High-performance cured epoxy material as well as preparation method and application thereof

Abstract

The invention provides a high-performance cured epoxy material as well as a preparation method and application thereof, and belongs to the field of advanced materials. According to the preparation method, the epoxy compound shown in the formula I is finally obtained through high-throughput screening calculation by combining quantum chemistry and molecular structure design, and the epoxy compound shown in the formula I is further taken as a raw material to be cured to obtain the high-strength and high-modulus epoxy cured product. The epoxy cured product has more excellent tensile strength, tensile modulus, bending strength and bending modulus, also has high glass transition temperature and high storage modulus, shows excellent thermal mechanical properties, and expands the application range of the epoxy cured product in the field of high-strength and high-modulus materials. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of advanced materials, and specifically relates to a high-performance epoxy cured product and a preparation method and application thereof. Background Art

[0002] Epoxy curing materials have excellent chemical resistance and mechanical properties, as well as good electrical insulation and bonding properties. These properties make them ideal for making a variety of high-performance materials, such as parts used in aerospace, automotive manufacturing, and electronic equipment. In addition, the variability of epoxy curing materials enables them to cure quickly or remain unreactive for a long time, which is suitable for different needs.

[0003] In applications, the flexural modulus of epoxy cured products is an important performance indicator. The flexural modulus reflects the ability of the material to resist bending deformation when subjected to force, so it is particularly important for applications that need to withstand large mechanical stress. For example, in the aerospace field, epoxy cured products with high flexural modulus can improve the structural strength and durability of composite materials.

[0004] At present, the high-performance epoxy curing materials on the market mainly include mAFG90, AFG90, AG80, TGIC, E51, AG601, etc. They are generally glycidyl ester and glycidyl amine type epoxies, which mainly generate intermolecular forces through the hydroxyl groups generated after the epoxy ring opening, and cannot effectively provide more hydrogen bond interaction sites, and the improvement of modulus and strength is limited. In the process of preparing high-performance epoxy curing materials, they can no longer meet the performance index requirements.

[0005] Example 1 of patent application document CN111303081A discloses an epoxy resin composition, the preparation method of which is as follows: add 100 parts by mass of m-phenylenediamine tetra-epoxypropyl epoxy resin shown in formula I and 15 parts by mass of polyether sulfone in a stirring and dispersing machine, heat to 135°C and stir to dissolve evenly, then cool to 70°C and add 70 parts by mass of 3,3'-diaminodiphenyl sulfone, stir and disperse evenly and then discharge to obtain an epoxy resin composition. However, the bending modulus of the epoxy resin composition is poor and needs to be further improved.

[0006]

[0007] Therefore, it is necessary to design and develop new epoxy resin structures with high strength and high modulus. Summary of the invention

[0008] The purpose of the present invention is to provide a high-performance epoxy cured product and a preparation method and use thereof.

[0009] The present invention provides an epoxy compound, the structure of which is shown in Formula I:

[0010]

[0011] Among them, R is selected from hydrogen or

[0012] a, b, c, d, e, f, g, h are each independently selected from 0, 1, 2, 3.

[0013] Furthermore, the structure of the epoxy compound is shown in Formula II:

[0014]

[0015] Among them, R is selected from hydrogen or a, b, c are each independently selected from 1, 2, 3.

[0016] Furthermore, the structure of the epoxy compound is as follows:

[0017]

[0018] Furthermore, the epoxy compound is a product prepared from an aminobenzoic acid compound, epichlorohydrin, a catalyst and a base. Among them, the mass ratio of the aminobenzoic acid compound, epichlorohydrin, the catalyst and the base is 50-60:1100-1400:1:35-60.

[0019] Furthermore, the aminobenzoic acid compound is m-aminobenzoic acid or 5-aminoisophthalic acid, preferably 5-aminoisophthalic acid;

[0020] The catalyst is an imidazole compound, a pyridine compound, a pyrrole compound or a pyrazole compound;

[0021] The base is an organic base; the mass ratio of the aminobenzoic acid compound, epichlorohydrin, the catalyst and the base is 50:1200-1400:1:50-60, preferably 50:1260-1280:1:55-56.

[0022] Furthermore, the catalyst is 2-methylimidazole; the base is sodium hydroxide.

[0023] The present invention also provides an epoxy cured product, which is a product prepared from the above epoxy compound and an amine curing agent. Among them, the molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 1-5:1.

[0024] Furthermore, the molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 2-3:1.

[0025] Further, the molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 2:1.

[0026] Further, the amine curing agent is an aromatic amine curing agent, preferably m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzanilide, p-aminophenyl p-aminobenzoate.

[0027] Further, the amine curing agent is m-phenylenediamine.

[0028] The present invention also provides a method for preparing the above epoxy cured product, and the method includes the following steps: fully mixing an epoxy compound and an amine curing agent evenly, and curing to obtain the product.

[0029] Further, the curing conditions are: heating up at a program of 80-120°C for 1-3 hours respectively.

[0030] Further, the curing conditions are: curing at 100°C for 2h, 120°C for 2h, 150°C for 2h, and 180°C for 2h in sequence.

[0031] The present invention also provides the use of the above epoxy cured product in preparing aerospace materials, automotive manufacturing materials, electronic device materials, coating materials, and carbon fiber composite materials.

[0032] The present invention has achieved the following beneficial effects:

[0033] The present invention combines quantum chemistry and molecular structure design. After a large number of screenings, epoxy compounds 3ABA and 5AIPA are finally obtained. Further, using epoxy compounds 3ABA and 5AIPA as raw materials, a high-strength and high-modulus epoxy cured product is obtained by curing. The epoxy cured product of the present invention has more excellent tensile strength, tensile modulus, flexural strength, and flexural modulus. At the same time, it also has a high glass transition temperature and a high storage modulus, showing excellent thermomechanical properties. The present invention expands the application range of epoxy cured products in the field of high-strength and high-modulus materials.

[0034] Compared with the epoxy resin composition added with polyethersulfone disclosed in the patent application document CN111303081A, the flexural modulus (6.06 GPa) of the epoxy cured product of the present invention is better than that of the optimal sample added with polyethersulfone in CN111303081A (5.7 GPa), achieving an unexpected technical effect.

[0035] Obviously, based on the above content of the present invention, according to the common general knowledge and conventional means in the art, without departing from the above basic technical idea of the present invention, various other forms of modifications, substitutions, or changes can also be made.

[0036] The following is a further detailed description of the above content of the present invention in the form of specific embodiments. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following embodiments. Any technology implemented based on the above content of the present invention falls within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 1H NMR spectrum of 3ABA epoxy resin.

[0038] Figure 2 1H NMR spectrum of 5AIPA epoxy resin.

[0039] Figure 3 (a) Tensile strength, tensile modulus and (b) elongation at break of 3ABA_MPD, 5AIPA_MPD and IPA_MPD.

[0040] Figure 4 (a) Flexural strength and (b) flexural modulus of 5AIPA_MPD.

[0041] Figure 5 (a) Glass transition temperature and (b) storage modulus of 3ABA_MPD, 5AIPA_MPD and IPA_MPD. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The raw materials and equipment used in the present invention are all known products, obtained by purchasing commercially available products.

[0043] Example 1. Preparation of 3ABA epoxy resin

[0044]

[0045] 30 g of m-aminobenzoic acid was thoroughly mixed with 809.57 g of epichlorohydrin. Using 0.6 g of 2-methylimidazole as a catalyst, the reaction was carried out at 80 °C to obtain an epoxy resin intermediate. Subsequently, an aqueous solution (50 wt%) prepared with 32.82 g of sodium hydroxide was added, and the reaction was continued at 40 °C to obtain an orange-yellow resin solution. The target product 3ABA was obtained through suction filtration, washing with water, and rotary evaporation.

[0046] Example 2. Preparation of 5ABA epoxy resin

[0047]

[0048] 30 g of 5 - aminoisophthalic acid was thoroughly mixed with 766.11 g of epichlorohydrin. Using 0.6 g of 2 - methylimidazole as a catalyst, the reaction was carried out at 80 °C to obtain an epoxy resin intermediate. Subsequently, an aqueous solution (50 wt%) prepared with 33.12 g of sodium hydroxide was added, and the reaction was continued at 40 °C to obtain an orange - yellow resin solution. The target product 5AIPA was obtained through suction filtration, washing with water, and rotary evaporation.

[0049] Example 3. Preparation of 3ABA matrix material

[0050] The 3ABA resin and m - phenylenediamine (MPD) were thoroughly mixed. The molar ratio of epoxy groups to amino groups in the amine curing agent was 2:1. Subsequently, the mixture was evenly coated on an automatic film - coating machine equipped with a PET substrate, and a doctor blade was used for film coating. The PET substrate containing the mixture was placed in an oven and cured according to the programmed temperature rise at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h to obtain a thermosetting film (denoted as 3ABA_MPD).

[0051] Example 4. Preparation of 3ABA matrix material

[0052] The 3ABA resin and m - phenylenediamine (MPD) were thoroughly mixed. The molar ratio of epoxy groups to amino groups in the amine curing agent was 2.6:1. Subsequently, the mixture was evenly coated on an automatic film - coating machine equipped with a PET substrate, and a doctor blade was used for film coating. The PET substrate containing the mixture was placed in an oven and cured according to the programmed temperature rise at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h to obtain a thermosetting film.

[0053] Example 5. Preparation of 3ABA matrix material

[0054] The 3ABA resin and m - phenylenediamine (MPD) were thoroughly mixed. The molar ratio of epoxy groups to amino groups in the amine curing agent was 3:1. Subsequently, the mixture was evenly coated on an automatic film - coating machine equipped with a PET substrate, and a doctor blade was used for film coating. The PET substrate containing the mixture was placed in an oven and cured according to the programmed temperature rise at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h to obtain a thermosetting film.

[0055] Example 6. Preparation of 5AIPA matrix material

[0056] Mix 5AIPA resin and m-phenylenediamine (MPD) thoroughly and evenly, with the molar ratio of epoxy groups to amino groups in the amine curing agent being 2:1. Subsequently, evenly coat the mixture on an automatic film coater equipped with a PET substrate, and use a scraper to coat the film. Place the PET substrate containing the mixture in an oven and cure it at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h according to a programmed temperature increase to obtain a thermosetting film (denoted as 5AIPA_MPD).

[0057] Example 7. Preparation of 5AIPA matrix material

[0058] Mix 5AIPA resin and m-phenylenediamine (MPD) thoroughly and evenly, with the molar ratio of epoxy groups to amino groups in the amine curing agent being 2.6:1. Subsequently, evenly coat the mixture on an automatic film coater equipped with a PET substrate, and use a scraper to coat the film. Place the PET substrate containing the mixture in an oven and cure it at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h according to a programmed temperature increase to obtain a thermosetting film.

[0059] Example 8. Preparation of 5AIPA matrix material

[0060] Mix 5AIPA resin and m-phenylenediamine (MPD) thoroughly and evenly, with the molar ratio of epoxy groups to amino groups in the amine curing agent being 3:1. Subsequently, evenly coat the mixture on an automatic film coater equipped with a PET substrate, and use a scraper to coat the film. Place the PET substrate containing the mixture in an oven and cure it at 100 °C / 2 h, 120 °C / 2 h, 150 °C / 2 h, and 180 °C / 2 h according to a programmed temperature increase to obtain a thermosetting film.

[0061] Example 9. Preparation of 3ABA matrix material

[0062] Replace m-phenylenediamine in Examples 3, 4, and 5 with aromatic amine curing agents such as 4,4'-diaminodiphenylamine, 4,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, and p-aminophenyl p-aminobenzoate, and cure to obtain a thermosetting matrix material of 3AIPA.

[0063] Example 10. Preparation of 5ABA matrix material

[0064] Replace m-phenylenediamine in Examples 6, 7, and 8 with aromatic amine curing agents such as 4,4'-diaminodiphenylamine, 4,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, and p-aminophenyl p-aminobenzoate, and cure to obtain a thermosetting matrix material of 5AIPA.

[0065] The following is the preparation of comparative samples through comparative examples.

[0066] Comparative Example 1, Preparation of Glycidyl Isophthalate (IPA) Matrix

[0067] Mix glycidyl isophthalate (IPA) resin with the structural formula of and m-phenylenediamine (MPD) thoroughly and evenly. The molar ratio of epoxy groups to amino groups in the amine curing agent is 2:1. Subsequently, coat the mixture evenly on an automatic film coater equipped with a PET substrate, and use a scraper to coat the film. Place the PET substrate containing the mixture in an oven and cure it according to the programmed temperature rise at 100°C / 2h, 120°C / 2h, 150°C / 2h, and 180°C / 2h to obtain a thermosetting film (denoted as IPA_MPD).

[0068] The beneficial effects of the present invention are demonstrated by the following experimental examples.

[0069] Experimental Example 1, Characterization and Performance Testing of the Matrix Material of the Present Invention

[0070] 1. Experimental Method

[0071] (1) Structural Characterization

[0072] Characterize the molecular structure of the synthesized epoxy resin by a nuclear magnetic resonance spectrometer. The specific operation method is as follows: Dissolve 15 - 20 mg of the sample in a deuterated DMSO-d6 or deuterated chloroform solution containing 1% tetramethylsilane, and use a 600 MHz AV II type Fourier nuclear magnetic resonance spectrometer produced by Bruker Corporation of Switzerland for measurement.

[0073] (2) Performance Testing

[0074] Compare the tensile strength, tensile modulus, glass transition temperature, and storage modulus of Comparative Example 3 (3ABA_MPD), Example 6 (5AIPA_MPD), and Comparative Example 1 (IPA_MPD). At the same time, use a Suns UTM4204 universal material testing machine produced by Sansi Zongheng to conduct a bending performance test. Adopt the three-point bending method, with a test speed of 2 mm / min and a test span of 64 mm, and conduct the bending strength and bending modulus tests of 5AIPA_MPD.

[0075] Among them, the tensile strength and tensile modulus of the thin film material were measured using an Instron 5567 instrument. The sample length was 60 mm, width 10 mm, and thickness 0.06 mm. The tensile test was carried out at room temperature with a test speed of 1 mm / min. The glass transition temperature and storage modulus were tested by dynamic mechanical analysis (DMA), and the test was carried out in the thin film tensile mode on a TA Q800. The sample size was 30 mm * 6 mm * 0.06 mm, the temperature range was 25 - 260 °C, the heating rate was 5 °C / min, the frequency was 1.0 Hz, and the amplitude was 15.0 μm.

[0076] 2. Experimental Results

[0077] (1) Figure 1 、 2 are the 1H NMR spectra of 3ABA and 5AIPA epoxy resins respectively. The results show that the 3ABA and 5AIPA epoxy resins have been successfully synthesized in this invention.

[0078] (2) Figure 3 shows the ( Figure 3 a) tensile strength, tensile modulus and Figure 3 b) elongation at break results of 3ABA_MPD, 5AIPA_MPD and IPA_MPD. It can be seen that the tensile strength of IPA_MPD is 105.44 MPA and the tensile modulus is 3.23 GPa. Among them, the tensile strength and tensile modulus of 3ABA_MPD are 115.61 MPa and 4.43 GPa respectively; the tensile strength and tensile modulus of 5AIPA_MPD are 120.75 MPa and 5.17 GPa respectively. At the same time, the flexural strength and flexural modulus of 5AIPA_MPD are 185.7 MPa and 6.06 GPa Figure 4 ). In comparison, 5AIPA_MPD exhibits more excellent tensile strength and tensile modulus, and also has excellent flexural strength and flexural modulus.

[0079] Figure 5 shows the ( Figure 5 a) glass transition temperature and Figure 5 b) storage modulus results of 3ABA_MPD, 5AIPA_MPD and IPA_MPD. It can be seen that the glass transition temperature of 3ABA_MPD is 189.21 °C and the storage modulus is 3.76 GPa. The glass transition temperature of 5AIPA_MPD is 232.27 °C and the storage modulus is 4.51 GPa. Compared with 3ABA_MPD, 5AIPA_MPD exhibits more excellent thermomechanical properties.

[0080] The above results indicate that, compared with IPA_MPD, the 3ABA_MPD and 5AIPA_MPD prepared by the present invention have better tensile strength, tensile modulus, flexural strength and flexural modulus; among them, the thermosetting film 5AIPA_MPD prepared from 5AIPA epoxy resin has more excellent tensile strength, tensile modulus, flexural strength and flexural modulus, and also has a high glass transition temperature and a high storage modulus, showing more excellent thermomechanical properties.

[0081] In summary, the present invention provides a high-performance epoxy curing agent and its preparation method and uses. By combining quantum chemistry and molecular structure design, the present invention screened a molecular structure containing both carboxyl and amino groups, and finally obtained an epoxy curing agent with high strength and high modulus. The epoxy curing agent of the present invention has more excellent tensile strength, tensile modulus, flexural strength and flexural modulus, and also has a high glass transition temperature and a high storage modulus, showing excellent thermomechanical properties. The present invention expands the application range of epoxy curing agents in the field of high-strength and high-modulus materials.

Claims

1. An epoxy compound, characterized in that, The structure of the epoxy compound is shown in Formula I: wherein, R is selected from hydrogen or a, b, c, d, e, f, g, h are each independently selected from 0, 1, 2, 3.

2. The epoxy compound according to claim 1, characterized in that, The structure of the epoxy compound is shown in Formula II: wherein, R is selected from hydrogen or a, b, and c are each independently selected from 1, 2, and 3.

3. An epoxy cured product, characterized in that, It is a product prepared from the epoxy compound according to any one of Claims 1-2 and an amine curing agent, wherein the molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 1-5:

1.

4. The epoxy cured product according to claim 3, wherein The molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 2-3:

1.

5. The epoxy cured product according to claim 4, characterized in that, The molar ratio of the epoxy group in the epoxy compound to the amino group in the amine curing agent is 2:

1.

6. The epoxy cured product according to claim 3, wherein The amine curing agent is an aromatic amine curing agent, preferably m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzanilide, p-aminophenyl p-aminobenzoate.

7. A method for preparing the epoxy cured product according to any one of claims 3 to 6, characterized in that, The method comprises the following steps: fully mixing the epoxy compound and the amine curing agent evenly, and curing to obtain the product.

8. The method according to claim 7, wherein The conditions for curing are: heating up respectively according to a program of 80-120°C for 1-3 hours.

9. The method according to claim 8, characterized in that, The conditions for curing are: curing at 100°C for 2 h, 120°C for 2 h, 150°C for 2 h, and 180°C for 2 h in sequence.

10. Use of the epoxy cured product according to any one of Claims 3-6 in the preparation of aerospace materials, automotive manufacturing materials, electronic device materials, coating materials and carbon fiber composite materials.

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