Biomass equol-furfuryl amine type benzoxazine resin and preparation method thereof
The synthesis of benzoxazine resin from biomass equadol and furfurylamine solves the dependence on petroleum-based resins, achieving environmentally friendly and efficient biomass resin preparation. It features high performance and low cost, and is suitable for preparing heat-resistant composite materials.
Patent Information
- Application Number
- CN202511817905.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-01-09
AI Technical Summary
Existing benzoxazine resins mainly rely on petroleum-based compounds, leading to excessive dependence on fossil fuels. Furthermore, traditional synthesis processes are complex and costly, making it difficult to meet the demands for environmentally friendly and high-performance materials.
Using equorum and furfurylamine as biomass sources, biomass equorum-furfurylamine type benzoxazine resin was synthesized via the Mannich reaction. The resin was prepared by heating the reaction and then curing it in a stepwise manner using toluene and anhydrous ethanol as solvents.
The green and environmentally friendly synthesis of biomass-based resins has been achieved, which has high purity, high yield, and low cost. The resins also have good low-temperature curing characteristics and heat resistance, making them suitable for the preparation of high-performance composite materials.
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Figure CN121293494A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of thermosetting resin and its preparation, and particularly relates to a biomass equol-furfurylamine type benzoxazine resin and a preparation method thereof. BACKGROUND
[0002] Benzoxazine resin is a kind of thermosetting resin similar to epoxy resin, which has the advantages of rich raw material selection, low dielectric constant, low surface energy, good hydrophobicity, high glass transition temperature, excellent mechanical properties, no small molecule release in curing process and low curing shrinkage, and has very wide application scenarios. Benzoxazine is a N, O-containing six-membered heterocyclic compound, which is formed by Mannich reaction of phenols, amines and formaldehyde or polyformaldehyde. Traditional benzoxazine is mainly prepared from petroleum-based compounds such as bisphenol A, phenol, methylamine, aniline and formaldehyde. However, with the overuse of fossil fuels, many negative effects have been brought to people's daily life. Therefore, searching for new renewable resources has become the focus of researchers. Therefore, biomass benzoxazine resin as a new type of material has become a hot spot in the field of thermosetting resin research.
[0003] Equol (chemical name: 3-(4-hydroxyphenyl)-7-chromanols) contains two phenolic hydroxyl groups and a dihydrobenzopyran ring in the molecule, is an important organic synthesis intermediate and monomer of polymer derived from biomass. At the same time, equol is also a derivative of daidzein, which is produced by intestinal bacteria of humans and animals, and is converted from waste by-products of the soybean industry in industry. It has not been used as a phenolic source for the synthesis of benzoxazine before. It can be synthesized by industrial methods including microbial fermentation, chemical synthesis and biological enzyme catalysis, and can be mass-produced. Furfurylamine is a kind of bio-based primary amine prepared by green reductive amination process using furfural or furfuryl alcohol as raw material. Furfurylamine can be obtained by one-step dilute acid dehydration-decarboxylation of agricultural and forestry by-product hemicellulose such as corn cob, sugarcane bagasse and cottonseed hull, and the process is mature and has realized commercial production of ten thousand tons. The benzoxazine resin produced by equol as phenolic source and furfurylamine as amine source in the present application is paid more and more attention, which can get rid of the excessive dependence of traditional benzoxazine resin on petroleum products. SUMMARY
[0004] The technical problem to be solved by the present application is to provide a biomass benzoxazine resin equol-furfurylamine type benzoxazine resin and a preparation method thereof.
[0005] The technical scheme adopted by the present application is as follows:
[0006] A biomass equol-furfurylamine type benzoxazine resin, the structure of which is shown as follows:
[0007]
[0008] The biomass equol-furfurylamine type benzoxazine resin has the following monomer structure:
[0009] and
[0010] The monomer structure of the benzoxazine resin has an oxazine ring, so that the polymerization reaction can occur under the condition of heating or adding a catalyst to generate a reticular structure containing nitrogen and similar to a phenolic resin.
[0011] The preparation method of the biomass equol-furfurylamine type benzoxazine resin has the following steps:
[0012] (1) First, furfurylamine, formaldehyde and equol are directly added into a reactor, and then toluene and anhydrous ethanol solution are added; then heated to reflux state for 10-15 h; after the reaction is completed, the excess solvent is removed, the final product is precipitated with n-hexane, the n-hexane is removed, and the biomass equol-furfurylamine type benzoxazine monomer is obtained by drying.
[0013] (2) The biomass equol-furfurylamine type benzoxazine monomer obtained in step (1) is placed in a mold, and then step curing is performed to obtain the biomass equol-furfurylamine type benzoxazine resin.
[0014] The solvent in step (1) is toluene and anhydrous ethanol.
[0015] The formaldehyde in step (1) is one of paraformaldehyde and formaldehyde aqueous solution.
[0016] The equol, furfurylamine and formaldehyde in step (1) are directly added.
[0017] The ratio of equol, furfurylamine, paraformaldehyde and solvent in step (1) is 0.03-0.10 mol, 0.06-0.20 mol, 0.12-0.40 mol and 90-300 ml, respectively. The ratio of toluene and anhydrous ethanol is 2:1. The above ratio is not limited by specific units, and equal proportion reduction or increase based on the above numerical ratio is considered to fall within the above ratio range.
[0018] The step (2) of the present application is: 130-150 ℃, 0.5-1.5 h, 160-180 ℃, 1.5-2.5 h, 180-200 ℃, 0.5-1.5 h, 200-220 ℃, 1.5-2.5 h, 230-250 ℃, 0.5-1.5 h. Preferably, the step (2) of the present application is: 140 ℃, 1 h, 170 ℃, 2 h, 190 ℃, 1 h, 210 ℃, 2 h, 240 ℃, 1 h.
[0019] Compared with the prior art, the present application has the following remarkable advantages and beneficial effects:
[0020] (1) The biomass benzoxazine resin of the present application uses equol as a phenol source and furfurylamine as an amine source, both of which are by-products of biomass products, and is green and environmentally friendly.
[0021] (2) The synthesis process of the biomass equol-furfurylamine type benzoxazine resin of the present application is simple and reasonable, has high purity, high yield and low cost;
[0022] (3) The biomass equol-furfurylamine type benzoxazine resin prepared by the method of the present application has good low-temperature curing characteristics and is suitable for preparing natural fiber reinforced green composite materials.
[0023] (4) The biomass equol-furfurylamine type benzoxazine resin prepared by the present application has high heat resistance and carbon residue rate, and is suitable for preparing some high-performance and high-temperature resistant materials.
[0024] (5) The TG spectrum of the equol-furfurylamine type benzoxazine resin of the present application shows that the initial decomposition temperature (T d5% ) of the equol-furfurylamine type benzoxazine resin of the present application is as high as 369 ℃, and the carbon residue retention rate at 800 ℃ is as high as 51.9%. The TG results show that the biomass benzoxazine resin of the present application has good heat resistance and high carbon residue retention rate. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 The FT-IR spectrum of the biomass equol-furfurylamine type benzoxazine monomer of the present application is shown in the figure;
[0026] Figure 2 The H-NMR spectrum of the biomass equol-furfurylamine type benzoxazine monomer of the present application is shown in the figure; 1
[0027] Figure 3 The DSC spectrum of the biomass equol-furfurylamine type benzoxazine monomer of the present application at different heating rates is shown in the figure;
[0028] Figure 4 TG and DTG spectra of biomass equol-furfurylamine type benzoxazine resin of the present application are shown. Specific embodiments
[0029] The present application is further described in conjunction with the following examples. It should be noted that the following examples are intended to provide further illustration of the present application. Unless otherwise indicated, all scientific and technical terms used in connection with the present application have the same meaning as those of the skilled in the art to which the present application pertains. Example
[0030] The preparation method of biomass benzoxazine resin of the present application comprises the following steps:
[0031] (1) A three-necked round bottom flask equipped with a magnetic stirrer, a spherical condenser, a thermometer and 0.03 mol equol, 0.06 mol furfurylamine and 0.12 mol formaldehyde were added directly, followed by the addition of 60 ml toluene and 30 ml ethanol as solvents. The mixture was heated to reflux and reacted at constant temperature for 14 hours. The excess solvent was removed by rotary evaporation. Then n-hexane was directly added to precipitate the product. The product was separated from n-hexane by filtration and then placed in an oven for drying for 24 h to obtain a white powder, i.e. equol-furfurylamine type benzoxazine monomer, with a yield of 88.2%.
[0032] (2) The bisphenol amine type benzoxazine monomer obtained in step (1) was placed in a mold prepared in advance, and then placed in a forced air drying oven for stepwise curing (the stepwise curing temperature was the same as that of the comparative example) to obtain a thermosetting biomass equol-furfurylamine type benzoxazine resin. Example
[0033] The biomass equol-furfurylamine type benzoxazine resin and the intermediate product benzoxazine monomer obtained in Example 1 were subjected to relevant index detection, and the results are shown in Table 1. Figures 1-4
[0034] Figure 1 The FTIR spectrum of biomass equol-furfurylamine type benzoxazine monomer is shown in Figure 1. As can be seen from the figure, the asymmetric peak and the stretching vibration peak of the oxazine ring (C-O-C) can be observed at 1015, 1228 cm -1 , and the peak at 927 cm -1 is a typical absorption peak of the oxazine ring. The typical spectral bands at 738, 1090, 1490 cm -1 are respectively the stretching of C=C double bond, the anti-symmetrical stretching vibration of C-O and the out-of-plane wagging deformation, which confirms the presence of furan groups in Eq-fa and confirms the synthesis of equol-furfurylamine type benzoxazine monomer.
[0035] Figure 2 The biomass equol-furfurylamine type benzoxazine monomer 1 HNMR spectrum. As can be seen from the figure: there are characteristic peaks of oxazine ring at 3.78~3.82 ppm (Ph-CH2-N) and at 4.74~4.80 ppm (O-CH2-N). Since the H of 11 and the H of 12 are non-enantiomeric relationship, the chemical / magnetic environment is no longer symmetrical, so the H of 11 and 12 should have two chemical shifts. It is worth noting that in 6.75 ppm, there is a small peak of about 0.3 H, and 0.7 H at 6.86 ppm is the same position H, and their content ratio is about 2:1, and we can also observe that 11, 11'; 13, 13'; 15, 15' also exist similar H number ratio, from these NMR peaks we can infer that the product obtained exists position isomerism isomer. We name it as Eq-fa-1 and Eq-fa-2, according to 1 The peak area ratio in HNMR can approximately obtain the ratio of 2:1 (Eq-fa-1: Eq-fa-2).
[0036] Therefore, from FT-IR and 1 H NMR spectrum, the structure of the prepared product is consistent with that of the target product, i.e. the structure of the biomass equol-furfurylamine type benzoxazine monomer.
[0037] Figure 3 DSC spectrum of the biomass equol-furfurylamine type benzoxazine monomer at different heating rates. As can be seen from the figure: at the heating rate of 2.5 ℃ / min and 5 ℃ / min, two melting peaks can be obviously seen, which further explains that the product exists isomer. We can also see that there is a long temperature interval between the melting peak and the solidification peak, which shows that the biomass equol-furfurylamine type benzoxazine monomer has good processing performance.
[0038] Figure 4 TG and DTG spectrum of the cured biomass equol-furfurylamine type benzoxazine resin. As can be seen from the figure: the initial decomposition temperature (T d5% ) of the new biomass equol-furfurylamine type benzoxazine resin is as high as 369 ℃, and the carbon residue retention rate at 800 ℃ is as high as 51.9%. The TG result shows that the new biomass benzoxazine resin has good heat resistance and high carbon residue retention rate.
[0039] The materials, reagents and experimental equipment involved in the embodiments of the present application are all commercially available products in the field of thermosetting resin preparation technology unless otherwise specified.
[0040] The above merely describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, improvements and refinements can be made without departing from the core technology of the present application, and these improvements and refinements shall also fall within the scope of patent protection of the present application. Any changes within the meaning and scope equivalent to the claims of the present application shall be considered to be included in the scope of the claims.
Claims
1. A biomass equaphlebamine-furfurylamine type benzoxazine resin, characterized in that: The structural formula of the resin is shown below:
2. The biomass equaphlebamine-furfurylamine type benzoxazine resin according to claim 1, characterized in that: The biomass equaphlebamine-furfurylamine type benzoxazine resin is synthesized from monomers with the following general structural formula: and 3. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 1 or 2 is characterized in that: The preparation steps include: (1) First, furfurylamine, formaldehyde and equol were added to the reactor, and then toluene and anhydrous ethanol solution were added to the reactor. Then, the mixture was stirred and heated to reflux for 10-15 h. After the reaction was completed, the excess solvent was removed, the final product was precipitated with n-hexane, the n-hexane was removed, and the product was dried to obtain the biomass equol-furfurylamine type benzoxazine monomer.
4. (2) Place the biomass equaphlebamine-furfurylamine benzoxazine monomer obtained in step (1) into a mold, and then perform step curing to obtain biomass equaphlebamine-furfurylamine benzoxazine resin.
5. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 3, characterized in that: The solvents in step (1) are toluene and anhydrous ethanol.
6. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 3, characterized in that: The formaldehyde in step (1) is either paraformaldehyde or an aqueous formaldehyde solution.
7. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 3, characterized in that: In step (1), equaphene is added directly into the reactor, and furfurylamine is added directly into the reactor.
8. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 3, characterized in that: In step (1), the ratios of equaphenone, furfurylamine, paraformaldehyde, and solvent are 0.03~0.10 mol; 0.06~0.20 mol; 0.12~0.40 mol; and 90~300 ml, respectively. The ratio of toluene to anhydrous ethanol is 2:
1.
9. The method for preparing biomass equaphenone-furfurylamine type benzoxazine resin according to claim 3, characterized in that: The step curing time in step (2) is as follows: 130~150 ℃, 0.5~1.5 h, 160~180 ℃, 1.5~2.5 h, 180~200 ℃, 0.5~1.5 h, 200~220 ℃, 1.5~2.5 h, 230~250 ℃, 0.5~1.5 h.
10. The method for preparing biomass equaphlebamine-furfurylamine type benzoxazine resin according to claim 8, characterized in that: In step (2), the step curing process is performed at 140 ℃ for 1 h, 170 ℃ for 2 h, 190 ℃ for 1 h, 210 ℃ for 2 h, and 240 ℃ for 1 h.