Method for preparing porous resin micro-nano material based on lignin template method

Abstract

The invention belongs to the field of high-molecular compounds, and provides a method for preparing a porous resin micro-nano material based on a lignin template method. Lignin is used as a soft template to prepare the lignin-based phenolic resin nanosphere with a unique hollow mesoporous structure and controllable particle size. The lignin used in the invention plays a variety of roles in the synthesis of the nano material, on one hand, the lignin can partially replace 3-aminophenol to be subjected to a cross-linking reaction with formaldehyde to form a resin ball matrix material; on the other hand, lignin can serve as a'template 'to be dissolved out in subsequent ethanol treatment. The preparation method is simple and high in practicability, the lignin-based phenolic resin micro-nanospheres which are stable and controllable in particle size can be obtained, the nanospheres have unique hollow structures, multiple pore channels are formed in the shell walls of the nanospheres, and the morphology structure is obtained on phenolic resin micro-nanomaterials for the first time.

Description

Technical Field

[0001] The invention belongs to the field of polymer compounds, and in particular relates to a method for preparing porous resin micro-nano materials based on a lignin template method. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] As an important chemical material, phenolic resin is widely used in the fields of construction, energy storage, catalysis and biomedicine. Phenolic resin is a high molecular polymer prepared by polycondensation of phenolic substances and aldehyde substances (such as formaldehyde, acetaldehyde, etc.) under acid or base catalysis. Due to its high carbon-hydrogen ratio and unique aromatic ring rigid skeleton structure, phenolic resin has high thermal stability and excellent mechanical properties. Under hydrothermal synthesis conditions, phenolic resin materials can present regular micro-nanoscale spherical structures, which further expands its application.

[0004] In recent years, spherical phenolic resin micro-nanomaterials have received a lot of attention due to their excellent chemical stability and high specific surface area, especially because they contain a large number of highly active phenolic hydroxyl structures on their surface, which allows them to be used in combination with many cutting-edge materials. For example, in recent studies on catechol-based phenolic resins, the ortho-phenol structure can form a reversible chelating force with metal ions, making it show great potential in the fields of sewage treatment and biomedicine. However, the average diameter of phenolic resin nanospheres formed by the phenolic substances (such as phenol, resorcinol or catechol) commonly used in actual production and the aldehyde substances is relatively large, usually ranging from a few microns to tens of microns; and whether phenol, resorcinol or catechol is used as a reaction monomer for the synthesis of phenolic resin nanospheres, the raw material cost is too high and the particle size is too large, which brings difficulties to its commercial application. In addition, there are few reports on the morphology control of resin micro-nanomaterials, especially the research on the internal pore structure is obviously insufficient. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for preparing porous resin micro-nano materials based on the lignin template method. The present invention replaces part of 3-aminophenol with lignin to synthesize lignin-based phenolic resin micro-nanospheres, which effectively reduces the particle size of the phenolic resin micro-nanospheres. The prepared lignin-based phenolic resin nanospheres have a hollow structure and a large number of hollow mesoporous structures inside their shells.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: The first aspect of the present invention provides a method for preparing porous resin micro-nano materials based on a lignin template method, comprising: 3-aminophenol, lignin, formaldehyde, ammonia water and water are mixed evenly to carry out polycondensation reaction. After the reaction is completed, anhydrous ethanol is added to continue the reaction. After the reaction is completed, curing treatment is carried out to obtain lignin-based phenolic resin micro-nanospheres, that is, porous resin micro-nanomaterials; The temperature of the polycondensation reaction is 30°C-35°C; Wherein, the lignin accounts for 5%-40% of the total mass of 3-aminophenol and lignin, that is, the ratio of lignin replacing 3-aminophenol is 5%-40%. Preferably, the lignin accounts for 5% of the total mass of 3-aminophenol and lignin. The phenolic resin micro-nanospheres at this ratio have the best spherical morphology and yield, which is conducive to the subsequent multifunctional application of the micro-nanospheres.

[0007] Preferably, the mass ratio of lignin to water is 1-8:6×10 3 , to ensure the smooth progress of the reaction.

[0008] In the present invention, 3-aminophenol reacts with formaldehyde to generate phenolic resin nanospheres. In order to fully carry out the reaction, the present invention also studies the dosage of components such as formaldehyde. Preferably, the volume ratio of formaldehyde to ammonia water is 0.3:0.3-0.4.

[0009] If the reaction time is too short, the reaction is incomplete, and if the reaction time is too long, the reaction has reached the end point, which will increase energy consumption. Therefore, the present invention studies the reaction time, and preferably, the polycondensation reaction time is 30min-35min.

[0010] The present invention uses anhydrous ethanol to form pores and expand the volume to achieve the purpose of reducing the particle size of phenolic resin micro-nanospheres. In order to obtain a better particle size, the present invention studies the dosage of anhydrous ethanol. Preferably, the volume ratio of anhydrous ethanol to ammonia water is 120:0.3-0.4.

[0011] In order to ensure that anhydrous ethanol can fully form pores and expand the capacity of the phenolic resin micro-nanospheres, the present invention studies the reaction time. Preferably, the continued reaction time is 30 minutes to 35 minutes.

[0012] The present invention separates the prepared lignin-based phenolic resin micro-nanospheres from the liquid through a curing treatment. Therefore, preferably, the curing treatment comprises the steps of centrifugation, washing and drying.

[0013] More preferably, the washing is repeated with water and ethanol to effectively remove impurities on the surface of the lignin-based phenolic resin micro-nanospheres.

[0014] Preferably, the prepared porous resin micro-nano material has an average particle size of 90nm-350nm and a spherical structure.

[0015] Beneficial Effects of the Invention (1) Lignin is the most abundant renewable aromatic bioresource on earth. As a byproduct of bioethanol production and pulping industry, it has been commercialized. Lignin has a benzene ring skeleton similar to phenolic resin, and it contains a large number of active functional groups, including phenolic hydroxyl, carboxyl, aldehyde and methoxy. These functional groups make lignin a phenolic substitute in the synthesis of phenolic resin. Using it as a raw material for phenolic resin micro-nanomaterials can not only reduce the cost of resin synthesis, but also be green, sustainable and have huge output. In addition, it shows reaction activity in the synthesis of phenolic resin micro-nanomaterials. Using it to prepare resin micro-nanospheres meets the current requirements of green production.

[0016] (2) Compared with the phenolic resin micro-nanospheres in which 3-aminophenol is involved, the present invention uses lignin to replace part of the 3-aminophenol. Due to the hydrophilicity of lignin, it can be used as a surfactant to reduce the surface tension of the nanospheres, thereby reducing the diameter of the nanospheres, making the structure of the lignin-based phenolic resin nanospheres more stable, the nanometer size smaller, and the specific surface area larger.

[0017] (3) The preparation steps of the present invention are simple and efficient. The low-crosslinked core of the lignin-based phenolic resin nanospheres can be dissolved by only a certain amount of ethanol treatment to prepare lignin-based phenolic resin nanospheres with a hollow structure. In addition, the presence of the lignin "soft template" enables the prepared hollow resin micro-nano shell wall to have many channels.

[0018] (4) The lignin-based phenolic resin micro-nanospheres prepared by the present invention have stable chemical properties and controllable particle size. At the same time, they have a unique hollow structure with many pores on their shell wall. This morphology is the first synthesis of phenolic resin micro-nanomaterials. In addition, due to the unique hollow mesoporous structure of the lignin-based phenolic resin micro-nanospheres, they have an ultra-large specific surface area and a unique spatial effect, making the micro-nanospheres have the potential to be candidate materials such as hydrogel / membrane fillers and carbon materials, and thus play a role in the fields of catalysts, nanomaterial additives, supercapacitors, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 : Mechanism diagram of the present invention.

[0021] Figure 2: (a) zeta potential (electromotive potential) diagram of lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, (b) stability photographs of lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5 after standing in deionized water at room temperature for 5 hours, (c) dispersion stability and Tyndall effect of lignin-based phenolic resin micro-nanospheres prepared in Example 2 in solutions of different pH values; wherein 0%, 5%, 10%, 20%, and 40% correspond to the lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, respectively.

[0022] Figure 3 : (a) Real picture of lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, (b) Energy dispersive spectroscopy (EDS) element mapping image of lignin-based phenolic resin micro-nanospheres prepared in Example 2, wherein 0%, 5%, 10%, 20%, and 40% correspond to the lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, respectively, C represents carbon element, N represents nitrogen element, O represents oxygen element, and S represents sulfur element.

[0023] Figure 4 : (a)-(e) are scanning electron micrographs of the lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, respectively; (f)-(j) are transmission electron micrographs of the lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, respectively; (k)-(o) are size distributions of the lignin-based phenolic resin micro-nanospheres prepared in Examples 1-5, respectively. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0025] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0026] Example 1 Weigh 600 mg of 3-aminophenol, the ratio of lignin replacing 3-aminophenol is 0%, add 0.6 mL of 99 wt% formaldehyde solution and 0.6 mL of 25 wt% ammonia water, and mix them thoroughly in deionized water (180 mL). Then transfer the mixed solution to a water bath and heat it at 30 ° C for 30 minutes. Then add 240 mL of anhydrous ethanol and continue the reaction for 30 minutes. Finally, centrifuge the reaction solution at a speed of 9500 rpm, repeatedly rinse the solid after centrifugation with distilled water and ethanol, and dry it in a vacuum drying oven to obtain lignin-based phenolic resin micro-nanospheres.

[0027] Example 2 Weigh 570 mg of 3-aminophenol and 30 mg of lignin, with the ratio of lignin replacing 3-aminophenol being 5%, add 0.6 mL of 99 wt% formaldehyde solution and 0.6 mL of 25 wt% ammonia water, and mix them thoroughly in deionized water (180 mL). Then transfer the mixed solution to a water bath and heat it at 30 ° C for 30 min. Then add 240 mL of anhydrous ethanol and continue the reaction for 30 min. Finally, centrifuge the reaction solution at 9500 rpm, repeatedly rinse the solid after centrifugation with distilled water and ethanol, and dry it in a vacuum drying oven to obtain lignin-based phenolic resin micro-nanospheres.

[0028] Example 3 Weigh 540 mg of 3-aminophenol and 60 mg of lignin, with the ratio of lignin replacing 3-aminophenol being 10%, add 0.6 mL of 99 wt% formaldehyde solution and 0.6 mL of 25 wt% ammonia water, and mix them thoroughly in deionized water (180 mL). Then transfer the mixed solution to a water bath and heat it at 30 ° C for 30 min. Then add 240 mL of anhydrous ethanol and continue the reaction for 30 min. Finally, centrifuge the reaction solution at 9500 rpm, repeatedly rinse the solid after centrifugation with distilled water and ethanol, and dry it in a vacuum drying oven to obtain lignin-based phenolic resin micro-nanospheres.

[0029] Example 4 Weigh 480 mg of 3-aminophenol and 120 mg of lignin, with the ratio of lignin replacing 3-aminophenol being 20%, add 0.6 mL of 99 wt% formaldehyde solution and 0.8 mL of 25 wt% ammonia water, and mix them thoroughly in deionized water (180 mL). Then transfer the mixed solution to a water bath and heat it at 35 °C for 35 min. Then add 240 mL of anhydrous ethanol and continue the reaction for 35 min. Finally, centrifuge the reaction solution at 9500 rpm, repeatedly rinse the solid after centrifugation with distilled water and ethanol, and dry it in a vacuum drying oven to obtain lignin-based phenolic resin micro-nanospheres.

[0030] Example 5 Weigh 360 mg of 3-aminophenol and 240 mg of lignin, with the ratio of lignin replacing 3-aminophenol being 40%, add 0.6 mL of 99 wt% formaldehyde solution and 0.6 mL of 25 wt% ammonia water, and mix them thoroughly in deionized water (180 mL). Then transfer the mixed solution to a water bath and heat it at 30 ° C for 30 min. Then add 240 mL of anhydrous ethanol and continue the reaction for 30 min. Finally, centrifuge the reaction solution at 9500 rpm, repeatedly rinse the solid after centrifugation with distilled water and ethanol, and dry it in a vacuum drying oven to obtain lignin-based phenolic resin micro-nanospheres.

[0031] The morphology and properties of the lignin-based phenolic resin micro-nanospheres of Examples 1-5 are shown in Table 1: Table 1 Morphology and properties of lignin-based phenolic resin micro-nanospheres of Examples 1-5

[0032] The principle diagram of the present invention is as follows Figure 1 As shown by Figure 2-Figure 4 It can be seen that the lignin-based phenolic resin micro-nanospheres prepared from 3-aminophenol, lignin and formaldehyde have uniform size and good spherical structure.

[0033] From Table 1 and Figure 4 From the comparison between f and g, it can be seen that after partially replacing 3-aminophenol with lignin, the prepared hollow resin micro-nano shell wall has many pores, the specific surface area and total pore volume are significantly improved, and the particle size of the lignin-based phenolic resin micro-nanospheres is also significantly reduced.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing porous resin micro-nano materials based on lignin template method, characterized in that: include: 3-aminophenol, lignin, formaldehyde, ammonia water and water are mixed evenly to carry out polycondensation reaction. After the reaction is completed, anhydrous ethanol is added to continue the reaction. After the reaction is completed, curing treatment is carried out to obtain lignin-based phenolic resin micro-nanospheres, that is, porous resin micro-nanomaterials; Wherein, the lignin accounts for 5%-40% of the total mass of 3-aminophenol and lignin; The temperature of the polycondensation reaction is 30°C-35°C.

2. The method for preparing porous resin micro-nano materials based on the lignin template method according to claim 1, characterized in that: The mass ratio of lignin to water is 1-8:6×10 3 .

3. The method for preparing porous resin micro-nano materials based on the lignin template method according to claim 1, characterized in that: The volume ratio of the formaldehyde to the ammonia water is 0.3:0.3-0.

4.

4. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 1, characterized in that: The polycondensation reaction time is 30 min-35 min.

5. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 1, characterized in that: The volume ratio of the anhydrous ethanol to the ammonia water is 120:0.3-0.

4.

6. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 1, characterized in that: The time for the continued reaction is 30 min-35 min.

7. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 1, characterized in that: The steps of the solidification treatment include: centrifugation, washing and drying.

8. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 7, characterized in that: The washing is performed by repeatedly rinsing with water and ethanol.

9. The method for preparing porous resin micro-nano materials based on lignin template method according to claim 1, characterized in that: The prepared porous resin micro-nano material has an average particle size of 90nm-350nm and a spherical structure.

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