Preparation method of carbon nanotube modified furyl polyamide composite material, composite material and application

Abstract

The invention discloses a preparation method of a carbon nano tube modified furyl polyamide composite material, the composite material and application, and relates to the technical field of polymer composites.The method comprises the steps that under the protective gas atmosphere, 2, 2 '-difluoro-2, 2'-difluoro-2, 2 '-difluoro-2, 2'-difluoro-2, 2 '-difluoro-2 The preparation method comprises the following steps: carrying out a first heating reaction, a first reduced pressure reaction, a second reduced pressure reaction and a second heating reaction on a 1, 5-furandicarboxylic acid compound, aliphatic diamine, a catalyst and an organic solvent to prepare a polyamide prepolymer, continuously adding a dispersed carbon nanotube solution, carrying out a first vacuum reaction and a second vacuum reaction, and carrying out post-treatment to prepare the composite material. The functionalized carbon nanotubes are introduced into the bio-based polyamide prepolymer in a chemical bond form to prepare the modified polyamide composite material, so that the interface bonding effect between the functionalized carbon nanotubes and a polymer matrix is improved, and the functionalized carbon nanotubes are prevented from being ineffectively agglomerated and bundled in the matrix, thereby improving the thermal stability and other properties of the polymer.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and more particularly to a preparation method of a carbon nanotube-modified furan-based polyamide composite material, the composite material and its application. Background Art

[0002] Nanomaterials are an important part of today's new material research field. Among them, carbon nanomaterials, with their unique structure and size, have ultra-high mechanical properties, electrical properties, as well as thermal, optical, rheological, adsorption and other excellent properties. They are ideal reinforcing materials in composite materials systems.

[0003] Among them, carbon nanotubes have a special tubular structure and a large specific surface area, which makes carbon nanotube composites have more excellent properties. In the field of scientific and technological applications, carbon nanotube / polymer composites are considered to be one of the most promising materials. How to achieve uniform dispersion of carbon nanotubes in the matrix and establish a strong interface bond is a difficult problem faced in the current research process of carbon nanotube composites.

[0004] Polyamide (PA) is an engineering plastic widely used in industry, with high melting point, high thermal stability, high strength and toughness, and good solubility resistance. Bio-based polyamides are derived from renewable biomass, and compared with petroleum-based raw materials, they have a more obvious carbon reduction effect. However, their physical and mechanical properties still cannot meet certain specific use areas. Existing furan-aliphatic polyamides, especially the five-carbon diamine pentamethylenediamine, have a low molecular weight and a low thermal decomposition temperature due to their odd-numbered carbon linear structure, which limits their further development and application. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a preparation method, composite material and application of a carbon nanotube-modified furan-based polyamide composite material. The present invention introduces functionalized carbon nanotubes into a bio-based polyamide prepolymer in the form of chemical bonds to prepare a modified polyamide composite material, thereby improving the interface bonding effect between the functionalized carbon nanotubes and the polymer matrix, preventing the functionalized carbon nanotubes from ineffectively agglomerating into bundles in the matrix, and thus improving the thermal stability and other properties of the polymer.

[0006] One of the purposes of the present invention is to provide a method for preparing a carbon nanotube-modified furan-based polyamide composite material.

[0007] The preparation method of the carbon nanotube-modified furan-based polyamide composite material of the present invention comprises:

[0008] Under a protective gas atmosphere, a 2,5-furandicarboxylic acid compound, an aliphatic diamine, a catalyst and an organic solvent are subjected to a first heating reaction, a first decompression reaction, a second decompression reaction and a second heating reaction to obtain a polyamide prepolymer, and a dispersed carbon nanotube solution is continuously added, and the composite material is obtained after a first vacuum reaction and a second vacuum reaction and post-treatment.

[0009] Preferably,

[0010] The molar ratio of the 2,5-furandicarboxylic acid compound to the aliphatic diamine is 1:(0.5-1.5), preferably 1:(0.9-1.2);

[0011] The amount of the catalyst is 0.1 to 25 wt % of the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine, preferably 0.2 to 20 wt %;

[0012] The amount of the organic solvent is 200 to 800 wt % of the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine, preferably 300 to 550 wt %;

[0013] The amount of the carbon nanotubes used is 0.01-1 wt %, preferably 0.05-0.5 wt %, based on the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine.

[0014] Preferably,

[0015] The 2,5-furandicarboxylic acid compound is at least one of 2,5-furandicarboxylic acid, 2,5-furandicarboxylic acid dimethyl ester, 2,5-furandicarboxylic acid diethyl ester and 2,5-furandicarboxylic acid chloride, and the 2,5-furandicarboxylic acid compound can be prepared by a biological method; and / or,

[0016] The aliphatic diamine is a bio-based aliphatic diamine, preferably at least one of butanediamine, pentamethylenediamine, hexamethylenediamine, octanediamine and decanediamine; and / or,

[0017] The catalyst is a metal catalyst or lipase;

[0018] The lipase is a lipase commonly used in the art, such as Novozymes' N435 lipase, CALB lipase, TM lipase, TL lipase, RM lipase, Purolite's 435 lipase, etc.; and / or,

[0019] The organic solvent is at least one of toluene, diphenyl ether, xylene, N-methylpyrrolidone and dimethylacetamide; and / or,

[0020] The carbon nanotube is at least one of a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, and a composite carbon nanotube; and / or,

[0021] The carbon nanotube is at least one of an amino carbon nanotube, a carboxyl carbon nanotube, a hydroxyl carbon nanotube, and a thiol carbon nanotube.

[0022] Preferably,

[0023] The metal catalyst is at least one of a zinc-containing compound, an organic tin compound, and an organic titanium compound;

[0024] Preferably,

[0025] The zinc-containing compound is at least one of zinc citrate, zinc oxide, zinc halide, and zinc gluconate; and / or,

[0026] The organotin compound is at least one of stannous octoate, stannous oxalate, dibutyltin oxide, butyltin acid, diethyl dibutyltin, dioctyltin oxide, and monobutyltin triisooctoate; and / or,

[0027] The organic titanium compound is at least one of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate and ethylene glycol titanium.

[0028] Preferably,

[0029] The weight ratio of the solvent to the carbon nanotubes in the carbon nanotube solution is (15-200):1; and / or,

[0030] The solvent of the carbon nanotube solution is at least one of toluene, diphenyl ether, xylene, N-methylpyrrolidone and dimethylacetamide.

[0031] Preferably,

[0032] The first heating reaction temperature is 60-160° C., and / or the heating rate is 10-20° C. / h, and / or the reaction time is 6-10 h; and / or,

[0033] The first decompression reaction pressure is 40-80 kPa, and / or the reaction time is 12-24 h; and / or,

[0034] The second reduced pressure reaction pressure is 10 to 30 kPa, and / or the reaction time is 24 to 40 hours; and / or,

[0035] The second temperature-raising reaction temperature is 120-160° C., and / or the heating rate is 10-20° C. / h, and / or the reaction time is 12-24 h; and / or,

[0036] The vacuum degree of the first vacuum reaction is 1000-5000 Pa, and / or the reaction temperature is 140-210° C., preferably 190-210° C., and / or the reaction time is 0.5-2.5 hours, preferably 1-1.5 hours; and / or,

[0037] The vacuum degree of the second vacuum reaction is ≤300Pa, preferably ≤50Pa, and / or the reaction temperature is 210-260°C, preferably 220-250°C, and / or the reaction time is 1-5 hours, preferably 2-3 hours.

[0038] Preferably, the method for dispersing the carbon nanotube solution comprises:

[0039] The carbon nanotube solution was sonicated in a water bath for 20-30 min.

[0040] Preferably, the post-processing comprises:

[0041] Precipitation, filtration, centrifugation and vacuum drying.

[0042] Preferably,

[0043] The precipitant used in the precipitation process is at least one of methanol, ethanol, isopropanol, acetonitrile, dioxane and dichloromethane; and / or,

[0044] The centrifugal agent used in the centrifugation process is at least one of methanol, ethanol and acetone, and the supernatant is discarded after centrifugation; and / or,

[0045] The vacuum drying may be performed in a vacuum drying oven, the vacuum drying temperature may be 40-60° C., and / or the vacuum drying time may be 24-72 hours.

[0046] The following solutions can be adopted:

[0047] Under the protection of inert gas, a 2,5-furandicarboxylic acid compound, an aliphatic diamine and a catalyst are dissolved in an organic solvent, heated to 60-160°C at a heating rate of 10-20°C / h, and reacted for 6-10 hours; the system is decompressed to 40-80 kPa within 1 hour, and reacted at the pressure for 12-24 hours; the system is decompressed to 10-30 kPa within 1 hour, and reacted at the pressure for 24-40 hours; the system is heated to 120-160°C at a heating rate of 10-20°C / h, and the reaction is continued for 12-24 hours to obtain a polyamide prepolymer.

[0048] Disperse the carbon nanotubes in a solvent, place in a water bath and ultrasonicate for 20-30 minutes, add the ultrasonicate mixture to the polyamide prepolymer under the protection of an inert gas, gradually establish vacuum reaction conditions within 1 hour, keep the vacuum degree between 1000 and 5000 Pa, and the reaction temperature between 140 and 210° C.; the reaction time is 0.5 to 2.5 hours;

[0049] The vacuum degree is controlled at ≤300Pa, the reaction temperature is 210-260°C, the reaction time is 1-5 hours, and after the reaction, the product is precipitated in a precipitant, washed, centrifuged and the supernatant is discarded, and dried in a vacuum drying oven at 40°C for 48 hours to prepare a carbon nanotube-modified furan-based polyamide composite material.

[0050] A second object of the present invention is to provide a carbon nanotube-modified furan-based polyamide composite material.

[0051] Preferably,

[0052] The number average molecular weight of the composite material is 3500 g / mol to 7000 g / mol.

[0053] The third object of the present invention is to provide an application of a carbon nanotube-modified furan-based polyamide composite material in the field of bio-based plastic products, bio-based fibers and bio-based films.

[0054] The present invention realizes the regulation of the performance of the polymer by modifying the polymer structure, which is an effective method for modifying the rigidity of polyamide and regulating the performance, and is conducive to expanding the application field of polyamide. Carbon nanotubes (CNTs) have unique surface effects and scale effects, extremely high elastic modulus and tensile strength, excellent electrical conductivity, thermal conductivity and other properties. When CNTs are added to polymers, on the one hand, the size of CNTs is comparable to the size of polymer molecular chain segments, which can slow down or even prevent the movement of polymer molecular chain segments and increase the glass transition temperature of the polymer; on the other hand, CNTs have a large aspect ratio, which can effectively transmit stress when the polymer is subjected to impact loads, thereby improving the toughness of the polymer material.

[0055] The traditional preparation of carbon nanotube modified polymers is generally through physical mixing of carbon nanotube materials and polymers, and then preparing composite materials by connecting different groups through hydrogen bonds. Due to the large specific surface area of ​​CNTs and the strong van der Waals force between graphite sheets, physical blending of carbon nanotubes with resins can easily cause large-area aggregation in the matrix and entangle with each other while strengthening polymer-based composite materials. Functional groups with certain reactivity, such as -OH, -COOH and -NH2, are grafted on the surface of CNTs in the form of chemical bonds. The terminal groups of furan-based polyamides include ester end groups, amine end groups, acid end groups, amide end groups and other groups, which can react chemically with functionalized CNTs, and can undergo esterification, transesterification, amidation and other reactions, thereby improving the interfacial bonding effect between them and the polymer matrix, preventing them from ineffectively agglomerating into bundles in the matrix, and improving the comprehensive performance of CNTs-reinforced polymer-based composite materials.

[0056] The present invention introduces functionalized carbon nanotubes into bio-based polyamide prepolymers in the form of chemical bonds to prepare modified polyamide composite materials, thereby improving the interface bonding effect between the prepolymer and the polymer matrix and preventing the prepolymer from ineffectively agglomerating into bundles in the matrix, thereby improving the thermal stability and other properties of the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a TGA graph of the carbon nanotube-modified furan-based polyamide composite material prepared in Example 2;

[0058] Figure 2 is the infrared spectrum of the carbon nanotube-modified furan-based polyamide composite material prepared in Example 2; Figure 2 The infrared spectrum of the carbon nanotube-modified furan-based polyamide composite material shows that 1730 cm -1 The carbonyl stretching vibration at 100 nm indicates the presence of esters in the system, proving that the hydroxylated CNTs and the furan-based polyamide in the carbon nanotube-modified furan-based polyamide composite material prepared in Example 2 are chemically bonded;

[0059] Figure 3 This is the infrared spectrum of the polyamide prepolymer prepared in Comparative Example 1;

[0060] Figure 4 is a TGA graph of the polyamide prepolymer prepared in Comparative Example 1;

[0061] Figure 5 is a TGA graph of the carbon nanotube-modified furan-based polyamide composite material prepared in Comparative Example 2;

[0062] Thermogravimetric analysis (TGA) was performed on a TGA550 instrument with a heating rate of 10 °C / min; infrared spectra were recorded on a Bruker spectrometer with a resolution of 2 cm -1 . DETAILED DESCRIPTION

[0063] The present invention is described in detail below in conjunction with specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0064] Raw materials preparation:

[0065] Dimethyl 2,5-furandicarboxylate: purity 98%, purchased from innochem;

[0066] Pentamethylenediamine: purity 98%, purchased from innochem;

[0067] N435 lipase: purity ≥95%, purchased from Accela;

[0068] Hydroxylated multi-walled CNTs: purity > 95%, inner diameter: 5-10 nm, outer diameter: 10-20 nm, length: 10-30 μm, purchased from innochem;

[0069] Carboxylated multi-walled CNTs: purity > 95%, inner diameter: 5-10 nm, outer diameter: 20-30 nm, length: 0.5-2 μm, purchased from innochem;

[0070] Aminated multi-walled CNTs: purity > 95%, inner diameter: 3-5 nm, outer diameter: 8-15 nm, length: 30-50 μm, purchased from innochem;

[0071] The other raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art and can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0072] Example 1

[0073] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine and 4.56g of N435 lipase were dissolved in 120g of toluene, heated to 90°C, with a heating rate of 20°C / h, and reacted for 10h. The system was depressurized to 60kPa within 1 hour, and reacted at this pressure for 24h; the system was depressurized to 20kPa within 1 hour, and reacted at this pressure for 36h; the system was heated to 140°C, and the reaction was continued for 24h to obtain a polyamide prepolymer.

[0074] 22.9 mg of hydroxylated multi-walled CNTs were dispersed in 2 g of toluene and ultrasonicated in a water bath for 20 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 190° C. and the reaction time was 1 hour.

[0075] The vacuum degree was controlled at ≤150Pa, the reaction temperature was 230℃, and the reaction time was 2 hours. The product was precipitated in dioxane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 50℃ for 48h. The initial decomposition temperature T of the prepared carbon nanotube-modified furan-based polyamide composite material was d,5％ The temperature was 132°C, the number average molecular weight was 3510 g / mol by NMR, and the yield was 54%.

[0076] Example 2

[0077] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine, 0.03g of stannous octoate and 0.03g of zinc chloride were dissolved in 120g of diphenyl ether, heated to 90°C, reacted for 10h, with a heating rate of 20°C / h, the system was decompressed to 60kPa within 1 hour, and reacted at this pressure for 24h; the system was decompressed to 20kPa within 1 hour, and reacted at this pressure for 36h; the system was heated to 140°C, and the reaction was continued for 24h to obtain a polyamide prepolymer.

[0078] 80.08 mg of hydroxylated multi-walled CNTs were dispersed in 2 g of toluene and ultrasonicated in a water bath for 20 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 190° C. and the reaction time was 1 hour.

[0079] The vacuum degree was controlled at ≤150Pa, the reaction temperature was 230℃, and the reaction time was 2 hours. The product was precipitated in dioxane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 50℃ for 48h. The initial decomposition temperature T of the prepared carbon nanotube-modified furan-based polyamide composite material was d,5％ The temperature was 167°C, the number average molecular weight was 5260 g / mol by NMR, and the yield was 69%.

[0080] Example 3

[0081] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine, 0.03g of stannous octoate and 0.03g of zinc chloride were dissolved in 120g of diphenyl ether, heated to 90°C, reacted for 10h, with a heating rate of 20°C / h, the system was decompressed to 60kPa within 1 hour, and reacted at this pressure for 24h; the system was decompressed to 20kPa within 1 hour, and reacted at this pressure for 36h; the system was heated to 140°C, and the reaction was continued for 24h to obtain a polyamide prepolymer.

[0082] 121 mg of hydroxylated multi-walled CNTs were dispersed in 2 g of toluene and ultrasonicated in a water bath for 20 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 190° C. and the reaction time was 1 hour.

[0083] The vacuum degree was controlled at ≤150Pa, the reaction temperature was 230℃, and the reaction time was 2 hours. The product was precipitated in dioxane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 50℃ for 48h. The initial decomposition temperature T of the prepared carbon nanotube-modified furan-based polyamide composite material was d,5％ The temperature was 147°C, the number average molecular weight was 4460 g / mol by NMR, and the yield was 61%.

[0084] Example 4

[0085] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine, 0.03g of stannous octoate and 4.56g of N435 lipase were dissolved in 120g of diphenyl ether, heated to 90°C, reacted for 10h, with a heating rate of 20°C / h, the system was depressurized to 60kPa within 1 hour, and reacted at this pressure for 24h; the system was depressurized to 20kPa within 1 hour, and reacted at this pressure for 36h; the system was heated to 140°C, and the reaction was continued for 24h to obtain a polyamide prepolymer.

[0086] 80.08 mg of carboxylated multi-walled CNTs were dispersed in 2 g of toluene and ultrasonicated in a water bath for 20 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 190° C. and the reaction time was 1 hour.

[0087] The vacuum degree was controlled at ≤150Pa, the reaction temperature was 230℃, and the reaction time was 2 hours. The product was precipitated in dioxane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 50℃ for 48h. The initial decomposition temperature T of the prepared carbon nanotube-modified furan-based polyamide composite material was d,5％The temperature was 130°C, and the number average molecular weight was 4190 g / mol by NMR. The yield was 59%.

[0088] Example 5

[0089] Under the protection of inert gas, 14.7g of 2,5-furandimethyl dimethyl ester, 6.35g of diaminobutane and 1.89g of N435 lipase were dissolved in 57g of xylene, heated to 150°C, reacted for 6h, and the heating rate was 5°C / h; the system was depressurized to 80kPa within 1 hour, and reacted at this pressure for 12h; the system was depressurized to 30kPa within 1 hour, and reacted at this pressure for 24h; the system was heated to 160°C, the heating rate was 5°C / h, and the reaction was continued for 12h to obtain a polyamide prepolymer.

[0090] 22.9 mg of amino-modified multi-walled carbon nanotubes were dispersed in 2 g of diphenyl ether and ultrasonicated in a water bath for 20 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above-mentioned polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 210°C and the reaction time was 0.5 h.

[0091] The vacuum degree was controlled at ≤50Pa, the reaction temperature was 250°C, and the reaction time was 3 hours; the product was precipitated in methanol, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 60°C for 48 hours; the prepared carbon nanotube-modified furan-based polyamide composite material was obtained.

[0092] Example 6

[0093] Under the protection of inert gas, 17.0g of diethyl 2,5-furandicarboxylate, 9.28g of hexamethylenediamine and 5.63g of N435 lipase were dissolved in 113g of toluene, heated to 70°C, reacted for 10h, and the heating rate was 20°C / h; the system was depressurized to 50kPa within 1 hour, and reacted at this pressure for 20h; the system was depressurized to 15kPa within 1 hour, and reacted at this pressure for 40h; the system was heated to 120°C, the heating rate was 8°C / h, and the reaction was continued for 20h to obtain a polyamide prepolymer.

[0094] 22.9 mg of carboxylated composite carbon nanotubes were dispersed in 2 g of xylene and ultrasonicated in a water bath for 30 min. Under the protection of inert gas, the ultrasonicated mixture was added to the above polyamide prepolymer. The vacuum degree was maintained below 2000 Pa within 1 h. The reaction temperature was 210°C and the reaction time was 0.5 h.

[0095] The vacuum degree was controlled at ≤100Pa, the reaction temperature was 220℃, and the reaction time was 2 hours; the product was precipitated in ethanol, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 40℃ for 72 hours; the initial decomposition temperature T of the prepared carbon nanotube-modified furan-based polyamide composite material was d,5％ The temperature was 210°C and the number average molecular weight was 6700 g / mol as measured by NMR.

[0096] Comparative Example 1

[0097] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine and 4.56g of N435 lipase were dissolved in 120g of toluene, heated to 90°C, reacted for 10h, and the heating rate was 20°C / h; the system was depressurized to 60kPa within 1 hour, and reacted at this pressure for 24h; the system was depressurized to 20kPa within 1 hour, and reacted at this pressure for 36h; the system was heated to 140°C and continued to react for 24h to obtain a polyamide prepolymer. The polyamide prepolymer product was precipitated in dioxane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum drying oven at 40°C for 48h. The initial decomposition temperature of the obtained polyamide prepolymer was T d,5％ The temperature was 109°C, the number average molecular weight was 3250 g / mol by NMR, and the yield was 51%.

[0098] It can be seen from Comparative Example 1 that the initial decomposition temperature of the embodiment in which the functionalized carbon nanotubes are introduced into the bio-based polyamide prepolymer in the form of chemical bonds is significantly higher than the polyamide prepolymer of Comparative Example 1, indicating that the functionalized carbon nanotubes can effectively improve the thermal stability of the polymer.

[0099] Comparative Example 2

[0100] Under the protection of inert gas, 14.7g of dimethyl 2,5-furandicarboxylate, 8.18g of pentamethylenediamine, 4.56g of N435 lipase, and 22.9mg of hydroxylated multi-walled CNTs were dissolved in 130g of toluene, heated to 90°C, and reacted for 10h at a heating rate of 20°C / h; the system was depressurized to 60kPa within 1 hour and reacted at this pressure for 24h; the system was depressurized to 20kPa within 1 hour and reacted at this pressure for 36h; the system was heated to 140°C and the reaction was continued for 24h.

[0101] The vacuum degree was maintained below 2000 Pa within 1 hour, the reaction temperature was 190° C., and the reaction time was 1 hour.

[0102] The vacuum degree was controlled at ≤150Pa, the reaction temperature was 230℃, and the reaction time was 2 hours. After the reaction, the product was precipitated in dichloromethane, washed with dichloromethane, centrifuged and the supernatant was discarded, and dried in a vacuum oven at 40℃ for 48 hours. The initial decomposition temperature of the prepared composite material was T d,5％ The temperature was 132.4°C, the molecular weight was 2270 g / mol, and the yield was 36%.

[0103] It can be seen from Comparative Example 2 that since the ester aminolysis reaction of 2,5-furandicarboxylic acid compounds and aliphatic diamines has strict requirements on the molar ratio, the addition of carbon nanotubes with hydroxyl groups at the time of reaction feeding disrupts the molar ratio between the diacid and the diamine, disrupts the growth of the polyamide molecular chain structure, affects the increase in the molecular weight of the polymerization product and the product yield, resulting in relatively low molecular weight and yield of Comparative Example 2; while the embodiment of the present invention effectively solves this problem by adding carbon nanotubes after forming a polyamide prepolymer with a certain molecular weight.

Claims

1. A method for preparing a carbon nanotube-modified furan-based polyamide composite material, characterized in that The method comprises: Under a protective gas atmosphere, a 2,5-furandicarboxylic acid compound, an aliphatic diamine, a catalyst and an organic solvent are subjected to a first heating reaction, a first decompression reaction, a second decompression reaction and a second heating reaction to obtain a polyamide prepolymer, and a dispersed carbon nanotube solution is continuously added, and the composite material is obtained after a first vacuum reaction and a second vacuum reaction and post-treatment.

2. The preparation method according to claim 1, characterized in that: The molar ratio of the 2,5-furandicarboxylic acid compound to the aliphatic diamine is 1:(0.5-1.5), preferably 1:(0.9-1.2); The amount of the catalyst is 0.1 to 25 wt % of the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine, preferably 0.2 to 20 wt %; The amount of the organic solvent is 200 to 800 wt % of the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine, preferably 300 to 550 wt %; The amount of the carbon nanotubes used is 0.01-1 wt % of the total weight of the 2,5-furandicarboxylic acid compound and the aliphatic diamine, preferably 0.05-0.5 wt %.

3. The preparation method according to claim 1, characterized in that: The 2,5-furandicarboxylic acid compound is at least one of 2,5-furandicarboxylic acid, dimethyl 2,5-furandicarboxylate, diethyl 2,5-furandicarboxylate, and 2,5-furandicarboxylic acid chloride; and / or, The aliphatic diamine is a bio-based aliphatic diamine, preferably at least one of butanediamine, pentamethylenediamine, hexamethylenediamine, octanediamine and decanediamine; and / or, The catalyst is a metal catalyst or a lipase; and / or, The organic solvent is at least one of toluene, diphenyl ether, xylene, N-methylpyrrolidone and dimethylacetamide; and / or, The carbon nanotube is at least one of a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, and a composite carbon nanotube; and / or, The carbon nanotube is at least one of an amino carbon nanotube, a carboxyl carbon nanotube, a hydroxyl carbon nanotube, and a thiol carbon nanotube.

4. The preparation method according to claim 3, characterized in that: The metal catalyst is at least one of a zinc-containing compound, an organic tin compound, and an organic titanium compound; Preferably, The zinc-containing compound is at least one of zinc citrate, zinc oxide, zinc halide, and zinc gluconate; and / or, The organotin compound is at least one of stannous octoate, stannous oxalate, dibutyltin oxide, butyltin acid, diethyl dibutyltin, dioctyltin oxide, and monobutyltin triisooctoate; and / or, The organic titanium compound is at least one of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate and ethylene glycol titanium.

5. The preparation method according to claim 1, characterized in that: The weight ratio of the solvent to the carbon nanotubes in the carbon nanotube solution is (15-200):1; and / or, The solvent of the carbon nanotube solution is at least one of toluene, diphenyl ether, xylene, N-methylpyrrolidone and dimethylacetamide.

6. The preparation method according to claim 1, characterized in that: The first heating reaction temperature is 60-160° C., and / or the heating rate is 10-20° C. / h, and / or the reaction time is 6-10 h; and / or, The first decompression reaction pressure is 40-80 kPa, and / or the reaction time is 12-24 h; and / or, The second reduced pressure reaction pressure is 10 to 30 kPa, and / or the reaction time is 24 to 40 hours; and / or, The second temperature-raising reaction temperature is 120-160° C., and / or the heating rate is 10-20° C. / h, and / or the reaction time is 12-24 h; and / or, The vacuum degree of the first vacuum reaction is 1000-5000 Pa, and / or the reaction temperature is 140-210° C., preferably 190-210° C., and / or the reaction time is 0.5-2.5 hours, preferably 1-1.5 hours; and / or, The vacuum degree of the second vacuum reaction is ≤300Pa, preferably ≤50Pa, and / or the reaction temperature is 210-260°C, preferably 220-250°C, and / or the reaction time is 1-5 hours, preferably 2-3 hours.

7. The preparation method according to claim 1, characterized in that The dispersion method of the carbon nanotube solution comprises: The carbon nanotube solution was sonicated in a water bath for 20-30 min.

8. The preparation method according to claim 1, characterized in that The post-processing includes: Precipitation, filtration, centrifugation and vacuum drying.

9. The preparation method according to claim 8, characterized in that: The precipitant used in the precipitation process is at least one of methanol, ethanol, isopropanol, acetonitrile, dioxane and dichloromethane; and / or, The centrifugal agent used in the centrifugation process is at least one of methanol, ethanol and acetone; and / or, The vacuum drying temperature is 40-60° C., and / or the vacuum drying time is 24-72 hours.

10. A carbon nanotube-modified furan-based polyamide composite material obtained by the preparation method according to any one of claims 1 to 9.

11. The composite material according to claim 10, characterized in that: The number average molecular weight of the composite material is 3500 g / mol to 7000 g / mol.

12. Use of a composite material obtained by the preparation method according to any one of claims 1 to 9 or a composite material according to claim 10 or 11 in the fields of bio-based plastic products, bio-based fibers and bio-based films.

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