Daidzein bio-based phenolic resin, preparation method therefor and application thereof

Abstract

The present invention belongs to the field of bio-based polymer materials. Disclosed are a daidzein bio-based phenolic resin, a preparation method therefor, and an application thereof. The present invention utilizes daidzin, a low-cost natural compound which has abundant sources, in order to reduce costs. At the same time, the preparation method provided by the present invention is simple to operate, and the daidzein bio-based phenolic resin prepared in the present invention has excellent mechanical properties and heat resistance, and can be widely used for manufacturing in industries such as adhesives, flame retardant materials, sanding pads, etc.

Description

A daidzein bio-based phenolic resin and its preparation method and application

[0001] This application claims priority to a Chinese patent application filed with the Patent Office of China on August 11, 2022, with application number CN202210960941.4 and invention name “A method for preparing daidzein bio-based phenolic resin”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The invention belongs to the field of bio-based polymer materials, and particularly relates to a daidzein bio-based phenolic resin and a preparation method and application thereof. Background Art

[0003] Since 1905, when American scientist Buckland conducted systematic and extensive research on phenolic resins, commercial applications of phenolic resins have been explored. Over the course of a century, their exceptional properties have led to their widespread adoption. While traditional and key components are phenol and formaldehyde, the resulting phenolic resins exhibit excellent performance, they also suffer from significant drawbacks: resource shortages, high toxicity and carcinogenicity, and brittle fracture due to high crosslinking, which directly restrict their development and application. Therefore, the research on how to modify phenolic resins to achieve environmentally friendly properties and expand product varieties and applications holds great promise.

[0004] Biomass modification is a current research hotspot, undoubtedly a wise choice in the context of environmental pollution and the increasing shortage of fossil resources. Biomass is abundant in nature, with a wide variety of species and sources, making it a promising renewable energy source. Incorporating biomass into phenolic resins not only improves performance but also reduces costs, generating significant economic benefits. Therefore, the development of modified phenolic resins with enhanced performance, affordability, and environmental friendliness holds great potential for practical application.

[0005] Currently, commonly used biomass-modified phenolic resins include lignin, tung oil, linseed oil, starch, rosin, bio-oil, and cardanol. These modified resins have varying properties, advantages, and disadvantages, and are beginning to gain application. However, bio-based phenolic resins also have some drawbacks. Compared with petroleum compounds, biomass has relatively low activity, requires more stringent reaction conditions, and the introduction of biomass can lead to uneven product quality.

[0006] Summary of the Invention

[0007] To address the current problems in the production of phenolic resins, the present invention provides a daidzein bio-based phenolic resin, a preparation method, and applications thereof. This method uses daidzein, a natural flavonoid phenolic compound, to replace a portion of phenol. In the presence of a catalyst in a certain proportion, the compound reacts with formaldehyde to produce a daidzein bio-based phenolic resin. The natural compound daidzein is a renewable resource with abundant sources and low price, thus reducing costs. Furthermore, the preparation method provided by the present invention is simple to operate, and the resulting daidzein bio-based phenolic resin is a green phenolic resin with excellent performance.

[0008] The technical solution of the present invention is:

[0009] A method for preparing a daidzein bio-based phenolic resin comprises the following steps:

[0010] (1) Under stirring conditions, daidzein, phenol and formaldehyde solution are mixed uniformly in proportion, and then sodium hydroxide is added. The reaction mixture is gradually heated to a certain temperature and refluxed for a period of time;

[0011] (2) gradually heating the reaction mixture of step (1) to a certain temperature and stirring the reaction at the temperature for a period of time;

[0012] (3) The reaction mixture of step (2) is cooled to room temperature, washed several times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at a certain temperature to obtain a daidzein bio-based phenolic resin product.

[0013] Preferably, in step (1), the phenol is 10 parts, daidzein is 0.5-2 parts, formaldehyde solution is 13-19 parts, and sodium hydroxide is 0.2-0.8 parts, in parts by mass, wherein the mass percentage concentration of the formaldehyde solution is 37%.

[0014] Preferably, in step (1), the reaction temperature is 95-105° C., and the reaction time is 1-1.5 h.

[0015] Preferably, in step (2), the reaction temperature is 115-125° C., and the reaction time is 1.5-3 h.

[0016] Preferably, in step (3), the drying and dehydration temperature is 50-70° C. and the time is 24 hours.

[0017] Preferably, in step (3), the ultrasonic cleaning is performed by washing several times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine respectively.

[0018] The present invention also provides the use of the daidzein bio-based phenolic resin prepared by the preparation method described in the above scheme for preparing friction and wear resistance materials, ablation-resistant materials or damping materials.

[0019] The beneficial effects of the present invention are:

[0020] (1) The daidzein bio-based phenolic resin prepared by the present invention has good acid resistance, mechanical properties, and heat resistance, and can be widely used in industries such as anti-corrosion engineering, adhesives, flame retardant materials, and grinding wheel manufacturing;

[0021] (2) The method of the present invention uses daidzein, a natural flavonoid phenolic compound, to partially replace phenol to prepare phenolic resin, which can greatly reduce the residual phenol content of the phenolic resin.

[0022] (3) The present invention introduces the high-rigidity structural unit of daidzein, which greatly improves the strength of phenolic resin and broadens the application field of phenolic resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is an infrared spectrum of ordinary phenolic resin a and daidzein bio-based phenolic resin b;

[0024] FIG2 is a DSC curve of the curing temperature of ordinary phenolic resin a and daidzein bio-based phenolic resin b;

[0025] FIG3 is a thermogravimetric TG diagram of a common phenolic resin;

[0026] FIG4 is a thermogravimetric TG diagram of daidzein bio-based phenolic resin;

[0027] FIG5 is a cross-sectional SEM scan of a conventional phenolic resin;

[0028] FIG6 is a cross-sectional SEM scan of daidzein bio-based phenolic resin. DETAILED DESCRIPTION

[0029] In a 250mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, add 10 parts phenol, 0.5-2 parts daidzein, and 13-19 parts formaldehyde solution (where the mass percentage concentration of the formaldehyde solution is 37%). Mix thoroughly, then add 0.2-0.8 parts sodium hydroxide. The reaction mixture is gradually heated to 95-105°C and allowed to react for 1-1.5 hours. The reaction mixture is then gradually heated to 115-125°C and allowed to react for 1.5-3 hours. Finally, the reaction mixture is cooled to room temperature and washed three times with anhydrous ethanol and then deionized water in an ultrasonic cleaner. The product is then dried in a vacuum oven at 50-70°C for 24 hours to obtain a daidzein bio-based phenolic resin.

[0030] To make the above-mentioned objects, features and advantages of the present invention more clearly understood, the technical solutions of the present invention are further described below with reference to specific embodiments. However, the present invention is not limited to the embodiments listed, but also includes any other known modifications within the scope of the claimed invention.

[0031] Example 1

[0032] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 0.5 parts of daidzein, and 13 parts of formaldehyde solution were added and mixed uniformly. 0.2 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 105°C and refluxed for 1 hour.

[0033] (2) gradually heating the reflux reaction mixture obtained in step (1) to 115° C. and stirring the reaction for 1.5 h;

[0034] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 60° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0035] The daidzein bio-based phenolic resin prepared in Example 1 has a tensile strength of 19 MPa, an elongation of 2.41%, a hardness of 121.74 HRR, a curing peak temperature of 169.2° C., and a residual rate of 61.76% at 800° C.

[0036] Example 2

[0037] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 1 part of daidzein, and 13 parts of formaldehyde solution were added and mixed uniformly. 0.4 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 95°C and refluxed for 1 hour.

[0038] (2) gradually heating the reflux reaction mixture obtained in step (1) to 115° C. and stirring the reaction for 1.5 h;

[0039] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 60° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0040] The daidzein bio-based phenolic resin prepared in Example 2 has a tensile strength of 20 MPa, an elongation of 2.45%, a hardness of 119 HRR, a curing peak temperature of 160.2° C., and a residual rate of 62.15% at 800 degrees.

[0041] Example 3

[0042] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 1.5 parts of daidzein, and 15 parts of formaldehyde solution were added and mixed uniformly. 0.6 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 105°C and refluxed for 1 hour.

[0043] (2) gradually heating the reflux reaction mixture obtained in step (1) to 115° C. and stirring the reaction for 2 h;

[0044] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 60° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0045] The daidzein bio-based phenolic resin prepared in Example 3 has a tensile strength of 39 MPa, an elongation of 2.705%, a hardness of 119.78 HRR, a curing peak temperature of 162.4° C., and a residual rate of 57.75% at 800° C.

[0046] Example 4

[0047] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 1.5 parts of daidzein, and 17 parts of formaldehyde solution were added and mixed uniformly. 0.6 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 105°C and refluxed for 1 hour.

[0048] (2) gradually heating the reflux reaction mixture obtained in step (1) to 120° C. and stirring for 2 h;

[0049] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 60° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0050] The daidzein bio-based phenolic resin prepared in Example 4 has a tensile strength of 32 MPa, an elongation of 3.31%, a hardness of 120.38 HRR, a curing peak temperature of 158.7° C., and a residual rate of 61.93% at 800 degrees.

[0051] Example 5

[0052] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 1.5 parts of daidzein, and 17 parts of formaldehyde solution were added and mixed uniformly. 0.8 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 95°C and refluxed for 1.5 hours.

[0053] (2) gradually heating the reflux reaction mixture obtained in step (1) to 125° C. and stirring the reaction for 2.5 h;

[0054] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 70° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0055] The daidzein bio-based phenolic resin prepared in Example 5 has a tensile strength of 36 MPa, an elongation of 2.51%, a hardness of 119.88 HRR, a curing peak temperature of 162.2° C., and a residual rate of 62.96% at 800° C.

[0056] Example 6

[0057] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 1.5 parts of daidzein, and 19 parts of formaldehyde solution were added and mixed uniformly. 0.6 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 95°C and refluxed for 1.5 hours.

[0058] (2) gradually heating the reflux reaction mixture obtained in step (1) to 125° C. and stirring the mixture for 2.5 h;

[0059] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven at 70° C. and dried for 24 hours to obtain daidzein bio-based phenolic resin.

[0060] The daidzein bio-based phenolic resin prepared in Example 6 has a tensile strength of 23 MPa, an elongation of 2.05%, a hardness of 119.34 HRR, a curing peak temperature of 156.5° C., and a residual rate of 61.25% at 800° C.

[0061] Example 7

[0062] (1) In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 2 parts of daidzein, and 19 parts of formaldehyde solution were added and mixed uniformly. 0.6 parts of sodium hydroxide was then added, and the reaction mixture was gradually heated to 105°C and refluxed for 1.5 hours.

[0063] (2) gradually heating the reflux reaction mixture obtained in step (1) to 125° C. and stirring the reaction for 3 h;

[0064] (3) The stirred reaction mixture obtained in step (2) is cooled to room temperature, washed three times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine, and the product is placed in a vacuum oven and dried and dehydrated at 60° C. for 24 hours to obtain daidzein bio-based phenolic resin.

[0065] The daidzein bio-based phenolic resin prepared in Example 7 has a tensile strength of 21 MPa, an elongation of 2.01%, a hardness of 118.98 HRR, a curing peak temperature of 155.3° C., and a residual rate of 59.94% at 800 degrees.

[0066] Comparative Example 1

[0067] In a 250mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, add 10 parts phenol and 17 parts formaldehyde solution, mix thoroughly, then add 0.6 parts sodium hydroxide. The reaction mixture is gradually heated to 60°C and allowed to react for 0.5 hours. The resulting reaction mixture is then gradually heated to 90°C and reacted for 4 hours. Finally, the reaction mixture is cooled to room temperature and washed three times with anhydrous ethanol and then deionized water in an ultrasonic cleaner. The product is then dried in a vacuum oven at 60°C for 24 hours to obtain a standard phenolic resin.

[0068] The conventional phenolic resin prepared in Comparative Example 1 has a tensile strength of 26 MPa, an elongation of 2.13%, a hardness of 122.78 HRR, a curing peak temperature of 139.5°C, and a residual rate of 58.14% at 800°C.

[0069] The performance of the daidzein bio-based phenolic resin prepared in Examples 1-7 of the present invention was compared with the ordinary phenolic resin prepared in Comparative Example 1. The results are shown in Figures 1-6 and Table 1.

[0070] Table 1

[0071] In summary, the preparation method of the daidzein bio-based phenolic resin provided by the present invention utilizes daidzein, which is abundant in resources and cheap, and adopts a simple synthetic modification method to prepare the daidzein bio-based phenolic resin, which is a green phenolic resin with excellent performance. The product thermal stability and heat resistance are greatly improved. According to Figures 1-6 and Table 1, the daidzein bio-based phenolic resins prepared by different synthesis processes have differences in tensile strength and elongation, curing temperature and 800 degrees Celsius residual rate, while the hardness is basically the same. In terms of tensile strength alone, Example 3 has the best strength, reaching 39MPa, while the pure phenolic resin is only 26MPa; Example 4 has the highest elongation, reaching 3.31%, which is higher than the elongation of the pure phenolic resin with the same curing process. Comparing thermal properties, it is found that the thermal stability and heat resistance of the daidzein bio-based phenolic resin are greatly improved. The daidzein bio-based phenolic resin prepared by the present invention has excellent mechanical properties and heat resistance, and can be widely used in industries such as friction materials, flame retardant materials, and grinding wheel manufacturing.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a daidzein bio-based phenolic resin, characterized in that: The steps include: (1) Under stirring conditions, daidzein, phenol and formaldehyde solution are mixed uniformly in proportion, and then sodium hydroxide is added. The reaction mixture is gradually heated to a certain temperature and refluxed for a period of time; (2) gradually heating the reflux reaction mixture obtained in step (1) to a certain temperature, and stirring the reaction at the temperature for a period of time; (3) Cooling the stirred reaction mixture obtained in step (2) to room temperature, ultrasonically cleaning, and placing the product in a vacuum oven at a certain temperature for drying and dehydration to obtain daidzein bio-based phenolic resin.

2. The preparation method according to claim 1, characterized in that In step (1), by mass, the phenol is 10 parts, the daidzein is 0.5-2 parts, the formaldehyde solution is 13-19 parts, and the sodium hydroxide is 0.2-0.8 parts, wherein the mass percentage concentration of the formaldehyde solution is 37%.

3. The preparation method according to claim 1, characterized in that In step (1), the temperature of the reflux reaction is 95-105° C., and the reaction time is 1-1.5 h.

4. The preparation method according to claim 1, characterized in that In step (2), the stirring reaction temperature is 115-125° C., and the reaction time is 1.5-3 h.

5. The preparation method according to claim 1, characterized in that In step (3), the drying and dehydration temperature is 50-70° C. and the time is 24 hours.

6. The preparation method according to claim 1, characterized in that In step (3), the ultrasonic cleaning is performed by washing several times with anhydrous ethanol and deionized water in an ultrasonic cleaning machine respectively.

7. The preparation method according to claim 6, characterized in that The number of washings was three times.

8. The daidzein bio-based phenolic resin prepared by the preparation method according to any one of claims 1 to 7.

9. The daidzein bio-based phenolic resin according to claim 8, characterized in that The tensile strength is greater than 19 MPa, the elongation is greater than 2.01%, the Rockwell hardness is greater than 118.98 HRR, the curing peak temperature is greater than 155.3°C, and the 800-degree residual rate is greater than 57.75%.

10. The daidzein bio-based phenolic resin according to claim 9, characterized in that The tensile strength is 19-39 MPa, the elongation is 2.01-3.31%, the Rockwell hardness is 118.98-121.74 HRR, the curing peak temperature is 155.3-169.2° C., and the 800-degree residual rate is greater than 57.75-62.96%.

11. Use of the daidzein bio-based phenolic resin prepared by the preparation method according to any one of claims 1 to 7 or the daidzein bio-based phenolic resin according to any one of claims 8 to 10 in preparing friction and wear resistance materials, ablation-resistant materials or damping materials.