier for carbon fiber / vinyl ester composite material according to claim 1, characterized in that: The interfacial modifier is any one or more of a linear polysiloxane containing active hydroxyl groups, a hyperbranched polysiloxane containing active hydroxyl groups, a linear polysiloxane containing epoxy groups, a hyperbranched polysiloxane containing epoxy groups, a linear polysiloxane containing amino groups, a hyperbranched polysiloxane containing amino groups, a linear polyamide amine containing amino groups and amide groups, and a hyperbranched polyamide amine containing amino groups and amide groups.

3. The interfacial modifier for carbon fiber / vinyl ester composite material 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 interfacial modifier for carbon fiber / vinyl ester composite material according to claim 1, characterized in that: The amino monomer is a diamine or a triamine; the amide precursor monomer is any one of anhydrides, acyl chlorides and acrylates.

5. A method for preparing an interfacial modifier for carbon fiber / vinyl ester composite materials, characterized in that: The method is applied to an interface modifier for a carbon fiber / vinyl ester composite material according to any one of claims 1 to 4, and the method comprises 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 into a three-necked flask; Step 2: Build an experimental device, immerse the part of the three-necked flask containing the raw material in an oil bath pot for oil bath treatment, and extend 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 in a dynamic adjustment manner until no distillate continues to be generated in the reaction system, and then stop the reaction; Step 4: After the reaction system is cooled to room temperature, the interface modifier polymer in the three-necked flask is collected to obtain the interface modifier for the composite material to be prepared.

6. The method for preparing an interfacial modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that: The second step comprises: Step S21: Select the equipment required for the laboratory and build the required laboratory equipment; the required equipment includes an oil bath, a heating device, a thermometer or a temperature controller, a stirrer, a bracket, a clamp, thermal oil, a three-necked flask, and safety equipment; Step S22: immersing the portion of the three-necked flask containing the raw materials into an oil bath pot for oil bath treatment; Step S23: inserting a stirrer into the raw material through the inlet of the three-necked flask to stir.

7. The method for preparing an interfacial modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that: The step three comprises: Step S31: preset the reaction starting temperature to be T1°C, the reaction time after reaching the reaction starting temperature to be t1, the reaction temperature rising interval to be t2, the temperature rising number in each reaction temperature rising interval to be T2°C, and the maximum reaction temperature to be T3°C; Step S32: first, in a dynamic adjustment manner, control the temperature of the heat transfer oil in the oil bath pot to reach T1°C, and after t1 hours of reaction, increase the temperature by T2°C every t2 hours until the temperature reaches T3°C, and then stop heating; Step S33: Continue the reaction at a temperature of T3°C until no distillate is generated in the reaction system, and then stop the reaction.

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

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

10. The method for preparing an interfacial modifier for carbon fiber / vinyl ester composite materials according to claim 5, characterized in that: In the step 4, the structural formula of the prepared interfacial modifier polymer is: ,in, .

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