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CN-121975316-A - Polyamide composite material and preparation method thereof

CN121975316ACN 121975316 ACN121975316 ACN 121975316ACN-121975316-A

Abstract

The application belongs to the technical field of polymer composite materials, and discloses a polyamide composite material and a preparation method thereof, wherein the preparation method comprises the following preparation steps of mixing diamine with aromatic dibasic acid containing carbodiimide groups, and heating for reaction to obtain prepolymer; adding end-capped stabilizer containing hindered phenol group into prepolymer, heating to obtain molten polymer, adding bio-based functional assistant into molten polymer, heating to react and granulating to obtain polyamide composite material. The polyamide composite material prepared by the method has good strength and toughness, and the durability of the polyamide composite material is improved.

Inventors

  • WU LIGUO

Assignees

  • 广东美塑塑料科技有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. A method for preparing a polyamide composite material, which is characterized by comprising the following steps: S1, mixing diamine with aromatic dibasic acid containing carbodiimide groups, and carrying out heating reaction to obtain a prepolymer; S2, adding a blocked stabilizer containing a hindered phenol group into the prepolymer, and heating for reaction to obtain a molten polymer; s3, adding the bio-based functional auxiliary into the molten polymer, heating for reaction, granulating and cooling to obtain the polyamide composite material.
  2. 2. The method according to claim 1, wherein the diamine in the step S1 comprises at least one of hexamethylenediamine, butanediamine and sunflower diamine, and the aromatic diacid in the aromatic diacid containing carbodiimide groups comprises at least one of terephthalic acid, isophthalic acid, phthalic acid and biphenyl-4, 4' -dicarboxylic acid.
  3. 3. The method for producing a polyamide composite material according to claim 1, wherein step S1 comprises: S1.1, adding aromatic dibasic acid into a mixed solution of concentrated sulfuric acid and fuming nitric acid at 0-5 ℃ for reaction for 3-4 hours, pouring the mixed solution into ice water at 0-5 ℃, filtering, recovering solid, adding the solid into a methanol solution containing 5-10wt% of palladium-carbon catalyst, stirring and reacting for 10-12 hours at normal temperature under the hydrogen pressure of 0.3-0.5 MPa, filtering, and drying to obtain an amination product, wherein the mass ratio of the concentrated sulfuric acid to the fuming nitric acid in the mixed solvent is (3-5): 1, the mass ratio of the aromatic dibasic acid to the mixed solvent is (8-12), and the mass ratio of the recovered solid to the methanol solution is (1-15); S1.2, adding an amination product into an anhydrous N, N-dimethylformamide solvent containing 15-25wt% of isocyanate, stirring and reacting for 3-5 hours at 65-75 ℃, cooling to room temperature, pouring into 0-5 ℃ ice water, stirring, filtering to obtain a biurea intermediate, mixing the biurea intermediate with p-toluenesulfonyl chloride and triethylamine, melting and stirring for 2-3 hours at 90-100 ℃, and then distilling for 1-2 hours under the vacuum condition of 150 ℃ and 0.1mmHg to obtain an aromatic dibasic acid containing carbodiimide groups, wherein the isocyanate comprises at least one of phenyl isocyanate, hexamethylene diisocyanate and toluene-2, 4-diisocyanate, the mass ratio of the amination product to the anhydrous N, N-dimethylformamide solvent is 1 (15-20), and the mass ratio of the biurea intermediate, p-toluenesulfonyl chloride and triethylamine is 1 (1.2-1.5) (0.9-1.1); S1.3, adding diamine into aromatic dibasic acid containing carbodiimide groups, and heating to 240-260 ℃ for reacting for 2-4 hours to obtain a prepolymer, wherein the molar ratio of the diamine to the aromatic dibasic acid is 1 (1.01-1.03).
  4. 4. A method of producing a polyamide composite material as claimed in claim 3, wherein step S1.3 further comprises: S1.3, adding diamine and a dehydrating agent into aromatic dibasic acid containing carbodiimide groups, reacting for 0.5-1.5 h at 80-120 ℃, and heating to 240-260 ℃ for 2-4 h to obtain a prepolymer, wherein the molar ratio of the diamine to the aromatic dibasic acid is 1 (1.01-1.03), the mass ratio of the diamine to the dehydrating agent is 1 (0.05-0.3), and the dehydrating agent comprises at least one of triethyl orthoformate, N' -carbonyl diimidazole and hexamethyldisilazane.
  5. 5. The method for producing a polyamide composite material according to claim 1, wherein the blocked stabilizer containing a hindered phenol group in step S2 comprises at least one of 4-amino-2, 6-di-t-butylphenol, 4-amino-2, 6-diisopropylphenol, 4-amino-2, 6-dicyclohexylphenol, 4-amino-2, 6-bis (α -methylbenzyl) phenol.
  6. 6. The method for producing a polyamide composite material according to claim 1, wherein step S2 comprises: S2.1, adding 2, 6-disubstituted phenol into glacial acetic acid, stirring and dropwise adding a glacial acetic acid solution containing 10-15wt% of concentrated nitric acid at a temperature of 0-5 ℃, keeping the temperature and stirring for reacting for 2-4 hours, pouring into ice water at the temperature of 0-5 ℃, filtering, washing with deionized water to be neutral, and drying to obtain nitrophenol, wherein the 2, 6-disubstituted phenol comprises at least one of 2, 6-di-tert-butylphenol, 2, 6-diisopropylphenol, 2, 6-dicyclohexylphenol and 2, 6-bis (alpha-methylbenzyl) phenol, the concentration of the 2, 6-disubstituted phenol in the glacial acetic acid is 10-20wt%, the concentration of nitric acid in the concentrated nitric acid is 65-68 wt%, and the molar ratio of the 2, 6-disubstituted phenol to the concentrated nitric acid is 1 (1.03-1.07); S2.2, adding nitrophenol into a methanol solution containing 5-10wt% of palladium-carbon catalyst, stirring and reacting for 4-8 hours under the condition that the hydrogen pressure is 0.3-0.5 MPa and the temperature is 40-60 ℃, cooling, filtering and taking filtrate, and rotary evaporating to obtain a blocked stabilizer containing hindered phenol groups, wherein the mass ratio of the nitrophenol to the methanol solution is 1 (5-10); S2.3, adding a blocked stabilizer containing a hindered phenol group into the prepolymer, and heating to 240-260 ℃ to react for 2-4 hours to obtain a molten polymer, wherein the mass of the blocked stabilizer containing the hindered phenol group is 1-3wt% of the mass of the prepolymer.
  7. 7. The method according to claim 1, wherein the bio-based functional auxiliary in the step S3 comprises a bio-based toughening agent and/or a bio-based plasticizer, the bio-based toughening agent comprises at least one of flax fiber, hemp fiber and sisal fiber, and the bio-based plasticizer comprises at least one of epoxidized soybean oil, epoxidized linseed oil and epoxidized tall oil acid ester.
  8. 8. The preparation method of the polyamide composite material according to claim 7, wherein the bio-based functional auxiliary agent consists of a bio-based toughening agent and a bio-based plasticizer according to a mass ratio of (1.5-2.5): 1.
  9. 9. The method for producing a polyamide composite material according to claim 8, wherein step S3 comprises: S3.1, adding a viscosity modifier into the molten polymer, and adjusting the viscosity of the molten polymer to reach a preset viscosity to obtain a viscosity-modified polymer, wherein the viscosity modifier comprises pyromellitic dianhydride for increasing the viscosity and stearamide for reducing the viscosity; S3.2, adding the bio-based functional auxiliary agent into the viscosity regulating polymer, heating to 250-280 ℃ for reacting for 0.5-1.5 h, granulating, and cooling to obtain the polyamide composite material, wherein the mass of the bio-based functional auxiliary agent is 10-20wt% of the mass of the viscosity regulating polymer.
  10. 10. A polyamide composite material, characterized in that it is produced by a process for producing a polyamide composite material according to any one of claims 1 to 9.

Description

Polyamide composite material and preparation method thereof Technical Field The application relates to the technical field of polymer composite materials, in particular to a polyamide composite material and a preparation method thereof. Background Polyamide, commonly known as nylon, is a linear thermoplastic polymer with a main chain containing characteristic repeated amide bonds (-CONH-) and has a highly ordered crystalline structure formed by amide groups with strong polarity in the molecular chain through hydrogen bonds, so that the material is endowed with excellent mechanical strength, toughness, wear resistance and self-lubricity. Based on the comprehensive properties, the polyamide and the reinforced modified engineering plastic thereof are widely applied to core high-temperature components in the fields of automobiles, new energy sources, household appliances and the like, such as engine turbocharging air inlet pipes, new energy source automobile battery pack structural members, electric hair drier air cylinders, coffee machine hot water pipelines and the like. However, the problem of performance decay of the material under the long-term high-temperature or wet-heat working condition is particularly remarkable, and the root of the material is the chemical structure depending on the molding. On one hand, the amide bond can be subjected to thermooxidative degradation under a high-temperature aerobic environment to cause molecular chain fracture and crosslinking, and on the other hand, the polar amide group has strong affinity to water molecules, so that the polar amide group is very easy to absorb moisture in the high-temperature environment, and the moisture can catalyze the amide bond to generate irreversible hydrolysis reaction under the high temperature, so that the molecular chain is also broken. These chemical degradation processes are accompanied by changes in the degree of micro-crystallization and degradation of the reinforcing fiber-matrix interface, which are macroscopically manifested as embrittlement of the material, a significant decrease in strength and toughness, dimensional instability, and even cracking, ultimately leading to failure of the function and shortened life of the component. Disclosure of Invention The invention aims to solve the technical problems that the polyamide composite material is subjected to thermooxidative hydrolysis and moisture absorption hydrolysis in a long-term high-temperature state, so that the durability of the material is reduced. In order to solve the technical problems, the invention provides a preparation method of a polyamide composite material, which comprises the following steps: S1, mixing diamine with aromatic dibasic acid containing carbodiimide groups, and carrying out heating reaction to obtain a prepolymer; S2, adding a blocked stabilizer containing a hindered phenol group into the prepolymer, and heating for reaction to obtain a molten polymer; s3, adding the bio-based functional auxiliary into the molten polymer, heating for reaction, granulating and cooling to obtain the polyamide composite material. In some embodiments, the diamine in step S1 comprises at least one of hexamethylenediamine, butanediamine, and sunflower diamine, and the aromatic diacid in the aromatic diacid containing carbodiimide groups comprises at least one of terephthalic acid, isophthalic acid, phthalic acid, biphenyl-4, 4' -dicarboxylic acid. In some embodiments, step S1 comprises: S1.1, adding aromatic dibasic acid into a mixed solution of concentrated sulfuric acid and fuming nitric acid at 0-5 ℃ for reaction for 3-4 hours, pouring the mixed solution into ice water at 0-5 ℃, filtering, recovering solid, adding the solid into a methanol solution containing 5-10wt% of palladium-carbon catalyst, stirring and reacting for 10-12 hours at normal temperature under the hydrogen pressure of 0.3-0.5 MPa, filtering, and drying to obtain an amination product, wherein the mass ratio of the concentrated sulfuric acid to the fuming nitric acid in the mixed solvent is (3-5): 1, the mass ratio of the aromatic dibasic acid to the mixed solvent is (8-12), and the mass ratio of the recovered solid to the methanol solution is (1-15); S1.2, adding an amination product into an anhydrous N, N-dimethylformamide solvent containing 15-25wt% of isocyanate, stirring and reacting for 3-5 hours at 65-75 ℃, cooling to room temperature, pouring into 0-5 ℃ ice water, stirring, filtering to obtain a biurea intermediate, mixing the biurea intermediate with p-toluenesulfonyl chloride and triethylamine, melting and stirring for 2-3 hours at 90-100 ℃, and then distilling for 1-2 hours under the vacuum condition of 150 ℃ and 0.1mmHg to obtain an aromatic dibasic acid containing carbodiimide groups, wherein the isocyanate comprises at least one of phenyl isocyanate, hexamethylene diisocyanate and toluene-2, 4-diisocyanate, the mass ratio of the amination product to the anhydrous N, N-dimethylformamide so