Organosiloxane functionalized epoxy resin curing agent based on eugenol, cured product and synthesis method thereof

Abstract

The invention discloses an organosilicon functionalized epoxy resin curing agent based on eugenol, a cured product and a synthesis method of the curing agent. Eugenol diphenol and a halogenated nitrobenzene compound react to be converted into a corresponding dinitro compound, nitro is reduced, and the organosilicon functionalized aromatic diamine curing agent based on eugenol is obtained; or reacting the eugenol-based epoxy resin with imidazole and the derivative thereof to obtain the organosilicon functionalized imidazole epoxy resin curing agent based on eugenol. The organic silicon functionalized epoxy resin curing agent with good performance is synthesized by taking bio-based eugenol diphenol as a raw material, and the organic silicon functionalized epoxy resin curing agent is simple to synthesize and separate, stable in quality and easy to prepare in a large scale; the obtained cured epoxy resin has good flexibility, processability, water resistance and the like which are superior to those of similar commercially available conventional curing agents, and has wide application prospects in the fields of high-performance materials such as green and sustainable composite materials, coatings and adhesives.

Description

Technical Field

[0001] The present application belongs to the field of epoxy resin curing agents, and specifically relates to silicone-functionalized aromatic diamine or imidazole epoxy resin curing agents based on eugenol. Background Art

[0002] Epoxy resins offer excellent mechanical, thermal, electrical insulation, dimensional stability, and processability, making them widely used in coatings, adhesives, composite materials, electronics, transportation, civil engineering, aerospace, and other fields. However, over 90% of epoxy resins on the market are bisphenol A-based. The raw material, bisphenol A, is non-renewable and can disrupt the human endocrine system. The search for alternatives to bisphenol A-based epoxy resins and their derivatives is urgent, and research into bio-based epoxy resins and their curing agents derived from renewable resources is increasingly attracting research attention.

[0003] Bio-based phenols are naturally derived, renewable, and possess a rigid benzene ring structure. They are expected to play a significant role in developing alternatives to bisphenol A epoxy resins and curing agents, promoting sustainable development and attracting significant attention. A variety of natural bio-based compounds, including lignin, tannic acid, cardanol, eugenol, vanillin, guaiacol, flavonoids, and resveratrol, have been used as bio-based epoxy resin curing agents. Chinese patent CN119978316A discloses the use of tannic acid and resveratrol as epoxy resin curing agents.

[0004] The silicon-oxygen bonds in the siloxane segments are relatively stable, with good thermal and chemical stability, and the intermolecular bond length of the siloxane segments is larger, which is beneficial to improving flexibility and reducing viscosity. Chinese patent CN109400638A discloses a method for preparing a eugenol-based epoxy resin, in which eugenol is converted into eugenol glycidyl ether, and then hydrosilylated with a hydrogen-containing double-headed epoxy resin to obtain a low-viscosity silicone-functionalized epoxy resin, the cured product of which has good flame retardant, adhesive, and dielectric properties. Chinese authorized patent CN112851903B discloses a method for preparing a silicone-functionalized waterborne polyurethane, which discloses a method for preparing eugenol-based diphenol, which uses eugenol and 1,1,3,3-tetramethyldisiloxane as raw materials to synthesize eugenol-based diphenol through hydrosilylation reaction.

[0005] Traditional aromatic diamine epoxy resin curing agents lack toughness, resulting in brittle epoxy resins. Some diamines, such as m-phenylenediamine and 4,4'-diaminodiphenylmethane, are carcinogenic. Furthermore, most traditional aromatic diamine curing agents are crystalline solids with poor processability, requiring high temperatures to mix evenly with the resin. For example, 4,4'-diaminodiphenylmethane requires heating to around 100°C, 4,4'-diaminodiphenylsulfone typically requires 140°C, and 3,3'-diaminodiphenylsulfone requires temperatures above 130°C. Summary of the Invention

[0006] The object of the present invention is to provide a bio-based high-performance epoxy resin curing agent with excellent process performance, fracture toughness, low dielectric, low moisture absorption and low toxicity.

[0007] To achieve the above objectives, the present invention provides an organosiloxane functionalized epoxy resin curing agent based on eugenol, the structural formula of which is shown below:

[0008]

[0009] Where Ar represents R1 represents H or trifluoromethyl, R2 to R4 each independently represent H, C1 to C 10 Any one of alkyl, phenyl, benzyl, nitro, carboxyl, cyanoethyl, and C1-C4 alkoxy.

[0010] The above Ar represents When the eugenol-based organosiloxane functionalized epoxy resin curing agent is prepared, the method comprises the following steps:

[0011] Step 1: The eugenol-based diphenol of Formula I and the halogenated nitrobenzene compound of Formula II are reacted in the presence of potassium carbonate to produce the dinitro compound of Formula III; the reaction equation is shown below:

[0012]

[0013] Step 2: reducing the dinitro compound to obtain a eugenol-based organosilicon-functionalized aromatic diamine epoxy resin curing agent as shown in Formula IV.

[0014]

[0015] In formula II, X represents F, Cl or Br.

[0016] In the above step 1, the molar ratio of the halogenated nitrobenzene compound to eugenol diphenol and potassium carbonate is preferably 1-3:1:1-3, the reaction temperature is preferably 80-140° C., and the reaction time is preferably 8-80 h; the solvent used in the reaction is any one of N,N-dimethylformamide, N,N-dimethylacetamide and γ-valerolactone.

[0017] The eugenol-based diphenol is prepared according to the process described in patent CN112851903B.

[0018] In the above step 2, the reducing agent used in the reduction is preferably any one of hydrazine hydrate and hydrogen, and the catalyst used is any one of a carbon palladium catalyst and a Raney nickel catalyst; wherein, when the reducing agent is hydrogen, the dinitro compound and the catalyst are mixed, and catalytic reduction is carried out in a hydrogen atmosphere, and the catalytic reduction temperature is room temperature and the time is 2 to 100 hours; when the reducing agent is hydrazine hydrate, the nitro compound, hydrazine hydrate and the catalyst are added to a solvent and reacted at 0 to 80° C. for 2 to 100 hours, preferably the molar ratio of the dinitro compound to hydrazine hydrate is 1:4 to 20, the mass ratio of the dinitro compound to the catalyst is 5 to 100:1, and the solvent is any one of methanol and ethanol.

[0019] The above Ar represents When, the synthesis method of the eugenol-based organosiloxane functionalized epoxy resin curing agent is as follows: a eugenol-based epoxy resin represented by formula V is reacted with an imidazole derivative represented by formula VI to obtain a eugenol-based organosilicon functionalized imidazole epoxy resin curing agent represented by formula VII; the reaction equation is as follows:

[0020]

[0021] In the above synthesis method, the molar ratio of the eugenol-based epoxy resin to the imidazole derivative is preferably 1:2-20, the reaction temperature is 0-50°C, and the reaction time is 1-200h; the solvent used in the reaction is any one of methanol, ethanol, and acetone.

[0022] The eugenol-based epoxy resin is prepared according to the process described in patent CN109400638A.

[0023] The present invention also provides a eugenol-based epoxy resin cured product, which is formed by curing the above-mentioned eugenol-based silicone functionalized epoxy resin curing agent and epoxy resin.

[0024] The epoxy resin is any one of bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, o-cresol novolac epoxy resin, biphenyl epoxy resin, glycidylamine epoxy resin and the like.

[0025] In the above-mentioned epoxy resin cured product, the molar ratio of the amino group or imidazole ring in the eugenol-based silicone functionalized epoxy resin curing agent to the epoxy group in the epoxy resin is preferably 1:1 to 30, the two are mixed evenly, and heated to cure to obtain the epoxy resin cured product.

[0026] Furthermore, it is preferred that the curing temperature is 50 to 220° C. and the curing time is 2 to 100 hours.

[0027] Compared with the existing bio-based epoxy resin technology, the present invention has the following advantages:

[0028] 1. The synthetic raw material of the organosilicon-functionalized epoxy resin curing agent based on eugenol of the present invention is mainly renewable eugenol. Eugenol has the advantages of low cost, low toxicity, wide source, and multiple active sites (double bonds and hydroxyl groups). In addition, siloxane segments can be introduced through double bonds by hydrosilylation, and the yield of hydrosilylation is very high and the reaction can be almost quantitative. In addition, the synthetic yield of the organosilicon-functionalized epoxy resin curing agent based on eugenol is high, the purity of the dinitro intermediate is high, and it is easy to separate and process and can be synthesized in large quantities.

[0029] 2. Compared with traditional amine curing agents, the silicone functionalized epoxy resin curing agent based on eugenol in the present invention has the advantages of easy synthesis, low cost, good processing performance (it can be mixed with the resin at 60-70°C, while traditional aromatic diamine curing agents generally need to be heated to above 100°C, and 4,4'-diaminodiphenyl sulfone even needs to be heated to above 140°C), and can give the cured product very excellent fracture toughness (compared with the comparative sample, K IC and G IC The improvement is more than two times, which is much higher than that of general aromatic diamine curing agents), thus overcoming the brittleness problem of general thermosetting epoxy resins.

[0030] 3. The present invention's silicone-functionalized epoxy resin curing agent based on eugenol not only improves the thermomechanical properties and fracture toughness of the cured product, but also reduces the dielectric constant and dielectric loss of the cured product, and reduces the water absorption rate of the cured product. The synthesized epoxy resin curing agent has a large molecular weight, is easy to feed, is not easy to volatilize, and the water absorption of the curing agent itself is also greatly reduced. It has practical value and good market prospects in fields such as electronic packaging. It can also be used in the fields of composite materials, coatings, and adhesives, and also reflects the continuous pursuit of environmental protection and high efficiency in epoxy resin curing agent technology. It is of great value in the greening and high performance of epoxy resin curing agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the eugenol-based diphenol in Example 1.

[0032] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the dinitro compound in Example 1.

[0033] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the silicone-functionalized aromatic diamine epoxy resin curing agent based on eugenol in Example 1.

[0034] Figure 4 This is the hydrogen nuclear magnetic resonance pattern of the eugenol-based epoxy resin in Example 2.

[0035] Figure 5H NMR spectrum of the eugenol-based silicone-functionalized imidazole epoxy resin curing agent in Example 2.

[0036] Figure 6 This is a comparison chart of the water absorption rates of the eugenol-based silicone-functionalized imidazole epoxy resin curing agent and diethyltetramethylimidazole in Example 2.

[0037] Figure 7 3 is a comparison chart of the dynamic mechanical temperature curves of epoxy resin cured product molding specimens in Example 3 and Comparative Example 1.

[0038] Figure 8 3. It is a comparison diagram of the dynamic mechanical temperature curves of the epoxy resin cured material molded strips in Example 4 and Comparative Example 2. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and examples, but the protection scope of the present invention is not limited to these examples.

[0040] Various structural characterization methods and performance testing methods in the following examples are as follows:

[0041] NMR characterization of molecular structure: Analyze and detect sample structure using NMR spectroscopy. Tetramethylsilane (TMS) is used as the internal standard reagent, and deuterated chloroform (Chloroform-d) is used as the solvent.

[0042] Fourier transform infrared spectroscopy: using a Fourier transform infrared spectrometer, the wavelength of 4000 ~ 500cm -1 Solid samples were analyzed using the potassium bromide pellet method, while liquid samples were analyzed using the ATR mode.

[0043] Characterization of the thermomechanical properties of epoxy resin cured products: The thermomechanical properties of epoxy resin cured products were analyzed by using a dynamic thermomechanical analyzer. The dual-cantilever mode was used and the test was performed by heating from room temperature to 240°C at a heating rate of 3°C / min.

[0044] Fracture mechanics testing of epoxy resin cured products: Fracture mechanics testing of epoxy cured products (80 mm × 10 mm × 4 mm, V-notch) was conducted using a universal testing machine according to ASTM D5045. The test temperature was room temperature, the test rate was 10 mm / min, and the span was 40 mm.

[0045] Epoxy resin curing material bending test: According to GB / T 9341-2008, epoxy resin curing material (80 mm × 10 mm × 4 mm) was subjected to bending tests using a universal materials testing machine. Temperature: room temperature, bending speed: 2 mm / min, span: 60 mm.

[0046] Water absorption test for epoxy resin cured materials: Immerse the dried epoxy resin cured material in boiling water and weigh it at regular intervals until a constant weight is reached. The ratio of the mass gain to the original mass is the water absorption rate.

[0047] Dielectric properties of epoxy resin cured products: The dielectric constant and dielectric loss of epoxy resin cured products at room temperature were measured using an impedance analyzer (4294A, Agilent) at a frequency between 40 Hz and 1 GHz. The sample size was a 0.5-0.7 mm thick disc of known area. The sample was tested after gold spraying on the upper and lower surfaces.

[0048] Fracture mechanics testing of cured epoxy resin: Fracture mechanics testing was conducted on cured epoxy resin (80 mm × 10 mm × 5 mm, V-notch, vertically oriented at the notch root, with a pre-crack created using a sharp blade) using a universal testing machine according to ASTM D5045. The test was conducted at room temperature, a test rate of 10 mm / min, and a span of 40 mm.

[0049] Water contact angle test of epoxy resin cured material: The surface contact angle of epoxy resin cured material was measured at room temperature using a contact angle meter (JC14000C, Shanghai Zhongchen Digital Technology Equipment Co., Ltd.) using the hanging drop method, with a water drop size of 1 μL.

[0050] Curing agent water absorption test: Place the dry epoxy resin curing agent in air and weigh it at regular intervals until it reaches a constant weight. The ratio of the mass gain to the original mass is the water absorption rate.

[0051] Example 1

[0052] Step 1: Add 10.61 g (22.9 mmol) of eugenol-based diphenol, 6.66 g (48.2 mmol) of potassium carbonate and 7.59 g (48.2 mmol) of p-chloronitrobenzene to 60 mL of N,N-dimethylformamide, stir and react at 120°C for 48 hours. After the reaction, repeatedly wash the remaining potassium carbonate with boiling water until neutral, then wash the remaining p-chloronitrobenzene with methanol, and vacuum dry at 100°C for 12 hours to obtain the eugenol-based organosilicon-functionalized dinitro compound shown in Formula III-1.

[0053]

[0054] like Figure 2 The H-NMR spectrum data showed that except for the resonance of hydrogen on the adjacent carbon of nitro group at 8.16ppm and the increase of hydrogen on the benzene ring skeleton at around 7ppm, the other positions were similar to Figure 1 The NMR data of eugenol-based diphenols were the same, indicating that the organosilicon-functionalized dinitro compounds based on eugenol were successfully synthesized.

[0055] Step 2: Add 15.19 g (21.6 mmol) of the organosilicon-functionalized dinitro compound based on eugenol as shown in formula III-1 to 90 mL of ethanol, add 0.1519 g of carbon palladium catalyst under stirring, and then dropwise add 6.20 g (105.3 mmol) of 85% mass concentration of hydrazine hydrate aqueous solution, heat to 70°C and react for 72 hours. After the reaction is completed, filter to remove the carbon palladium catalyst, and then evaporate the filtrate to remove ethanol, and vacuum dry in an oven at 100°C for 12 hours to obtain the organosilicon-functionalized aromatic diamine epoxy resin curing agent based on eugenol as shown in formula IV-1.

[0056]

[0057] like Figure 3 The H-NMR spectrum data show that after the nitro group is reduced to an amino group, the electron-withdrawing effect weakens, the electron cloud density on the connected benzene ring increases, the chemical shift moves to the high field, the resonance signal of the hydrogen on the adjacent carbon disappears (δ = 8.16ppm), and a new signal appears in the high field (δ = 6.7ppm). At the same time, the active hydrogen resonance signal of the aromatic amine group also appears (δ = 3.6ppm), and the other positions are similar to Figure 1 The NMR data matched.

[0058] Example 2

[0059] 5.21 g (11.3 mmol) of eugenol-based epoxy resin and 3.90 g (35.4 mmol) of 2-ethyl-4-methylimidazole were mixed evenly, reacted at 15°C for 168 hours, dissolved in methanol, cooled and precipitated, and filtered to obtain a eugenol-based silicone-functionalized imidazole epoxy resin curing agent shown in Formula VII-1.

[0060]

[0061] like Figure 4 、 Figure 5 As shown by H NMR spectra, the introduced imidazole group carries methyl and methylene groups. Due to the electron-withdrawing effect of the imidazole ring on the alkyl group, its chemical shift shifts downfield, resulting in resonance signals (δ = 1-3 ppm) of the methyl and methylene groups shifted downfield, clearly distinguishing them from the peaks of the methyl and methylene groups on the siloxane backbone. Furthermore, both the imidazole ring and the aromatic ring can undergo electron delocalization conjugation, resulting in similar chemical shifts of the ring hydrogens (δ = approximately 7 ppm).

[0062] 1.96g of the eugenol-based organosilicon-functionalized imidazole epoxy resin curing agent obtained in this example and 2.35g (0.021mol) of diethyltetramethylimidazole were placed in air for one week, and their water absorption was measured. Figure 6As can be seen, the eugenol-based silicone-functionalized imidazole epoxy resin curing agent obtained in this example exhibits significantly lower water absorption than diethyltetramethylimidazole. The introduction of siloxane and eugenol segments significantly increases the molecular weight of the eugenol-based silicone-functionalized imidazole epoxy resin curing agent, reducing its volatility. This increased molecular weight allows for more accurate dosing, and the introduced hydrophobic groups also reduce its hygroscopicity to a certain extent.

[0063] Example 3

[0064] 6.87 g (amino group molar weight is 21.3 mmol) of the eugenol-based silicone functionalized aromatic diamine epoxy resin curing agent in Example 1 and 8.0 g (epoxy group molar weight is 42.6 mmol) of bisphenol A epoxy resin (E54, epoxy value is 0.5331) were thoroughly mixed and poured into the mold. Vacuum for 2 minutes to remove bubbles, and the curing temperature program was set to 150°C / 2h and 200°C / 5h. After curing, it was cooled and the mold was disassembled to obtain epoxy resin cured product molding strips.

[0065] Example 4

[0066] 1.33 g (molar amount of imidazole ring is 2.66 mmol) of the eugenol-based silicone functionalized imidazole epoxy resin curing agent in Example 2 and 10.0 g (molar amount of epoxy group is 53.3 mmol) of bisphenol A epoxy resin (E54, epoxy value is 0.5331) are thoroughly mixed and poured into the mold. Vacuum for 2 minutes to remove bubbles, and the curing temperature program is set to 100°C / 2h, 150°C / 2h, and 200°C / 2h. After curing is completed, cool and disassemble the mold to obtain epoxy resin cured product molding strips.

[0067] Comparative Example 1

[0068] 2.64 g (amino group molar weight is 26.6 mmol) of diaminodiphenylmethane and 10.0 g (epoxy group molar weight is 53.3 mmol) of bisphenol A epoxy resin (E54, epoxy value is 0.5331) were fully mixed and poured into the mold. Vacuum was applied for 2 minutes to remove bubbles. The curing temperature program was set to 150°C / 2h and 200°C / 5h. After curing was completed, it was cooled and the mold was disassembled to obtain epoxy resin cured product molding specimens.

[0069] Comparative Example 2

[0070] 0.29 g (imidazole ring molar weight is 2.66 mmol) of diethyltetramethylimidazole and 10.0 g (epoxy group molar weight is 53.3 mmol) of bisphenol A epoxy resin (E54, epoxy value is 0.5331) were thoroughly mixed and poured into the mold. Vacuum was applied for 2 minutes to remove bubbles. The curing temperature program was set to 100°C / 2h, 150°C / 2h, and 200°C / 2h. After curing was completed, the mixture was cooled and the mold was disassembled to obtain epoxy resin cured product molding strips.

[0071] Various performance tests were conducted on the epoxy resin cured molding strips of Example 3 and Comparative Example 1 and Example 4 and Comparative Example 2. The results are shown in Tables 1, 2, Figure 7 and Figure 8 .

[0072] Table 1 Test results of thermomechanical properties of specimens

[0073] sample Example 3 Comparative Example 1 Example 4 Comparative Example 2 <![CDATA[E' 25 / GPa]]> 2.14 2.33 2.38 2.12 <![CDATA[T g，Tanδ(max) / ℃]]> 108 190 190 198 <![CDATA[E' 95 / MPa]]> 1380 1510 1360 1370 <![CDATA[Tanδ max ]]> 0.94 0.94 0.20 0.23

[0074] Table 2 Test results of mechanical properties, dielectric properties and water absorption of splines

[0075]

[0076] From Table 1 and Figure 7 It can be seen that the epoxy resin cured product prepared in Example 3 using the eugenol-based organosilicon-functionalized aromatic diamine epoxy resin curing agent of Example 1 has good thermomechanical properties and a lower glass transition temperature than that of Comparative Example 1 under the same conditions. This is because the introduction of the siloxane flexible main chain increases the overall flexible group content in the cured product. When the temperature is increased, the chain segment mobility is enhanced, and the activity of the flexible chain segment is relatively less restricted, which reduces the activation energy of the chain segment movement, making T g Decreased. In contrast, the more rigid comparative example 1 has a higher storage modulus E' most of the time, but the storage modulus of Example 3 decreases less than that of comparative example 1, and still has a certain strength. This is because the flexible silicone segment is introduced into the curing agent molecule while also introducing multiple benzene rings, which improves flexibility while still having a certain rigidity and heat resistance, which is very beneficial for the application of epoxy curing agents. As can be seen from Table 2, in addition to conventional thermomechanical properties, the epoxy resin cured product prepared by using the eugenol-based silicone functionalized aromatic diamine epoxy resin curing agent of Example 1 in Example 3 also has good bending strength, good fracture toughness, dielectric properties and surface properties. The introduction of flexible segments significantly improves the fracture mechanical properties of the epoxy resin cured product of Example 3, and its K IC and G ICThe improvement is more than doubled, and its bending performance is slightly reduced, but still around 110 MPa, which is good. Thanks to the siloxane segments it contains, the molecular polarity is reduced, so that its dielectric properties are greatly improved compared to Comparative Example 1, and both the dielectric constant and dielectric loss are significantly reduced. The siloxane segments play a certain role in reducing the surface energy, and the methoxy group provides a certain hydrophobicity, so that the water contact angle of the epoxy resin cured material of Example 3 is also significantly increased compared to the epoxy resin cured material of Comparative Example 1, while the saturated water absorption rate is reduced.

[0077] From Table 1, Table 2 and Figure 8 As can be seen, the cured epoxy resin material prepared in Example 4 using the eugenol-based silicone-functionalized imidazole epoxy resin curing agent of Example 2 exhibits thermomechanical and flexural properties close to those of the cured epoxy resin material of Comparative Example 2. Because the siloxane segments contribute to surface energy reduction and the methoxy groups provide a certain degree of hydrophobicity, the cured epoxy resin material of Example 4 has a higher water contact angle than that of Comparative Example 2, while also having a lower saturated water absorption rate.

Claims

1. A silicone-functionalized epoxy resin curing agent based on eugenol, characterized in that: The structural formula of the epoxy resin curing agent is shown below: Where Ar represents R1 represents H or trifluoromethyl, R2 to R4 each independently represent H, C1 to C 10 Any one of alkyl, phenyl, benzyl, nitro, carboxyl, cyanoethyl, and C1-C4 alkoxy.

2. A method for synthesizing the organosilicon functionalized epoxy resin curing agent based on eugenol according to claim 1, wherein Ar represents When, it is characterized by: The synthesis method comprises the following steps: Step 1: reacting the eugenol-based diphenol of formula I with the halogenated nitrobenzene compound of formula II in the presence of potassium carbonate to produce the dinitro compound of formula III; Step 2: reducing the dinitro compound to obtain a eugenol-based organosilicon-functionalized aromatic diamine epoxy resin curing agent represented by Formula IV; In formula II, X represents F, Cl or Br.

3. The method for synthesizing the eugenol-based organosilicon-functionalized epoxy resin curing agent according to claim 2, wherein: In step 1, the molar ratio of the halogenated nitrobenzene compound to eugenol diphenol and potassium carbonate is 1-3:1:1-3, the reaction temperature is 80-140° C., and the reaction time is 8-80 h; the solvent used in the reaction is any one of N,N-dimethylformamide, N,N-dimethylacetamide and γ-valerolactone.

4. The method for synthesizing the eugenol-based organosilicon-functionalized epoxy resin curing agent according to claim 2, wherein: In step 2, the reducing agent used for the reduction is any one of hydrazine hydrate and hydrogen, and the catalyst used is any one of a carbon palladium catalyst and a Raney nickel catalyst; wherein, when the reducing agent is hydrogen, the dinitro compound and the catalyst are mixed, and catalytic reduction is carried out in a hydrogen atmosphere, and the catalytic reduction temperature is room temperature and the time is 2 to 100 hours; when the reducing agent is hydrazine hydrate, the nitro compound, hydrazine hydrate and the catalyst are added to a solvent, and the reaction is carried out at 0 to 80° C. for 2 to 100 hours, the molar ratio of the dinitro compound to hydrazine hydrate is 1:4 to 20, the mass ratio of the dinitro compound to the catalyst is 5 to 100:1, and the solvent is any one of methanol and ethanol.

5. A method for synthesizing the organosilicon functionalized epoxy resin curing agent based on eugenol according to claim 1, wherein Ar represents When, it is characterized by: reacting a eugenol-based epoxy resin represented by formula V with an imidazole derivative represented by formula VI to obtain a eugenol-based organosilicon-functionalized imidazole epoxy resin curing agent represented by formula VII; 6. The method for synthesizing the eugenol-based silicone-functionalized epoxy resin curing agent according to claim 5, characterized in that: The molar ratio of the eugenol-based epoxy resin to the imidazole derivative is 1:2-20, the reaction temperature is 0-50° C., and the reaction time is 1-200 hours. The solvent used in the reaction is any one of methanol, ethanol, and acetone.

7. A cured epoxy resin material based on eugenol, characterized in that: The epoxy resin curing agent is prepared by curing the eugenol-based silicone functionalized epoxy resin curing agent according to claim 1 with an epoxy resin.

8. The eugenol-based epoxy resin cured product according to claim 7, wherein: The epoxy resin is any one of bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, o-cresol novolac epoxy resin, biphenyl epoxy resin, and glycidylamine epoxy resin.

9. The eugenol-based epoxy resin cured product according to claim 7 or 8, characterized in that: The molar ratio of the amino group or imidazole ring in the eugenol-based silicone functionalized epoxy resin curing agent to the epoxy group in the epoxy resin is 1:1-30, the two are evenly mixed, and heated to cure to obtain an epoxy resin cured product.

10. The eugenol-based epoxy resin cured product according to claim 9, characterized in that: The curing temperature is 50-220° C., and the curing time is 2-100 hours.

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