Preparation method of bio-based phenolic resin composite material

Abstract

The invention discloses a preparation method of a bio-based phenolic resin composite material, and belongs to the technical field of phenolic resin. According to the method, waste sugar residues and lignin are taken as raw materials, the waste sugar residues are catalytically converted into furfural, and waste liquid obtained after the waste sugar residues are catalytically converted into furfural is used for cascade operation of lignin activation, so that biomass-based 5-acetylmethoxyfurfural partially replaces formaldehyde and lignin partially replaces phenol; the use of formaldehyde and phenol for preparing phenolic resin is effectively reduced; the phenolic resin composite material prepared by the method has the advantages of high formaldehyde substitution amount, high phenol substitution amount, good thermal stability, cheap and easily available raw materials, hopeful realization of substitution of traditional phenolic resin materials, and high practical application significance.

Description

Technical Field

[0001] The invention specifically relates to a method for preparing a bio-based phenolic resin composite material, and belongs to the technical field of phenolic resins. Background Art

[0002] Phenolic resin is a polymer obtained by polycondensation of phenol and formaldehyde. It has the advantages of good heat resistance, high dimensional stability, strong resistance to chemical media, etc. It is widely used in adhesives, panels, high-temperature resistant materials, etc. However, due to their volatility and toxicity, phenol and formaldehyde will cause significant damage to the human body and the environment, which also limits the promotion and application of phenolic resin; on the other hand, in the current context of the increasing depletion of global fossil resources and the increasingly serious energy crisis, the large-scale use of formaldehyde and phenol as petrochemical products also makes the promotion and application of phenolic resin not so "green and environmentally friendly". Therefore, finding alternative materials for synthetic phenolic resin and reducing dependence on fossil resources has become an urgent problem to be solved.

[0003] Biomass energy is carbon-balanced and renewable. Using biomass to replace traditional phenolic resin raw materials formaldehyde and phenol has far-reaching research significance. At present, the use of biomass compounds to obtain high-value products has attracted widespread attention and research. Lignin is the second largest renewable natural polymer in the plant kingdom after cellulose. Because its structure contains structural units similar to phenol, it has become an excellent choice for replacing or partially replacing phenol in the production of phenolic resins. my country produces about 100 million tons of lignocellulosic biomass resources every year. However, due to the complexity and heterogeneity of lignin structure, lignin has low reaction activity with formaldehyde, which also limits the high-value utilization of lignocellulose in the preparation of phenolic resins, and lignin resources are facing great waste.

[0004] There are a lot of waste sugar residues in industrial production and daily life. They can be converted into corresponding aldehydes through chemical reactions. Compared with formaldehyde, the corresponding aldehydes obtained by conversion have relatively high molecular weight and good volatility resistance. Therefore, using the waste sugar residue conversion products to completely or partially replace formaldehyde to produce phenolic resin is an effective means to reduce formaldehyde volatilization and application and reduce formaldehyde residue in the field of phenolic resin preparation. Acid or Lewis acid catalyzing the conversion of sugars in a medium is a common way to achieve high-value application of sugars, but this also results in the generation of acid waste liquid, which is not conducive to the green application of biomass resources.

[0005] In summary, there is currently a lack of efficient means to utilize lignin and waste sugar residues as resources in the preparation of phenolic resins. Summary of the invention

[0006] In view of the existing problems, the present invention proposes a method for preparing a bio-based phenolic resin composite material. The method uses waste sugar residue and lignin as raw materials, and realizes a cascade operation of catalytic conversion of waste sugar residue into furfural and catalytic conversion of waste sugar residue into furfural waste liquid for lignin activation, thereby partially replacing formaldehyde with biomass-based 5-acetylmethoxyfurfural and partially replacing phenol with lignin, effectively reducing the use of formaldehyde and phenol in the preparation of phenolic resin; the preparation method is green, environmentally friendly, simple and convenient, the raw materials are cheap and easy to obtain, and the prepared phenolic resin composite material has good high temperature resistance, which is expected to replace traditional phenolic resin materials.

[0007] The technical solution of the present invention is as follows: The present invention provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: adding stannous chloride and stannic chloride mixture catalyst and concentrated sulfuric acid to waste sugar residue concentrate, stirring the solution at 120° C. and performing reflux reaction for 2 to 12 hours. After the reaction is completed, the reaction solution is cooled, extracted with distilled water and dichloromethane to obtain aqueous acidic waste liquid and an extraction phase, and the extraction phase is subjected to solvent rotary evaporation and purified by a silica gel column to obtain 5-acetylmethoxyfurfural; S2, lignin activation: adding lignin powder to the aqueous acidic waste liquid extracted in step S1 and stirring the mixture at 30-100° C. for at least 24 h. After the reaction is completed, the reaction liquid is filtered to obtain activated lignin; S3, preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol are mixed and preheated at 80°C for at least 1 h, and after the solution is cooled, formaldehyde is added thereto and the solution is adjusted to neutrality using a NaOH solution; the solution is then stirred and a 1 wt% NaOH solution as a catalyst is added thereto, and the solution is reacted at 90°C for 1 h to obtain the bio-based phenolic resin composite material; The ratio of the total mass of the added 5-acetylmethoxyfurfural and formaldehyde to the total mass of the added activated lignin and phenol is 1.5.

[0008] Furthermore, the method for preparing the waste sugar residue concentrate described in step S1 comprises the following steps: soaking bagasse in water, with the addition amount of bagasse being 250 g / L, and obtaining the waste sugar residue concentrate by filtering and evaporating.

[0009] Furthermore, the ratio of the added amount of the stannous chloride and stannic chloride mixture catalyst to the waste sugar residue concentrate in step S1 is 5 mg / mL, and the volume ratio of the added amount of the concentrated sulfuric acid to the waste sugar concentrate is 1:20.

[0010] Furthermore, in step S1, the mass ratio of stannous chloride to stannic chloride is 1:0 to 0:1.

[0011] Furthermore, the ratio of the amount of lignin powder added in step S2 to the amount of aqueous acidic waste liquid is 50 mg / mL.

[0012] Furthermore, the mass of 5-acetylmethoxyfurfural added in step S3 accounts for 10% to 80% of the total mass of the aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde).

[0013] Furthermore, the mass of the activated lignin added in step S3 accounts for 10% to 80% of the total mass of the phenolic compounds (activated lignin and phenol).

[0014] Different from the prior art, the present invention has the following beneficial effects: 1. The present invention first uses a catalyst to convert sugar in waste sugar residue into biomass-based 5-acetylmethoxyfurfural through a chemical reaction; then uses the acidic waste liquid of synthesizing 5-acetylmethoxyfurfural to treat lignin, so as to achieve the effect of activating lignin and reducing the molecular weight of lignin; finally, the phenolic resin composite material is synthesized using 5-acetylmethoxyfurfural, a sugar residue conversion product, activated lignin, phenol and formaldehyde; this process uses waste sugar residue and lignin as raw materials, the raw materials are simple and easy to obtain, and partial substitution of formaldehyde and phenol in phenolic resin can be achieved without complicated treatment, which effectively improves the formaldehyde residual problem commonly faced by current phenolic resins and promotes the high value and green utilization of biomass resources.

[0015] 2. Different from the previous lignin-based phenolic resins, the sulfuric acid-activated lignin used in the present invention has good reactivity with formaldehyde or biomass-based 5-acetylmethoxyfurfural, which can effectively solve the problem of low reactivity of lignin with formaldehyde, which leads to low amount of formaldehyde and phenol replaced by biomass raw materials; the 5-acetylmethoxyfurfural and lignin of the present invention can replace formaldehyde and phenol in an amount of up to 80 wt%, respectively, and the technology has good practical application significance.

[0016] 3. The traditional process of producing furfural with sulfuric acid is widely used due to the advantages of cheap and easy-to-obtain catalyst and high reaction efficiency, but it faces the problem of generating acidic wastewater after the reaction. Compared with the previous technology, the preparation method provided by the present invention catalytically converts waste sugar residue into furfural, and uses the waste liquid obtained by catalytically converting waste sugar residue into furfural for lignin activation in a cascade operation, which effectively solves the problem of recycling and utilizing the acidic waste liquid obtained by catalytically converting waste sugar residue into furfural and realizes the production of phenolic resin with good high temperature resistance, and has broad industrialization prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is the infrared spectrum of furfural / lignin / phenolic resin composite material.

[0018] Figure 2 This is the DCS heating curve of furfural / lignin / phenolic resin composite material.

[0019] Figure 3 This is the thermal gravimetric curve of furfural / lignin / phenolic resin composite material. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments. The given embodiments are only for illustrating the present invention, rather than for limiting the scope of the present invention.

[0021] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources; The methods in the following embodiments are all conventional methods unless otherwise specified.

[0022] Example 1 This embodiment provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: weigh 500 g of sugarcane bagasse, soak it in 2 L of water, filter it, evaporate and concentrate it into 100 mL of waste sugarcane bagasse concentrate; put 100 mL of waste sugarcane bagasse concentrate into a three-necked flask, add 0.5 g of stannous chloride and tin chloride mixture catalyst and 5 ml of concentrated sulfuric acid, wherein the ratio of stannous chloride to tin chloride is 1:0; then stir the solution continuously at 120°C and reflux for 2 hours; after the reaction is completed, wait for it to cool, add 200 mL of distilled water and stir, then add 200 mL of dichloromethane to extract, and obtain aqueous acidic waste liquid and extraction phase; finally, use a rotary evaporator to perform solvent rotary evaporation on the extraction phase, concentrate it to about 20 mL, and purify it with a silica gel column (petroleum ether: ethyl acetate = 3:1) to obtain 5-acetylmethoxyfurfural; S2, lignin activation: take 100 mL of the aqueous acidic waste liquid extracted in step S1, add 5 g of lignin powder thereto and stir the mixture at 30°C for at least 24 h. After the reaction is completed, filter the reaction solution to obtain activated lignin; S3. Preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol were mixed and preheated at 80°C for at least 1 h. After the solution was cooled, formaldehyde was added thereto and the pH of the solution was adjusted to pH=7 using NaOH solution. The total mass of the added aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde) was 14.2 g, and the proportion of 5-acetylmethoxyfurfural was 10 wt%. The total mass of the added phenolic compounds (activated lignin and phenol) was 9.4 g, and the proportion of activated lignin was 10 wt%. The solution was then stirred for 0.5 h and 0.5 g of 1 wt% NaOH solution as a catalyst was added thereto. The solution was reacted at 90°C for 1 h to obtain a bio-based phenolic resin composite material. According to the proportions of 5-acetylmethoxyfurfural and activated lignin in aldehyde compounds and aldehyde compounds, respectively, the product was labeled as furfural 10 / lignin 10 / phenolic resin composite material.

[0023] Example 2 This embodiment provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: weigh 500 g of sugarcane bagasse, soak it in 2 L of water, filter it, evaporate and concentrate it into 100 mL of waste sugarcane bagasse concentrate; put 100 mL of waste sugarcane bagasse concentrate into a three-necked flask, add 0.5 g of stannous chloride and tin chloride mixture catalyst and 5 ml of concentrated sulfuric acid, wherein the ratio of stannous chloride to tin chloride is 0:1; then stir the solution continuously at 120°C and reflux for 12 hours; after the reaction is completed, wait for it to cool, add 200 mL of distilled water and stir, then add 200 mL of dichloromethane to extract, and obtain aqueous acidic waste liquid and extraction phase; finally, use a rotary evaporator to perform solvent rotary evaporation on the extraction phase, concentrate it to about 20 mL, and purify it on a silica gel column (petroleum ether: ethyl acetate = 3:1) to obtain 5-acetylmethoxyfurfural; S2, lignin activation: take 100 mL of the aqueous acidic waste liquid extracted in step S1, add 5 g of lignin powder thereto and stir the mixture at 100°C for at least 24 h. After the reaction is completed, the reaction solution is filtered to obtain activated lignin; S3. Preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol were mixed and preheated at 80°C for at least 1 h. After the solution was cooled, formaldehyde was added thereto and the pH of the solution was adjusted to pH=7 using NaOH solution. The total mass of the added aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde) was 14.2 g, and the proportion of 5-acetylmethoxyfurfural was 80 wt%. The total mass of the added phenolic compounds (activated lignin and phenol) was 9.4 g, and the proportion of activated lignin was 80 wt%. The solution was then stirred for 0.5 h and 0.5 g of 1 wt% NaOH solution as a catalyst was added thereto. The solution was reacted at 90°C for 1 h to obtain a bio-based phenolic resin composite material. According to the proportions of 5-acetylmethoxyfurfural and activated lignin in aldehyde compounds and aldehyde compounds, respectively, the product was labeled as furfural 80 / lignin 80 / phenolic resin composite material.

[0024] Example 3 This embodiment provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: weigh 500 g of sugarcane bagasse, soak it in 2 L of water, filter it, evaporate and concentrate it into 100 mL of waste sugarcane bagasse concentrate; put 100 mL of waste sugarcane bagasse concentrate into a three-necked flask, add 0.5 g of stannous chloride and tin chloride mixture catalyst and 5 ml of concentrated sulfuric acid, wherein the ratio of stannous chloride to tin chloride is 1:1; then stir the solution continuously at 120°C and reflux for 5 hours; after the reaction is completed, wait for it to cool, add 200 mL of distilled water and stir, then add 200 mL of dichloromethane to extract, and obtain aqueous acidic waste liquid and extraction phase; finally, use a rotary evaporator to perform solvent rotary evaporation on the extraction phase, concentrate it to about 20 mL, and purify it with a silica gel column (petroleum ether: ethyl acetate = 3:1) to obtain 5-acetylmethoxyfurfural; S2, lignin activation: take 100 mL of the aqueous acidic waste liquid extracted in step S1, add 5 g of lignin powder thereto and stir the mixture at 60°C for at least 24 h. After the reaction is completed, filter the reaction solution to obtain activated lignin; S3. Preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol were mixed and preheated at 80°C for at least 1 h. After the solution was cooled, formaldehyde was added thereto and the pH of the solution was adjusted to pH=7 using NaOH solution. The total mass of the added aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde) was 14.2 g, and the proportion of 5-acetylmethoxyfurfural was 30 wt%. The total mass of the added phenolic compounds (activated lignin and phenol) was 9.4 g, and the proportion of activated lignin was 30 wt%. The solution was then stirred for 0.5 h and 0.5 g of 1 wt% NaOH solution as a catalyst was added thereto. The solution was reacted at 90°C for 1 h to obtain a bio-based phenolic resin composite material. According to the proportions of 5-acetylmethoxyfurfural and activated lignin in aldehyde compounds and aldehyde compounds, respectively, the product was labeled as furfural 30 / lignin 30 / phenolic resin composite material.

[0025] Example 4 This embodiment provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: weigh 500 g of sugarcane bagasse, soak it in 2 L of water, filter it, evaporate and concentrate it into 100 mL of waste sugarcane bagasse concentrate; put 100 mL of waste sugarcane bagasse concentrate into a three-necked flask, add 0.5 g of stannous chloride and tin chloride mixture catalyst and 5 ml of concentrated sulfuric acid, wherein the ratio of stannous chloride to tin chloride is 1:1; then stir the solution continuously at 120°C and reflux for 5 hours; after the reaction is completed, wait for it to cool, add 200 mL of distilled water and stir, then add 200 mL of dichloromethane to extract, and obtain aqueous acidic waste liquid and extraction phase; finally, use a rotary evaporator to perform solvent rotary evaporation on the extraction phase, concentrate it to about 20 mL, and purify it with a silica gel column (petroleum ether: ethyl acetate = 3:1) to obtain 5-acetylmethoxyfurfural; S2, lignin activation: take 100 mL of the aqueous acidic waste liquid extracted in step S1, add 5 g of lignin powder thereto and stir the mixture at 60°C for at least 24 h. After the reaction is completed, filter the reaction solution to obtain activated lignin; S3. Preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol were mixed and preheated at 80°C for at least 1 h. After the solution was cooled, formaldehyde was added thereto and the pH of the solution was adjusted to pH=7 using NaOH solution. The total mass of the added aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde) was 14.2 g, and the proportion of 5-acetylmethoxyfurfural was 50 wt%. The total mass of the added phenolic compounds (activated lignin and phenol) was 9.4 g, and the proportion of activated lignin was 30 wt%. The solution was then stirred for 0.5 h and 0.5 g of 1 wt% NaOH solution as a catalyst was added thereto. The solution was reacted at 90°C for 1 h to obtain a furfural 50 / lignin 30 / phenolic resin composite material.

[0026] Example 5 This embodiment provides a method for preparing a bio-based phenolic resin composite material, comprising the following steps: S1. Preparation of 5-acetylmethoxyfurfural: weigh 500 g of sugarcane bagasse, soak it in 2 L of water, filter it, evaporate and concentrate it into 100 mL of waste sugarcane bagasse concentrate; put 100 mL of waste sugarcane bagasse concentrate into a three-necked flask, add 0.5 g of stannous chloride and tin chloride mixture catalyst and 5 ml of concentrated sulfuric acid, wherein the ratio of stannous chloride to tin chloride is 1:1; then stir the solution continuously at 120°C and reflux for 5 hours; after the reaction is completed, wait for it to cool, add 200 mL of distilled water and stir, then add 200 mL of dichloromethane to extract, and obtain aqueous acidic waste liquid and extraction phase; finally, use a rotary evaporator to perform solvent rotary evaporation on the extraction phase, concentrate it to about 20 mL, and purify it with a silica gel column (petroleum ether: ethyl acetate = 3:1) to obtain 5-acetylmethoxyfurfural; S2, lignin activation: take 100 mL of the aqueous acidic waste liquid extracted in step S1, add 5 g of lignin powder thereto and stir the mixture at 60°C for at least 24 h. After the reaction is completed, filter the reaction solution to obtain activated lignin; S3. Preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol were mixed and preheated at 80°C for at least 1 h. After the solution was cooled, formaldehyde was added thereto and the pH of the solution was adjusted to pH=7 using NaOH solution. The total mass of the added aldehyde compounds (5-acetylmethoxyfurfural and formaldehyde) was 14.2 g, and the proportion of 5-acetylmethoxyfurfural was 50 wt%. The total mass of the added phenolic compounds (activated lignin and phenol) was 9.4 g, and the proportion of activated lignin was 50 wt%. The solution was then stirred for 0.5 h and 0.5 g of 1 wt% NaOH solution as a catalyst was added thereto. The solution was reacted at 90°C for 1 h to obtain a bio-based phenolic resin composite material. According to the proportions of 5-acetylmethoxyfurfural and activated lignin in aldehyde compounds and aldehyde compounds, respectively, the product was labeled as furfural 50 / lignin 50 / phenolic resin composite material.

[0027] Performance Testing In order to illustrate the structure and high temperature resistance of the synthesized phenolic resin composite material, the samples of Examples 3 to 5 above were selected to perform structure and thermal stability performance tests.

[0028] (1) Infrared analysis of phenolic resin composites The infrared spectrum of furfural / lignin / phenolic resin composite material is shown in Figure 1 As shown in the infrared spectrum, it can be seen that at 756 cm -1 and 818 cm -1 The CC characteristic peak of the benzene ring appears at 1101 cm -1 Appears at 1140 cm -1 and 1001 cm -1 The absorption peak of COC may be at 3384 cm -1 The characteristic peak of -OH appears at 1225 cm -1 The characteristic peaks of the infrared spectrum indicate that the synthesized product is a phenolic resin composite material. With the different substitution amounts of furfural and lignin, the intensity of the above peaks changes, but the peak positions remain basically unchanged, indicating that the structure of the composite material is basically the same, only the composition ratio of each functional group changes, and the target products are all phenolic resin composite materials.

[0029] (2) Differential scanning calorimetry Figure 2It is the DSC temperature rising curve of the infrared spectrum of the furfural / lignin / phenolic resin composite material. From the curve, it can be seen that the endothermic peak of the furfural 50 / lignin 50 / phenolic resin composite material is about 618°C, the endothermic peak of the furfural 30 / lignin 30 / phenolic resin composite material curve is about 582°C, and the endothermic peak of the furfural 50 / lignin 30 / phenolic resin composite material is about 605°C, indicating that the thermal stability of the prepared furfural / lignin / phenolic resin composite materials is good.

[0030] (3) Thermogravimetric analysis from Figure 3 It can be seen from the thermogravimetric curve of furfural / lignin / phenolic resin composites that the initial decomposition temperature (T 5% ) is about 429℃, and the initial decomposition temperature (T 5% ) is 289℃, and the initial decomposition temperature (T 5% ) is 147℃, which proves that the initial decomposition temperature (T 5% ) are relatively high. The mass residual rate at 800℃, the residual carbon rate of furfural 50 / lignin 50 / phenolic resin composite material is about 80%, the residual carbon rate of furfural 50 / lignin 30 / phenolic resin composite material is about 77.5%, and the residual carbon rate of furfural 30 / lignin 30 / phenolic resin composite material is about 75%, indicating that the furfural / lignin / phenolic resin composite material prepared by this method has good thermal stability, and with the gradual increase of the replacement amount of furfural and lignin, the thermal stability of the phenolic resin composite material is further improved.

Claims

1. A method for preparing a bio-based phenolic resin composite material, characterized in that: The steps include: S1. Preparation of 5-acetylmethoxyfurfural: adding stannous chloride and stannic chloride mixture catalyst and concentrated sulfuric acid to waste sugar residue concentrate, stirring the solution at 120° C. and performing reflux reaction for 2 to 12 hours. After the reaction is completed, the reaction solution is cooled, extracted with distilled water and dichloromethane to obtain aqueous acidic waste liquid and an extraction phase, and the extraction phase is subjected to solvent rotary evaporation and purified by a silica gel column to obtain 5-acetylmethoxyfurfural; S2, lignin activation: adding lignin powder to the aqueous acidic waste liquid extracted in step S1 and stirring the mixture at 30-100° C. for at least 24 h. After the reaction is completed, the reaction liquid is filtered to obtain activated lignin; S3, preparation of phenolic resin composite material: 5-acetylmethoxyfurfural, activated lignin and phenol are mixed and preheated at 80°C for at least 1 h, and after the solution is cooled, formaldehyde is added thereto and the solution is adjusted to neutrality using a NaOH solution; the solution is then stirred and a 1 wt% NaOH solution as a catalyst is added thereto, and the solution is reacted at 90°C for 1 h to obtain the bio-based phenolic resin composite material; The ratio of the total mass of the added 5-acetylmethoxyfurfural and formaldehyde to the total mass of the added activated lignin and phenol is 1.

5.

2. The method for preparing a bio-based phenolic resin composite material according to claim 1, characterized in that: The method for preparing the waste sugar residue concentrate described in step S1 comprises the following steps: soaking bagasse in water, with the addition amount of bagasse being 250 g / L, and obtaining the waste sugar residue concentrate by filtering and evaporating.

3. The method for preparing a bio-based phenolic resin composite material according to claim 1, characterized in that: The ratio of the added amount of the stannous chloride and stannic chloride mixture catalyst to the waste sugar residue concentrate in step S1 is 5 mg / mL; the volume ratio of the added amount of the concentrated sulfuric acid to the waste sugar concentrate is 1:

20.

4. The method for preparing a bio-based phenolic resin composite material according to claim 3, characterized in that: The mass ratio of stannous chloride to stannic chloride in step S1 is 1:0 to 0:

1.

5. The method for preparing a bio-based phenolic resin composite material according to claim 1, characterized in that: The ratio of the amount of lignin powder added to the aqueous acidic waste liquid in step S2 is 50 mg / mL.

6. The method for preparing a bio-based phenolic resin composite material according to claim 1, characterized in that: The mass of 5-acetylmethoxyfurfural added in step S3 accounts for 10% to 80% of the total mass of 5-acetylmethoxyfurfural and formaldehyde.

7. The method for preparing a bio-based phenolic resin composite material according to claim 1, characterized in that: The mass of the activated lignin added in step S3 accounts for 10% to 80% of the total mass of the activated lignin and phenol.

8. A bio-based phenolic resin composite material, characterized in that: The composite material is prepared by the method according to any one of claims 1 to 7.

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