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 inv

Description

[0002] The present disclosure belongs to the technical field of bio-based polymer materials, and specifically provides a daidzein bio-based phenolic resin, and a preparation method and use thereof. BACKGROUND

[0003] Since 1905, American scientist Buckland conducted systematic and extensive research on phenolic resin, and the commercial application of phenolic resin had been attempted since then. In the course of a hundred years of development, the phenolic resin has been used in many applications due to excellent properties. The traditional and important components of phenolic resin are phenol and formaldehyde, and the synthesized phenolic resin has excellent properties. However, the phenolic resin also shows fatal defects, such as resource shortage, high toxicity, carcinogenesis, and brittle fracture caused by high cross-linking degree, which directly restrict the development and application. Accordingly, there are broad research prospects to modify the phenolic resin to make it environmental-friendly, thus expanding product varieties and application fields.

[0004] Biomass modification is a hot topic in current research, as well as undoubtedly a wise choice in the context of environmental pollution and the increasing shortage of fossil resources. The biomass has large resource reserves in nature, is particularly diverse and comes from a wide range of sources, and exhibits great development prospects as a renewable energy source. Introducing biomass into phenolic resin can not only improve performance, but also reduce costs to produce higher economic benefits. Therefore, the development of modified phenolic resins with better performance, low price, and environmental friendliness has huge potential in practical applications.

[0005] Currently, commonly used biomass-modified phenolic resins mainly include lignin, tung oil, linseed oil, starch, rosin, bio-oil, and cardanol, which show different properties as well as inherent advantages and disadvantages, and also begin to be applied. However, the bio-based phenolic resin also has some shortcomings so far: biomass shows a relatively low activity compared with that of petroleum compounds, higher reaction conditions, and uneven product quality and other defects due to the introduction of biomass. SUMMARY

[0006] In view of the current problems in the production of phenolic resin, the present disclosure provides a daidzein bio-based phenolic resin, and a preparation method and use thereof. In this method, a natural compound daidzein from flavonoid phenols, is used to replace part of the phenol, and then reacted with formaldehyde under the action of a catalyst with a certain proportion to obtain the daidzein bio-based phenolic resin. The natural compound daidzein is a renewable resource with abundant sources, low price, and reduced cost. Meanwhile, the preparation method is simple to operate, and the prepared daidzein bio-based phenolic resin is a green phenolic resin with excellent performances.

[0007] The technical solutions of the present disclosure are as follows:

[0008] The present disclosure provides a preparation method of a daidzein bio-based phenolic resin, including the following steps:

[0009] (1) mixing daidzein, phenol, and a formaldehyde solution according to specified proportions under stirring to obtain a mixed solution, adding sodium hydroxide into the mixed solution to obtain a reaction mixture, and gradually heating the reaction mixture to a certain temperature to allow a reflux reaction for a period of time;

[0010] (2) gradually heating a reflux reaction mixture obtained in step (1) to a certain temperature to allow a stirring reaction for a period of time; and

[0011] (3) cooling a reaction mixture step (2) to a room temperature, conducting ultrasonic cleaning multiple times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and placing an obtained cleaned product in a vacuum oven to allow drying dehydration at a certain temperature to obtain the daidzein bio-based phenolic resin.

[0012] Preferably, there are 10 parts by mass of the phenol, 0.5 parts to 2 parts by mass of the daidzein, 13 parts to 19 parts by mass of the formaldehyde solution, and 0.2 parts to 0.8 parts by mass of the sodium hydroxide, while the formaldehyde solution has a mass concentration of 37% in step (1).

[0013] Preferably, the reflux reaction in step (1) is conducted at 95°C to 105°C for 1 h to 1.5 h.

[0014] Preferably, the stirring reaction in step (2) is conducted at 115°C to 125°C for 1.5 h to 3 h.

[0015] Preferably, the drying dehydration in step (3) is conducted at 50°C to 70°C for 24 h.

[0016] Preferably, the ultrasonic cleaning in step (3) is conducted multiple times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately.

[0017] The present disclosure further provides use of a daidzein bio-based phenolic resin prepared by the preparation method or the daidzein bio-based phenolic resin in preparation of a friction resistance material, an ablation-resistant material, or a damping material.

[0018] The present disclosure has the following beneficial effects:

[0019] (1) In the present disclosure, the daidzein bio-based phenolic resin shows excellent 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.

[0020] (2) In the present disclosure, the preparation method uses the natural compound daidzein from flavonoid phenols to partially replace phenol to prepare the phenolic resin, thus greatly reducing a residual phenol content in the phenolic resin.

[0021] (3) In the present disclosure, a high-rigidity structural unit of the daidzein is introduced to greatly improve a strength of the phenolic resin and broaden an application field of the phenolic resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows the infrared spectra of ordinary phenolic resin a and daidzein bio-based phenolic resin b;

[0023] FIG. 2 shows the differential scanning calorimetry (DSC) curves of the curing temperatures of ordinary phenolic resin a and daidzein bio-based phenolic resin b;

[0024] FIG. 3 shows the thermogravimetric (TG) diagram of ordinary phenolic resin;

[0025] FIG. 4 shows the TG diagram of daidzein bio-based phenolic resin;

[0026] FIG. 5 shows the scanning electron microscopy (SEM) image of a cross section of the ordinary phenolic resin; and

[0027] FIG. 6 shows the SEM image of a cross section of the daidzein bio-based phenolic resin. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol, 0.5 parts to 2 parts of daidzein, and 13 parts to 19 parts of a formaldehyde solution (the formaldehyde solution has a mass concentration of 37%) are mixed evenly, added with 0.2 parts to 0.8 parts of sodium hydroxide, and then a resulting reaction mixture is gradually heated to 95°C to 105°C to allow a reaction for 1 h to 1.5 h. The reaction mixture is then gradually heated to 115°C to 125°C for 1.5 h to 3 h. The reaction mixture is cooled to a room temperature, ultrasonic cleaning is conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product is placed in a vacuum oven to allow drying dehydration at 50°C to 70°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0029] To make the above-mentioned objective, features, and advantages of the present disclosure clearer and more comprehensible, the present disclosure will be further described below in conjunction with the examples. The present disclosure, however, is not limited to the listed examples, and any other well-known changes shall fall within the protection scope of the present disclosure.

[0030] Example 1

[0031] (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 a formaldehyde solution were mixed evenly, added with 0.2 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 105°C to allow a reaction for 1 h;

[0032] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 115°C to allow a stirring reaction for 1.5 h; and

[0033] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0034] The daidzein bio-based phenolic resin prepared in Example 1 had a tensile strength of 19 MPa, an elongation of 2.41%, a Rockwell hardness of 121.74 HRR, a curing peak temperature of 169.2°C, and a residual rate at 800°C of 61.76%.

[0035] Example 2

[0036] (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 a formaldehyde solution were mixed evenly, added with 0.4 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 95°C to allow a reaction for 1 h;

[0037] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 115°C to allow a stirring reaction for 1.5 h; and

[0038] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0039] The daidzein bio-based phenolic resin prepared in Example 2 had a tensile strength of 20 MPa, an elongation of 2.45%, a Rockwell hardness of 119 HRR, a curing peak temperature of 160.2°C, and a residual rate at 800°C of 62.15%.

[0040] Example 3

[0041] (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 a formaldehyde solution were mixed evenly, added with 0.6 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 105°C to allow a reaction for 1 h;

[0042] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 115°C to allow a stirring reaction for 2 h; and

[0043] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0044] The daidzein bio-based phenolic resin prepared in Example 3 had a tensile strength of 39 MPa, an elongation of 2.705%, a Rockwell hardness of 119.78 HRR, a curing peak temperature of 162.4°C, and a residual rate at 800°C of 57.75%.

[0045] Example 4

[0046] (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 a formaldehyde solution were mixed evenly, added with 0.6 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 105°C to allow a reaction for 1 h;

[0047] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 120°C to allow a stirring reaction for 2 h; and

[0048] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0049] The daidzein bio-based phenolic resin prepared in Example 4 had a tensile strength of 32 MPa, an elongation of 3.31%, a Rockwell hardness of 120.38 HRR, a curing peak temperature of 158.7°C, and a residual rate at 800°C of 61.93%.

[0050] Example 5

[0051] (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 a formaldehyde solution were mixed evenly, added with 0.8 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 95°C to allow a reaction for 1.5 h;

[0052] (2) a reflux reaction mixture of obtained in step (1) was gradually heated to 125°C to allow a stirring reaction for 2.5 h; and

[0053] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 70°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0054] The daidzein bio-based phenolic resin prepared in Example 5 had a tensile strength of 36 MPa, an elongation of 2.51%, a Rockwell hardness of 119.88 HRR, a curing peak temperature of 162.2°C, and a residual rate at 800°C of 62.96%.

[0055] Example 6

[0056] (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 a formaldehyde solution were mixed evenly, added with 0.6 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 95°C to allow a reaction for 1.5 h;

[0057] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 125°C to allow a stirring reaction for 2.5 h; and

[0058] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 70°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0059] The daidzein bio-based phenolic resin prepared in Example 6 had a tensile strength of 23 MPa, an elongation of 2.05%, a Rockwell hardness of 119.34 HRR, a curing peak temperature of 156.5°C, and a residual rate at 800°C of 61.25%.

[0060] Example 7

[0061] (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 a formaldehyde solution were mixed evenly, added with 0.6 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 105°C to allow a reaction for 1.5 h;

[0062] (2) a reflux reaction mixture obtained in step (1) was gradually heated to 125°C to allow a stirring reaction for 3 h; and

[0063] (3) the stirring reaction mixture obtained in step (2) was cooled a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain the daidzein bio-based phenolic resin.

[0064] The daidzein bio-based phenolic resin prepared in Example 7 had a tensile strength of 21 MPa, an elongation of 2.01%, a Rockwell hardness of 118.98 HRR, a curing peak temperature of 155.3°C, and a residual rate at 800°C of 59.94%.

[0065] Comparative Example 1

[0066] In a 250 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser, 10 parts of phenol and 17 parts of a formaldehyde solution were mixed evenly, added with 0.6 parts of sodium hydroxide, and then a resulting reaction mixture was gradually heated to 60°C to allow a reaction for 0.5 h. The reaction mixture was then gradually heated to 90°C for 4 h. The reaction mixture was cooled to a room temperature, ultrasonic cleaning was conducted three times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately, and an obtained cleaned product was placed in a vacuum oven to allow drying dehydration at 60°C for 24 h to obtain an ordinary phenolic resin.

[0067] The ordinary phenolic resin prepared in Comparative Example 1 had a tensile strength of 26 MPa, an elongation of 2.13%, a Rockwell hardness of 122.78 HRR, a curing peak temperature of 139.5°C, and a residual rate at 800°C of 58.14%.

[0068] The properties of the daidzein bio-based phenolic resins prepared in Examples 1 to 7 were compared with those of the ordinary phenolic resin prepared in Comparative Example 1. The results were shown in FIG. 1 to FIG. 6 and Table 1.

[0069] Table 1

[0070] Formula Tensile strength (MPa) Elongation 0 / / 0 Rockwell hardness HRR Curing peak temperature / °C Residual rate at 800°C / % Example 1 18-19 2.41% 121.74 169.2 61.76 Example 2 19-20 2.45% 119 160.2 62.15 Example 3 35-39 2.705% 119.78 162.4 57.75 Example 4 31-32 3.31% 120.38 158.7 61.93 Example 5 34-36 2.51% 119.88 162.2 62.96 Example 6 19-23 2.05% 119.34 156.5 61.25 Example 7 19-21 2.01% 118.98 155.3 59.94 Comparative Example 1 26 2.13% 122.78 139.5 58.14

[0071] In summary, the preparation method of daidzein bio-based phenolic resin provided by the present disclosure utilizes daidzein, which is abundant in resources and low in price, and adopts a synthetic modification process that is simple to operate. The prepared daidzein bio-based phenolic resin is a green phenolic resin with excellent performances. The thermal stability and heat resistance of the product are greatly improved. According to FIG. 1 to FIG. 6 and Table 1, it was seen that the daidzein bio-based phenolic resins prepared by different synthesis processes showed differences in tensile strength, elongation, curing temperature, and residual rate at 800°C, but there was basically no difference in Rockwell hardness. In terms of tensile strength alone, Example 3 had the best strength, reaching 39 MPa, while pure phenolic resin was only 26 MPa; the elongation of Example 4 was the highest, reaching 3.31%, which was higher than the elongation of pure phenolic resin with the same curing process. Comparing the thermal properties, it was found that the thermal stability and heat resistance of daidzein bio-based phenolic resin were greatly improved. The daidzein bio-based phenolic resin prepared by the present disclosure has excellent mechanical properties and heat resistance, and can be widely used in friction materials, flame-retardant materials, grinding wheel manufacturing and other industries.

[0072] The above descriptions are merely preferred implementations of the present disclosure. It should be noted that a person of ordinary skill in the art may further make several improvements and modifications without departing from the principle of the present disclosure, but such improvements and modifications should be deemed as falling within the protection scope of the present disclosure.

Claims

1. A preparation method of a daidzein bio-based phenolic resin, comprising the following steps:(1) mixing daidzein, phenol, and a formaldehyde solution according to specified proportions under stirring to obtain a mixed solution, adding sodium hydroxide into the mixed solution to obtain a reaction mixture, and gradually heating the reaction mixture to a certain temperature to allow a reflux reaction for a period of time;(2) gradually heating a reflux reaction mixture obtained in step (1) to a certain temperature to allow a stirring reaction for a period of time; and(3) cooling a stirring reaction mixture obtained in step (2) to a room temperature, conducting ultrasonic cleaning, and placing an obtained cleaned product in a vacuum oven to allow drying dehydration at a certain temperature to obtain the daidzein bio-based phenolic resin.

2. The preparation method according to claim 1, wherein there are 10 parts by mass of the phenol, 0.5 parts to 2 parts by mass of the daidzein, 13 parts to 19 parts by mass of the formaldehyde solution, and 0.2 parts to 0.8 parts by mass of the sodium hydroxide, while the formaldehyde solution has a mass concentration of 37% in step (1).

3. The preparation method according to claim 1, wherein the reflux reaction in step (1) is conducted at 95°C to 105°C for 1 h to 1.5 h.

4. The preparation method according to claim 1, wherein the stirring reaction in step (2) is conducted at 115°C to 125°C for 1.5 h to 3 h.

5. The preparation method according to claim 1, wherein the drying dehydration in step (3) is conducted at 50°C to 70°C for 24 h.

6. The preparation method according to claim 1, wherein the ultrasonic cleaning in step (3) is conducted multiple times in an ultrasonic cleaning machine using absolute ethanol and deionized water separately.

7. The preparation method according to claim 6, wherein the ultrasonic cleaning is conducted three times using the absolute ethanol and the deionized water separately.

8. A daidzein bio-based phenolic resin prepared by the preparation method according to any oneof claims 1 to 7.

9. The daidzein bio-based phenolic resin according to claim 8, wherein the daidzein bio-based phenolic resin has a tensile strength of greater than 19 MPa, an elongation of greater than 2.01%, a Rockwell hardness of greater than 118.98 HRR, a curing peak temperature of greater than 155.3°C, and a residual rate at 800°C of greater than 57.75%.

10. The daidzein bio-based phenolic resin according to claim 9, wherein the daidzein bio-based phenolic resin has a tensile strength of 19 MPa to 39 MPa, an elongation of 2.01% to 3.31%, a Rockwell hardness of 118.98 HRR to 121.74HRR, a curing peak temperature of 155.3°Cto 169.2°C, and a residual rate at 800°C of greater than 57.75% to 62.96%.

11. Use of a 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 preparation of a friction resistance material, an ablation-resistant material, or a damping material.

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