A sizing agent for carbon fibers used in matching (poly) dicyclopentadiene and its application

Abstract

The present application relates to a kind of matching (poly) dicyclopentadiene carbon fiber sizing agent and its application, belong to polydicyclopentadiene technical field.The two most important components of the sizing agent of the present application coupling agent (component 1) and film forming agent (component 2) are synthesized by one-pot method, without separation, without recovery solvent, water washing purification, efficient and green environmental protection.Finally, the present application optimizes the introduction strategy of coupling catalyst (component 3), maximizes the reaction efficiency of carbon fiber and sizing agent layer.The present application is simple in operation, energy saving and environmental protection, reaction efficiency is high, interface reinforcing effect is good, can realize the batch production of sizing agent, can realize the batch production of special carbon fiber.

Description

Technical Field

[0001] This invention belongs to the field of poly(dicyclopentadiene) technology, specifically relating to a carbon fiber sizing agent that matches (poly)dicyclopentadiene and its application. Background Technology

[0002] Polydicyclopentadiene (PDCPD) is a thermosetting resin that offers advantages over epoxy resins, including low moisture absorption, high strength, and impact resistance. Furthermore, its raw material (dicyclopentadiene) is a byproduct of petroleum distillation, and the curing process does not release small molecules, making it environmentally friendly. Therefore, it has experienced rapid development in recent years. The viscosity of the dicyclopentadiene (DCPD) resin matrix can be as low as 0.1 Pa·s, making it an excellent resin matrix for composite materials. However, when carbon fiber (CF) is used as reinforcement, the interfacial bonding is poor due to the low interfacial energy and lack of effective interaction between the two materials. The interfacial shear strength (IFSS) is as low as 13 MPa (compared to approximately 60 MPa for CF and epoxy resin under the same conditions). Therefore, interfacial energy absorption is a limiting factor in the application of CF-reinforced PDCPD resin-based composites.

[0003] To address the aforementioned issues, patent CN114478887A first employs supercritical swelling treatment, followed by treatment of carbon fibers with a silane coupling agent (4-(4-aminophenyl)benzonitrile triethanolylsiloxane). However, the entire process is complex, especially the supercritical swelling treatment, which cannot be applied to continuous carbon fiber production. Patent TW202138643A involves acidifying and acylchlorinating carbon fibers, followed by grafting norbornene via esterification. However, both acylchlorination and esterification require anhydrous and oxygen-free environments, making them unsuitable for continuous carbon fiber production. Patent CN110387115A involves washing carbon fibers and then treating them with a silane coupling agent KH570. However, the washing process cannot introduce functional groups on the carbon fiber surface that can interact with the silane coupling agent or PDCPD. Patent CN113400683A uses a secondary infusion method to prepare composite materials, but the secondary infusion process cannot introduce functional groups that can interact with silane coupling agents or PDCPDs on the carbon fiber surface. Patent CN116003943A improves the interaction with fibers by introducing epoxy resin into DCPD resin, but this loses the advantages of PDCPD's low moisture absorption, high strength and impact resistance. Patents CN106366300A, CN106749949A, CN106749947A, CN106589250A, CN104448084A and CN102827318A all use silane coupling agents (such as KH570) to modify glass fibers to improve their interfacial bonding ability with PDCPDs, but the glass fiber surface is rich in hydroxyl groups that can form chemical bonds with silane coupling agents, which is a characteristic that carbon fibers do not possess. Furthermore, the amino, hydroxyl, and epoxy functional groups provided by conventional silane coupling agents cannot form strong interactions with PDCPD, thus failing to improve interfacial properties. KH570 can provide aliphatic ethylene functional groups, but the crosslinking mechanism of DCPD is ring-opening metathesis polymerization, which differs from that of aliphatic ethylene functional groups. Therefore, the chemical bond strength between KH570 and DCPD is limited, resulting in limited interfacial improvement. Patent CN116063823A uses a norbornene-based silane coupling agent to treat CF. Norbornene and DCPD have the same crosslinking mechanism, both being ring-opening metathesis polymerization, but this still failed to improve the bonding problem between the silane coupling agent and CF. Summary of the Invention

[0004] In order to simultaneously solve the technical problems existing in the CF-reinforced PDCPD resin-based composite materials, this invention provides a carbon fiber sizing agent based on click chemistry that matches (poly)dicyclopentadiene and its application, which can be synthesized without harsh conditions such as anhydrous and oxygen-free conditions, can be applied to the continuous production of carbon fibers, has chemical bond interactions between the coupling agent and the carbon fiber surface, has chemical bond interactions between the coupling agent and the PDCPD on the carbon fiber surface, has efficient and easy construction of chemical bond interactions, and is reasonably priced.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] The present invention provides a carbon fiber sizing agent for use with (poly)dicyclopentadiene, the sizing agent comprising a coupling agent and a film-forming agent, wherein the coupling agent is referred to as component 1 and the film-forming agent is referred to as component 2;

[0007] The sizing agent is synthesized from dicyclopentadiene and a mercapto compound in a one-pot process, purified by water washing, and the reaction system after water washing can be directly used to prepare solution-type or emulsion-type sizing agents.

[0008] The structural formula of the dicyclopentadiene is as follows:

[0009]

[0010] The structural formula of the thiol compound is as follows:

[0011]

[0012] Wherein, the three R groups are the same or different, and are one of the following structures, or one of the following branched derivatives containing a thiol structure, or one of the following hyperbranched derivatives containing a thiol structure, and at least one of the three R groups is not a hydrogen atom; n is any positive integer between 1 and 5;

[0013]

[0014] The sizing agent also includes a coupling catalyst, denoted as component 3.

[0015] In the above technical solution, preferably, the molar ratio of component 1 to component 2 in the sizing agent is 1:0.8-1:5.

[0016] In the above technical solution, preferably, the molar ratio of the dicyclopentadiene to the thiol compound is 2:1 to 5:1.

[0017] In the above technical solution, preferably, the solvent used for synthesizing the sizing agent is toluene or acetonitrile, the catalyst is aluminum chloride, aluminum bromide, trifluoroacetic acid or methanesulfonic acid, and the concentration of dicyclopentadiene is 0.1-2.0 mol / L.

[0018] In the above technical solution, preferably, the reaction temperature for synthesizing the sizing agent is 60-200℃ and the time is 2-7h.

[0019] In the above technical solution, preferably, the coupling catalyst is benzoyl peroxide and dimethylaniline, or azobisisobutyronitrile, or benzoyl peroxide, or benzoyl dimethyl ether, or benzophenone and azobisisobutyronitrile.

[0020] A method for surface treatment of carbon fiber using the sizing agent described in this invention includes the following steps:

[0021] When component 3 requires high-temperature initiation or photoinitiation, the carbon fiber surface is treated by one-step or two-step sizing.

[0022] When component 3 requires room temperature initiation, a two-step emulsion sizing method is used to treat the carbon fiber surface.

[0023] In the above technical solution, it is preferred that when component 3 is azobisisobutyronitrile, or benzoyl peroxide, or benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber surface is treated by one-step emulsion sizing or one-step solution sizing.

[0024] The one-step emulsion sizing method for treating carbon fiber surfaces includes the following steps:

[0025] a. Prepare an emulsion by mixing component 1 and component 2, denoted as emulsion 1;

[0026] b. Prepare component 3 as an emulsion, denoted as emulsion 2;

[0027] c. Emulsion 1, Emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5-20:0.5-10:0.1-0.5:0.2-0.8: balance, where the balance is the mass of deionized water, and the total mass parts are 100, to form an emulsion-type sizing agent.

[0028] d. When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 100-150℃, and then wound up; when component 3 is benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is sized, treated with ultraviolet light, dried at 100-150℃, and then wound up.

[0029] The one-step solution coating method for treating carbon fiber surfaces includes the following steps:

[0030] a. Prepare a solution-type sizing agent by mixing component 1 + component 2 (excluding solvent), component 3, antistatic agent, lubricant and organic solvent in a mass ratio of 1~2:0.01~0.1:0.1~0.5:0.2~0.8: the balance being the mass of organic solvent, for a total mass of 100 parts.

[0031] b. When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 120-150℃, and then wound up; when component 3 is benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 120-150℃ before being wound up.

[0032] In the above technical solutions, it is preferred that the organic solvent used in the one-step emulsion coating or one-step solution coating is acetonitrile or toluene.

[0033] In the above technical solution, preferably, when component 3 is benzoyl peroxide and dimethylaniline, or azobisisobutyronitrile, or benzoyl peroxide, or benzoyl dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is surface treated by a two-step emulsion sizing method, including the following steps:

[0034] a. Prepare an emulsion by mixing component 1 and component 2, denoted as emulsion 1;

[0035] b. Prepare component 3 as an emulsion, denoted as emulsion 2;

[0036] c. Prepare an emulsion-type sizing agent by mixing emulsion 1, antistatic agent, lubricant and deionized water in a mass ratio of 5-20:0.1-0.5:0.2-0.8:balance, where the balance is the mass of deionized water, for a total mass of 100 parts.

[0037] d. The carbon fiber is first sized with emulsion 2, then blown dry until no liquid drips, and then sized with emulsion 1. When component 3 is benzoyl peroxide and dimethylaniline, azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is dried at 100-150℃ and then wound up after sizing. When component 3 is benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 100-150℃ and then wound up.

[0038] The beneficial effects of this invention are:

[0039] The advantages of the carbon fiber sizing agent used with the present invention for matching (poly)dicyclopentadiene are as follows:

[0040] 1. Contains a series of thiol-containing coupling agents (one of the components of sizing agents).

[0041] 2. The coupling agent containing thiol group and the film-forming agent (one of the components of the sizing agent) are synthesized directly in one pot. No separation, solvent collection, or water washing and purification is required. After water washing, the reaction system can be directly used to prepare solution or emulsion sizing agents.

[0042] The method of preparing a special sizing agent using the coupling agent and film-forming agent described above in this invention, and then treating the carbon fiber surface, achieves in-situ chemical bonding with the carbon fiber surface during the sizing process. Specific advantages are as follows:

[0043] 1. The thiol-containing coupling agent developed in this invention can interact with the carbon fiber surface through click chemical reaction to form chemical bonds. The reaction rate is fast and the reaction efficiency is high. During the sizing process, functional groups that can crosslink with DCPD can be introduced into the carbon fiber surface through carbon-sulfur bonds.

[0044] 2. The coupling agent and film-forming agent developed in this invention can be directly synthesized in a one-pot method without separation or solvent recovery. After washing with water, they can be directly used to prepare sizing agents. This method has industrialization potential, low cost, high efficiency, and is environmentally friendly.

[0045] 3. The carbon fiber surface treatment method developed in this invention does not require anhydrous or oxygen-free reaction conditions such as acidification, acyl chloride, or esterification, nor does it require high-temperature and high-pressure reaction conditions such as supercritical treatment. It can be achieved in an atmospheric environment using conventional carbon fiber production equipment, and has low requirements for equipment and personnel.

[0046] 4. The carbon fiber surface treatment method developed in this invention improves the IFSS by 50%-130% compared to commercially sized CF. Attached Figure Description

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] Figure 1 This is a schematic diagram of the one-pot synthesis reaction equation for components 1 and 2.

[0049] Figure 2 This is a schematic diagram of the composition and chemical structure of component 1.

[0050] Figure 3 This is a schematic diagram of the composition and chemical structure of component 2. Detailed Implementation

[0051] The inventive concept of this invention is as follows: To solve the technical problems in the prior art, it is necessary to construct an interfacial phase that can chemically interact with both carbon fiber and DCPD. Therefore, three interfacial reinforcement strategies have been developed. Based on the order in which chemical bonds are formed between the interfacial phase and both sides, these strategies can be categorized as resin-first followed by fiber, simultaneous chemical bonding, and fiber-first followed by resin. The resin-first followed by fiber strategy requires overall modification of the resin matrix, which is not only costly but also easily damages the inherent advantages of the resin matrix. The simultaneous chemical bonding strategy is usually achieved during processing; DCPD typically has low viscosity and is easily dissolved by the unstable interfacial phase during preforming. The CF-first followed by resin strategy can be achieved through the sizing process, which is easy to operate and has low dependence on equipment and personnel. Therefore, this invention adopts a strategy that establishes chemical interactions between CF and the sizing agent (interfacial phase) during the sizing process, while simultaneously maintaining cross-linked groups in the sizing agent (interfacial phase) similar to those in DCPD. Based on this strategy, this invention first designs and develops a highly active coupling agent. This coupling agent can interact with the unsaturated bonds on the carbon fiber surface through a conditional click chemistry reaction, while retaining part of the bicyclic / tricyclopentadiene structure, thus preserving its ability to crosslink with the DCPD matrix. Based on this, this invention further optimizes the coupling agent synthesis process, enabling the two most important components of the sizing agent—the coupling agent (component 1) and the film-forming agent (component 2)—to be synthesized in a one-pot process (reaction equations are available in [reference]). Figure 1 Component 1 is a mixture of the corresponding R structure, the structural formula of which can be found in [reference needed]. Figure 2 See the structural formula of component 2. Figure 3 This invention eliminates the need for separation, solvent recovery, and water washing purification, resulting in high efficiency and environmental friendliness. Finally, the invention optimizes the introduction strategy of the coupling catalyst (component 3) to maximize the reaction efficiency between the carbon fiber and the sizing agent layer. This invention is simple to operate, energy-saving and environmentally friendly, with high reaction efficiency and good interface reinforcement, enabling mass production of sizing agents and specialized carbon fibers.

[0052] The present invention provides a carbon fiber sizing agent for use with (poly)dicyclopentadiene, the sizing agent comprising a coupling agent and a film-forming agent, wherein the coupling agent is referred to as component 1 and the film-forming agent is referred to as component 2;

[0053] The sizing agent is synthesized from dicyclopentadiene and a mercapto compound in a one-pot process, purified by water washing, and the reaction system after water washing can be directly used to prepare solution or emulsion sizing agents.

[0054] The structural formula of the dicyclopentadiene is as follows:

[0055]

[0056] The structural formula of the thiol compound is as follows:

[0057]

[0058] Wherein, the three R groups are the same or different, and are one of the following structures, or one of the following branched derivatives containing a thiol structure, or one of the following hyperbranched derivatives containing a thiol structure, and at least one of the three R groups is not a hydrogen atom; n is any positive integer between 1 and 5;

[0059]

[0060] The sizing agent also includes a coupling catalyst, denoted as component 3.

[0061] The sizing agent is synthesized from dicyclopentadiene and a mercapto compound via a one-pot method, purified by water washing, and the reaction system after water washing can be directly used to prepare solution or emulsion sizing agents. This invention is achieved through the following steps:

[0062] (1) Add DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject organic solvent, and stir to fully dissolve DCPD; add catalyst and stir evenly; dissolve thiol compound in organic solvent and add it dropwise to the reactor; heat to the specified temperature, and cool to room temperature after the reaction is complete; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 in a specific ratio (hereinafter referred to as the stock solution);

[0063] (2) The original solution can be diluted and then added with component 3, antistatic agent and lubricant to be used directly as a one-step solution coating agent. Alternatively, emulsifier and deionized water can be added to prepare emulsion 1 for later use.

[0064] Or (3) Dissolve component 3 in an organic solvent, add emulsifier and deionized water, and prepare emulsion 2;

[0065] (4) Depending on the sizing method, one-step solution sizing agent, one-step emulsion sizing agent or two-step emulsion sizing agent are prepared respectively; carbon fiber surface modification is achieved by one-step solution sizing, one-step emulsion sizing or two-step emulsion sizing. During the sizing (including drying) process, the coupling agent can efficiently generate chemical bond interaction with CF, while retaining part of the bicyclic / tricyclopentadiene structure.

[0066] Furthermore, in step (1) above, the molar ratio of the reactant dicyclopentadiene to the mercapto compound is 2:1 to 5:1;

[0067] Furthermore, the organic solvent used in step (1) above is toluene or acetonitrile, and the concentration of dicyclopentadiene is 0.1-2.0 mol / L, more preferably 0.1-1.0 mol / L;

[0068] Furthermore, the catalyst used in step (1) above is aluminum chloride, aluminum bromide, trifluoroacetic acid, or methanesulfonic acid;

[0069] Furthermore, the temperature of the synthesis reaction of component 1 and component 2 in step (1) above is 60-200℃;

[0070] Furthermore, the reaction time for the synthesis of components 1 and 2 in step (1) above is 2-7 hours;

[0071] Furthermore, in step (1) above, the molar ratio of component 1 to component 2 in the original solution is 1:0.8-1:5;

[0072] Furthermore, the emulsion 1 prepared in step (2) above contains 10% to 20% by mass of component 1 and component 2;

[0073] Preferably, the oil-to-water ratio in the emulsion 1 prepared in step (2) above is 1:1 to 1:2;

[0074] Further, in step (3) above, component 3 is: benzoyl peroxide + dimethylaniline, azobisisobutyronitrile, benzoyl peroxide, benzoyl dimethyl ether or benzophenone + azobisisobutyronitrile; when component 3 requires high temperature initiation or photoinitiation, the carbon fiber surface is treated by one-step sizing or two-step sizing; when component 3 requires room temperature initiation, the carbon fiber surface is treated by two-step emulsion sizing.

[0075] Furthermore, the emulsion 2 prepared in step (3) above contains 10% to 20% of component 3 by mass.

[0076] Preferably, the oil-to-water ratio in the emulsion 2 prepared in step (3) above is 1:1 to 1:2;

[0077] Furthermore, in step (4) above, when component 3 is azobisisobutyronitrile, benzoyl peroxide, benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, a carbon fiber surface treatment method of one-step emulsion sizing, one-step solution sizing or two-step emulsion sizing can be adopted.

[0078] Furthermore, in step (4) above, when component 3 is benzoyl oxide + dimethylaniline, only the two-step emulsion sizing carbon fiber surface treatment method can be used;

[0079] Furthermore, the method for treating the carbon fiber surface using the one-step emulsion sizing in step (4) above is specifically as follows:

[0080] ① Prepare an emulsion-type sizing agent by mixing emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water in a mass ratio of 5-20:0.5-10:0.1-0.5:0.2-0.8: balance (total 100);

[0081] ② When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 100-150℃, and then wound up; when component 3 is benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 100-150℃ before being wound up.

[0082] Furthermore, the method of treating the carbon fiber surface using the one-step solution coating in step (4) above is specifically as follows:

[0083] ① The components 1 and 2 (excluding solvent), 3, antistatic agent, lubricant and organic solvent are prepared in the following mass ratio: 1~2:0.01~0.1:0.1~0.5:0.2~0.8: balance (total 100) to form a solution-type sizing agent;

[0084] ② When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 120-150℃, and then wound up; when component 3 is benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 120-150℃ before being wound up.

[0085] Furthermore, the two-step emulsion coating method for treating the carbon fiber surface in step (4) above is specifically as follows:

[0086] ① Prepare an emulsion-type sizing agent by mixing emulsion 1, antistatic agent, lubricant and deionized water in a mass ratio of 5~20:0.1~0.5:0.2~0.8: balance (total 100);

[0087] ② The carbon fiber is first sized with emulsion 2, then blow-dried until no more liquid drips, and then sized with emulsion 1. When component 3 is benzoyl peroxide + dimethylaniline, azobisisobutyronitrile, or benzoyl peroxide, the carbon fiber is dried at 100-150℃ after sizing and then wound up; when component 3 is benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 100-150℃ before being wound up.

[0088] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0089] The amount of catalyst used in the following examples can be based on the conventional catalytic amount in the art. The present invention does not make any special limitations. As for antistatic agents, lubricants and emulsifiers, any reagent that can achieve its function is acceptable, and there are no special limitations on their respective types.

[0090] Example 1

[0091] (1) Add 132.2g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add 5g of aluminum chloride and stir evenly; dissolve 55.1g of thiophenol in 3L of toluene and add it dropwise to the reactor; heat to 60℃ and react for 2h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:0.8 (hereinafter referred to as the stock solution);

[0092] (2) After diluting the stock solution, add azobisisobutyronitrile, antistatic agent and lubricant to prepare a one-step solution sizing agent. Component 1 + Component 2 (without solvent), azobisisobutyronitrile, antistatic agent, lubricant and toluene are prepared in a mass ratio of 1:0.01:0.1:0.2:balance (total 100) to prepare a solution-type sizing agent.

[0093] (3) After the carbon fiber is sized, it is dried at 120℃ and then wound up;

[0094] (4) The IFSS of carbon fiber and PDCPD after sizing is 18MPa, while the IFSS of commercially sized CF and PDCDP is 12MPa.

[0095] Example 2

[0096] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of acetonitrile, and stir to fully dissolve DCPD; add the catalytic amount of aluminum bromide and stir evenly; dissolve 496.8g of benzyl mercaptan in 3L of acetonitrile and add it dropwise to the reactor; heat to 200℃ and react for 7h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0097] (2) After diluting the stock solution, add benzoyl peroxide, antistatic agent and lubricant to prepare a one-step solution sizing agent. Component 1 + Component 2 (without solvent), benzoyl peroxide, antistatic agent, lubricant and toluene are prepared in a mass ratio of 2:0.1:0.5:0.8:balance (total 100) to prepare a solution-type sizing agent; (3) After sizing the carbon fiber, it is dried at 150℃ and then wound up;

[0098] (4) The IFSS of carbon fiber and PDCPD after sizing is 27.6 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0099] Example 3

[0100] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add catalytic amount of trifluoroacetic acid and stir evenly; dissolve 552.62g of 2-phenylethanethiol in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0101] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0102] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0103] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0104] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0105] (6) The IFSS of carbon fiber and PDCPD after sizing is 25 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0106] Example 4

[0107] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add catalytic amount of methanesulfonic acid and stir evenly; dissolve 609.2g of 3-phenylpropanethiol in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0108] (2) Add toluene to dilute the stock solution to a mass fraction of 60% for component 1 + component 2. Add deionized water and emulsifier in a volume twice that of the organic solution and emulsify under stirring. Prepare emulsion 1 by mixing the aforementioned emulsion, antistatic agent, lubricant and deionized water in a mass ratio of 20:0.5:0.8:balance (total 100).

[0109] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 60%), add deionized water and emulsifier in 2 times the volume of organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:2 in emulsion 2, mass fraction of component 1 + component 2 is 20%).

[0110] (4) After the carbon fiber is sized with emulsion 1, it is blown dry until no liquid drips, then sized with emulsion 2, then treated with ultraviolet light, and finally dried at 130°C and wound up.

[0111] (5) The IFSS of carbon fiber and PDCPD after sizing is 22 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0112] Example 5

[0113] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add catalytic amount of methanesulfonic acid and stir evenly; dissolve 665.2g of 4-phenylbutyritin in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0114] (2) Add toluene to dilute the stock solution to a mass fraction of 60% for component 1 + component 2. Add deionized water and emulsifier in a volume twice that of the organic solution and emulsify under stirring. Prepare emulsion 1 by mixing the aforementioned emulsion, antistatic agent, lubricant and deionized water in a mass ratio of 20:0.5:0.8:balance (total 100).

[0115] (3) Dissolve benzoyl oxide + dimethylaniline in toluene (mass fraction 60%) in a molar ratio of 1:1, add deionized water and emulsifier twice the volume of the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:2 in emulsion 2, mass fraction of component 1 + component 2 is 20%).

[0116] (4) After the carbon fiber is sized with emulsion 1, it is blown dry until no liquid drips, then sized with emulsion 2, then treated with ultraviolet light, and finally dried at 130°C and wound up.

[0117] (5) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0118] Example 6

[0119] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add catalytic amount of methanesulfonic acid and stir evenly; dissolve 665.2g of 4-phenylpentanethiol in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0120] (2) Add toluene to dilute the stock solution to a mass fraction of 60% for component 1 + component 2. Add deionized water and emulsifier in a volume twice that of the organic solution and emulsify under stirring. Prepare emulsion 1 by mixing the aforementioned emulsion, antistatic agent, lubricant and deionized water in a mass ratio of 20:0.5:0.8:balance (total 100).

[0121] (3) Dissolve benzophenone oxide and azobisisobutyronitrile in toluene (mass fraction of 60%) in a molar ratio of 1:1, add deionized water and emulsifier twice the volume of organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:2 in emulsion 2, and mass fraction of component 1 + component 2 of 20%).

[0122] (4) After the carbon fiber is sized with emulsion 1, it is blown dry until no liquid drips, then sized with emulsion 2, then treated with ultraviolet light, and finally dried at 130°C and wound up.

[0123] (5) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0124] Example 7

[0125] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add catalytic amount of trifluoroacetic acid and stir evenly; dissolve 672.8g of phenyl mercaptoacetate in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0126] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0127] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0128] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0129] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0130] (6) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0131] Example 8

[0132] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add a catalytic amount of trifluoroacetic acid and stir evenly; dissolve 952.8g of phenylamyl mercaptoacetate in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0133] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0134] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0135] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0136] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0137] (6) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0138] Example 9

[0139] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add a catalytic amount of trifluoroacetic acid and stir evenly; dissolve 625.2g of 3-mercaptobenzyl mercaptan in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0140] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0141] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0142] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0143] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0144] (6) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0145] Example 10

[0146] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add a catalytic amount of trifluoroacetic acid and stir evenly; dissolve 865.6g of 1,3,5-tris(mercaptomethyl)benzene in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0147] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0148] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0149] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0150] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0151] (6) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0152] Example 11

[0153] (1) Add 2644g of DCPD to the reactor, seal the reactor, evacuate nitrogen three times, inject 7L of toluene, and stir to fully dissolve DCPD; add a catalytic amount of trifluoroacetic acid and stir evenly; dissolve 865.6g of 1,3,5-tris(mercaptomethyl)benzene in 3L of toluene and add it dropwise to the reactor; heat to 180℃ and react for 5h. After the reaction is completed, cool to room temperature; filter to remove residue, wash the filtrate three times with water, and separate the liquid to obtain a mixed solution of component 1 and component 2 with a molar ratio of 1:5 (hereinafter referred to as the stock solution);

[0154] (2) Add toluene to dilute the stock solution to a mass fraction of 20% for component 1 + component 2, add deionized water and emulsifier of equal volume to the organic solution, and prepare emulsion 1 under stirring (the oil-water ratio in emulsion 1 is 1:1, and the mass fraction of component 1 + component 2 is 10%).

[0155] (3) Dissolve benzoin dimethyl ether in toluene (mass fraction of 20%), add deionized water and emulsifier in the same volume as the organic solution, and prepare emulsion 2 under stirring (oil-water ratio of 1:1 in emulsion 2, mass fraction of component 1 + component 2 is 10%).

[0156] (4) Emulsion 1, emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5:0.5:0.1:0.2:balance (total 100) to form a one-step emulsion sizing agent;

[0157] (5) After the carbon fiber is coated with the one-step emulsion sizing agent prepared in step (4), it is treated with ultraviolet light and finally dried at 130°C and then wound up.

[0158] (6) The IFSS of carbon fiber and PDCPD after sizing is 23 MPa, while the IFSS of commercially sized CF and PDCDP is 12 MPa.

[0159] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A carbon fiber sizing agent for use with (poly)dicyclopentadiene, characterized in that, The sizing agent includes a coupling agent and a film-forming agent, wherein the coupling agent is referred to as component 1 and the film-forming agent is referred to as component 2; The sizing agent is synthesized from dicyclopentadiene and a mercapto compound in a one-pot process, purified by water washing, and the reaction system after water washing can be directly used to prepare solution-type or emulsion-type sizing agents. The structural formula of the dicyclopentadiene is as follows: The structural formula of the thiol compound is as follows: Wherein, the three R groups are the same or different, and are one of the following structures, or one of the following branched derivatives containing a thiol structure, or one of the following hyperbranched derivatives containing a thiol structure, and at least one of the three R groups is not a hydrogen atom; n is any positive integer between 1 and 5; The reaction equation for the sizing agent is as follows: The structural formula of component 1 is as follows: The structural formula of component 2 is as follows: The sizing agent also includes a coupling catalyst, denoted as component 3.

2. The carbon fiber sizing agent according to claim 1, characterized in that, The molar ratio of component 1 to component 2 in the sizing agent is 1:0.8-1:

5.

3. The carbon fiber sizing agent according to claim 1, characterized in that, The molar ratio of the dicyclopentadiene to the thiol compound is 2:1 to 5:

1.

4. The carbon fiber sizing agent according to claim 1, characterized in that, The solvent used in the synthesis of the sizing agent is toluene or acetonitrile, the catalyst is aluminum chloride, aluminum bromide, trifluoroacetic acid or methanesulfonic acid, and the concentration of dicyclopentadiene is 0.1-2.0 mol / L.

5. The carbon fiber sizing agent according to claim 1, characterized in that, The reaction temperature for synthesizing the sizing agent is 60-200℃, and the reaction time is 2-7h.

6. The carbon fiber sizing agent according to claim 1, characterized in that, The coupling catalyst is benzoyl peroxide and dimethylaniline, or azobisisobutyronitrile, or benzoyl peroxide, or benzoyl dimethyl ether, or benzophenone and azobisisobutyronitrile.

7. A method for surface treatment of carbon fiber using the carbon fiber sizing agent according to claim 1, characterized in that, Includes the following steps: When component 3 requires high-temperature initiation or photoinitiation, the carbon fiber surface is treated by one-step or two-step sizing. When component 3 requires room temperature initiation, a two-step emulsion sizing method is used to treat the carbon fiber surface.

8. The carbon fiber surface treatment method according to claim 7, characterized in that, When component 3 is azobisisobutyronitrile, or benzoyl peroxide, or benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber surface is treated by one-step emulsion sizing or one-step solution sizing. The one-step emulsion sizing method for treating carbon fiber surfaces includes the following steps: a. Prepare an emulsion by mixing component 1 and component 2, denoted as emulsion 1; b. Prepare component 3 as an emulsion, denoted as emulsion 2; c. Emulsion 1, Emulsion 2, antistatic agent, lubricant and deionized water are prepared in a mass ratio of 5-20:0.5-10:0.1-0.5:0.2-0.8: balance, where the balance is the mass of deionized water, and the total mass parts are 100, to form an emulsion-type sizing agent. d. When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 100-150℃, and then wound up; when component 3 is benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is sized, treated with ultraviolet light, dried at 100-150℃, and then wound up. The one-step solution coating method for treating carbon fiber surfaces includes the following steps: a. Prepare a solution-type sizing agent by mixing component 1, component 2, component 3, antistatic agent, lubricant, and organic solvent in the following mass ratio: 1~2:0.01~0.1:0.1~0.5:0.2~0.8: balance, where the balance is the mass of organic solvent, for a total mass of 100 parts. b. When component 3 is azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is sized, dried at 120-150℃, and then wound up; when component 3 is benzoin dimethyl ether or benzophenone + azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 120-150℃ before being wound up.

9. The carbon fiber surface treatment method according to claim 8, characterized in that, The organic solvent used in one-step emulsion coating or one-step solution coating is acetonitrile or toluene.

10. The carbon fiber surface treatment method according to claim 7, characterized in that, When component 3 is benzoyl peroxide and dimethylaniline, or azobisisobutyronitrile, or benzoyl peroxide, or benzoyl dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is surface treated using a two-step emulsion sizing method, including the following steps: a. Prepare an emulsion by mixing component 1 and component 2, denoted as emulsion 1; b. Prepare component 3 as an emulsion, denoted as emulsion 2; c. Prepare an emulsion-type sizing agent by mixing emulsion 1, antistatic agent, lubricant and deionized water in a mass ratio of 5-20:0.1-0.5:0.2-0.8:balance, where the balance is the mass of deionized water, for a total mass of 100 parts. d. The carbon fiber is first sized with emulsion 2, then blown dry until no liquid drips, and then sized with emulsion 1. When component 3 is benzoyl peroxide and dimethylaniline, azobisisobutyronitrile or benzoyl peroxide, the carbon fiber is dried at 100-150℃ and then wound up after sizing. When component 3 is benzoin dimethyl ether, or benzophenone and azobisisobutyronitrile, the carbon fiber is first sized, then treated with ultraviolet light, and then dried at 100-150℃ and then wound up.

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