阅读说明：本技术 一种基于石墨烯的水性环氧树脂乳液的制备方法 (Preparation method of graphene-based waterborne epoxy resin emulsion ) 是由 程浩源 于 2020-07-15 设计创作，主要内容包括：本发明公开一种基于石墨烯的水性环氧树脂乳液的制备方法,称取如下重量份原料：10-15份改性石墨烯,3-5份乳化剂,35-50份环氧树脂,5-10份聚乙二醇,120-150份丙二醇甲醚,20-30份去离子水,1-2份三氟化硼,1-3份流平剂；该改性石墨烯本身具有物理阻隔作用,当该乳液用于漆膜燃烧时可以减少热量传递和可燃性气体挥发,而且能够形成碳层,保护基体不被燃烧,赋予该乳液优异的阻燃性能；解决了石墨烯之间存在超强的范德华力和共轭作用力,容易形成三维结构,使其在有机相以及水相溶剂中分散性较差的技术问题。(The invention discloses a preparation method of a graphene-based waterborne epoxy resin emulsion, which comprises the following raw materials in parts by weight: 10-15 parts of modified graphene, 3-5 parts of an emulsifier, 35-50 parts of epoxy resin, 5-10 parts of polyethylene glycol, 120-150 parts of propylene glycol methyl ether, 20-30 parts of deionized water, 1-2 parts of boron trifluoride and 1-3 parts of a flatting agent; the modified graphene has a physical barrier effect, can reduce heat transfer and combustible gas volatilization when the emulsion is used for paint film combustion, can form a carbon layer to protect a substrate from being combusted, and endows the emulsion with excellent flame retardant property; the method solves the technical problems that the graphene has super van der Waals force and conjugate acting force, is easy to form a three-dimensional structure and has poor dispersibility in organic phase and aqueous phase solvents.)

1. A preparation method of a graphene-based waterborne epoxy resin emulsion is characterized by comprising the following steps:

firstly, weighing the following raw materials in parts by weight: 10-15 parts of modified graphene, 3-5 parts of an emulsifier, 35-50 parts of epoxy resin, 5-10 parts of polyethylene glycol, 120-150 parts of propylene glycol methyl ether, 20-30 parts of deionized water, 1-2 parts of boron trifluoride and 1-3 parts of a flatting agent;

secondly, adding epoxy resin into a beaker filled with propylene glycol monomethyl ether, heating in water bath at 60-65 ℃ and stirring at constant speed until a transparent solution is formed, then adding an emulsifier and polyethylene glycol, and continuing stirring for 30 min;

and thirdly, adding boron trifluoride and modified graphene, cooling to 30-35 ℃, uniformly stirring for 10min, heating to 85 ℃, reacting for 2h at the temperature, cooling to 60 ℃, dropwise adding deionized water, controlling the dropwise adding time to be 1h, uniformly stirring, reacting for 30min, adding a leveling agent, and uniformly mixing to obtain the graphene-based waterborne epoxy resin emulsion.

2. The method for preparing the graphene-based aqueous epoxy resin emulsion according to claim 1, wherein the leveling agent is one or both of BD-3307 and GSK-550.

3. The preparation method of the graphene-based aqueous epoxy resin emulsion according to claim 1, wherein the modified graphene is prepared from the following raw materials in parts by weight: 10-15 parts of graphene, 5-8 parts of sodium nitrate, 100-containing 150 parts of 98% concentrated sulfuric acid, 1-2 parts of potassium chlorate, 20-30 parts of 10% aqueous hydrogen peroxide, 180-containing 200 parts of maleic anhydride, 15-20 parts of 1-hydroxybenzotriazole, 100-containing 150 parts of dimethylformamide and 3-10 parts of dicyclohexylcarbon.

4. The preparation method of the graphene-based aqueous epoxy resin emulsion according to claim 3, wherein the modified graphene is prepared by the following method:

(1) grinding graphene, adding the ground graphene into a beaker, adding sodium nitrate and 98% concentrated sulfuric acid, stirring in an ice bath for 15min, then adding potassium chlorate, heating in a water bath at 45 ℃, reacting for 2-3h at the temperature, adding deionized water, heating to 75 ℃, reacting for 30min, adding 10% aqueous hydrogen peroxide, and continuing to react for 5-8min to obtain a graphene oxide solution;

(2) adding maleic anhydride into deionized water, heating to melt, transferring into a graphene oxide solution, stirring at a rotating speed of 120r/min for 3 hours, adding distilled water, heating to 65-70 ℃, stirring and reacting at the temperature for 10 hours, condensing, refluxing and drying to obtain treated graphene oxide;

(3) adding the treated graphene oxide and 1-hydroxybenzotriazole into dimethylformamide for uniform dispersion, then adding dicyclohexyl carbon, introducing nitrogen, heating in an oil bath at 80-85 ℃, reacting for 40-45h at the temperature, filtering, washing with absolute ethyl alcohol for three times, and drying at 50-60 ℃ for 8-10h to obtain the modified graphene.

5. The preparation method of the graphene-based aqueous epoxy resin emulsion according to claim 1, wherein the emulsifier is prepared by the following method:

step S1, adding epoxy resin and propylene glycol monomethyl ether into a three-neck flask, heating in a water bath at 45-50 ℃, magnetically stirring at a rotating speed of 140-;

step S2, adding polyethylene glycol diglycidyl ether into the mixed solution A prepared in the step S1, uniformly mixing, then dropwise adding ethanolamine, controlling the dropwise adding speed to be 0.5-1mL/min, continuously stirring for 30imn after the dropwise adding is finished, then heating to 75-80 ℃, reacting for 3-3.5h at the temperature, cooling to 55-60 ℃ after the reaction is finished, adding glacial acetic acid, and reducing pressure and distilling to prepare the emulsifier.

6. The method for preparing the graphene-based waterborne epoxy resin emulsion according to claim 5, wherein the weight ratio of the mixed solution A, the polyethylene glycol diglycidyl ether, the ethanolamine and the glacial acetic acid is controlled to be 100: 2: 3: 2-3 in the step S2.

Technical Field

The invention belongs to the technical field of epoxy resin emulsion preparation, and particularly relates to a preparation method of a graphene-based waterborne epoxy resin emulsion.

Background

Due to the excellent physical and mechanical properties of the epoxy resin, such as good adhesion, good chemical resistance, excellent solvent resistance, high hardness, good wear resistance and the like, the epoxy resin is widely applied to military use, civil use, industrial maintenance and the like, and particularly is widely applied in the field of coating industry. In order to effectively replace the common solvent-based epoxy resin coating, people continuously develop and research the water-based epoxy resin emulsion, and the common water-based epoxy resin emulsion is obtained by a method of adding an emulsifier, namely, the resin is dispersed in a water phase by external force in the presence of the emulsifier, but the method has the limitations, such as higher requirement on production equipment, high-speed dispersion equipment, larger particle size, and less ideal storage stability and application performance. At present, how to obtain a water-based epoxy resin system with high performance, good stability and rapid curing has become a great hot point of research.

Chinese patent CN101402739A discloses a method for producing aqueous epoxy resin emulsion, which comprises preparing aqueous epoxy resin emulsion by phase inversion method, dispersing the prepared epoxy resin emulsion with high-speed disperser, crushing and grinding with colloid mill, and emulsifying under high pressure with homogenizer. The dispersing speed of the high-speed dispersing machine is 100-140 r/min. Grinding with colloid mill at rotation speed of 2500-. Emulsifying under high pressure in a homogenizer at 30-100MPa for 0.5-1.5 h. The aqueous epoxy resin emulsion obtained by the invention has excellent performance: the effect of the centrifugal stability was 3000 rpm, and no separation occurred in 30 minutes.

Disclosure of Invention

In order to overcome the technical problems, the invention provides a preparation method of a graphene-based waterborne epoxy resin emulsion.

The technical problems to be solved by the invention are as follows:

(1) superstrong van der waals force and conjugate force exist between the graphene, so that a three-dimensional structure is easily formed, and the graphene is poor in dispersibility in an organic phase and a water phase solvent;

(2) in the prior art, the particle size of the emulsion cannot be controlled in the preparation process of the epoxy resin emulsion, the emulsion has poor stability due to uneven particle size distribution, the amine hydrogen and the epoxy group of the ethanolamine are converted into tertiary amine through ring opening, and the tertiary amine can promote the epoxy group to generate ring opening crosslinking, so that the epoxy group is gelatinized in the reaction process of a system.

The purpose of the invention can be realized by the following technical scheme:

a preparation method of a graphene-based waterborne epoxy resin emulsion comprises the following steps:

firstly, weighing the following raw materials in parts by weight: 10-15 parts of modified graphene, 3-5 parts of an emulsifier, 35-50 parts of epoxy resin, 5-10 parts of polyethylene glycol, 120-150 parts of propylene glycol methyl ether, 20-30 parts of deionized water, 1-2 parts of boron trifluoride and 1-3 parts of a flatting agent;

secondly, adding epoxy resin into a beaker filled with propylene glycol monomethyl ether, heating in water bath at 60-65 ℃ and stirring at constant speed until a transparent solution is formed, then adding an emulsifier and polyethylene glycol, and continuing stirring for 30 min;

and thirdly, adding boron trifluoride and modified graphene, cooling to 30-35 ℃, uniformly stirring for 10min, heating to 85 ℃, reacting for 2h at the temperature, cooling to 60 ℃, dropwise adding deionized water, controlling the dropwise adding time to be 1h, uniformly stirring, reacting for 30min, adding a leveling agent, and uniformly mixing to obtain the graphene-based waterborne epoxy resin emulsion.

Further, the leveling agent is one or two of BD-3307 and GSK-550.

Further, the modified graphene is prepared from the following raw materials in parts by weight: 10-15 parts of graphene, 5-8 parts of sodium nitrate, 100-150 parts of 98% concentrated sulfuric acid by mass fraction, 1-2 parts of potassium chlorate, 20-30 parts of 10% aqueous hydrogen peroxide by mass fraction, 180-200 parts of maleic anhydride, 15-20 parts of 1-hydroxybenzotriazole, 100-150 parts of dimethylformamide and 3-10 parts of dicyclohexylcarbon.

Further, the modified graphene is prepared by the following method:

(1) grinding graphene, adding the ground graphene into a beaker, adding sodium nitrate and 98% concentrated sulfuric acid, stirring in an ice bath for 15min, then adding potassium chlorate, heating in a water bath at 45 ℃, reacting for 2-3h at the temperature, adding deionized water, heating to 75 ℃, reacting for 30min, adding 10% aqueous hydrogen peroxide, and continuing to react for 5-8min to obtain a graphene oxide solution;

(2) adding maleic anhydride into deionized water, heating to melt, transferring into a graphene oxide solution, stirring at a rotating speed of 120r/min for 3 hours, adding distilled water, heating to 65-70 ℃, stirring and reacting at the temperature for 10 hours, condensing, refluxing and drying to obtain treated graphene oxide;

(3) adding the treated graphene oxide and 1-hydroxybenzotriazole into dimethylformamide for uniform dispersion, then adding dicyclohexyl carbon, introducing nitrogen, heating in an oil bath at 80-85 ℃, reacting for 40-45h at the temperature, filtering, washing with absolute ethyl alcohol for three times, and drying at 50-60 ℃ for 8-10h to obtain the modified graphene.

The method comprises the following steps that (1) superstrong van der Waals force and conjugate acting force exist among graphene, a three-dimensional structure is easy to form, and the dispersibility of the graphene in an organic phase and an aqueous phase solvent is poor, graphene oxide is prepared from the graphene under the action of potassium chlorate, 10% hydrogen peroxide water solution and the like, the graphene oxide can be dispersed in water and can also be dispersed in the organic solvent, and rich oxygen-containing functional groups are added on the surface of the graphene oxide, so that the graphene oxide is not easy to agglomerate; and (3) mixing maleic anhydride and the prepared graphene oxide for reaction in the step (2) to obtain the treated graphene oxide, wherein hydroxyl on the surface of the graphene oxide is modified into carboxyl by the maleic anhydride, adding 1-hydroxybenzotriazole in the step (3), using dimethylformamide as a solvent, and reacting the hydroxyl on the 1-hydroxybenzotriazole with the carboxyl on the surface of the treated graphene oxide to form an ester bond to obtain the modified graphene.

Further, the emulsifier is prepared by the following method:

step S1, adding epoxy resin and propylene glycol monomethyl ether into a three-neck flask, heating in a water bath at 45-50 ℃, magnetically stirring at a rotating speed of 140-;

step S2, adding polyethylene glycol diglycidyl ether into the mixed solution A prepared in the step S1, uniformly mixing, then dropwise adding ethanolamine, controlling the dropwise adding speed to be 0.5-1mL/min, continuously stirring for 30imn after the dropwise adding is finished, then heating to 75-80 ℃, reacting for 3-3.5h at the temperature, cooling to 55-60 ℃ after the reaction is finished, adding glacial acetic acid, and reducing pressure and distilling to prepare the emulsifier.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.