A bio-based polyamide carbon fiber reinforced material and its preparation method

Abstract

This invention relates to a bio-based polyamide carbon fiber reinforced material, comprising the following components: 100 parts by weight of pentanediamine polyamide resin; 10-30 parts by weight of furanyl polyester resin; 1-5 parts by weight of chain extender; and 10-50 parts by weight of carbon fiber. The preparation method includes acid-alcohol treatment of the carbon fiber: impregnating the carbon fiber in a liquid of polybasic acid and polyol, heating and dehydrating it, then blending the acid-alcohol treated carbon fiber with pentanediamine polyamide resin, furanyl polyester resin, and chain extender, and curing to obtain the reinforced material. This invention improves the bond strength and water absorption of pentanediamine polyamide and carbon fiber, resulting in a reinforced material with strong mechanical properties, low water absorption, and a certain degree of biomass content.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to a bio-based polyamide carbon fiber reinforced material and its preparation method. Background Technology

[0002] Polyamides possess excellent mechanical properties, self-lubricating properties, good abrasion resistance, high heat resistance, and high electrical insulation, making them widely used in machinery, automobiles, electrical appliances, textile equipment, chemical equipment, aerospace, metallurgy, and other fields. As a major engineering plastic, they are of great significance to national economy, social development, and national defense security. With social development, the demand for polyamide compounds continues to grow rapidly.

[0003] Compared to petroleum-based polyamides, bio-based polyamides are derived from biomass derived from renewable resources, resulting in significantly lower CO2 emissions compared to petroleum-based feedstocks, thus greatly improving their environmental friendliness. Bio-based polyamides can be classified according to the amount of biomass used, including fully bio-based polyamides such as poly(ω-aminodecanoyl), poly(decanoyl decanediamine), furanyl dibutyl diamine, poly(hexamethylene furanyl diamine), poly(octyl furanyl diamine), and poly(decanoyl furanyl diamine), and partially bio-based polyamides such as polypentanediamine adipate, poly(hexamethylene decanediamine), and poly(decanoyl terephthalamide). Furthermore, the production process for bio-based pentanediamine is relatively mature. It can be produced in a one-step decarboxylation process using lysine. By adjusting the enzyme production process and the lysine catalysis, the molar conversion rate of pentanediamine can be greater than 98%. Therefore, pentanediamine polyamide synthesized from pentanediamine has good development prospects. Similar to other polyamides, pentanediamine polyamide has a high water absorption rate, and its mechanical strength is insufficient in some applications.

[0004] Polyamide and carbon fiber composites are a common method for polyamide modification. Patent CN114656782A discloses using carbon fiber as a reinforcing material, but the poor bonding between carbon fiber and polyamide results in low notched impact strength. Patent CN101313023A discloses adding an adhesive layer to the surface of carbon fiber to improve the bonding between carbon fiber and polyamide. This method produces polyamide-carbon fiber composites with high mechanical properties, but the polyamide used is petroleum-based and not bio-friendly. Summary of the Invention

[0005] One object of the present invention is to provide a bio-based polyamide carbon fiber reinforced material with excellent mechanical properties and low water absorption.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A bio-based polyamide carbon fiber reinforced material, comprising the following components:

[0008] 100 parts by weight of pentanediamine polyamide resin;

[0009] 10-30 parts by weight of furanyl polyester resin;

[0010] Chain extender 1-5 parts by weight;

[0011] 10 to 50 parts by weight of carbon fiber.

[0012] Preferably, the pentanediamine polyamide resin described above is a polyamide resin polymerized from pentanediamine and a diacid, and is selected from polypentanediamine adipamide, polypentanediamine terephthalamide, polypentanediamine adip-terephthalamide, polypentanediamine sebacate, polypentanediamine succinate, polypentanediamine lauroyl, etc. In this invention, the pentanediamine polyamide comprises one or more of polypentanediamine adipamide, polypentanediamine terephthalamide, and polypentanediamine adip-terephthalamide.

[0013] More preferably, the pentanediamine polyamide resin is polyadipamide-terephthalamide, which has better processing difficulty and performance.

[0014] Preferably, the furan-based polyester described above is a furan resin whose repeating unit in the molecular chain contains an ester group (-COO-). The furan-based polyester resin is selected from one or more of polyethylene furanate, propylene furanate, butylene furanate, hexane furanate, octyl furanate, and decyl furanate. The furan-based polyester plays a role in modifying polyamide and enhancing the interfacial adhesion between polyamide and carbon fiber.

[0015] More preferably, the furan-based polyester resin is polybutylene furanate, which has a better bonding effect with the matrix.

[0016] Preferably, in the above technical solution, the furan-based polyester resin is 15-25 parts by weight, such as 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 parts, which effectively improves the interfacial adhesion between pentanediamine polyamide and carbon fiber without affecting its mechanical properties. If the amount of furan-based polyester is too small, it cannot effectively improve the interfacial adhesion between pentanediamine polyamide and carbon fiber; if the amount of furan-based polyester is too large, it will lead to weak intermolecular forces and damage the overall mechanical properties.

[0017] Preferably, the chain extender described above is a substance that can react with functional groups on polymer chains to extend molecular chains and increase molecular weight. The chain extender is selected from one or more of isocyanates, carbodiimides, and epoxy compounds, and plays the role of curing resin and improving the bonding ability between carbon fibers and resin matrix.

[0018] More preferably, the isocyanate chain extender is selected from one or more of toluene diisocyanate and diphenylmethane diisocyanate;

[0019] The carbodiimide chain extender is selected from one or more of N,N-dihydroxy(diisopropyl)aniline, N,N'-diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dicyclohexylcarbodiimide, polytriethyl-1,3-phenylcarbodiimide, and polymeric carbodiimide.

[0020] The epoxy chain extender is selected from one or more of bis(3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexyl-3′,4-epoxycyclohexane carboxylate, 1,4-cyclohexanediethanol glycidyl ether, and 1,4-butanediol diglycidyl ether.

[0021] More preferably, the chain extender is an isocyanate or a carbodiimide, which can reduce water absorption and improve the interfacial adhesion of carbon fibers.

[0022] Preferably, the chain extender in the above technical solution is 2 to 4 parts by weight, such as 2, 3, or 4 parts, which effectively improves the bonding ability between carbon fiber and resin matrix without affecting processing performance. If too little chain extender is used, some resin will not be cured, resulting in a decrease in mechanical properties; if too much chain extender is used, the resin will crosslink and become difficult to process.

[0023] In the preferred embodiment of the above technical solution, the carbon fiber has a carbon content of over 90%, which improves its strength and toughness.

[0024] Preferably, the carbon fiber in the above technical solution is selected from long-bundle carbon fiber filaments, short-bundle fiber filaments, chopped carbon fiber, carbon fiber powder, carbon fiber fabric, etc.

[0025] Preferably, the carbon fiber in the above technical solution is 20 to 40 parts by weight, such as 20 parts, 25 parts, 30 parts, 35 parts, or 40 parts, which effectively improves the strength and toughness of the composite material without affecting its processing performance. If the amount of carbon fiber is too small, the strength and toughness of the composite material cannot be effectively improved; if the amount of carbon fiber is too large, the viscosity of the resin will be too high, making it difficult to process.

[0026] Another object of the present invention is to provide a method for preparing bio-based polyamide carbon fiber reinforced materials.

[0027] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0028] A method for preparing bio-based polyamide carbon fiber reinforced materials includes:

[0029] (1) Acid-alcohol treatment of carbon fibers: The carbon fibers are impregnated in a liquid of polyacid and polyol, and then heated and dehydrated.

[0030] (2) The carbon fiber treated with acid alcohol is blended with pentanediamine polyamide resin, furanyl polyester resin and chain extender and cured to obtain a reinforcing material.

[0031] In order to enable the resin matrix to better protect the carbon fiber from external damage and enable the carbon fiber to bear the load more effectively, it is necessary to improve the interfacial properties between the carbon fiber and the resin matrix. Therefore, this application requires acid-alcohol treatment of the carbon fiber to form a polyester layer on the surface of the carbon fiber, so that it can better bond with the matrix under the action of chain extender to obtain excellent interfacial properties.

[0032] Preferably, in the above technical solution, the molar ratio of the polyacid and polyol is 1:0.7-0.9, which further improves the bonding ability between the polyester layer and the matrix and increases the polarity of the polyester layer. If the ratio is too large, the polyester layer will be too acidic, affecting the durability of the material; if the ratio is too small, it will be difficult to improve the interfacial performance.

[0033] Preferably, the polybasic acid mentioned above refers to a compound containing two or more carboxyl groups (-COOH), and the polybasic acid is one or more of dibasic acid and tribasic acid; the polybasic acid is selected from one or more of oxalic acid, succinic acid, citric acid, sebacic acid, malic acid, sebacic acid, tartaric acid, and ascorbic acid.

[0034] More preferably, the polyacid is citric acid, in order to control the branching degree and polarity of the polyester.

[0035] Preferably, the polyol in the above technical solution is one or more of diols and triols.

[0036] More preferably, the polyol is ethylene glycol, in order to control the degree of branching and polarity of the polyester.

[0037] Preferably, in (1), the heating temperature is 105-150°C and the time is 5-30 hours, which further improves the cohesive force of the polyester layer, improves the ability to disperse load, and improves the molecular weight of the polyester.

[0038] Preferably, in the above technical solution, after acid and alcohol treatment, the carbon fiber increases in weight by 5-20%, and the thickness of the polyester layer is controlled so that the polyester layer can effectively improve the interfacial performance without causing the carbon fiber to lose its ability to disperse load, and the excess part can be washed off.

[0039] More preferably, the heating temperature is 120°C and the time is 10 to 20 hours. If the temperature is too high, it is difficult to control the reaction process. If the temperature is too low, the reaction process is too slow, which is not conducive to production. If the reaction time is too long, the molecular weight will be too large, and the polyester layer will be solidified on the carbon fiber surface, which will be difficult to wash off and cause the carbon fiber to lose its function. If the reaction time is too short, the molecular weight will be small, the cohesion will be low, and it will be difficult to effectively play the role of dispersing load.

[0040] Preferably, in (2), the molding process includes hand lay-up molding, spray molding, resin transfer molding (RTM technology), bag molding (pressure bag method), vacuum bag molding, autoclave molding, hydraulic autoclave molding, thermal expansion molding, sandwich structure molding, compression molding (SMC sheet, BMC clump), continuous sheet molding, resin casting molding, pultrusion molding, continuous winding molding, injection molding, extrusion molding, centrifugal casting for tube molding, etc.

[0041] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0042] This invention improves the bonding strength and water absorption of pentanediamine polyamide and carbon fiber, thereby enhancing the material's mechanical properties, reducing water absorption, and giving it a certain degree of biomass content. Detailed Implementation

[0043] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The raw materials used in each embodiment and comparative example are as follows:

[0045] Pentylene diamine polyamide resin

[0046] A1: Poly(pentyl adipamide)

[0047] The preparation method is as follows:

[0048] Step 1: Weigh 5 mol of pentanediamine (1210 g) and 5.05 mol of adipic acid (737 g) and pour them into 30000 ml of distilled water. Stir at 100 rpm for 30 min at room temperature to prepare a homogeneous aqueous solution.

[0049] Step 2: Pour the aqueous solution from Step 1 into a 50L autoclave. React at 150℃, under nitrogen protection, and at 40rpm for 1 hour while removing the generated water vapor. Then, increase the pressure of the autoclave to 1.8MPa. Slowly increase the temperature over one hour until it reaches 260℃, then stop heating. After that, open the pressure relief valve and slowly release the pressure. After about 1 hour, the pressure drops to 1MPa. Then, use a vacuum device to reduce the pressure inside the autoclave to 86kPa and maintain it for 10 minutes to obtain molten polyamide resin.

[0050] Step 3: Pressurize with nitrogen to form a thread-like product from the lower spinning nozzle. Cool the product with water, cut it, and discharge it as granules. Dry it at 120°C in a nitrogen atmosphere for 10 hours to obtain polyamide resin (A1).

[0051] A2: Polypentyl terephthalamide (PTFE)

[0052] In preparation: replace 5.05 mol of adipic acid in the A1 manufacturing method with 5.05 mol of terephthalic acid, and keep the other steps the same to obtain A2.

[0053] A3: Poly(hexamethylene adipamide) terephthalamide

[0054] In preparation: replace 5.05 mol of adipic acid in the A1 manufacturing method with 2.02 mol of adipic acid and 3.03 mol of terephthalic acid, and keep the other steps the same to obtain A3.

[0055] Furan-based polyester resin

[0056] B1: Polyethylene furanate, produced by Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences.

[0057] B2: Polypropylene furanate, produced by Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences.

[0058] B3: Polybutylene furanate, produced by Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences.

[0059] Chain extender

[0060] C1: m-Toluene Isocyanate, produced by Beijing Wokai Biotechnology Co., Ltd.

[0061] C2: Polycarbodiimide, produced by Rheinland Technology.

[0062] C3: Butylimine diethanol, produced by Tianyuan Aviation Materials.

[0063] Carbon fiber

[0064] D1: MLD-30, manufactured by Toray Industries, Inc., Japan, with a fiber length of 30μm.

[0065] [Dibasic Acids]

[0066] E1: Citric acid, produced by Zhejiang Yingxuan Biotechnology Co., Ltd.

[0067] E2: Tartaric acid, produced by Ruijing Biotechnology.

[0068] Polyols

[0069] F1: Ethylene glycol, produced by Nanjing Rongji Chemical Co., Ltd.

[0070] F2: Glycerol, produced by Beijing Hengchengxingsheng.

[0071] [Eluent]

[0072] Ethyl acetate, produced by Bohr Chemicals.

[0073] Examples 1-25 and Comparative Example 2 were prepared according to the following method:

[0074] Step 1: Weigh the polyacid, polyol and carbon fiber according to the formula in Table 1 and pour them into the reaction vessel. Close the reaction vessel and react under negative pressure and high temperature for a period of time, where the negative pressure is -0.1MPa. The reaction temperature and reaction time are as shown in Table 1. After the reaction is completed, take out the carbon fiber and place it on a 200-mesh sieve. Spray it with a spray bottle containing ethyl acetate for 10 minutes. After spraying, put the sieve into a vacuum drying oven and dry it at 100℃ and -0.1MPa for 10 minutes. After drying, the acid-alcohol treated carbon fiber is obtained and weighed.

[0075] Step 2: Weigh the pentanediamine polyamide resin, furanyl polyester resin, and chain extender according to the formula in Table 1, and add them together with the acid-alcohol treated carbon fiber into a mixer. Mix at 320°C and 100 rpm for 10 min to obtain the composition.

[0076] Step 3: While the composition is still hot, pour it into the female mold brushed with silicone oil, let it stand for a period of time to defoam, then press the male mold into the female mold with a pressure of 5MPa. After cooling until the composition is cured, remove the male mold and take the composition out of the female mold to obtain the pentanediamine polyamide carbon fiber reinforced material board.

[0077] Comparative Examples 1-3 were prepared according to the following method:

[0078] Step 1: Heat the pentanediamine polyamide resin to 320℃ to melt it, and pour it into the female mold brushed with silicone oil while it is still hot. Let it stand for a period of time to defoam, and then press the male mold into the female mold with a pressure of 5MPa. After cooling until the composition is solidified, remove the male mold to obtain the pentanediamine polyamide resin board.

[0079] Comparative Example 4 was prepared as follows:

[0080] Step 1: Weigh the pentanediamine polyamide resin, furanyl polyester resin, and chain extender according to the formula in Table 1, and add them together with the acid-alcohol treated carbon fiber into a mixer. Mix at 320°C and 100 rpm for 10 min to obtain the composition.

[0081] Step 2: While the composition is still hot, pour it into the female mold brushed with silicone oil, let it stand for a period of time to defoam, then press the male mold into the female mold with a pressure of 5MPa. After cooling until the composition is cured, remove the male mold and take the composition out of the female mold to obtain the pentanediamine polyamide carbon fiber reinforced material board.

[0082] Comparative Example 5 was prepared as follows:

[0083] Step 1: Weigh the polyacid, polyol, and carbon fiber according to the formula in Table 1 and pour them into a reaction vessel. Close the reaction vessel and react under negative pressure and high temperature for a period of time, where the negative pressure is -0.1 MPa. The reaction temperature and reaction time are as shown in Table 1. After the reaction is complete, remove the carbon fiber and place it on a 200-mesh sieve. Spray it with a spray bottle containing ethyl acetate for 10 minutes. After spraying, place the sieve in a vacuum drying oven and dry it at 100℃ and -0.1 MPa for 10 minutes. After drying, the acid-alcohol treated carbon fiber is obtained and weighed.

[0084] Step 2: Weigh the pentanediamine polyamide resin and chain extender according to the formula in Table 1, and add them together with the acid-alcohol treated carbon fiber into a mixer. Mix at 320°C and 100 rpm for 10 min to obtain the composition.

[0085] Step 3: While the composition is still hot, pour it into the female mold brushed with silicone oil, let it stand for a period of time to defoam, then press the male mold into the female mold with a pressure of 5MPa. After cooling until the composition is cured, remove the male mold and take the composition out of the female mold to obtain the pentanediamine polyamide carbon fiber reinforced material board.

[0086] The testing performance and methods are as follows:

[0087] 1. Tensile strength: Tested according to GB / T1040.1-2018.

[0088] 2. Elongation at break: Tested according to GB / T1040-92.

[0089] 3. Flexural modulus: Tested according to GB / T9341-2008.

[0090] 4. Bending strength: Tested according to GB / T9341-2008.

[0091] 5. Notched impact strength of simply supported beams: tested according to GB / T1043.1-2008.

[0092] 6. Carbon fiber weight gain rate: The weight of carbon fiber before and after acid and alcohol treatment is measured. The weight gain rate of carbon fiber is obtained by dividing the weight of carbon fiber after acid and alcohol treatment by the weight of carbon fiber before acid and alcohol treatment.

[0093] 7. Water absorption rate: After drying the sample at a constant temperature of 50℃ for 1 hour, take it out and measure its weight at this time. Then, soak it in deionized water at 23℃ for 24 hours, take it out, wipe off the surface moisture with a paper towel, and measure its weight at this time. The water absorption rate is obtained by dividing the increase in weight of the sample after soaking by the mass of the sample after drying.

[0094] Table 1:

[0095]

[0096]

[0097] Table 2:

[0098]

[0099] As shown in Tables 1 and 2, compared with the comparative examples, the composite materials prepared in the examples have excellent mechanical properties, low water absorption, and a certain amount of biomass.

[0100] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A bio-based polyamide carbon fiber reinforced material, characterized in that: It consists of the following components: 100 parts by weight of pentanediamine polyamide resin; 10-30 parts by weight of furanyl polyester resin; Chain extender 1-5 parts by weight; 10-50 parts by weight of acid-alcohol treated carbon fiber The acid-alcohol treatment of carbon fiber includes immersing the carbon fiber in a liquid of polyacid and polyol, followed by heating and dehydration. The heating temperature is 120°C and the time is 10-20 hours. After the acid-alcohol treatment, the carbon fiber increases in weight by 5-20%. The polyacid is selected from one or more of oxalic acid, succinic acid, citric acid, sebacic acid, malic acid, tartaric acid, and ascorbic acid, and the polyol is ethylene glycol.

2. The bio-based polyamide carbon fiber reinforced material according to claim 1, characterized in that: The pentanediamine polyamide resin is selected from polypentanediamine adipamide, polypentanediamine terephthalamide, polypentanediamine adipamide-terephthalamide, polypentanediamine sebacyldiamide, polypentanediamine succinate, and polypentanediamine lauroyldiamide.

3. The bio-based polyamide carbon fiber reinforced material according to claim 1, characterized in that: The furan-based polyester resin is selected from one or more of polyethylene furanate, propylene furanate, butylene furanate, hexanediol furanate, octylene furanate, and decanediol furanate.

4. The bio-based polyamide carbon fiber reinforced material according to claim 1, characterized in that: The chain extender is selected from one or more of isocyanates, carbodiimides, and epoxides.

5. The bio-based polyamide carbon fiber reinforced material according to claim 1, characterized in that: The carbon fiber has a carbon content of over 90%.

6. A method for preparing the bio-based polyamide carbon fiber reinforced material as described in any one of claims 1 to 5, characterized in that: include: (1) Acid and alcohol treatment of carbon fiber: The carbon fiber is immersed in a liquid of polyacid and polyol, heated and dehydrated. (2) The acid and alcohol treated carbon fiber is blended with pentanediamine polyamide resin, furanyl polyester resin and chain extender and cured to obtain a reinforcing material.

7. The method for preparing bio-based polyamide carbon fiber reinforced materials according to claim 6, characterized in that: The molar ratio of the polyacid and polyol is 1:0.7 to 0.

9.

8. The method for preparing bio-based polyamide carbon fiber reinforced materials according to claim 6, characterized in that: The aforementioned polybasic acid is one or more of dibasic acids and tribasic acids.

9. The method for preparing bio-based polyamide carbon fiber reinforced materials according to claim 8, characterized in that: The polyacids mentioned are selected from one or more of oxalic acid, succinic acid, citric acid, sebacic acid, malic acid, tartaric acid, and ascorbic acid.

10. The method for preparing bio-based polyamide carbon fiber reinforced materials according to claim 6, characterized in that: The polyol is one or more of diols and triols.

11. The method for preparing bio-based polyamide carbon fiber reinforced materials according to claim 6, characterized in that: In (1), the heating temperature is 105-150℃ and the time is 5-30 hours; After acid-alcohol treatment, the carbon fiber increases in weight by 5-20%.

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