Resveratrol and boron synergistically modified phenolic resin, and preparation method and application thereof

Abstract

This invention discloses a resveratrol-boron synergistic modified phenolic resin, its preparation method, and its applications, belonging to the field of phenolic resin preparation technology. The invention first reacts resveratrol with boron-containing organic compounds under inert gas protection, followed by quenching, extraction, drying, and column chromatography to obtain boron-modified resveratrol. Then, the obtained boron-modified resveratrol is reacted with phenolic and aldehyde compounds under alkaline catalysts, heated, and dehydrated under reduced pressure to undergo a polycondensation reaction, yielding the resveratrol-boron synergistic modified phenolic resin. This invention effectively blocks phenolic hydroxyl groups by introducing high-bond-energy boron-oxygen bonds and the rigid conjugated stilbene structure of resveratrol, increasing the number of benzene rings in the resin and improving the crosslinking density, significantly enhancing the ablation resistance, char residue, and tensile properties of the phenolic resin. The obtained resin can be widely used in high-temperature braking friction materials, fire-retardant coatings, refractory materials, aerospace vehicles, and advanced composite materials.

Description

Technical Field

[0001] This invention belongs to the field of phenolic resin preparation technology, and more specifically relates to a phenolic resin synergistically modified with resveratrol and boron, its preparation method and application. Background Technology

[0002] Due to its inherent structure and the presence of easily oxidized groups, the ablation resistance and tensile properties of phenolic resins need improvement. These properties can be further enhanced through modification, primarily through chemical modification. The main purpose of this modification is to increase the number of stabilizing groups and rigid structures within the phenolic resin, while simultaneously introducing high-energy chemical bonds to improve its carbon residue and tensile strength.

[0003] Resveratrol is a non-flavonoid polyphenolic organic compound and a widely available and abundant renewable resource. Structurally, resveratrol has three phenolic hydroxyl groups and contains a rigid conjugated stilbene structure, making it suitable as a phenol source for synthesizing phenolic resins with high heat resistance and mechanical properties. The BO bond has a bond energy of 774.04 kJ / mol, and introducing a BO bond can effectively improve the heat resistance of phenolic resins. However, current research on the synergistic modification of phenolic resins using resveratrol and BO bonds is lacking.

[0004] Based on this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a synergistic modification of phenolic resin with resveratrol and boron, its preparation method and application, in order to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] One of the technical solutions of this invention is to provide a phenolic resin synergistically modified with resveratrol and boron, with the following structural formula:

[0008] Where n is 1~18, x is 1~20, and y is 1~15.

[0009] The second technical solution of the present invention provides a method for preparing the above-mentioned resveratrol and boron synergistic modified phenolic resin, comprising the following steps:

[0010] (1) Under the protection of inert gas, resveratrol was mixed with organic solvent and catalyst and stirred evenly. Then, boron-containing organic matter was added to react. After the reaction was completed, a quencher was added. After extraction, drying and column chromatography, boron-modified resveratrol was obtained.

[0011] (2) The boron-modified resveratrol obtained in step (1) is mixed with phenolic compounds, alkaline catalysts and aldehyde compounds, heated and simultaneously dehydrated under reduced pressure to carry out polycondensation reaction, thereby obtaining resveratrol and boron synergistic modified phenolic resin.

[0012] In this invention, the boron-containing organic compound in step (1) is 4-formylchlorophenylboronic acid, and the molar ratio of resveratrol to the boron-containing organic compound is 1:0.50~6.50, preferably 1:0.50~3.50.

[0013] In this invention, the organic solvent in step (1) is at least one of dimethyl sulfoxide, dimethylacetamide, acetonitrile, and acetone, and the mass ratio of resveratrol to the organic solvent is 1:0.01~0.09, preferably 1:0.01~0.05.

[0014] In this invention, the catalyst in step (1) is at least one of potassium carbonate, sodium hydride, and triethylamine, and the molar ratio of the catalyst to resveratrol is 1:0.50~2.50, preferably 1:0.50~1.50.

[0015] In this invention, the quenching agent in step (1) is at least one of saturated sodium carbonate solution, saturated sodium bicarbonate solution, dilute sodium hydroxide solution, and distilled water, and the molar ratio of the quenching agent to the boron-containing organic matter is 1:1.00~8.00, preferably 1:1.00~4.00.

[0016] In this invention, the extractant in step (1) is at least one of dichloromethane, diethyl ether, ethyl acetate, acetone, and diethyl ether, and the volume ratio of organic solvent to extractant is 1:0.50~5.50, preferably 1:0.50~2.50.

[0017] In this invention, the reaction temperature in step (1) is 30~80℃, preferably 45~65℃; the reaction time is 1~9 hours, preferably 2~5 hours.

[0018] In this invention, the phenolic compound mentioned in step (2) is at least one of phenol, methylphenol, naphthol, phenylphenol, resorcinol, and hydroquinone, and the mass ratio of boron-modified resveratrol to the phenolic compound is 1:10.00~60.00, preferably 1:10.00~30.00.

[0019] In this invention, the alkaline catalyst in step (2) is at least one of barium hydroxide, sodium hydroxide, triethylamine, and ammonia water, and the molar ratio of phenolic compound to alkaline catalyst is 1:0.01~0.10, preferably 1:0.01~0.05.

[0020] In this invention, the aldehyde compound mentioned in step (2) is at least one of formaldehyde aqueous solution, paraformaldehyde, triformaldehyde, acetaldehyde, and salicylaldehyde, and the molar ratio of phenolic compound to aldehyde compound is 1:1.00~3.00, preferably 1:1.00~1.50.

[0021] In this invention, the polycondensation reaction temperature in step (2) is 80~150℃, preferably 90~120℃; the reaction time is 2~8 hours, preferably 2~5 hours.

[0022] The third technical solution of the present invention provides the application of the above-mentioned resveratrol and boron synergistic modified phenolic resin in the preparation of high-temperature braking friction materials, refractory materials, aerospace vehicle components or advanced composite materials.

[0023] The technical principle of this invention is as follows:

[0024] This invention utilizes the abundant phenolic hydroxyl groups and rigid conjugated stilbene structure in resveratrol molecules. First, it undergoes esterification or condensation reactions with boron-containing organic compounds (such as 4-formylchlorophenylboronic acid) to introduce high-energy (774.04 kJ / mol) boron-oxygen (BO) bonds into the resveratrol structure, generating boron-modified resveratrol. Subsequently, this modified product serves as a phenol source, undergoing polycondensation reactions with phenolic and aldehyde compounds under alkaline catalysis to form modified phenolic resins with boron-oxygen bonds and a multi-benzene ring structure. In this process, on the one hand, boron and the rigid multi-benzene ring structure of resveratrol produce a synergistic effect, significantly enhancing the thermal stability and resistance to thermal degradation of the resin molecular chain at high temperatures. On the other hand, the conjugated structure of resveratrol also improves the rigidity of the molecular chain, resulting in a modified resin that possesses high carbon residue, excellent ablation resistance, and good tensile mechanical properties.

[0025] The present invention discloses the following technical effects:

[0026] 1. In this invention, by introducing high-bond-energy boron-oxygen bonds and resveratrol structures into phenolic resin, the number of benzene rings in the phenolic resin is increased, thereby improving its structural stability. The synthesized resveratrol and boron synergistically modified phenolic resin has both high carbon residue rate, excellent ablation resistance and good tensile mechanical properties, and has broad application prospects.

[0027] 2. This invention, through the synergistic effect of boron, significantly enhances the stability of the resin molecular structure at high temperatures. The presence of boron-oxygen bonds effectively hinders the thermal degradation process of the molecular chains, and the boron-promoted cross-linking structure further improves the resin's thermal stability. At high temperatures, the resin of this invention can maintain a higher carbon residue rate and better structural integrity, thereby effectively improving the reliability and safety of components in high-temperature applications such as aerospace, and reducing the risk of failure caused by insufficient high-temperature resistance of materials. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0034] Example 1

[0035] (1) Add 0.498 g of resveratrol and 2 mL of DMSO to a 100 mL round-bottom flask that has been dried by flame, and purge with nitrogen. Add 0.33 g of K2CO3, stir for 15 minutes, then add 0.549 g of 4-formylchlorophenylboronic acid, and continue stirring for 2 hours. Then quench the reaction with saturated NaHCO3 solvent and extract three times with EtOAc. Wash the organic layer with brine and dry with anhydrous Na2SO4. After concentration, perform column chromatography to obtain a white solid product;

[0036] The obtained white solid product is boron-modified resveratrol, with the following structural formula:

[0037] ;

[0038] (2) Add the product of step (1), phenol, sodium hydroxide and paraformaldehyde to a 250ml round bottom flask after drying. Heat to 120℃ for 60min and react for 2 hours. At the same time, dehydrate under reduced pressure with a vacuum degree of 0.030Mpa to carry out polycondensation reaction to obtain resveratrol and boron synergistic modified phenolic resin.

[0039] The structural formula of the obtained resveratrol and boron synergistic modified phenolic resin is as follows:

[0040] Where n is 1~18, x is 1~20, and y is 1~15.

[0041] Comparative Example 1

[0042] 300g of phenol, 313.89g of formaldehyde aqueous solution (37%), and 1.59g of sodium hydroxide were added. The pH was adjusted to 7.00, the stirring speed was set to 400 rpm, the temperature was raised to 120℃, and the reaction was carried out for 2 hours. Simultaneously, the product was dehydrated under reduced pressure (vacuum degree -0.09~0.10MPa) to obtain 258.40g of phenolic resin.

[0043] The solid content, residual carbon content, tensile strength, and elongation at break of the products obtained in Example 1 and Comparative Example 1 were tested, and the results are shown in Table 1 and Table 2.

[0044] Table 1. Solid content and residual carbon content of Example 1 and Comparative Example 1

[0045] project Solid content (%) Carbon residue rate at 800℃ (%) Example 1 92.18 71.33 Comparative Example 1 80.25 58.43

[0046] Table 2 Tensile strength and elongation at break of Example 1 and Comparative Example 1

[0047] project Tensile strength (MPa) Elongation at break (%) Example 1 30.75 3.38 Comparative Example 1 21.38 2.16

[0048] As shown in Tables 1 and 2, compared with the unmodified ordinary phenolic resin (Comparative Example 1), the resveratrol and boron synergistic modified phenolic resin prepared by the method of this invention (Example 1) shows significant improvements in several key properties. Specifically, the solid content of the modified resin increased from 80.25% to 92.18%, and the carbon residue at 800℃ increased significantly from 58.43% to 71.33%, indicating that the introduction of boron and resveratrol effectively enhanced the resin's thermal stability and char-forming ability at high temperatures, and inhibited thermal degradation. At the same time, the tensile strength of the modified resin increased from 21.38 MPa to 30.75 MPa, and the elongation at break increased from 2.16% to 3.38%, indicating that the rigid conjugated structure of resveratrol and the crosslinking effect of boron-oxygen bonds also significantly improved the mechanical properties of the resin. In summary, the synergistic modification of resveratrol and boron makes the phenolic resin superior to traditional phenolic resin in terms of high temperature resistance, ablation resistance, and mechanical properties, thus verifying the technical superiority and application potential of the present invention.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A phenol-formaldehyde resin modified with resveratrol in synergy with boron, characterized in that, The structure is as follows: wherein n is 1 to 18, x is 1 to 20, and y is 1 to 15.

2. The method for preparing the resveratrol and boron synergistic modified phenolic resin according to claim 1, characterized in that, Includes the following steps: (1) Under the protection of inert gas, resveratrol was mixed with organic solvent and catalyst and stirred evenly. Then, boron-containing organic matter was added to react. After the reaction was completed, a quencher was added. After extraction, drying and column chromatography, boron-modified resveratrol was obtained. (2) The boron-modified resveratrol obtained in step (1) is mixed with phenolic compounds, alkaline catalysts and aldehyde compounds, heated and simultaneously dehydrated under reduced pressure to carry out polycondensation reaction, thereby obtaining resveratrol and boron synergistic modified phenolic resin.

3. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The boron-containing organic compound mentioned in step (1) is 4-formylchlorophenylboronic acid, and the molar ratio of resveratrol to the boron-containing organic compound is 1:0.50~6.

50.

4. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The organic solvent mentioned in step (1) is at least one of dimethyl sulfoxide, dimethylacetamide, acetonitrile, and acetone, and the mass ratio of resveratrol to organic solvent is 1:0.01~0.

09.

5. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The catalyst mentioned in step (1) is at least one of potassium carbonate, sodium hydride, and triethylamine, and the molar ratio of the catalyst to resveratrol is 1:0.50~2.

50.

6. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The reaction temperature in step (1) is 30~80℃; the reaction time is 1~9 hours.

7. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The phenolic compound mentioned in step (2) is at least one of phenol, methylphenol, naphthol, phenylphenol, resorcinol, and hydroquinone, and the mass ratio of boron-modified resveratrol to the phenolic compound is 1:10.00~60.00; the alkaline catalyst is at least one of barium hydroxide, sodium hydroxide, triethylamine, and ammonia water, and the molar ratio of the phenolic compound to the alkaline catalyst is 1:0.01~0.

10.

8. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The aldehyde compound mentioned in step (2) is at least one of formaldehyde solution, paraformaldehyde, triformaldehyde, acetaldehyde, and salicylaldehyde, and the molar ratio of phenolic compound to aldehyde compound is 1:1.00~3.

00.

9. The method for preparing resveratrol and boron synergistic modification of phenolic resin according to claim 2, characterized in that, The polycondensation reaction temperature in step (2) is 80~150℃; the reaction time is 2~8 hours.

10. The application of the resveratrol and boron synergistic modified phenolic resin according to claim 1 in the preparation of high-temperature braking friction materials, refractory materials, aerospace vehicle components or advanced composite materials.

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