阅读说明：本技术 氨基化go/环糊精改性水性环氧树脂防腐涂料 (Amination GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint ) 是由 杨建军 陈虹雨 吴庆云 吴明元 张建安 刘久逸 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种氨基化GO/环糊精改性水性环氧树脂防腐涂料,涉及一种涂料,包括先用聚乙烯亚胺(PEI)改性氧化石墨烯(GO),然后将环糊精(β-CD)接枝到GO表面,制成石墨烯基容器,在此基础上,将缓蚀剂2-巯基苯并噻唑(MBT)装载到容器中,将包覆MBT缓蚀剂的石墨烯基容器(PGCd-MBT)嵌入到水性环氧树脂(EP)基体中,合成了一种新型防腐涂料。本发明的水性环氧树脂防腐涂料结合环糊精的包覆性质和氧化石墨烯纳米片的抗渗性质,所制备的PGCd-MBT复合涂层同时具有自愈性和抗渗性双重功能,可实现可长效防腐的水性环氧树脂涂料,且具有合成工艺简单,原料易得,反应条件易于控制、稳定性好等特点。可广泛应用于工业,建筑等各防腐领域。(The invention discloses an aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive coating, and relates to a coating, wherein a Graphene Oxide (GO) is modified by Polyethyleneimine (PEI), cyclodextrin (beta-CD) is grafted to the surface of the GO to prepare a graphene-based container, on the basis, 2-Mercaptobenzothiazole (MBT) serving as a corrosion inhibitor is loaded into the container, and the graphene-based container (PGCd-MBT) coated with the MBT corrosion inhibitor is embedded into a waterborne epoxy resin (EP) matrix to synthesize a novel anticorrosive coating. The aqueous epoxy resin anticorrosive paint disclosed by the invention combines the coating property of cyclodextrin and the anti-permeability property of graphene oxide nanosheets, the prepared PGCd-MBT composite coating has dual functions of self-healing property and anti-permeability property, can realize a long-acting anticorrosive aqueous epoxy resin paint, and has the characteristics of simple synthesis process, easiness in obtaining raw materials, easiness in controlling reaction conditions, good stability and the like. Can be widely applied to various anticorrosion fields such as industry, building and the like.)

1. An aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint is characterized in that the preparation method of the anticorrosive paint comprises the following steps:

step 1, preparing graphene oxide which is called GO for short;

step 2, preparing aminated GO/cyclodextrin abbreviated as PGCd;

step 3, preparing a dispersion liquid with the PGCd concentration of 1mg/mL obtained in the step 2 to obtain a solution A, weighing 0.5g of 2-mercaptobenzothiazole (MBT for short) to dissolve in 10mL of acetone to obtain a solution B, mixing part of the solution A and part of the solution B, and reacting for 5 hours to obtain a solution C, wherein the mass ratio of PGCd to MBT is 1: 5; centrifugally cleaning the suspension by pure water at 5000r/min for the solution C, and drying the suspension in a vacuum drying oven at 50 ℃ and-0.1 MPa for 24 hours to obtain PGCd-MBT powder;

and 4, dissolving the PGCd-MBT powder obtained in the step 3 in deionized water to prepare a PGCd-MBT aqueous solution of 10mg/ml, adding a water-based epoxy curing agent, performing ultrasonic treatment for 1h, removing excessive solvent by using a rotary evaporator, adding E-51 epoxy resin, and stirring for 30min to obtain a target product, wherein the mass ratio of the water-based epoxy curing agent to the E-51 epoxy resin is 3: 1, the mass fraction of PGCd-MBT powder in the total solid obtained by removing water from the target product is 0.25-2 wt%.

2. The aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive coating of claim 1, wherein the graphene oxide preparation step in step 1 is:

uniformly mixing 2.4g of graphite powder with 72ml of mixed acid, adding sodium nitrate and potassium permanganate, wherein the mass ratio of the graphite powder to the potassium permanganate is 1:4, the mass ratio of the graphite powder to the sodium nitrate is 1:1.25, stirring for 2-3h at 35-39 ℃, adding deionized water, stirring for 1-2h at 90-95 ℃, and the volume ratio of the deionized water to the mixed acid is 2: 1-1.5:1, adding 30ml of 30% H in sequence₂O₂And stirring with 300ml of 1mol/L hydrochloric acid aqueous solution, washing, centrifuging, and freeze-drying to obtain the solid graphene oxide.

3. The aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint of claim 2, wherein the mixed acid is a mixture of sulfuric acid and phosphoric acid, and the volume ratio of the sulfuric acid to the phosphoric acid is 9:1-9: 2.

4. The aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint of claim 1, wherein the preparation of PGCd in step 2 comprises the following steps:

preparing 1mg/mL GO water dispersion, ultrasonically dispersing for 30min in a three-necked bottle provided with a stirring paddle and a thermometer, and dropwise adding 1.2mL NH₃·H₂Adjusting the pH value of the solution to 9-10, stirring at room temperature for half an hour, weighing 2.5g of cyclodextrin powder, adding the cyclodextrin powder, controlling the temperature to 70-75 ℃, stirring at medium speed for reaction for 4 hours, dropwise adding 40mL of 10mg/mL polyethyleneimine aqueous solution, controlling the temperature to about 70 ℃, reacting for 8 hours, and centrifuging, washing and drying to obtain PGCd container powder; wherein the mass ratio of GO to cyclodextrin is 1: 50.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to an aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint.

Background

Corrosion imposes a serious economic burden on the country and has posed a serious social safety and environmental hazard. Among various corrosion inhibition measures, the organic protective coating is the most widely used, and has excellent barrier effect on corrosive ions and moisture when the coating is in a good state, the traditional protective coating only can play a passive protection role on a substrate, and however, the barrier property of the coating is seriously influenced due to environmental and mechanical damages in the transportation or use process. Without timely and effective repair, these damages accelerate the rate of corrosion, ultimately leading to premature failure of the coating, and currently, most damaged coatings require manual repair or replacement, which is very expensive and cumbersome. Inspired by the self-healing properties of natural organisms, self-healing coatings have recently received increased attention, and when the coatings are subjected to external stimuli, such as changes in light, heat, pH, etc., corrosion inhibitors are released to heal damage.

In recent years, GO has huge potential in developing high-performance protective coatings due to good mechanical properties and extremely high impermeability, and related documents indicate that the uniformly distributed graphene or graphene oxide film can remarkably improve the corrosion resistance of polymer coatings. Cyclodextrin (CD for short) has the characteristics of 'internal hydrophobicity and external hydrophilicity', is free from environmental pollution and is concerned by researchers, and the research on the cyclodextrin mainly comprises three types, namely alpha-, beta-and gamma-cyclodextrin, so that the beta-CD is widely researched due to the small cavity of an alpha-CD molecule and the high production cost of the gamma-CD. Due to its hydrophobic inner cavity and hydrophilic outer cavity, and tapered hollow inner cavity, it is used to encapsulate guest molecules.

A novel aminated GO/cyclodextrin (PGCd) is prepared by modifying Graphene Oxide (GO) with Polyethyleneimine (PEI), grafting cyclodextrin (beta-CD) to the surface of GO to prepare a graphene-based container, loading a corrosion inhibitor 2-Mercaptobenzothiazole (MBT) into the container on the basis, and embedding the graphene-based container (PGCd-MBT) coated with the MBT corrosion inhibitor into a water-based epoxy resin (EP) matrix to synthesize a novel anticorrosive coating. The uniformly dispersed graphene oxide nanosheets largely prevent the penetration of corrosive ions and the release of a metal surface corrosion inhibitor MBT, so that the prepared coating has good corrosion resistance.

Disclosure of Invention

The invention aims to provide an aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint which can be durably and stably applied to the field of steel corrosion resistance.

In order to achieve the purpose, the invention adopts the technical scheme that:

an aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint is prepared by the following steps:

step 1, preparing graphene oxide;

step 2, amination GO/cyclodextrin (PGCd);

and 3, preparing a PGCd dispersion solution with the concentration of 1mg/mL, weighing 0.5g of 2-Mercaptobenzothiazole (MBT), dissolving in 10mL of acetone, mixing the two solutions, and reacting for 5 hours. The suspension was washed by centrifugation with pure water at 5000 r/min. And dried for 24 hours in a vacuum drying oven at 50 ℃ and-0.1 MPa. Obtaining PGCd-MBT powder; wherein the mass ratio of PGCd to MBT is 1: 5.

And 4, dissolving the obtained PGCd-MBT powder in deionized water to prepare a 10mg/ml PGCd-MBT aqueous solution. Adding a water-based epoxy curing agent, performing ultrasonic treatment for 1h, removing excessive solvent by using a rotary evaporator, adding E-51 epoxy resin, and stirring for 30min to obtain a target product (the aminated GO/cyclodextrin modified water-based epoxy anticorrosive paint). Preparing target products with the mass fractions of 0.25 wt%, 0.5 wt%, 1 wt% and 2 wt%, wherein the mass ratio of the water-based epoxy curing agent to the E-51 epoxy resin is 3: 1; the mass fraction of PGCd-MBT powder in the total solid of the target product after water removal was 0.25 wt%, 0.5 wt%, 1 wt%, 2 wt%.

Further, the preparation steps of the graphene oxide in the step 1 are as follows:

uniformly mixing graphite powder and mixed acid, and adding sodium nitrate and potassium permanganate, wherein the ratio of the graphite powder to the mixed acid is 1:30(g: ml), the mass ratio of the graphite powder to the potassium permanganate is 1:4, and the mass ratio of the graphite powder to the sodium nitrate is 1: 1.25. Stirring for 2-3h at 35-39 ℃, adding deionized water, stirring for 1-2h at 90-95 ℃, wherein the volume ratio of the deionized water to the mixed acid is 2: 1-1.5:1, adding 30% of H in sequence₂O₂And 1mol/L hydrochloric acid aqueous solution (volume ratio is 1:10) are stirred, washed, centrifuged and freeze-dried to obtain solid graphene oxide.

Further, the mixed acid is a mixture of sulfuric acid and phosphoric acid, and the volume ratio of the sulfuric acid to the phosphoric acid is 9:1-9: 2.

Further, the preparation step of the cyclodextrin (PGCd) in the step 2 is as follows:

preparing 1mg/mL GO water dispersion, ultrasonically dispersing for 30min in a three-necked bottle provided with a stirring paddle and a thermometer, and dropwise adding 1.2mL NH₃·H₂Adjusting the pH value of the solution to 9-10 by O, stirring at room temperature for half an hour, weighing 2.5g of cyclodextrin powder, adding the cyclodextrin powder into the solution, controlling the temperature to 70-75 ℃, and stirring at medium speed for reacting for 4 hours to obtain an intermediate product GCd. Measuring the pH value of the solution, determining the solution to be an alkaline condition, dropwise adding 40mL of 10mg/mL polyethyleneimine aqueous solution into the PGCd solution, controlling the temperature to be about 70 ℃, reacting for 8 hours, and then centrifuging, washing and drying to obtain PGCd container powder; wherein the mass ratio of GO to cyclodextrin is 1: 50.

The beneficial technical effects of the invention are as follows:

(1) the method has the characteristics of simple synthesis process, low cost, easily controlled reaction conditions, good stability and the like.

(2) The anticorrosive coating has both passive barrier layer and active protection. PEI and cyclodextrin are adopted to simultaneously modify GO, the dispersibility of GO is greatly enhanced, the uniformly dispersed GO can enable a coating to form a structure similar to a labyrinth, channels of corrosive ions are increased, and the corrosive ions are not easy to reach the surface of a collector, so that active protection is provided; the cyclodextrin is used for coating the corrosion inhibitor MBT, when local corrosion occurs, the corrosion inhibitor is released and adsorbed on the exposed metal surface, so that the slow release effect of the corrosion inhibitor is exerted.

Drawings

FIG. 1 is a graph showing the effect of tinplate coated with the waterborne epoxy resin anticorrosive paint of examples 1-4 of the present invention and comparative example 1 in salt spray for different periods of time.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood 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.

Example 1: an aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive paint comprises the following steps:

(1) uniformly mixing 2.4g of graphite powder with 72ml of mixed acid, adding 3g of sodium nitrate and 9.6g of potassium permanganate, stirring for 2-3H at 35-39 ℃, adding 123ml of deionized water, stirring for 1-2H at 90-95 ℃, and sequentially adding 30ml of 30% H₂O₂And stirring with 300ml of 1mol/L hydrochloric acid aqueous solution, washing, centrifuging, and freeze-drying to obtain solid Graphene Oxide (GO).

(2) Taking 0.05g GO to prepare 1mg/mL GO water dispersion, ultrasonically dispersing for 30min in a three-necked bottle provided with a stirring paddle and a thermometer, and dropwise adding 1.2mL NH₃·H₂Adjusting the pH value of the solution to 9-10 by O, stirring for half an hour at room temperature, weighing 2.5g of cyclodextrin powder, adding the cyclodextrin powder, controlling the temperature to 70-75 ℃, stirring at medium speed for 4 hours to react to obtain an intermediate product GCd, measuring the pH value of the solution, determining the solution to be an alkaline condition, dropwise adding 40mL of 10mg/mL polyethyleneimine water solution, controlling the temperature to about 70 ℃, reacting for 8 hours, and then centrifuging, washing and drying to obtain PGCd powder.

(3) 0.1g of PGCd powder is taken to prepare a PGCd dispersion solution with the concentration of 1mg/mL, 0.5g of 2-Mercaptobenzothiazole (MBT) is weighed and dissolved in 10mL of acetone, and the two solutions are mixed and reacted for 5 hours. The suspension was washed by centrifugation with pure water at 5000 r/min. And dried for 24 hours in a vacuum drying oven at 50 ℃ and-0.1 MPa. PGCd-MBT powder was obtained.

(4) Weighing 0.015g of PGCd-MBT powder, dispersing the PGCd-MBT powder in 1.5mL of deionized water, adding 4.5g of water-based epoxy curing agent, stirring for 10min, performing ultrasonic treatment for 1h, removing excessive solvent by using a rotary evaporator, adding 1.5g E-51 epoxy resin, and stirring for 30min to obtain a target product, wherein the mass fraction of PGCd-MBT in the solid obtained after water removal of the target product is 0.25 wt%.

Example 2: steps 1-3 in this embodiment are identical to those in embodiment 1, and are not repeated herein. The preparation method of the aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive coating provided by the embodiment is only different from step 4 of embodiment 1, and step 4 is specifically as follows:

weighing 0.03g of PGCd-MBT powder, dispersing the PGCd-MBT powder in 3mL of deionized water, stirring the mixture with 4.5g of aqueous epoxy curing agent for 10min, carrying out ultrasonic treatment for 1h, removing excessive solvent by using a rotary evaporator, adding 1.5g E-51 epoxy resin, and stirring for 30min to obtain the composite anticorrosive paint with the mass fraction of 0.5 wt%.

Example 3: steps 1-3 in this embodiment are identical to those in embodiment 1, and are not repeated herein. The preparation method of the aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive coating provided by the embodiment is only different from step 4 of embodiment 1, and step 4 is specifically as follows:

weighing 0.06g of PGCd-MBT powder, dispersing the PGCd-MBT powder in 6mL of deionized water, stirring the mixture with 4.5g of aqueous epoxy curing agent for 10min, carrying out ultrasonic treatment for 1h, removing excessive solvent by a rotary evaporator, adding 1.5g E-51 epoxy resin, and stirring for 30min to obtain the composite anticorrosive paint with the mass fraction of 1 wt%.

Example 4: steps 1-3 in this embodiment are identical to those in embodiment 1, and are not repeated herein. The preparation method of the aminated GO/cyclodextrin modified waterborne epoxy resin anticorrosive coating provided by the embodiment is only different from step 4 of embodiment 1, and step 4 is specifically as follows:

weighing 0.12g of PGCd-MBT powder, dispersing the PGCd-MBT powder in 12mL of deionized water, stirring the PGCd-MBT powder and 4.5g of waterborne epoxy curing agent for 10min, carrying out ultrasonic treatment for 1h, removing excessive solvent by a rotary evaporator, adding 1.5g E-51 epoxy resin, and stirring for 30min to obtain the composite anticorrosive paint with the mass fraction of 2 wt%.

The prepared coating is processed into a standard sample, and the corrosion resistance of the sample is tested.

The following table shows the performance test results of the composite anticorrosive coatings obtained in examples 1 to 4.

Comparative example 1

The preparation method of the pure water epoxy resin anticorrosive paint comprises the following steps:

stirring 4.5g of water-based epoxy curing agent for 10min, performing ultrasonic treatment for 1h, removing excessive solvent by a rotary evaporator, adding 1.5g E-51 epoxy resin, and stirring for 30min to obtain the pure water-based epoxy resin anticorrosive paint.

Test example: the anticorrosive coatings prepared in examples 1 to 4 and comparative example 1 were coated on tinplate painted with an "x" on the surface, and then placed in a salt spray test chamber to be continuously sprayed for 30d with 5% NaCl solution as a spraying medium.

The results are shown in FIG. 1, where EP refers to the material obtained in comparative example 1 and PGCd1-PGCd4 refers to the composite materials obtained in examples 1-4.

It can be seen from fig. 1 that there are many corrosion products and bubbles around the scratch of the EP-only coating, while the surface coverage of the samples of PGCd1-PGCd4 is significantly less corrosion products and bubbles, with the PGCd2 sample being bubble-free and corrosion products being minimal.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.