CN114835896A - Preparation method of monodisperse polyesteramine microspheres - Google Patents

Abstract

The invention discloses a preparation method of monodisperse polyesteramine microspheres, which takes polyamine and acid ester as reaction monomers and is prepared by aza-Michael addition precipitation polymerization in a solvent. The method has the advantages of simple operation, low production cost and low energy consumption. The method of the invention does not need any emulsifier, stabilizer or catalyst, and the obtained microspheres have clean surfaces. The surface of the microsphere contains a large number of alpha, beta unsaturated carbonyl groups, and the microsphere can be subjected to grafting reaction with an adhesive containing an acrylate group under UV irradiation, and can be directly used as a toughening filler of a UV curing adhesive without other coupling agents.

Description

Preparation method of monodisperse polyesteramine microspheres

Technical Field

The invention relates to the technical field of functional polymer materials, in particular to a preparation method of monodisperse polyesteramine microspheres.

Background

The solid content of the solvent-based adhesive is about 30-50%, and a large amount of organic solvent is needed, so that the problem of environmental pollution is prominent, the solid content of the emulsion-type adhesive is about 55%, water is used as a dispersion medium, but the water resistance of the emulsion-type adhesive is poor, and although no medium is used in the hot melt adhesive, the hot melt adhesive has poor heat resistance and solvent resistance, and is easy to implode. The novel adhesive which does not use an organic solvent and can avoid the defects of poor water resistance, heat resistance, poor solvent resistance and easy implosion of the common emulsion adhesive has become the object pursued by the industry. The UV curing adhesive is prepared by uniformly coating a mixture consisting of polymerizable monomers, oligomers or polymer elastomers, tackifying resin photoinitiators, anti-aging agents and other additives on a base material, and irradiating the coating by high-energy rays (ultraviolet rays or electron beams) with a certain dose to polymerize, crosslink and cure the coating, thereby obtaining adhesive products with various properties. The UV curing adhesive is environment-friendly, pollution-free and energy-saving green adhesive.

The filler is an essential component of the adhesive, so that the mechanical property of the adhesive is improved, the stress of a glue joint is reduced, the cost is reduced, the shrinkage rate is reduced, and a new function is endowed to the adhesive. Most of the fillers are inorganic micro-nano particles such as white carbon black, calcium carbonate and the like, the fillers are poor in compatibility with adhesive matrixes and poor in dispersibility, stress concentration points are often generated, the use performance of the adhesives is affected, and the inorganic fillers have to be modified by coupling agents.

Aiming at the problems, the preparation of the polymer micro-nano particle with the surface rich in the groups which can be excited by UV and can perform free radical reaction with the acrylate group has important research value and practical application value. The polymer microsphere not only has a designable chemical structure and composition, but also has good compatibility with an adhesive matrix. Since no stabilizer or surfactant is added during the polymerization process, the precipitation polymerization can prepare monodisperse polymer microspheres with clean surfaces. For this purpose, polyamine and acid ester are used as reaction monomers, and a series of monodisperse polyesteramine microspheres which can be used for UV curing adhesive fillers are prepared in a solvent through aza-Michael addition precipitation polymerization.

Disclosure of Invention

The invention aims to provide a preparation method of monodisperse polyesteramine microspheres. The preparation method of the monodisperse polyesteramine microsphere is characterized in that the monodisperse polyesteramine microsphere (polyester-amine microsphere) for the UV curing adhesive toughening filler is prepared by precipitation polymerization; the method does not need any emulsifier, stabilizer or catalyst and other components, and directly adds the polyamine and acid ester (polybasic acrylic ester) monomer into the solvent for precipitation polymerization, so that the method has the advantages of simple steps, very clean microspheres, and good surface cleanness and dispersibility of the prepared monodisperse polyesteramine microspheres, enables the surfaces of the prepared polyesteramine microspheres to have unsaturated carbonyl compounds, provides good active sites for subsequent UV curing, and has high thermal stability.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a preparation method of monodisperse polyesteramine microspheres comprises the following steps:

1) dissolving polyamine and polyacrylate in a reaction medium (organic solvent) according to the mol ratio of amino groups to double bonds, and standing at a controlled temperature to carry out gradual precipitation polymerization;

2) centrifuging to remove the organic solvent, and drying in vacuum to obtain monodisperse polyesteramine microspheres;

the total adding amount of the polyamine and the polyacrylate monomer accounts for 1-30% of the total mass of the reaction system;

dissolving the polyamine and the polyacrylate in an organic solvent according to the molar ratio of amino groups to double bonds, wherein the molar ratio (-NH/C ═ C) of imine groups in the polyamine to carbon-carbon double bonds in the polyacrylate is 0.5-1.7: 0.5-1.7.

Preferably, after the acid ester and the polyamine monomer are dissolved in a reaction medium, sealing a reaction system, and carrying out polymerization reaction at the temperature of 0-50 ℃ and the oscillation frequency of 0-150 osc/min; after the reaction is finished, performing centrifugal separation or suction filtration on the product, washing and drying the obtained solid to obtain the monodisperse polyester-amine microsphere.

Preferably, the polyamine is selected from one of the following: ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, piperazine, hexamethylenediamine, diethylenediamine, toluenediamine.

Preferably, the polyacrylate is selected from the group consisting of one or more of the following: propane trimethacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, hydroxymethyl acrylate, trimethylpropane triacrylate.

Preferably, the reaction medium is a mixture of any one or more of water, acetone and acetonitrile.

More preferably, the reaction medium is acetonitrile. The use of the reaction medium can completely dissolve the acid ester and the polyamine monomer, thereby improving the yield.

Preferably, the total adding amount of the polyamine and the polyacrylate monomer accounts for 2-25% of the total mass of the reaction system.

Preferably, the polyamine and the polyacrylate are dissolved in the organic solvent according to the molar ratio of the amino group to the double bond, and the molar ratio (-NH/C ═ C) of the imine group in the polyamine to the carbon-carbon double bond in the polyacrylate is 0.7 to 1.5: 0.7 to 1.5.

Preferably, the polymerization temperature of the precipitation polymerization is 0-50 ℃, and the vibration frequency in the reaction process is 0-150 osc/min.

Preferably, the polymerization reaction time is 5-150 min; more preferably, the polymerization reaction time is 10 to 30 min.

Preferably, after the polymerization reaction of the precipitation polymerization is finished, performing suction filtration on the product, or adding the product into a centrifugal tube, centrifuging for 2-8 min at the speed of 5000-20000 r/min, washing the obtained solid with acetone or acetonitrile for 2-3 times, and drying at the temperature of 70-100 ℃ for 2-8 h to obtain the monodisperse polyester-amine microsphere.

Preferably, the preparation method is as follows:

adding 15-70 g of reaction medium into a reaction container at room temperature, wherein the reaction medium is any one or a mixture of water, acetone and acetonitrile; respectively adding 10-30 g of diethylene diamine and trimethylolpropane triacrylate with the molar ratio of-NH/C to C being 0.5-1.7: 0.5-1.7 to ensure that the total mass of the system reaches 100 g; then, sealing the reaction bottle and standing at room temperature for 10-30 min; the product was filtered with suction to remove the supernatant, and the resulting solid was washed twice with acetone or acetonitrile and dried to constant weight at 50 ℃.

Preferably, at room temperature, a reaction flask is charged with 15 to 70g of a reaction medium comprising acetonitrile, and then 10 to 30g of diethylene diamine and trimethylolpropane triacrylate at a molar ratio of-NH/C to C of 1: 1 are added thereto, respectively, to thereby obtain a total mass of 100 g. And then, sealing the reaction bottle, placing the reaction bottle in a refrigerator storage room, and reacting for 10-30 min under the condition that the temperature is 4 ℃ and standing still. And (3) carrying out suction filtration on the product to remove supernatant, washing the obtained solid twice with acetone or acetonitrile, and drying at 70 ℃ for 5 hours to obtain the monodisperse polyester-amine microspheres.

In the invention, the obtained monodisperse polyesteramine microsphere has an average particle size of 3.0-5.0 μm and a particle size polydispersity of 1.006-1.201. The yield of the obtained monodisperse polyester-amine microspheres is 50.0-80.0%.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the invention takes diethylene diamine and trimethylolpropane triacrylate as monomers to prepare monodisperse polyester-amine microspheres by precipitation polymerization in acetonitrile solvent. The method is simple to operate, and does not need any emulsifier, stabilizer, catalyst and other components, and the obtained microspheres are very clean.

Compared with the existing precipitation polymerization system, the invention has the most outstanding characteristics that the amine-alkene reaction is successfully used for preparing the polymer microspheres, and simultaneously, the polymer microspheres are used as a carrier for toughening the UV curing adhesive. The PEA microspheres have a multi-cell adhesion phenomenon due to the fact that the reaction rate is too high when the monomer addition amount is too large or the temperature is high, and are non-uniform due to the fact that the reaction rate is slow when the monomer addition amount is small or the temperature is low, the time for forming primary particles is long. Specific reaction conditions need to be selected to make it possible to obtain novel monodisperse polyesteramine microspheres. Therefore, the monomer addition and the reaction temperature are the key to the preparation of the novel monodisperse polyesteramine microspheres according to the invention. The present inventors have surprisingly found that novel monodisperse polyesteramine microspheres can be prepared when diethylene diamine and trimethylolpropane triacrylate are used in a specific ratio and acetonitrile is used as the reaction medium, whereas the microspheres do not exhibit a good morphology when reacted in other molar ratios.

The method of the invention prepares the microsphere with clean surface and good dispersibility, and does not need any stirring and oscillating equipment in the polymerization process, so the production cost and the energy consumption are lower, which are another remarkable characteristic of the invention. The characterization of the particles in the polymerization process of the method shows that the prepared polyesteramine microsphere can be modified by controlling the molar ratio of the added monomers, so that the surface of the prepared polyesteramine microsphere has C ═ C active groups, and a good active site is provided for subsequent UV curing. Through the discussion of the stirring speed or the oscillation frequency, the method is found to be capable of preparing the monodisperse polyesteramine microsphere under the condition of standing without stirring, so that the method gets rid of the dependence on stirring or oscillation equipment, and the production cost and the energy consumption are also obviously reduced. From the above, the present invention enables the cost and efficiency of preparing monodisperse microspheres to be significantly improved.

Compared with the prior art, the method has the following advantages:

1. the preparation of the monodisperse polyesteramine microsphere in the prior art is complex in steps and harsh in conditions, and needs to add components such as an emulsifier, a stabilizer, a catalyst and the like, and the substances are difficult to remove after being adsorbed on the surface of the microsphere, so that the application and development of the polyesteramine polymer microsphere are limited, especially in the fields of biology, medicine and the like. The method prepares the monodisperse polyester-amine microspheres by precipitation polymerization, has simple operation, does not need any emulsifier, stabilizer, catalyst and other components, and the obtained microspheres are very clean and can be used in the fields of biological medicine and the like.

2. The polymer microsphere surface obtained when the existing precipitation polymerization technology is used for preparing the monodisperse polyesteramine microsphere does not contain or hardly contains UV active groups. The monodisperse polyesteramine microsphere prepared by the invention contains a large amount of controllable UV active groups on the surface.

3. The existing precipitation polymerization technology needs to react under the condition of standing when preparing the monodisperse polyesteramine microsphere. Meanwhile, in the reaction process, the reaction bottle is sealed and placed at room temperature without any stirring or oscillating equipment, and the method has the characteristics of high production efficiency, low production cost and low energy consumption.

4. The invention can adjust and control the particle size of the obtained monodisperse polyesteramine microsphere by changing the adding amount of the diethylene diamine and the trimethylolpropane triacrylate, the reaction temperature, the reaction time and other conditions, thereby meeting the requirements of different occasions on the microsphere.

Drawings

FIG. 1 is a scanning electron micrograph of monodisperse polyesteramine microspheres obtained in example 1.

FIG. 2 is a scanning electron micrograph of monodisperse polyesteramine microspheres of example 4.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present invention, the following description of the preferred embodiments of the present invention is provided in connection with specific examples, which should not be construed as limiting the present patent.

The test methods or test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials, unless otherwise indicated, are conventionally obtained commercially or prepared by conventional methods.

Room temperature: having a meaning well known in the art, typically 25. + -. 2 ℃.

Unless otherwise specified, "%" in the present application is defined as mass%.

The morphology of the obtained monodisperse polyesteramine microspheres was observed using a scanning electron microscope model QuantaFEG-250 from FEI usa. The particle diameters of at least 100 microspheres were measured from the electron micrograph, and the average particle diameter (D) of the microspheres was calculated according to the following formula _n ) And its polydispersity index (D) _w /D _n )：

Wherein D is _n Is the number average particle diameter of the microspheres, D _w Is the weight average particle diameter, k is the total number of microspheres measured, D _i Is the particle size of the i-th microsphere, n _i Has a particle diameter of D _i The number of microspheres of (a).

Example 1.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ to be kept stand for reaction for 12 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the resulting polyester-amine microspheres was 72.44%, and the scanning electron micrograph of the microspheres is shown in FIG. 1, from which it was found that the average particle diameter of the microspheres was 4.52. mu.m, and the particle diameter polydispersity index was 1.011.

Example 2.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is taken as a reaction solvent, monomer TMPTA0.9398 g and piperazine 0.2602g are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ for standing reaction for 12h and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 69.88%, the average particle size of the microspheres was 4.01 μm, and the polydispersity of the particle size was 1.025.

Example 3.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 30 ℃ to be kept stand for reaction for 12 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 67.43%, the average particle size of the microspheres was 3.47 μm, and the particle size polydispersity was 1.046.

Example 4.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is taken as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix all the components, and the reaction bottle is placed at 10 ℃ for standing reaction for 12h and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the resulting polyester-amine microspheres was 71.20%, and the scanning electron micrograph of the microspheres is shown in FIG. 2, from which it was found that the microspheres had an average particle diameter of 3.54 μm and a particle diameter polydispersity of 1.014.

Example 5.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is taken as a reaction solvent, monomer TMPTA0.8522 g and piperazine 0.2477g are added, the adding amount accounts for 5.5 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix all the components, and the reaction bottle is placed in a refrigerator chamber at 4 ℃ for standing reaction for 12h and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 67.62%, the average particle size of the microspheres was 4.20 μm, and the particle size polydispersity was 1.013.

Example 6.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is taken as a reaction solvent, monomer TMPTA 1.0072g and piperazine 0.2928g are added, the adding amount accounts for 6.5 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix all the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ to be kept stand for reaction for 12 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 73.36%, the average particle size of the microspheres was 4.07 μm, and the polydispersity of the particle size was 1.037.

Example 7.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ to be kept stand for reaction for 13h and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 72.56%, the average particle size of the microspheres was 4.56 μm, and the polydispersity of the particle size was 1.016.

Example 8.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ for standing reaction for 15h and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The yield of the obtained polyester-amine microspheres was 72.61%, the average particle size of the microspheres was 4.55 μm, and the polydispersity of the particle size was 1.023.

Comparative example 1.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ to be kept stand for reaction for 5 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

This comparative example polymerization time was too short and many of the oligomers remained in the solvent without being captured by the primary particles, resulting in a decrease in particle size, thereby rendering the spheres sticky and defective in the separation process.

Comparative example 2.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is used as a reaction solvent, monomer TMPTA0.6198 g and piperazine 0.1802g are added, the addition amount accounts for 4 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix the components, and the reaction bottle is placed in a refrigerator storage room at 4 ℃ to be kept stand for reaction for 12 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The comparative example had too low a monomer concentration, had a longer clouding time, and the nucleation time of the microspheres in the system was longer, resulting in poor PEA uniformity.

Comparative example 3.

At room temperature, in a 30mL glass reaction bottle, 18.8g of acetonitrile is taken as a reaction solvent, 0.9678 g of monomer TMPTA and 0.2322g of piperazine are added, the addition amount accounts for 6 wt% of the total mass of the system, the reaction bottle is sealed and shaken to uniformly mix all the components, and the reaction bottle is placed in a refrigerator storage room at the temperature of-18 ℃ for standing reaction for 12 hours and then taken out. And (3) carrying out suction filtration on the product, washing the obtained solid for 3 times by using an acetonitrile solution, and drying the solid in a forced air drying oven at 70 ℃ to constant weight to obtain the PEA microspheres.

The comparative example has the advantages of low polymerization reaction temperature, slow reaction rate, long nucleation period and different particle sizes of the formed microspheres.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.

Claims (9)

1. A preparation method of monodisperse polyesteramine microspheres is characterized by comprising the following steps:

1) dissolving polyamine and polyacrylate in a reaction medium (organic solvent) according to the mol ratio of amino groups to double bonds, and standing at a controlled temperature to carry out gradual precipitation polymerization;

2) centrifuging to remove the organic solvent, and drying in vacuum to obtain monodisperse polyesteramine microspheres;

the total adding amount of the polyamine and the polyacrylate monomer accounts for 1-30% of the total mass of the reaction system;

dissolving the polyamine and the polyacrylate in an organic solvent according to the molar ratio of amino groups to double bonds, wherein the molar ratio (-NH/C ═ C) of imine groups in the polyamine to carbon-carbon double bonds in the polyacrylate is 0.5-1.7: 0.5-1.7.

2. A process for the preparation of monodisperse polyesteramine microspheres as claimed in claim 1, wherein the polyamine is selected from one of the following: ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, piperazine, hexamethylenediamine, diethylenediamine, toluenediamine.

3. A process for the preparation of monodisperse polyesteramine microspheres as claimed in claim 1, wherein the polyacrylate is selected from the group consisting of one or more of the following: propane trimethacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, hydroxymethyl acrylate, trimethylpropane triacrylate.

4. The method of claim 1, wherein the reaction medium is a mixture of one or more of water, acetone, and acetonitrile.

5. The method for preparing monodisperse polyesteramine microspheres as claimed in claim 1, wherein the total amount of polyamine and polyacrylate monomer added is 2-25% of the total mass of the reaction system.

6. The method for preparing monodisperse polyesteramine microspheres according to claim 1, wherein the molar ratio of the amine group in the polyamine to the carbon-carbon double bond in the polyacrylate (-NH/C ═ C) is 0.7 to 1.5: 0.7 to 1.5.

7. The method for preparing monodisperse polyesteramine microspheres as claimed in claim 1, wherein the polymerization temperature of precipitation polymerization is 0-50 ℃, and the vibration frequency during the reaction process is 0-150 osc/min.

8. The preparation method of the monodisperse polyesteramine microsphere as claimed in claim 1, wherein after the polymerization reaction of the precipitation polymerization is completed, the product is filtered, or the product is added into a centrifuge tube and centrifuged at 5000-20000 r/min for 2-8 min, the obtained solid is washed with acetone or acetonitrile for 2-3 times and dried at 70-100 ℃ for 2-8 h.

9. The method of claim 1, wherein the method comprises the following steps:

adding 15-70 g of reaction medium into a reaction container at room temperature, wherein the reaction medium is any one or a mixture of water, acetone and acetonitrile; respectively adding 10-30 g of diethylene diamine and trimethylolpropane triacrylate with the molar ratio of-NH/C ═ C being 0.5-1.7: 0.5-1.7 to make the total mass of the system reach 100 g; then, sealing the reaction bottle and standing at room temperature for 10-30 min; the product was filtered with suction to remove the supernatant, and the resulting solid was washed twice with acetone or acetonitrile and dried to constant weight at 50 ℃.

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