CN113201109B - Method for preparing benzoxazine resin based composite material by in-situ dispersion of carbon material - Google Patents

Abstract

The invention relates to the field of resin synthesis and modification, in particular to a method for preparing a benzoxazine resin-based composite material by dispersing carbon materials in situ; The m-cresol of the dispersed carbon material is the phenol source, and a primary amine is used as the amine source to react with paraformaldehyde to synthesize a benzoxazine monomer of the in-situ dispersed carbon material, and thermally solidify to obtain the carbon material/benzene The benzoxazine resin-based composite material, the carbon material is uniformly and stably dispersed in the benzoxazine resin prepared by the present invention, the carbon material will form a perfect and uniform inorganic network in the composite material, and the benzoxazine resin-based composite material is significantly improved. electrical and thermal conductivity. The resin of the invention has easy-to-obtain raw materials, simple steps, and is environmentally friendly, does not require the participation of any solvent, optimizes the preparation process, and is easy to realize industrialized production.

Description

A method for preparing benzoxazine resin-based composite material by dispersing carbon material in situ

technical field

The invention relates to the field of resin synthesis and modification, in particular to a method for preparing a benzoxazine resin-based composite material by dispersing carbon materials in situ.

Background technique

Benzoxazines are a new class of thermosetting phenolic resins with many attractive properties such as no by-products during curing, very low melt viscosity, good adhesion properties, polymers with high glass transition temperature, high thermal stability, good mechanical strength and modulus, low dielectric constant and high flame and chemical resistance. The very low melt viscosity and good adhesion properties of benzoxazine resins allow for easy wetting and mixing with fillers during molding compound preparation, resulting in excellent matrix material properties, especially for the manufacture of highly filled composites. Carbon materials mainly include activated carbon, carbon fiber, graphene, graphite, carbon nanotubes, diamond, fullerene, etc. Carbon materials have a series of excellent properties such as low density, high strength, good rigidity, high temperature resistance, chemical corrosion resistance, radiation resistance, fatigue resistance, high electrical conductivity, high thermal conductivity, ablation resistance, small thermal expansion, and good physiological compatibility. It is a new material for both military and civilian use, and is called the fourth type of industrial material. It is widely used in metallurgy, chemical industry, machinery, automobile, medical treatment, environmental protection, construction daily life and other fields, and is an indispensable engineering structural material in aerospace and nuclear industry sectors.

However, difficult dispersion and high cost are the key factors affecting the performance and application of carbon materials. Even in organic solvents with good dispersibility, it is difficult to obtain uniformly dispersed carbon materials. At the same time, carbon materials are incompatible with most organic polymers, and are more likely to agglomerate in organic polymers with higher viscosity. Serious agglomeration problems will greatly reduce the thermal and electrical properties of carbon materials/resin composites.

At present, the main method to improve the dispersibility of carbon materials is to modify carbon materials with surface functionalization. It has been reported that acid-base treatment, covalent or non-covalent modification are important methods for surface modification. However, in the case of ensuring that the carbon material is well dispersed and does not affect the resin polymerization, it is a big problem to fully remove the solvent used for modification. Another method is to prepare a high-porosity graphene three-dimensional network in advance to improve the graphene dispersion and form a thermally conductive through network. For example, graphene sponges, foams, and aerogels are first prepared, and then the polymer is impregnated. However, the preparation process of these methods is complicated and the period is long, which is not conducive to the large-scale preparation of carbon material resin matrix composites.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a preparation method for preparing a benzoxazine resin-based composite material by dispersing carbon materials in situ. A low-cost and simple method is used to obtain a well-dispersed carbon material/benzoxazine resin-based composite material to solve the above-mentioned problems in the prior art, so that the carbon material can form a perfect and uniform inorganic network in the composite material. The test results of electrical conductivity and thermal conductivity show that, compared with other methods for preparing benzoxazine resin-based composites from dispersed carbon materials, the electrical and thermal conductivity of benzoxazine resin-based composites prepared from the in-situ dispersed carbon materials is significantly improved.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A method for preparing a benzoxazine resin-based composite material by dispersing carbon materials in situ, firstly dispersing the carbon materials in m-cresol with ultrasonic waves and stirring for 1 hour, and then using m-cresol with well-dispersed carbon materials as a phenol source, A primary amine is used as an amine source, reacted with paraformaldehyde to synthesize a benzoxazine monomer of an in-situ dispersed carbon material, and thermally cured to obtain a carbon material/benzoxazine resin matrix composite material.

Further, the carbon material is graphene or carbon nanotubes.

Further, the amine source is one of aniline, methylamine, n-propylamine, cyclohexylamine, benzylamine, diaminophenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone or hexanediamine.

Further, the mass ratio of the carbon material to m-cresol is between 1:100 and 1:10.

Further, the molar ratio of m-cresol, primary amine and paraformaldehyde is 1:2:1.

Further, the reaction of m-cresol, primary amine and paraformaldehyde is to use a solvent-free method to heat and stir at 95° C. for 1 hour to synthesize the benzoxazine monomer of the in-situ dispersed carbon material.

Further, the synthesized benzoxazine monomers were subjected to vacuum drying at 100° C. for 2 hours before thermal curing.

Further, the thermal curing conditions are that the benzoxazine monomer is thermally cured at 160° C. and 170° C. for two hours each.

The present invention also provides the carbon material/benzoxazine resin-based composite material prepared by the above-mentioned preparation method.

In addition, the present invention also provides the application of the above-mentioned carbon material/benzoxazine resin-based composite material in preparing electrical and thermal conductive materials.

Compared with the prior art, the present invention has the following beneficial effects:

The carbon material is uniformly and stably dispersed in the benzoxazine resin prepared by the invention, the carbon material will form a perfect and uniform inorganic network in the composite material, and the electrical conductivity and thermal conductivity of the benzoxazine resin-based composite material are obviously improved.

The resin of the invention has easy-to-obtain raw materials, simple steps, and is environmentally friendly, does not require the participation of any solvent, optimizes the preparation process, and is easy to realize industrialized production.

Description of drawings

Fig. 1 is the hydrogen NMR spectrum of the carbon material/benzoxazine resin-based composite material prepared by in situ dispersed graphene (the hydrogen atom in the methyl group on 2.18ppm m-cresol in Fig. 1, 4.58ppm is -CH The H atom in ₂ -N-, 5.32ppm is the H atom in -O- _CH2 -N-, 6.7-7.3ppm is the proton absorption peak on the benzene ring).

Fig. 2 is the physical picture of the benzoxazine monomer prepared by the in-situ dispersed graphene still maintains good dispersion in the body).

Figure 3 is the physical picture of the benzoxazine resin-based composite material prepared by in-situ dispersion of graphene and carbon nanotubes (the left and right pictures are the preparation of benzoxazine resin-based composite by in-situ dispersion of graphene and carbon nanotubes, respectively The material is made of discs with a diameter of 2cm and a thickness of 1mm).

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Example 1

First, the graphene and m-cresol were dispersed in m-cresol with a mass ratio of 1:20 and stirred for 1 hour, then m-cresol with a well-dispersed carbon material was used as the phenol source, aniline was used as the amine source, and paraformaldehyde was used as the amine source. In the reaction, the molar ratio of m-cresol, aniline and paraformaldehyde is 1:2:1, and a solvent-free method is used to synthesize a kind of in-situ dispersion carbon material under the condition of heating for 1 hour at 95 °C. The oxazine monomer (as shown in Figure 2), the benzoxazine monomer was vacuum dried at 100 °C for 1 hour, and then the benzoxazine monomer was thermally cured at 160 °C and 170 °C for two hours each to obtain a carbon material /benzoxazine resin-based composite material (the real object is shown in Figure 3, and the hydrogen NMR spectrum of the composite material is shown in Figure 1). The measured thermal conductivity is as high as 2.06 W/mK and the highest in-plane conductivity is 3.53 S/cm. The thermal conductivity of pure polybenzoxazine is only 0.17W/mK. The measured thermal conductivity of benzoxazine resin-based composites prepared by physically blending and dispersing the same graphene content is 0.42 W/mK, and the highest in-plane electrical conductivity is 1.52 S/cm.

Example 2

First, the carbon nanotubes and m-cresol were dispersed in m-cresol with a mass ratio of 1:10 and stirred for 1 hour. Polyoxymethylene reaction, the molar ratio of m-cresol, aniline, and paraformaldehyde is 1:2:1, and a solvent-free method is used to synthesize an in-situ dispersed carbon material under the condition of heating at 95 ° C for 1 hour. The benzoxazine monomer was then thermally cured at 160 °C and 170 °C for two hours each to obtain a carbon material/benzoxazine resin matrix composite material (the real object is shown in Figure 3). The measured thermal conductivity is as high as 2.52W/mK, and the highest in-plane conductivity is 3.91 S/cm. The thermal conductivity of pure polybenzoxazine is only 0.17W/mK. The benzoxazine resin-based composites prepared by physically blending and dispersing carbon nanotubes with the same content have a measured thermal conductivity of 0.58 W/mK and a maximum in-plane conductivity of 2.03 S/cm.

Claims (9)

1. A method for preparing a benzoxazine resin based composite material by in-situ dispersing a carbon material is characterized in that the carbon material is dispersed in m-cresol by ultrasonic and stirring for 1 hour, then the m-cresol of the well-dispersed carbon material is taken as a phenol source, primary amine is taken as an amine source, and reacts with paraformaldehyde to synthesize a benzoxazine monomer of the in-situ dispersed carbon material, and the benzoxazine monomer is thermally cured to obtain the carbon material/benzoxazine resin based composite material; the carbon material is graphene or carbon nanotubes.

2. The method for preparing the benzoxazine resin based composite material according to claim 1, wherein the amine source is one of aniline, methylamine, n-propylamine, cyclohexylamine, benzylamine, diaminodiphenyl ether, diaminodiphenyl sulfone or hexamethylenediamine.

3. The method for preparing the benzoxazine resin based composite material according to claim 1, wherein the mass ratio of the carbon material to m-cresol is 1: 100 to 1: 10, respectively.

4. The method for preparing the benzoxazine resin based composite material according to claim 1, wherein the molar ratio of m-cresol, primary amine and paraformaldehyde is 1: 2: 1.

5. the method for preparing the benzoxazine resin based composite material according to claim 1, wherein the reaction of m-cresol, primary amine and paraformaldehyde is performed by heating and stirring at 95 ℃ for 1 hour by a solvent-free method to synthesize the benzoxazine monomer of the in-situ dispersed carbon material.

6. The method for preparing the benzoxazine resin based composite material according to claim 1, wherein the synthesized benzoxazine monomer is subjected to vacuum drying at 100 ℃ for 2 hours before thermal curing.

7. The method for preparing the benzoxazine resin based composite material according to claim 1, wherein the thermal curing condition is that benzoxazine monomers are thermally cured at 160 ℃ and 170 ℃ for two hours respectively.

8. A carbon material/benzoxazine resin based composite material produced by the production method according to any one of claims 1 to 7.

9. Use of the carbon material/benzoxazine resin based composite material according to claim 8 in the preparation of an electrically and thermally conductive material.

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