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CN-122011673-A - Fiber-reinforced thermosetting composite material and preparation method thereof

CN122011673ACN 122011673 ACN122011673 ACN 122011673ACN-122011673-A

Abstract

The invention discloses a fiber reinforced thermosetting composite material and a preparation method thereof, which belong to the technical field of thermosetting material processing, wherein melamine and hexamethylenediamine are firstly subjected to deamination and polycondensation under the catalysis of ammonium chloride to synthesize thermosetting amino resin, then carboxylation is carried out on carbon fiber cloth to obtain carboxylated carbon fiber cloth, then aminated POSS and aminated boron nitride nanosheets are respectively prepared, grafted on the carboxylated carbon fiber cloth through amide reaction to obtain the composite carbon fiber cloth, finally, the thermosetting amino resin is dissolved in ethanol aqueous solution, then the composite carbon fiber cloth is impregnated, and the fiber reinforced thermosetting composite material is obtained through pre-curing, vacuum treatment and multi-stage hot press curing methods, thereby realizing excellent interface bonding and mechanical properties.

Inventors

  • WANG DECHENG
  • CHEN AIMING
  • QI CHAOMING

Assignees

  • 宁国中奕橡塑有限公司

Dates

Publication Date
20260512
Application Date
20260407

Claims (10)

  1. 1. A fiber reinforced thermoset composite comprising the following raw materials in parts by mass: 63-78 parts of melamine, 116-156 parts of hexamethylenediamine, 3.8-5.2 parts of ammonium chloride, 30-40 parts of carbon fiber cloth, 30-50 parts of 3-aminopropyl trimethoxy silane, 3-5 parts of hexagonal boron nitride nanosheets, 20-25 parts of silane coupling agent KH, 1-3 parts of amination POSS, 1-3 parts of amination boron nitride nanosheets, 2-2.6 parts of phosphate, 80-100 parts of thermosetting amino resin and 10-14 parts of composite carbon fiber cloth.
  2. 2. The fiber reinforced thermoset composite of claim 1, wherein the thermoset amino resin is prepared by the following steps: Adding melamine, hexamethylenediamine and ammonium chloride into a three-necked flask, heating to 200-220 ℃ under the condition of oil bath, stirring for 30-40min, continuing to react for 2-3h after the mixture becomes colorless and transparent, and cooling to room temperature to obtain thermosetting amino resin; The mass ratio of the melamine to the hexamethylenediamine to the ammonium chloride is 63-78:116-156:3.8-5.2.
  3. 3. The fiber reinforced thermosetting composite material according to claim 1, wherein the specific preparation method of the composite carbon fiber cloth is as follows: Adding the aminated POSS and the aminated boron nitride nano-sheet into N, N-dimethylformamide, carrying out ultrasonic treatment for 1-2 hours, adding carboxylated carbon fiber cloth and phosphate, magnetically stirring for 20-24 hours, taking out a product, repeatedly washing the product with the N, N-dimethylformamide and deionized water for 3-5 times, and carrying out vacuum drying at 80-90 ℃ until the weight is constant, thus obtaining the composite carbon fiber cloth.
  4. 4. A fiber reinforced thermoset composite according to claim 3, wherein the amount of aminated POSS, aminated boron nitride nanoplatelets, N-dimethylformamide, carboxylated carbon fiber cloth and phosphate is in the ratio of 1-3g to 800-1000ml to 20-30g to 2-2.6g.
  5. 5. The fiber reinforced thermoset composite of claim 1, wherein the aminated POSS is prepared by the following specific process: Adding 3-aminopropyl trimethoxy silane into methanol, stirring for 20-30min, slowly dropwise adding 36wt% hydrochloric acid, condensing and refluxing for 18-20h at 90-95 ℃, removing methanol solvent by rotary evaporation at 50-60 ℃, adding tetrahydrofuran, standing for sedimentation, vacuum filtering, collecting a product, and repeatedly washing the product with tetrahydrofuran for 3-5 times to obtain aminated POSS; the volume ratio of the 3-aminopropyl trimethoxy silane to the methanol to the 36wt% hydrochloric acid to the tetrahydrofuran is 30-50:300-400:20-30:90-100.
  6. 6. The fiber reinforced thermosetting composite material according to claim 1, wherein the concrete preparation method of the aminated boron nitride nanosheets comprises the following steps: Adding hexagonal boron nitride nano-sheets into a 20vol% ethanol water solution, slowly dropwise adding a silane coupling agent KH550, stirring for 20-24 hours at 800-900rpm, vacuum-filtering, collecting products, washing the products with deionized water for 3-5 times, and vacuum-drying to constant weight to obtain aminated boron nitride nano-sheets; The dosage ratio of the hexagonal boron nitride nanosheets, the ethanol water solution with the concentration of 20vol% and the silane coupling agent KH550 is 3-5g:1500-2000mL:20-25mL.
  7. 7. A fiber reinforced thermoset composite according to claim 3, wherein the carboxylated carbon fiber cloth is prepared by the following specific method: adding the desized carbon fiber cloth into concentrated nitric acid with the weight of 68 percent, reacting for 2-4 hours at the temperature of 80-90 ℃, filtering, repeatedly washing a filter cake with deionized water until the filter liquor is neutral, and drying in vacuum until the weight is constant to obtain carboxylated carbon fiber cloth; the dosage ratio of the carbon fiber cloth to the acetone solution is 30-40g:600-800mL; the dosage ratio of the desized carbon fiber cloth to 68wt% of concentrated nitric acid is 24-28g:2400-2600mL.
  8. 8. A method of preparing a fiber reinforced thermoset composite comprising the steps of: Dissolving thermosetting amino resin in 28vol% ethanol water solution to obtain resin solution, adding composite carbon fiber cloth, fully soaking, taking out, pre-curing at 120-130 ℃ for 30-40min, transferring to a vacuum drying oven, treating at 190-200 ℃ and minus 0.06-0.04 MPa for 2-3h, placing the prepreg lamination in a mould, placing in a hot press, and obtaining the fiber reinforced thermosetting composite material through a multi-stage hot press curing method.
  9. 9. The method for preparing a fiber-reinforced thermosetting composite material according to claim 8, wherein the amount ratio of the thermosetting amino resin, the 28vol% aqueous ethanol solution and the composite carbon fiber cloth is 80-100g:130-150ml:10-14g.
  10. 10. The method for preparing a fiber reinforced thermosetting composite material according to claim 8, wherein the multi-stage hot press curing method comprises preheating at 220-230 ℃ for 40-50min, sequentially curing at 240-250 ℃, 2-3MPa,250-260 ℃, 3-4MPa,260-270 ℃ and 4.5-4.8MPa for 30-40min, releasing pressure for a plurality of times during the curing process to discharge micromolecular gas generated by curing, and finally curing at 270-280 ℃ and 4.5-4.9MPa for 2-3h, naturally cooling to room temperature under pressure, and demolding.

Description

Fiber-reinforced thermosetting composite material and preparation method thereof Technical Field The invention belongs to the technical field of thermosetting material processing, and particularly relates to a fiber reinforced thermosetting composite material and a preparation method thereof. Background The thermosetting composite material is a material which takes thermosetting resin as a matrix, forms a three-dimensional crosslinked network structure through irreversible chemical reaction by adding components such as reinforcing materials, fillers and the like, can not be remolded after solidification, and has the core advantages of heat resistance, corrosion resistance, dimensional stability and the like. By virtue of the characteristics of high specific strength, high modulus and the like, the composite material becomes a key material in the fields of aerospace, automobile weight reduction, wind power blades, water supply pipes and the like. In recent years, with the rising of intelligent material systems such as shape memory high molecular polymers, self-repairing materials and the like, and the expansion of the application of nonmetallic material-increasing materials in the molding of complex components, the base design and interface regulation means of thermosetting composite materials are also continuously developed to the directions of functionalization, refinement and high reliability. Meanwhile, high-performance thermoplastic materials represented by metallocene polyolefin, ethylene-vinyl alcohol copolymer, etc. are in some fields replacing thermosetting resins, but it is still difficult to completely replace thermosetting systems of three-dimensional crosslinked network structure in terms of heat resistance and dimensional stability. In the thermosetting composite material, the fiber is a core reinforcement, the simple resin has high brittleness and low strength, the fiber can bear main load, and the stress is transferred through an interface, so that the stretching, bending and impact resistance of the material are obviously improved, and the durability and the stability of the structure are enhanced. However, fiber reinforced thermosetting composite materials also have a plurality of problems, such as poor interfacial bonding property of fibers and resin, easy debonding, reduced overall performance of materials, complex molding process, difficult control of fiber layering and curing parameters, and easy occurrence of defects of pore, layering and the like of products. The Chinese patent application with publication number of CN112778549A discloses a carbon fiber reinforced thermosetting resin matrix composite material and a preparation method thereof, wherein matrix resin and various functional additives are compounded to prepare resin paste, then the resin paste is combined with carbon fiber non-woven fabrics in a specific form, a sheet molding compound process is adopted to prepare carbon fiber prepreg with a multi-layer structure, and finally the prepreg is overlapped and then subjected to vacuum hot-press molding, so that the carbon fiber reinforced thermosetting resin matrix composite material which has the advantages of designable strength and modulus, isotropy and easiness in large-area molding is prepared. In the scheme, the carbon fiber non-woven fabric is physically mixed with the resin paste, and the surface modification of the carbon fiber is not performed, so that the interface combination between the fiber and the resin matrix is weaker, and the mechanical property and durability of the composite material are affected. Disclosure of Invention The invention aims to provide a fiber-reinforced thermosetting composite material and a preparation method thereof, which are used for solving the problems of low interface bonding strength, uncontrollable functional distribution and the like caused by only physical blending between carbon fibers and a resin matrix in the prior art. The aim of the invention can be achieved by the following technical scheme: a method of preparing a fiber reinforced thermoset composite comprising the steps of: step one, synthesizing thermosetting amino resin by deamination and polycondensation of melamine and hexamethylenediamine under the catalysis of ammonium chloride. Carboxylating the carbon fiber cloth to obtain carboxylated carbon fiber cloth, respectively preparing an amination POSS and an amination boron nitride nanosheet, and grafting the carboxylated carbon fiber cloth to obtain the composite carbon fiber cloth through an amide reaction. And thirdly, after the thermosetting amino resin is dissolved in ethanol water solution, the composite carbon fiber cloth is impregnated, and the fiber reinforced thermosetting composite material is obtained through a pre-curing, vacuum treatment and a multi-stage hot-press curing method. Further, the specific preparation method of the thermosetting amino resin is as follows: adding melamine, hexamethylenediamine and