Low-cost and high-strength carbon fiber reinforced plate and preparation method thereof

Abstract

The invention discloses a low-cost and high-strength carbon fiber reinforced plate and a preparation method thereof, and belongs to the technical field of carbon fiber composite materials. The low-cost and high-strength carbon fiber reinforced plate comprises modified recycled carbon fibers, a composite resin base material and a compatible auxiliary agent, and the mass ratio of the modified recycled carbon fibers to the composite resin base material is (6-7): (2-3); the composite resin base material comprises the following components in parts by weight: 80-90 parts of compound epoxy resin and 40-60 parts of a curing agent. By adopting the modified recycled carbon fibers, on one hand, waste resources can be fully utilized, and the cost is reduced, and on the other hand, the modified recycled carbon fibers are matched with the compatible additive, and the compatibility of the recycled carbon fibers and the composite resin base material is improved while the dispersion uniformity of the recycled carbon fibers in the composite resin base material is improved through the matching effect of the modified recycled carbon fibers and the compatible additive. And the interface bonding strength is improved, so that better mechanical properties are obtained.

Description

Technical Field

[0001] The present application relates to a low-cost, high-strength carbon fiber reinforced plate and a preparation method thereof, and belongs to the technical field of carbon fiber composite materials. Background Art

[0002] With the development of the times, the requirements for materials in the fields of chemical industry, machinery, transportation, construction, etc. are getting higher and higher. Carbon fiber material is a high-strength, low-density material, and there are more and more composite materials based on carbon fiber. Carbon fiber not only has the inherent characteristics of carbon materials, but also has the softness and processability of textile fibers. It is a new generation of reinforcing fiber. Carbon fiber is a microcrystalline graphite material obtained by carbonizing and graphitizing organic fibers. The application of carbon fiber is mainly used to make composite materials. It is used as a reinforcing material for composite materials products with thermosetting resins or thermoplastic resins as the matrix.

[0003] Carbon fiber composite materials are difficult to degrade in the natural environment due to their stable performance. Improper handling after the end of their service life will have an impact on the environment. With the expansion of the application of carbon fiber composite materials in the carbon fiber composite materials industry, the replacement of product life cycle, and technological upgrading, more and more carbon fiber waste materials are generated, causing greater pressure on resources and the environment. The high price of carbon fiber is also one of the limiting factors restricting the development of carbon fiber composite materials. Therefore, the recycling of waste carbon fiber can greatly reduce the production cost of carbon fiber composite materials, which is conducive to the efficient use of resources and sustainable development of the industry.

[0004] The prior art has disclosed a variety of methods for decomposing the resin in the waste carbon fiber reinforced resin composite sheet so that the carbon fiber therein is separated, thereby realizing the recovery of carbon fiber. The prior art specifically discloses heating under inert atmosphere conditions to crack the resin in the composite material into other small molecular substances, separate the carbon fiber from the resin, and then realize the recovery of carbon fiber. Specifically, the carbon fiber composite sheet is treated at 450-600°C for 3-4 hours, and then the heating is stopped and cooled to room temperature; then the pretreated carbon fiber composite sheet is heated again to 500-550°C, kept warm for 2-3 hours, and then the heating is stopped again and cooled to room temperature to obtain the recycled carbon fiber.

[0005] However, the performance of recycled waste carbon fiber will inevitably decline. On the one hand, there is a difference in elastic modulus between carbon fiber and resin itself, which leads to the deterioration of its mechanical properties such as shear strength; on the other hand, the compatibility of recycled waste carbon fiber with the resin system deteriorates, the interface bonding force is weak, and it is difficult for carbon fiber to be evenly dispersed in the resin matrix, which in turn affects the overall mechanical properties of carbon fiber composites. Summary of the invention

[0006] To solve the above problems, a low-cost and high-strength carbon fiber reinforcement plate and a preparation method thereof are provided. The low-cost and high-strength carbon fiber reinforcement plate uses modified recycled carbon fibers. On the one hand, it can make full use of waste resources and reduce costs. On the other hand, the modified recycled carbon fibers are combined with a compatibilizing agent. The two work together to improve the dispersion uniformity of the recycled carbon fibers in the composite resin matrix, improve the compatibility between the recycled carbon fibers and the composite resin matrix, enhance the interfacial bonding strength, and thus obtain better mechanical properties.

[0007] According to one aspect of the present application, a low-cost and high-strength carbon fiber reinforcement plate is provided, which includes modified recycled carbon fibers, a composite resin matrix, and a compatibilizing agent. The mass ratio of the modified recycled carbon fibers to the composite resin matrix is (6-7):(2-3); the composite resin matrix, by weight fraction, includes 80-90 parts of a compounded epoxy resin and 40-60 parts of a curing agent.

[0008] Specifically, in the present application, the use of modified recycled carbon fibers can, on the one hand, reduce costs and achieve the full utilization of resources. On the other hand, the modified recycled carbon fibers are combined with a compatibilizing agent. The two work together to improve the dispersion uniformity of the recycled carbon fibers in the composite resin matrix, improve the compatibility between the recycled carbon fibers and the composite resin matrix, enhance the interfacial bonding strength, and thus obtain better mechanical properties.

[0009] Specifically, the present application makes specific limitations on the components and proportioning of the composite resin matrix, so that the modified recycled carbon fibers are evenly dispersed in the composite resin matrix. Among them, the composite resin matrix includes a compounded epoxy resin, and the modified recycled carbon fibers have good compatibility and interfacial bonding force with the compounded epoxy resin, making the carbon fiber reinforcement plate have good mechanical properties.

[0010] Specifically, the addition amount of the compatibilizing agent is 5-8 wt% of the composite resin matrix.

[0011] Optionally, the preparation method of the modified recycled carbon fibers includes the following steps:

[0012] S01 Place the recycled carbon fibers in nitric acid and react for 20-30 min, take them out and wash until neutral, then place them in absolute ethanol and ultrasonically clean for 5-10 min to obtain pretreated recycled carbon fibers;

[0013] S02 In a nitrogen atmosphere, place the pretreated recycled carbon fibers in a solvent, add glycidyl methacrylate and an initiator, stir evenly, and react at 60-80 °C for 3-4 h. After the reaction, centrifuge, wash, and dry to obtain recycled carbon fibers.

[0014] Specifically, the recycled carbon fibers are placed in nitric acid for oxidation treatment to introduce carboxyl groups on the surface of the recycled carbon fibers and enhance their surface activity. Then, a graft copolymer is introduced on the surface of the recycled carbon fibers to form an amphiphilic molecular chain. On the one hand, under the action of an initiator, the polymerization reaction of glycidyl methacrylate monomers is initiated to form a polymer molecular chain. On the other hand, glycidyl methacrylate contains epoxy groups, which can undergo a ring-opening reaction with the carboxyl groups on the surface of the modified recycled carbon fibers to form stable chemical bonds, firmly fixing the polymer molecular chain on the surface of the recycled carbon fibers. There is good compatibility between the polymer molecular chain and the compound epoxy resin, thereby significantly improving the interfacial bonding strength between the recycled carbon fibers and the composite resin matrix, and further improving the overall mechanical properties.

[0015] Specifically, the molecular chain formed by the graft copolymer on the surface of the recycled carbon fibers can also effectively fill the voids at the interface, increase the contact area between the recycled carbon fibers and the compound epoxy resin, and thus can also improve the interfacial bonding strength and enhance the overall mechanical properties.

[0016] Optionally, the mass ratio of the pretreated recycled carbon fibers, glycidyl methacrylate, and initiator is (1 - 1.5):(2 - 4):(0.1 - 0.2); the solvent includes N,N-dimethylformamide or xylene; the initiator includes benzoyl peroxide.

[0017] Specifically, the present application makes specific limitations on the mass ratio of the pretreated recycled carbon fibers, glycidyl methacrylate, and initiator to ensure the effect of graft modification.

[0018] Optionally, the compound epoxy resin includes aliphatic epoxy resin and bisphenol A epoxy resin, and the mass ratio of the aliphatic epoxy resin to the bisphenol A epoxy resin is (0.3 - 0.5):1; the curing agent is selected from one or more of polybasic primary amines, polybasic carboxylic acids, and imidazoles.

[0019] Specifically, the polybasic primary amines include diethylenetriamine or triethylenetetramine; the polybasic carboxylic acids include phthalic acid or oxalic acid, and the imidazoles include 2-methylimidazole or 2-ethyl-4-methylimidazole.

[0020] Specifically, the aliphatic epoxy resin and the bisphenol A epoxy resin are compounded in a specific ratio to obtain the compound epoxy resin. First, they have good compatibility, and the interfacial layer is very stable. When they are blended in a specific ratio, the toughness can be improved.

[0021] Specifically, the aliphatic epoxy resin includes 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

[0022] Specifically, the bisphenol A epoxy resin includes tetrabromobisphenol A epoxy resin or tetrachlorobisphenol A epoxy resin.

[0023] Specifically, tetrabromobisphenol A epoxy resin or tetrachlorobisphenol A epoxy resin has good thermal stability and certain flame retardant properties, and the use of tetrabromobisphenol A epoxy resin or tetrachlorobisphenol A epoxy resin makes the interfacial bonding strength higher.

[0024] Optionally, the preparation method of the compatibilizing agent includes the following steps:

[0025] S1 Dissolve and mix maleic anhydride and an initiator in N,N-dimethylformamide, heat and stir, then add polyethylene and stir evenly, and then add polypropylene and stir to obtain a premix;

[0026] S2 Melt-graft the premix obtained in step S1 to obtain a compatibilizing agent.

[0027] Specifically, double bonds are introduced into polyethylene and polypropylene through a melt-grafting reaction, and the compatibilizing agent is beneficial to improving the compatibility between the modified recycled carbon fiber and the compounded epoxy resin.

[0028] Optionally, the mass ratio of the polypropylene to the polyethylene is 1:(0.05 - 0.15); the mass of the maleic anhydride is 2% - 5% of the mass of the polypropylene; the initiator is dicumyl peroxide, and the addition amount of the initiator is 0.8 - 1.2 wt% of the premix.

[0029] Specifically, the present application limits the mass ratio of the polypropylene to the polyethylene. Under the action of the initiator, a specific proportion of polyethylene increases the formation of polypropylene methyl radicals, resulting in an increased grafting opportunity and an increased grafting rate, which is further beneficial to improving the compatibility between the modified recycled carbon fiber and the compounded epoxy resin.

[0030] Specifically, if the addition amount of the initiator is too low, the grafting reaction will be affected. If the addition amount of the initiator is too high, the free radical concentration will be too high, causing side reactions such as the degradation of polypropylene, which will further affect the progress of the grafting reaction.

[0031] Optionally, the temperature of heating and stirring in step S1 is 45 - 65 °C; the reaction time of melt-grafting in step S2 is 10 - 15 min, the temperature is 160 - 180 °C, and the rotation speed is 50 - 80 rpm.

[0032] Specifically, the present application specifically limits parameters such as the initiator, the addition amount of the initiator, the reaction time, the temperature, and the rotation speed to control the grafting rate within an appropriate range.

[0033] According to another aspect of the present application, the present application also provides a preparation method of the above-mentioned low-cost and high-strength carbon fiber reinforcement plate, including the following steps:

[0034] (1) Add the modified recycled carbon fiber into the composite resin base material, then add a compatibilizing agent and perform sizing.

[0035] (2) The sized modified recycled carbon fiber is preformed through a preforming die with a predetermined cross-section at the inlet to obtain a preformed reinforcement plate.

[0036] (3) The preformed reinforcement plate is heated and cured and then drawn into a low-cost and high-strength carbon fiber reinforcement plate.

[0037] Optionally, in step (1), the sizing temperature is 40 - 50 °C and the sizing time is 1 - 2 min; in step (2), the preforming temperature is 20 - 30 °C and the preforming time is 30 - 60 s.

[0038] Specifically, the preparation method of the low-cost and high-strength carbon fiber reinforcement plate provided by the present application successively undergoes steps such as sizing, preforming, and heating and curing to obtain the carbon fiber reinforcement plate, and the preparation process is simple and easy to operate and promote.

[0039] Specifically, the present application is prepared by a pultrusion process. After the modified recycled carbon fiber is sized, the sized modified recycled carbon fiber, under the pulling action of a traction device, enters a preforming die with a predetermined cross-section through tools such as a sizing plate and sizing holes for preforming. After preforming, a preformed reinforcement plate is obtained, and then through heating and curing and drawing, a low-cost and high-strength carbon fiber reinforcement plate is obtained.

[0040] Optionally, the heating and curing in step (3) includes a curing treatment and a heat preservation treatment. The curing treatment temperature is 155 - 220 °C and the time is 30 - 50 s; the heat preservation treatment temperature is 180 - 200 °C and the time is 30 - 50 s.

[0041] Specifically, the present application undergoes two heating and curing processes successively, and the temperature and time are specifically defined respectively to obtain higher mechanical strength.

[0042] The beneficial effects of the present application include but are not limited to:

[0043] 1. For the low-cost and high-strength carbon fiber reinforcement plate according to the present application, by using the modified recycled carbon fiber, on the one hand, waste resources can be fully utilized to reduce costs. On the other hand, the modified recycled carbon fiber and the compatibilizing agent cooperate with each other. While improving the dispersion uniformity of the recycled carbon fiber in the composite resin base material, the compatibility between the recycled carbon fiber and the composite resin base material is improved, and the interfacial bonding strength is enhanced, thereby obtaining better mechanical properties.

[0044] 2. The low-cost and high-strength carbon fiber reinforcement plate according to the present application modifies recycled carbon fibers, that is, places the recycled carbon fibers in nitric acid for oxidation treatment to introduce carboxyl groups on the surface of the recycled carbon fibers and enhance their surface activity; then graft copolymers are introduced on the surface of the recycled carbon fibers to form a molecular chain with amphiphilic properties. On the one hand, under the action of an initiator, the polymerization reaction of glycidyl methacrylate monomers is initiated to form a polymer molecular chain; on the other hand, glycidyl methacrylate contains epoxy groups, which can undergo a ring-opening reaction with the carboxyl groups on the surface of the modified recycled carbon fibers to form stable chemical bonds, firmly fixing the polymer molecular chain on the surface of the recycled carbon fibers. There is good compatibility between the polymer molecular chain and the compound epoxy resin, thereby significantly improving the interfacial bonding strength between the recycled carbon fibers and the composite resin base material, and further improving the overall mechanical properties.

[0045] 3. The preparation method of the low-cost and high-strength carbon fiber reinforcement plate according to the present application defines the process steps and process parameters. Through steps such as dipping in glue, pre-forming, and heating and curing in sequence, a carbon fiber reinforcement plate is obtained. The preparation process is simple and easy to operate and promote. Specific embodiments

[0046] The following describes the present application in detail with reference to embodiments, but the present application is not limited to these embodiments.

[0047] Unless otherwise specified, the raw materials in the embodiments and comparative examples of the present application are all purchased through commercial channels.

[0048] Unless otherwise specified, the methods used in the embodiments and comparative examples of the present application are conventional methods in the prior art. The recycled carbon fibers used in the following embodiments and comparative examples are prepared by the following method:

[0049] The carbon fiber composite plate is treated at 450 °C for 4 h, then heating is stopped and it is cooled to room temperature; then the pretreated carbon fiber composite plate is heated to 550 °C again, held for 3 h, and then heating is stopped again and it is cooled to room temperature to obtain recycled carbon fibers.

[0050] Example 1

[0051] Preparation of a low-cost and high-strength carbon fiber reinforcement plate:

[0052] (1) Add the modified recycled carbon fiber into the composite resin base material. The mass ratio of the modified recycled carbon fiber to the composite resin base material is 2:1. Then add a compatibilizing agent, and the addition amount of the compatibilizing agent is 5wt% of the composite resin base material. Carry out sizing. The sizing temperature is 40°C and the sizing time is 1min. Among them, the composite resin base material includes 80 parts of compounded epoxy resin and 40 parts of curing agent diethylenetriamine. The compounded epoxy resin includes aliphatic epoxy resin and bisphenol A epoxy resin, and the mass ratio of the aliphatic epoxy resin to the bisphenol A epoxy resin is 0.3:1;

[0053] (2) The sized modified recycled carbon fiber is preformed through a preforming die with a predetermined cross-section at the inlet. The preforming temperature is 20°C and the preforming time is 30s to obtain a preformed reinforcement plate;

[0054] (3) The preformed reinforcement plate is heated and cured and then pulled and formed to obtain a low-cost and high-strength carbon fiber reinforcement plate. Among them, the heating and curing includes a curing treatment and a heat preservation treatment. The curing treatment temperature is 155°C and the time is 30s; the heat preservation treatment temperature is 180°C and the time is 30s.

[0055] Preparation of the modified recycled carbon fiber:

[0056] S01 Place the recycled carbon fiber in nitric acid and react for 20min. Take it out and wash it until neutral, and then place it in absolute ethanol for ultrasonic cleaning for 5min to obtain pretreated recycled carbon fiber;

[0057] S02 In a nitrogen atmosphere, place the pretreated recycled carbon fiber in the solvent N,N-dimethylformamide, add glycidyl methacrylate and initiator benzoyl peroxide, and stir evenly. The mass ratio of the pretreated recycled carbon fiber, glycidyl methacrylate and initiator is 1:2:0.1. React at 60°C for 3h. After the reaction, centrifuge, wash and dry to obtain recycled carbon fiber.

[0058] Preparation of the compatibilizing agent:

[0059] S1 Dissolve and mix maleic anhydride and initiator diisopropylbenzene peroxide in N,N-dimethylformamide, and heat and stir. The temperature of the heat and stir is 45°C. Then add polyethylene and stir evenly, and then add it to polypropylene and stir to obtain a premix. The mass ratio of polypropylene to polyethylene is 1:0.05; the mass of maleic anhydride is 2% of the mass of polypropylene; the addition amount of initiator diisopropylbenzene peroxide is 0.8wt% of the premix;

[0060] S2 Carry out melt grafting on the premix obtained in step S1. The reaction time of the melt grafting is 10min, the temperature is 160°C, and the rotation speed is 50rpm to obtain a compatibilizing agent.

[0061] Example 2

[0062] Preparation of a low-cost and high-strength carbon fiber reinforced plate:

[0063] (1) Add the modified recycled carbon fiber into the composite resin base material. The mass ratio of the modified recycled carbon fiber to the composite resin base material is 3.5:1. Then add a compatibilizing agent, and the addition amount of the compatibilizing agent is 8 wt% of the composite resin base material. Carry out sizing. The sizing temperature is 50 °C and the sizing time is 1 min. Among them, the composite resin base material includes 90 parts of compounded epoxy resin and 60 parts of curing agent phthalic acid. The compounded epoxy resin includes aliphatic epoxy resin and bisphenol A epoxy resin, and the mass ratio of the aliphatic epoxy resin to the bisphenol A epoxy resin is 0.5:1;

[0064] (2) The sized modified recycled carbon fiber is preformed through a preforming die with a predetermined cross-section at the inlet. The preforming temperature is 30 °C and the preforming time is 60 s to obtain a preformed reinforced plate;

[0065] (3) The preformed reinforced plate is heated and cured and then drawn into a low-cost and high-strength carbon fiber reinforced plate. Among them, the heating and curing includes a curing treatment and a heat preservation treatment. The curing treatment temperature is 220 °C and the time is 50 s; the heat preservation treatment temperature is 200 °C and the time is 50 s.

[0066] Preparation of the modified recycled carbon fiber:

[0067] S01 Place the recycled carbon fiber in nitric acid and react for 30 min. Take it out, wash it until neutral, and place it in absolute ethanol for ultrasonic cleaning for 10 min to obtain the pretreated recycled carbon fiber;

[0068] S02 In a nitrogen atmosphere, place the pretreated recycled carbon fiber in the solvent xylene, add glycidyl methacrylate and initiator benzoyl peroxide, stir evenly. The mass ratio of the pretreated recycled carbon fiber, glycidyl methacrylate and initiator is 1.5:4:0.2. React at 80 °C for 4 h. After the reaction, centrifuge, wash and dry to obtain the recycled carbon fiber.

[0069] Preparation of the compatibilizing agent:

[0070] S1 Dissolve and mix maleic anhydride and initiator diisopropyl peroxide in N,N-dimethylformamide, heat and stir. The temperature of the heat and stir is 45 - 65 °C. Then add polyethylene and stir evenly. Then add it to polypropylene and stir to obtain a premix. The mass ratio of polypropylene to polyethylene is 1:

[0071] (0.05 - 0.15); the mass of maleic anhydride is 2% - 5% of the mass of polypropylene; the addition amount of initiator diisopropyl peroxide is 1.2 wt% of the premix;

[0072] S2 melts and grafts the premix obtained in step S1. The reaction time for melt grafting is 15 min, the temperature is 180 °C, and the rotation speed is 80 rpm to obtain a compatibilizing agent.

[0073] Example 3

[0074] Preparation of a low-cost and high-strength carbon fiber reinforced plate:

[0075] (1) Add the modified recycled carbon fibers to the composite resin base material. The mass ratio of the modified recycled carbon fibers to the composite resin base material is 3:1. Then add a compatibilizing agent, and the addition amount of the compatibilizing agent is 6 wt% of the composite resin base material. Impregnation is carried out at a temperature of 45 °C for 2 min. Among them, the composite resin base material includes 90 parts of a compounded epoxy resin and 50 parts of a curing agent 2-methylimidazole. The compounded epoxy resin includes an aliphatic epoxy resin and a bisphenol A epoxy resin, and the mass ratio of the aliphatic epoxy resin to the bisphenol A epoxy resin is 0.4:1;

[0076] (2) The impregnated modified recycled carbon fibers are preformed through a preforming mold with a predetermined cross-section at the inlet. The preforming temperature is 25 °C and the preforming time is 60 s to obtain a preformed reinforced plate;

[0077] (3) The preformed reinforced plate is heated and cured and stretched and formed to obtain a low-cost and high-strength carbon fiber reinforced plate. Among them, the heat curing includes a curing treatment and a heat preservation treatment. The curing treatment temperature is 180 °C and the time is 40 s; the heat preservation treatment temperature is 180 °C and the time is 40 s.

[0078] Preparation of modified recycled carbon fibers:

[0079] S01 React the recycled carbon fibers in nitric acid for 25 min, take them out and wash them until neutral, and place them in absolute ethanol for ultrasonic cleaning for 8 min to obtain pretreated recycled carbon fibers;

[0080] S02 In a nitrogen atmosphere, place the pretreated recycled carbon fibers in the solvent N,N-dimethylformamide, add glycidyl methacrylate and the initiator benzoyl peroxide, stir evenly. The mass ratio of the pretreated recycled carbon fibers, glycidyl methacrylate and the initiator is 1.5:3:0.2. React at 70 °C for 3 h. After the reaction, centrifuge, wash, and dry to obtain recycled carbon fibers.

[0081] Preparation of the compatibilizing agent:

[0082] S1 Dissolve and mix maleic anhydride and initiator dicumyl peroxide in N,N-dimethylformamide, heat and stir. The temperature of heating and stirring is 55°C, then add polyethylene and stir evenly, and then add it to polypropylene and stir to obtain a premix. The mass ratio of polypropylene to polyethylene is 1:0.1; the mass of maleic anhydride is 3% of the mass of polypropylene; the addition amount of initiator dicumyl peroxide is 1 wt% of the premix;

[0083] S2 Carry out melt grafting on the premix obtained in step S1. The reaction time of melt grafting is 10 min, the temperature is 180°C, and the rotation speed is 70 rpm to obtain a compatibilizing agent.

[0084] Example 4

[0085] The difference between Example 4 and Example 3 is that the compounded epoxy resin only includes aliphatic epoxy resin, and the rest are the same.

[0086] Example 5

[0087] The difference between Example 5 and Example 3 is that the mass ratio of aliphatic epoxy resin to bisphenol A epoxy resin is 1:1, and the rest are the same.

[0088] Example 6

[0089] The difference between Example 6 and Example 3 is that the bisphenol A epoxy resin is tetrachlorobisphenol A epoxy resin, and the rest are the same.

[0090] Example 7

[0091] The difference between Example 7 and Example 3 is that in the preparation process of the compatibilizing agent, the addition amount of initiator dicumyl peroxide is 2 wt% of the premix, and the rest are the same.

[0092] Example 8

[0093] The difference between Example 8 and Example 3 is that in the preparation method of the modified recycled carbon fiber, S02 is treated by soaking in a silane coupling agent, and the rest are the same.

[0094] Comparative Example 1

[0095] The difference between Comparative Example 1 and Example 3 is that it does not include a compatibilizing agent, and the rest are the same.

[0096] Comparative Example 2

[0097] The difference between Comparative Example 2 and Example 3 is that the recycled carbon fiber used is not modified, and the rest are the same.

[0098] Comparative Example 3

[0099] The difference between Comparative Example 3 and Example 3 is that the temperatures of the curing treatment and the heat preservation treatment are both 155°C, and the rest are the same.

[0100] Experimental Example 1

[0101] The carbon fiber reinforced plates obtained in Examples 1 to 8 and Comparative Examples 1 to 3 were subjected to performance tests. Among them, the tensile performance test was carried out in accordance with the relevant regulations of GB / T3354-2014, and the interlaminar shear strength test was carried out in accordance with the relevant regulations of Appendix D of GB 50728-2011. The test results are shown in Table 1.

[0102] Table 1 Test Results of Performance

[0103]

[0104]

[0105] It can be obtained from Table 1 that the carbon fiber reinforced plates of Examples 1 to 3 showed excellent mechanical properties, and Example 3 was the best. Example 6 used tetrachlorobisphenol A epoxy resin, and its mechanical properties were slightly better than those of Examples 1 to 3. In Comparative Example 1, the compatibilizing agent was not included, and the recycled carbon fiber in Comparative Example 2 was not modified, and its mechanical properties decreased significantly compared with Examples 1 to 3.

[0106] Experimental Example 2

[0107] The carbon fiber reinforced plates obtained in Examples 1 to 8 and Comparative Examples 1 to 3 were subjected to weather resistance tests. The specimens were obtained in accordance with the relevant regulations of GB / T3354-2014 and Appendix D of GB 50728-2011 respectively. The specimens were placed in a QUV ultraviolet light accelerated aging test machine, set to a UVB-313 lamp tube, a temperature of 55°C, a humidity of 95%, 12 hours of light + 12 hours of condensation per day, and tested for 1000 h. The specimens were taken out, the tensile performance test was carried out in accordance with the relevant regulations of GB / T3354-2014, and the interlaminar shear strength test was carried out in accordance with the relevant regulations of Appendix D of GB50728-2011. The performance degradation rates compared with Experimental Example 1 were tested and calculated, and the test results are shown in Table 2.

[0108] Table 2 Test Results of Performance Degradation Rate

[0109]

[0110]

[0111] It can be seen from Table 2 that among Examples 1 to 3, the performance degradation rates were relatively low. In Comparative Examples 1 and 2, the compatibilizing agent was not added and the recycled carbon fiber was not modified, and the performance degradation was obvious; followed by Comparative Example 3. The reason may be that the curing process parameters in Comparative Example 3 were changed, resulting in the influence of its weather resistance.

[0112] As described above, these are only embodiments of the present application. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modifications, equivalent replacements, improvements, etc. made within the technical idea and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A low-cost, high-strength carbon fiber reinforced plate, characterized in that: The invention comprises modified recycled carbon fiber, a composite resin base material and a compatibility aid, wherein the mass ratio of the modified recycled carbon fiber to the composite resin base material is (6-7):(2-3); the composite resin base material comprises, by weight fraction, 80-90 parts of a compounded epoxy resin and 40-60 parts of a curing agent.

2. A low-cost, high-strength carbon fiber reinforced plate according to claim 1, characterized in that: The preparation method of the modified recycled carbon fiber comprises the following steps: S01: placing the recovered carbon fiber in nitric acid for reaction for 20 to 30 minutes, taking it out and washing it until it is neutral, placing it in anhydrous ethanol for ultrasonic cleaning for 5 to 10 minutes, and obtaining the pretreated recovered carbon fiber; S02 In a nitrogen atmosphere, the pretreated recycled carbon fiber is placed in a solvent, glycidyl methacrylate and an initiator are added, stirred evenly, and reacted at 60-80°C for 3-4h. After the reaction is completed, centrifuge, wash, and dry to obtain the recycled carbon fiber.

3. A low-cost, high-strength carbon fiber reinforced plate according to claim 2, characterized in that: The mass ratio of the pretreated recycled carbon fiber, glycidyl methacrylate and initiator is (1-1.5):(2-4):(0.1-0.2); the solvent includes N,N-dimethylformamide or xylene; and the initiator includes benzoyl peroxide.

4. A low-cost, high-strength carbon fiber reinforced plate according to claim 1, characterized in that: The compound epoxy resin comprises aliphatic epoxy resin and bisphenol A epoxy resin, and the mass ratio of the aliphatic epoxy resin to the bisphenol A epoxy resin is (0.3-0.5):1; the curing agent is selected from one or more of polyvalent primary amines, polyvalent carboxylic acids, and imidazoles.

5. A low-cost, high-strength carbon fiber reinforced plate according to claim 4, characterized in that: The preparation method of the compatibilizer comprises the following steps: S1: maleic anhydride and initiator are added to N,N-dimethylformamide to dissolve and mix, and then heated and stirred, and then polyethylene is added and stirred evenly, and then added to polypropylene and stirred to obtain a premix; S2: melt-grafting the premix obtained in step S1 to obtain a compatibilizing agent.

6. A low-cost, high-strength carbon fiber reinforced plate according to claim 5, characterized in that: The mass ratio of polypropylene to polyethylene is 1:(0.05-0.15); the mass of maleic anhydride is 2%-5% of the mass of polypropylene; the initiator is dicumyl peroxide, and the added amount of the initiator is 0.8-1.2wt% of the premix.

7. A low-cost, high-strength carbon fiber reinforced plate according to claim 5, characterized in that: The temperature of heating and stirring in step S1 is 45-65° C.; the reaction time of melt grafting in step S2 is 10-15 min, the temperature is 160-180° C., and the rotation speed is 50-80 rpm.

8. A method for preparing a low-cost, high-strength carbon fiber reinforced plate according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) adding the modified recycled carbon fiber into a composite resin base material, and then adding a compatibility aid to perform dipping; (2) the modified recycled carbon fiber after the resin impregnation is preformed through a preforming mold with a predetermined cross section at the inlet to obtain a preformed reinforcement plate; (3) The preformed reinforcement plate is heated, cured, and drawn to obtain a low-cost, high-strength carbon fiber reinforcement plate.

9. The method for preparing a low-cost, high-strength carbon fiber reinforced plate according to claim 8, characterized in that: In step (1), the dipping temperature is 40-50° C., and the dipping time is 1-2 minutes; in step (2), the preforming temperature is 20-30° C., and the preforming time is 30-60 seconds.

10. The method for preparing a low-cost, high-strength carbon fiber reinforced plate according to claim 8, characterized in that: The heating curing in step (3) includes curing treatment and heat preservation treatment, wherein the curing treatment temperature is 155-220° C. and the time is 30-50 seconds; the heat preservation treatment temperature is 180-200° C. and the time is 30-50 seconds.

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