A dual cationic electro-migrating rust inhibitor, preparation method and application thereof

Abstract

The application discloses a kind of double cation type electromigration rust inhibitor, preparation method and application.The double cation type electromigration rust inhibitor described in the application generates intermediate under negative pressure condition with saturated fatty acid and polyethylene polyamine as raw material, and is reacted with quaternary ammonium reagent in organic solvent to obtain double cation type electromigration rust inhibitor.The number of carbon atoms of the saturated fatty acid described in the application is an integer of 3-31, and the quaternary ammonium reagent is XCH2(CH2) s OH or X (CH2) s COONa, wherein s is an integer of 1-15, and X is halogen element chlorine, bromine, iodine.The double cation type electromigration rust inhibitor described in the application can be internally doped in newly built concrete structure, adsorbed on the surface of steel bar to inhibit steel bar corrosion, and can also migrate to the interior of reinforced concrete through electric field effect to repair the corrosion of steel bar in existing structure, and has wide market application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of corrosion protection and repair of reinforced concrete, and particularly relates to a double-cation electro-migration rust inhibitor, a preparation method and application. BACKGROUND

[0002] Reinforced concrete is the most widely used building material, and not only for new or existing concrete structures, but steel corrosion has been a key factor affecting the service life of concrete. At present, the basic construction is gradually expanding, and the demand for concrete rust inhibitors is also increasing. Moreover, with the passage of time, some of the steel in the early concrete structure also gradually shows signs of rust, which is mainly caused by the corrosion of chloride ions and the carbonation of concrete. There are also many methods for repairing concrete, such as coating the surface of the concrete with a migration-type rust inhibitor. If the concrete protective layer is thick or dense, it is difficult to migrate to the surface of the steel to inhibit corrosion.

[0003] Therefore, compared with the traditional repair method, the electrochemical method is used for repair, which can remove chloride ions on one hand, and can accelerate the migration of the migration type corrosion inhibitor to the surface of the concrete steel bar by using the electric field on the other hand, repair the steel bar and prolong the service life of the concrete. Although some amine substances can be used as electro-migration corrosion inhibitors, the cations dissociated from the amine substances in aqueous solution are less, and the electro-migration ability is weak, which cannot quickly and fully migrate to the surface of the steel bar. CN 111116482A imidazole derivative and its preparation method and application as a reinforced concrete corrosion inhibitor discloses that the adsorption performance of the corrosion inhibitor to the steel bar is enhanced by connecting a hydroxyl group to the imidazole, and the long-chain group on the imidazole ring can increase the adsorption area of the corrosion inhibitor to the surface of the steel bar, effectively avoiding the damage of chloride ions and the like to the passivation film on the surface of the steel bar, thereby greatly improving the service life of the steel bar in the erosion environment. In addition, the cracked reinforced concrete structure can be repaired under the action of an external voltage, but the imidazole derivative is a single-cation type, and the migration ability is limited. CN 108164465A lauric acid bicyclic imidazoline and its synthesis method and application discloses a symmetric lauric acid bicyclic imidazole molecular structure, which contains two imidazoline heterocyclic rings and two alkyl long chains of lauric acid, and can provide a dense electron cloud and good hydrophobicity. However, the preparation process in the invention is complex, which is not conducive to production, and the thionyl chloride reagent used in the synthesis is highly irritating and toxic, which is harmful to the body and the environment. CN 106007445A imidazole ionic liquid electro-migration corrosion inhibitor and its preparation method discloses that the imidazole is reacted with C1-C12 halogenated to obtain N-alkyl substituted imidazole, and then the imidazole ionic liquid electro-migration corrosion inhibitor is prepared by reacting with a quaternary ammonium reagent. On one hand, the electro-migration corrosion inhibitor is a single imidazole ring, and the electron cloud density is weak, so the corrosion resistance is limited. On the other hand, the single-cation type has fewer cations dissociated than the double-cation type, and the migration ability is not strong. US 8012543B2 method for reducing corrosion application discloses an amino alcohol modified polyorganosiloxane, which penetrates into the concrete on one hand, and hydrophobizes the surface layer of the concrete to inhibit the corrosion of the steel bar on the other hand. However, the invention needs to be sprayed or brushed on the surface of the concrete, which is not conducive to construction. On the other hand, the penetration ability of the amino alcohol is limited, which is difficult to quickly penetrate to the surface of the steel bar, and the system is unstable and prone to delamination, which leads to unstable performance. SUMMARY

[0004] The migration type rust inhibitor is used to the reinforced concrete by electrochemical method, on one hand, the chloride ion in the concrete is removed, on the other hand, the migration type rust inhibitor is accelerated to migrate to the surface of the reinforced concrete by the electric field, the reinforced concrete is repaired, and the service life of the concrete is prolonged; the migration type rust inhibitor has the defects of less cation dissociated, weak electric migration capacity, and slow and insufficient migration to the surface of the reinforced concrete. In view of the defects of the prior art, the application provides a double-cationic electric migration rust inhibitor, which can be mixed in the new concrete structure, adsorbed on the surface of the reinforced concrete to inhibit the corrosion of the reinforced concrete, and migrated to the interior of the reinforced concrete to repair the corrosion of the reinforced concrete in the existing structure, and the cation dissociated from the rust inhibitor is rich, the migration capacity is strong, and the migration speed is fast.

[0005] The double-cationic electric migration rust inhibitor comprises a polyethylene polyamine base segment and two imidazoline heterocycles, and a general structure formula is as follows:

[0006]

[0007] In the formula (I), m is an integer of 0-20; R1 is the same or different, and is a C2-C16 alkyl alcohol or alkyl carboxylate; and R2 is the same or different, and is a C3-C31 hydrocarbon group.

[0008] The R1 group is derived from a quaternary ammonium reagent, and the quaternary ammonium reagent is XCH2(CH2) s OH or X(CH2) s COONa, wherein s is an integer of 1-15, and X is a halogen element of chlorine, bromine or iodine.

[0009] The R2 group is derived from a saturated fatty acid, and a general structure formula is C n H 2n+1 COOH, wherein n is an integer of 2-30.

[0010] The heteroatom of the R1 group can increase the electron cloud density, the lone pair of electrons is easy to form a bond with iron, the adsorption capacity of the substance is enhanced, the substance is more easy to form a film on the surface of the reinforced concrete, the reinforced concrete is protected, the rust resistance of the reinforced concrete is increased. Meanwhile, R1 and R2 are regulated, the main functional groups in the molecular structure are in a planar structure as much as possible, the main functional groups are adsorbed on the surface of the iron in a parallel mode, the protective film formed is more complete and dense, and the rust resistance is better.

[0011] The preparation method of the double-cationic electric migration rust inhibitor comprises the following steps: first, the saturated fatty acid and the polyethylene polyamine are subjected to an amidation reaction, then the reaction condition is adjusted under negative pressure to continue the reaction to generate a double ring imidazoline, and finally the double ring imidazoline is activated under the action of the quaternary ammonium reagent to obtain the double-cationic electric migration rust inhibitor.

[0012] The molar ratio of the fatty acid to the polyethylene polyamine is 1:(1-1.2).

[0013] The molar ratio of the bicyclic imidazoline to the quaternization reagent is 1:(2-2.2).

[0014] The negative pressure vacuum degree is -0.05 to -0.15 MPa.

[0015] The polyethylene polyamine is NH2CH2CH2NHCH2(CH2NHCH2) m CH2NHCH2CH2NH2, wherein m is an integer of 0-20.

[0016] The specific preparation method of the double-cationic electromigration rust inhibitor comprises the following steps:

[0017] (1) Under a gas protection environment, saturated fatty acid and organic solvent A are sequentially put into a reaction kettle to start stirring, polyethylene polyamine is added, and reaction is carried out at 100-160 DEG C for 2-10 hours; the reaction temperature is adjusted to 120-200 DEG C under negative pressure, and the reaction is continuously carried out for 6-24 hours; after the reaction is completed, the organic solvent A is recovered at high temperature, and the bicyclic imidazoline is obtained.

[0018] (2) The bicyclic imidazoline in step (1) is added into organic reagent B in a molar ratio of 1:(2-2.2) with a quaternization reagent, and reaction is carried out at 80-100 DEG C for 12-48 hours; after that, the organic reagent B is recovered at high temperature, and the double-cationic electromigration rust inhibitor is prepared.

[0019] The organic solvent A is one of toluene, m-xylene, p-xylene and o-xylene.

[0020] The organic reagent B is one of dimethyl sulfoxide, dimethyl formamide, acetonitrile and ethanol.

[0021] The double-cationic electromigration rust inhibitor can be used in new concrete structures and existing concrete structures for electromigration repair.

[0022] The significant feature of the present application is that the double-cationic electromigration corrosion inhibitor in the present application has double-cationic functional groups in the structure, which can generate more cations when electromigrating, and has strong migration ability, so that it can quickly migrate to the surface of the steel bar to inhibit the corrosion of the steel bar. On the other hand, the double-cationic electromigration corrosion inhibitor in the present application introduces the R1 group containing heteroatoms in the molecule, which can enhance the adsorption capacity of the double-cationic electromigration corrosion inhibitor itself, and by adjusting R1 and R2 and optimizing the molecular structure, the double-cationic electromigration corrosion inhibitor can be adsorbed on the surface of the steel bar in a plane, so that the protective film is more complete and dense, and the corrosion resistance of the double-cationic electromigration corrosion inhibitor is further improved. In the reaction process, the reaction is carried out under negative pressure to form a double-ring imidazoline structure, according to Le Chatelier's principle, the reaction equilibrium under negative pressure moves to the positive reaction direction, so that the negative pressure promotes the forward reaction, and the double-ring structure is more easily generated.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] 1. The raw materials used in the present application are easy to obtain and cheap, and the preparation process is simple and easy to produce.

[0025] 2. The double-cationic electromigration corrosion inhibitor system is stable and not prone to delamination; the intermediate conversion rate can be improved by negative pressure reaction, thereby improving the yield of the double-cationic electromigration corrosion inhibitor; the prepared double-cationic electromigration corrosion inhibitor can be used for both new structures and existing concrete structures;

[0026] 3. In addition, the double-cationic electromigration corrosion inhibitor has excellent corrosion resistance, can quickly migrate to the surface of the steel bar, effectively improves the critical chloride ion concentration of the steel bar, and prolongs the service life of the reinforced concrete. BRIEF DESCRIPTION OF DRAWINGS

[0027] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and the illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application.

[0028] Figure 1 Figure 1 is a schematic diagram of the application of the electromigration experiment device of Example 2;

[0029] In the figure: 1, stabilized DC power supply, 2, standard resistance, 3, voltmeter, 4, cathode zone, 5, concrete test piece, 6, anode solution and double-cationic electromigration corrosion inhibitor mixed solution. DETAILED DESCRIPTION

[0030] The following examples describe in more detail the preparation of the slow-release antifoam graft-modified silica material according to the present application, and are given by way of illustration and are not intended to limit the scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application shall fall within the scope of the present application.

[0031] Example 1

[0032] (1) In a nitrogen environment, the saturated fatty acid C5H 11 COOH and the organic solvent toluene were sequentially added to a reaction kettle and stirring was started, then NH2CH2CH2NHCH2CH2NHCH2CH2NH2 was added, after which the temperature was raised to 100°C and the reaction was carried out for 2 h, then the temperature was set to 120°C and the reaction was carried out under a negative pressure of -0.08 MPa for 24 h, after which the organic solvent toluene was recovered at high temperature to obtain a reaction intermediate, wherein the molar ratio of the saturated fatty acid to the polyethylene polyamine was 1:1.

[0033] (2) The reaction intermediate in step (1) and the quaternary ammonium reagent BrCH2(CH2)2OH were added together in a molar ratio of 1:2.1 to the organic reagent acetonitrile, and the reaction was carried out at 100°C for 12 h, after which the organic reagent acetonitrile was recovered at high temperature to obtain a double-cationic electromigration corrosion inhibitor, which was used as Example 1.

[0034] Example 2

[0035] (1) In a nitrogen environment, the saturated fatty acid C 10 H 21 COOH and the organic solvent m-xylene were sequentially added to a reaction kettle and stirring was started, then NH2CH2CH2NHCH2(CH2NHCH2)6CH2NH2 was added, after which the temperature was raised to 120°C and the reaction was carried out for 6 h, then the temperature was set to 150°C and the reaction was carried out under a negative pressure of -0.10 MPa for 24 h, after which the organic solvent m-xylene was recovered at high temperature to obtain a reaction intermediate, wherein the molar ratio of the saturated fatty acid to the polyethylene polyamine was 1:1.1.

[0036] (2) The reaction intermediate in step (1) and the quaternary ammonium reagent Cl(CH2)3COONa were added together in a molar ratio of 1:2.2 to the organic reagent dimethyl sulfoxide, and the reaction was carried out at 80°C for 48 h, after which the organic reagent dimethyl sulfoxide was recovered at high temperature to obtain a double-cationic electromigration corrosion inhibitor, which was used as Example 2.

[0037] Example 3

[0038] (1) In a nitrogen environment, the saturated fatty acid C 15 H31 COOH and the organic solvent o-xylene were added to the reactor and stirred. Then NH2CH2CH2NHCH2(CH2NHCH2)5CH2NH2 was added. The temperature was then raised to 100℃ and reacted for 10 h. The temperature was then set to 150℃ and the reaction was carried out under a negative pressure of -0.12 MPa for 24 h. After the reaction was completed, the organic solvent o-xylene was recovered at high temperature to obtain the reaction intermediate, in which the molar ratio of saturated fatty acid to polyethylene polyamine was 1:1.

[0039] (2) The reaction intermediate in step (1) and the quaternizing agent BrCH2(CH2)8OH were added to the organic reagent ethanol at a molar ratio of 1:2 and reacted at 100°C for 24 hours. After that, the organic reagent ethanol was recovered at high temperature to obtain the dual-cationic electromigration rust inhibitor. This is used as Example 3.

[0040] Example 4

[0041] (1) In a nitrogen atmosphere, saturated fatty acids C8H are sequentially introduced. 17 COOH and the organic solvent toluene were added to the reactor and stirring was started. Then NH2CH2CH2NHCH2(CH2NHCH2) was added. 15 CH2NH2 was heated to 160℃ and reacted for 10 hours. Then the temperature was set to 180℃ and the reaction was carried out under a negative pressure of -0.15MPa for 8 hours. After the reaction was completed, the organic solvent toluene was recovered at high temperature to obtain the reaction intermediate, in which the molar ratio of saturated fatty acid to polyethylene polyamine was 1:1.2.

[0042] (2) The reaction intermediate in step (1) and the quaternizing reagent ICH2(CH2)4OH were added together with the organic reagent acetonitrile at a molar ratio of 1:2.1 and reacted at 90°C for 36 h. After that, the organic reagent acetonitrile was recovered at high temperature to obtain the dual-cationic electromigration rust inhibitor. This is used as Example 4.

[0043] Example 5

[0044] (1) In a nitrogen atmosphere, saturated fatty acid C is sequentially added 20 H 41 COOH and the organic solvent p-xylene were added to the reactor and stirring was started. Then NH2CH2CH2NHCH2(CH2NHCH2) was added. 10 CH2NH2 was heated to 160℃ and reacted for 5 hours. Then the temperature was set to 200℃ and the reaction was carried out under a negative pressure of -0.10MPa for 6 hours. After the reaction was completed, the organic solvent p-xylene was recovered at high temperature to obtain the reaction intermediate, in which the molar ratio of saturated fatty acid to polyethylene polyamine was 1:1.

[0045] (2) The reaction intermediate in step (1) is added to the quaternary ammonium reagent Br(CH2) 12 COONa in a molar ratio of 1:2 in the organic reagent ethanol, and reacted at 100°C for 48 h, after which the organic reagent ethanol is recovered at high temperature, to obtain the double-cationic electromigration rust inhibitor, which is used as Example 5.

[0046] Example 6

[0047] (1) In a nitrogen environment, saturated fatty acid C 30 H 61 COOH and organic solvent m-xylene are sequentially added to a reaction kettle to start stirring, then NH2CH2CH2NHCH2(CH2NHCH2)7CH2NH2 is added, after which the temperature is raised to 120°C and reacted for 8 h, then the temperature is set to 170°C, and reacted at a negative pressure of -0.12 MPa for 24 h, after which the organic solvent toluene is recovered at high temperature to obtain the reaction intermediate, wherein the molar ratio of saturated fatty acid to polyethylene polyamine is 1:1.2.

[0048] (2) The reaction intermediate in step (1) is added to the quaternary ammonium reagent ClCH2(CH2) 15 OH in a molar ratio of 1:2.2 in the organic reagent dimethylformamide, and reacted at 90°C for 24 h, after which the organic reagent dimethylformamide is recovered at high temperature, then extracted with chloroform, the organic phases are combined, dried with anhydrous magnesium sulfate, filtered, and rotary evaporated to remove chloroform to obtain the double-cationic electromigration rust inhibitor, which is used as Example 6.

[0049] Example 7

[0050] (1) In a nitrogen environment, saturated fatty acid C 12 H 23 COOH and organic solvent toluene are sequentially added to a reaction kettle to start stirring, then NH2CH2CH2NHCH2(CH2NHCH2)7CH2NH2 is added, after which the temperature is raised to 120°C and reacted for 8 h, then the temperature is set to 170°C, and reacted at a negative pressure of -0.12 MPa for 24 h, after which the organic solvent toluene is recovered at high temperature to obtain the reaction intermediate, wherein the molar ratio of saturated fatty acid to polyethylene polyamine is 1:1.2.

[0051] (2) The reaction intermediate in step (1) is added to the quaternary ammonium reagent Br(CH2)8COONa in a molar ratio of 1:2.2 in the organic reagent acetonitrile, and reacted at 100°C for 30 h, after which the organic reagent acetonitrile is recovered at high temperature to obtain the double-cationic electromigration rust inhibitor, which is used as Example 7.

[0052] Comparative Example 1

[0053] (1) In the nitrogen environment, the saturated fatty acid C5H 11 COOH and organic solvent toluene were added into the reaction kettle and stirred, then NH2CH2CH2NHCH2CH2NHCH2CH2NH2 was added, then the temperature was increased to 100°C and reacted for 2h, then the temperature was set to 120°C and reacted for 24h under normal pressure, after the reaction was completed, the organic solvent toluene was recovered at high temperature, and the reaction intermediate was obtained, wherein the molar ratio of saturated fatty acid to polyethylene polyamine was 1:1.

[0054] (2) The reaction intermediate in step (1) and the quaternary ammonium reagent BrCH2(CH2)2OH were added together into the organic reagent acetonitrile at a molar ratio of 1:2.1, and reacted at 100°C for 12h, then the organic reagent acetonitrile was recovered at high temperature, and the double-cationic electromigration corrosion inhibitor was obtained, which was used as Comparative Example 1.

[0055] Comparative Examples 2 and 3

[0056] The commercially available analytical pure triethylene tetramine and imidazoline were used as Comparative Example 2 and Comparative Example 3, respectively.

[0057] Application Examples

[0058] Application Example 1. Corrosion resistance

[0059] The prepared double-cationic electromigration corrosion inhibitor was tested for corrosion resistance according to the salt water immersion and baking environment corrosion resistance test in JGJ / T192-2009 "Technical Specification for Application of Steel Corrosion Inhibitors". The coarse aggregate particle size was 5mm-15mm, the sand ratio was 0.38, and the water-cement ratio was 0.6. 3.5% sodium chloride was added to the blank concrete test block and the concrete test block with added steel corrosion inhibitor based on the mass of mixed water, and the dosage of the double-cationic electromigration corrosion inhibitor was 0.8% of the mass fraction of cementitious materials. The test pieces were dried at 80°C for 24h, then cooled, and then placed in a sealed plastic box containing 3.5% sodium chloride solution for 96h, and then placed in a 60°C oven for 72h. The test pieces were immersed for 96h and baked for 72h, which was one immersion and baking cycle. After the cycle was completed, the steel corrosion area was counted, and the corrosion area percentage was R n = A n / A0x100%, R n was the corrosion area percentage (%) of the steel after the cycle, A n was the average corrosion area of the steel test piece (mm 2 ), A0was the effective surface area of the steel (mm 2 ), which was 1884mm 2; and the percentage reduction of the steel bar corrosion area is the percentage reduction of the steel bar corrosion area of the example and the comparative example relative to the percentage reduction of the steel bar corrosion area of the blank group after the cycle.

[0060] Table 1 rust inhibition performance

[0061] Serial number [A5 / mm 2 ]]> [R5 / %] Decrease in steel reinforcement corrosion area percentage / % Blank 680 36.1 / Example 1 33 1.75 95.15 Example 2 28 1.49 95.88 Example 3 25 1.33 96.32 Example 4 31 1.65 95.44 Example 5 20 1.06 97.06 Example 6 15 0.80 97.79 Example 7 22 1.17 96.77 Comparative Example 1 203 10.77 70.15 Comparative Example 2 275 14.60 59.57 Comparative Example 3 284 15.07 58.24

[0062] As shown in Table 1, the dicationic electromigration rust inhibitor prepared in the examples 1-7 has a percentage reduction of the steel bar corrosion area of more than 80%, and has good rust inhibition capacity; the comparative examples 2 and 3 have no obvious effect on the inhibition of the steel bar corrosion at the dosage of 0.8%; the comparative example 1 is a dicationic electromigration rust inhibitor not prepared under negative pressure, and has other reaction conditions consistent with those of the example 1, but has an effect on the inhibition of the steel bar corrosion obviously lower than that of the example 1, but higher than those of the comparative examples 2 and 3, because the yield of the dicationic electromigration rust inhibitor with a double ring structure prepared under the negative pressure is reduced.

[0063] Application example 2: electromigration performance

[0064] The concrete test piece is formed with a water-cement ratio of 0.5, a coarse aggregate particle size of 5mm-15mm, and a sand ratio of 0.25, and is internally mixed with 3% of sodium chloride reagent relative to the mass of the cement. The concrete test piece is cured for 28 days, and then is cut into small test pieces with a thickness of 4.5cm for electromigration. The electromigration device is as shown in Fig. 1. The cut concrete small test piece is installed, and the cathode area is filled with saturated calcium hydroxide solution, and the anode area is filled with saturated calcium hydroxide solution containing 10% of the electromigration rust inhibitor. Figure 1 The current density is 2A / m 2 , and the nitrogen content is tested after the power is turned on for different time. Whether the nitrogen content is analyzed or not is used to determine whether the electromigration rust inhibitor is migrated out.

[0065] Table 2: nitrogen element in the cathode area after the power is turned on for different time

[0066] Serial number 25d 30d 35d 60d Example 1 Yes / / / Example 2 No Yes / / Example 3 No Yes / / Example 4 Yes / / / Example 5 No No Yes / Example 6 No No Yes / Example 7 No Yes / / Comparative Example 1 No No No Yes Comparative Example 2 No No No No Comparative Example 3 No No No No

[0067] It can be found through the test of the nitrogen element content that the nitrogen element is detected in the cathode area of the examples 1 and 4 after the power is turned on for 25d, and the nitrogen element is detected in the cathode area of the examples 2, 3 and 7 after the power is turned on for 30d. The nitrogen element is detected in the cathode area of the examples 1-7 after the power is turned on for 35d, and the nitrogen element is detected in the cathode area of the comparative example 1 after the power is turned on for 60d, which indicates that the migration performance of the comparative example 1 is not as good as that of the example 1, and the migration performance of the comparative examples 2 and 3 is the worst.

[0068] Application Example 3. Repair performance

[0069] The concrete test blocks were formed according to the proportions of Application Example 2 above, and 2 corroded steel bars were inserted in the concrete, with a protective layer thickness of 4.5 cm. After standard curing for 28 d, the test blocks were used for electromigration repair. The concentrations of the examples and the comparative examples were all adjusted to 10% during electromigration, and the power-on time lasted for 40 d. The current density was 2 A / m 2 After curing for 28 d, the initial potential was nondestructively tested using a Profometer Corrosion steel bar corrosion tester produced by Euro Geophysical Instrument Equipment Co., Ltd. After electromigration for 40 d, the potential was again nondestructively tested. The steel bar corrosion potential < -245 mV was defined as a depassivation state, and the corrosion was serious. The potential > -95 mV was defined as a passivation state of the steel bar.

[0070] Table 3. Corrosion potential

[0071] Serial number Initial corrosion potential / mV Corrosion potential after 40d / mV Blank -406 -389 Example 1 -411 -35 Example 2 -402 -69 Example 3 -415 -75 Example 4 -400 -40 Example 5 -405 -83 Example 6 -403 -90 Example 7 -398 -79 Comparative Example 1 -412 -265 Comparative Example 2 -401 -308 Comparative Example 3 -399 -301

[0072] The corrosion potential was tested by the nondestructive testing method. It was found that after standard curing for 28 d, the original corroded steel bar was still in a depassivation corrosion state, and the corrosion potentials of the steel bars were all within 50 mV, and the state of the steel bars was consistent. After electromigration for 40 d, the corrosion potentials of the steel bars of Examples 1-7 were all in a passivation state, and the electromigration repair performance was good. Although the potential of Comparative Example 1 was somewhat lower than that of Comparative Examples 2 and 3, the steel bar was still in a depassivation state, and the repair performance was poor.

Claims

1. A dual cationic electromigration rust inhibitor characterized by, The polyethylene polyamine base segment and two imidazoline heterocycles, the structure general formula is as follows formula (I): In formula (I), m is an integer of 0-20; R1 is the same or different, C2-C16 alkyl alcohol or alkyl carboxylate; R2 is the same or different, C3-C31 hydrocarbon group.

2. The dual cationic electromigration rust inhibitor according to claim 1, wherein, The R1group is derived from a quaternizing agent, which is: XCH2(CH2) s OH or X(CH2) s COONa, wherein s is an integer from 1 to 15 and X is a halogen element, chlorine, bromine or iodine.

3. The dual cationic electromigration rust inhibitor of claim 1, wherein, The R2group is derived from a saturated fatty acid having the general structure C n H 2n+1 COOH, wherein n is an integer from 2 to 30.

4. A process for the preparation of a dicationic electromigration corrosion inhibitor according to any one of claims 1 to 3, characterized in that, First, the saturated fatty acid is subjected to amidation reaction with polyethylene polyamine, and then the reaction conditions are adjusted under negative pressure to continue the reaction to generate bicyclic imidazoline, which is activated by the action of quaternary ammonium reagent to prepare the double cationic electromigration corrosion inhibitor.

5. The method of claim 4, wherein, The molar ratio of the fatty acid to the polyethylene polyamine is 1: (1-1.2), and the molar ratio of the bicyclic imidazoline to the quaternary ammonium reagent is 1: (2-2.2).

6. The method of claim 4, wherein, The negative pressure vacuum degree is -0.05 to -0.15 MPa.

7. The method of claim 4, wherein, said polyethylene polyamine is NH2CH2CH2NHCH2(CH2NHCH2) m CH2NHCH2CH2NH2, wherein m is an integer from 0 to 20.

8. The method of claim 4, wherein, The specific preparation method comprises the following steps: (1) under the protection of gas environment, the saturated fatty acid and the organic solvent A are sequentially put into the reaction kettle to start stirring, the polyethylene polyamine is added, and the reaction is carried out at 100-160℃ for 2-10h; the reaction temperature is adjusted to 120-200℃ under negative pressure, and the reaction is continued for 6-24h, after the reaction is completed, the organic solvent A is recovered at high temperature, and the bicyclic imidazoline is obtained. (2) the bicyclic imidazoline in step (1) and the quaternary ammonium reagent are added into the organic reagent B at a molar ratio of 1: (2-2.2), and the reaction is carried out at 80-100℃ for 12-48h, and then the organic reagent B is recovered at high temperature to prepare the double cationic electromigration corrosion inhibitor.

9. The method of claim 8, wherein, The organic solvent A is one of toluene, m-xylene, p-xylene and o-xylene, and the organic reagent B is one of dimethyl sulfoxide, dimethyl formamide, acetonitrile and ethanol.

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