Crosslinked polymer high temperature corrosion inhibitor

Abstract

In one aspect, a high temperature corrosion inhibitor comprises a crosslinked polymer, wherein the crosslinked polymer comprises at least one polycyclic aromatic carboxylic acid compound and at least one crosslinking agent. In another aspect, a crosslinked polymer for use as a high temperature corrosion inhibitor comprises at least one polycyclic aromatic carboxylic acid compound and an oxirane. The polycyclic aromatic carboxylic acid comprises benzene-1,2,4,5-tetracarboxylic acid, anhydride of benzene-1,2,4,5-tetracarboxylic acid, and combinations thereof. In yet another aspect, the present disclosure relates to a method for reducing naphthenic acid corrosion at high temperatures. The method comprises the steps of providing a high temperature corrosion inhibitor comprising a crosslinked polymer and treating a crude oil containing naphthenic acid with the high temperature corrosion inhibitor.

Description

Related applications

[0001] This application claims the benefit of U.S. Patent Application Serial No. 18 / 525,632, filed November 30, 2023, entitled “Crosslinked Polymeric High Temperature Corrosion Inhibitor,” the disclosure of which is incorporated herein by reference as fully set forth herein. Technical Field

[0002] The present invention relates generally to corrosion inhibitors, and more specifically, but not limited to, formulations and methods for inhibiting naphthenic acid corrosion at high temperatures. Background Technology

[0003] The oil and gas industry continuously improves equipment used for the exploration, production, transportation, storage, refining, and distribution of oil and gas resources. This requires ongoing maintenance of the equipment and protection of existing infrastructure from conditions that can lead to mechanical failure, such as metal corrosion.

[0004] Various corrosion inhibitors have been developed to protect oil and gas equipment from corrosion. At higher temperatures, most of these inhibitors quickly lose their affinity for metal surfaces, thus becoming ineffective. Only a very small number of high-temperature corrosion inhibitors are practically available, and most of these inhibitors are phosphorus-based. The organophosphorus compounds in these conventional high-temperature corrosion inhibitors can be detrimental to both zeolite-based hydrotreatment catalysts and fluid catalytic cracking catalysts. Other available high-temperature corrosion inhibitors are sulfur-based, but these inhibitors are both inefficient and very expensive.

[0005] This lack of suitable high-temperature corrosion inhibitors is particularly problematic for processing high-naphthenic crude oil. Naphthenic acids are components of heavy crude oil and contain a mixture of various carboxylic acids. Between approximately 400℉ and 700℉, naphthenic acid corrosion becomes a particular concern for crude oil processing equipment. Industrial methods to combat naphthenic acid corrosion include blending crude oil with oils having a lower naphthenic acid content, attempting to remove or neutralize naphthenic acids, and constructing specialized processing units using metals that are inherently more resistant to naphthenic acid corrosion. Each of these industrial solutions is expensive and destructive to crude oil processing systems.

[0006] Therefore, there is a need for a high-temperature corrosion inhibitor that addresses naphthenic acid corrosion through effective chemical intervention. This disclosure addresses these and other deficiencies in the prior art. Summary of the Invention

[0007] In one aspect, this disclosure relates to a crosslinked polymer for use as a high-temperature corrosion inhibitor, wherein the crosslinked polymer comprises at least one polycyclic aromatic carboxylic acid compound and ethylene oxide. The polycyclic aromatic carboxylic acid may comprise benzene-1,2,4,5-tetracarboxylic acid, anhydrides of benzene-1,2,4,5-tetracarboxylic acid, and combinations thereof.

[0008] In another aspect, a high-temperature corrosion inhibitor is disclosed, wherein the high-temperature corrosion inhibitor comprises a crosslinked polymer. The crosslinked polymer comprises at least one polycyclic aromatic carboxylic acid compound and at least one crosslinking agent.

[0009] In another aspect, this disclosure relates to a method for reducing naphthenic acid corrosion at high temperatures. The method includes the steps of: providing a high-temperature corrosion inhibitor comprising a cross-linked polymer and treating crude oil containing naphthenic acids with the high-temperature corrosion inhibitor. Detailed Implementation

[0010] It has been found that crosslinked polymers can be synthesized in the presence of naphthenic acids to overcome thermal stability barriers and inhibit corrosion. These crosslinked polymers may be particularly useful for corrosion inhibition at temperatures ranging from about 400℉ to about 700℉. Furthermore, these crosslinked polymers are phosphorus-free and sulfur-free systems. In an exemplary embodiment, the high-temperature corrosion inhibitor comprises a crosslinked polymer, which further comprises at least one polycyclic aromatic carboxylic acid compound and at least one crosslinking agent.

[0011] Polycyclic aromatic carboxylic acid compounds can be polycyclic aromatic carboxylic acids, their anhydrides, or mixtures of polycyclic aromatic carboxylic acids and / or anhydrides. For example, suitable polycyclic aromatic carboxylic acid compounds include benzene-1,2,4,5-tetracarboxylic acid (BTCA), BTCA anhydrides, and combinations thereof.

[0012] The crosslinking agent component is used to crosslink polycyclic aromatic carboxylic acid compounds, thus overcoming the thermal stability barrier that prevents conventional corrosion inhibitors from operating at high temperatures. Furthermore, the crosslinking agent promotes the solubility of the polycyclic aromatic carboxylic acid compounds themselves or in solvents, thus enabling commercial deployment. The crosslinking agent component may comprise alkylene oxides, alkylene glycols, alkylene carbonates, and combinations thereof. Suitable alkylene oxides include, but are not limited to, ethylene oxide, propylene oxide, butane oxide, and combinations thereof. Suitable alkylene glycols include ethylene glycol, polyethylene glycol, propylene glycol, butanediol, hexanediol, homopolymers and oligomers and polymers of one or more of the previously listed glycols, glycerol, and any combination thereof. Examples of suitable oligomers and polymers include, but are not limited to, polyethylene glycol (PEG), polypropylene glycol (PPG), random copolymers and block copolymers of PEG and PPG, and combinations thereof.

[0013] The crosslinking agent may be present in an amount or concentration derived from the amount or concentration of the polycyclic aromatic carboxylic acid compound. In some embodiments, the concentration ratio of the polycyclic aromatic carboxylic acid compound to the crosslinking agent is in the range of about 1:1 to about 1:20. The concentration ratio may also be in the range of about 1:2 to about 1:10 (polycyclic aromatic carboxylic acid compound: crosslinking agent).

[0014] In some non-limiting embodiments, the crosslinking polymer comprises between about 5 wt.% and about 50 wt.% of a polycyclic aromatic carboxylic acid compound and between about 0.5 wt.% and about 50 wt.% of a crosslinking agent. In a non-limiting exemplary embodiment, the crosslinking polymer comprises about 25 wt.% of a polycyclic aromatic carboxylic acid compound and about 25 wt.% of a crosslinking agent. In some embodiments, the high-temperature corrosion inhibitor may also comprise at least one fatty acid compound. The fatty acid component provides more control over the molecular weight and solubility of the high-temperature corrosion inhibitor. The fatty acid component may include natural fatty acids and synthetic fatty acids, fatty acid derivatives, and combinations thereof. Mono-fatty acids, dimer fatty acids, trimer fatty acids, and combinations thereof may all be suitable to be included in the fatty acid component. Suitable fatty acid derivatives include, but are not limited to, imidazolines, maleic acid-modified fatty acids, diol esters of fatty acids, and C5-C... 80 Diol esters of alkyl succinic acid / anhydride, diol esters of alkenyl succinic acid / anhydride, diol esters of polyisobutylene succinic acid / anhydride, and combinations thereof.

[0015] Some embodiments of the high-temperature corrosion inhibitor include a polycyclic aromatic carboxylic acid compound between about 10 wt.% and about 50 wt.%, an epoxy alkane between about 0.5 wt.% and about 50 wt.%, and a fatty acid compound between about 0 wt.% and about 50 wt.%. Other exemplary embodiments include a polycyclic aromatic carboxylic acid compound between about 5 wt.% and about 30 wt.%, an epoxy alkane between about 10 wt.% and about 40 wt.%, and a fatty acid compound between about 10 wt.% and about 50 wt.%. In yet another exemplary embodiment, the high-temperature corrosion inhibitor includes a polycyclic aromatic carboxylic acid compound between about 5 wt.% and about 25 wt.%, an epoxy alkane between about 5 wt.% and about 25 wt.%, and a fatty acid compound between about 10 wt.% and about 50 wt.%.

[0016] In another non-limiting exemplary embodiment, the crosslinking polymer comprises between about 5 wt.% and about 30 wt.% of a polycyclic aromatic carboxylic acid compound, between about 10 wt.% and about 40 wt.% of a crosslinking agent, and between about 10 wt.% and about 50 wt.% of a fatty acid compound, wherein the fatty acid compound is C5-C 80 Alkyl succinic acid, alkenyl succinic acid, diol esters of polyisobutylene succinic acid, or mixtures thereof.

[0017] High-temperature corrosion inhibitors may also contain a solvent that promotes a more homogeneous crosslinking reaction. The solvent component may include solvents such as alkylene carbonates, glycols, glycol ethers, aromatic solvents, alcohols, mineral oils, water, and combinations thereof. For example, in some embodiments, the solvent is propylene glycol carbonate. The amount or concentration of the solvent is not necessarily derived from the amount or concentration of the polycyclic aromatic carboxylic acid compound and / or the crosslinking agent. In some exemplary embodiments, the amount of solvent in the high-temperature corrosion inhibitor is between about 10 wt.% and about 40 wt.% solvent.

[0018] A method for reducing naphthenic acid corrosion at high temperatures includes the following steps: providing a high-temperature corrosion inhibitor comprising a cross-linked polymer and treating crude oil containing naphthenic acid with the high-temperature corrosion inhibitor.

[0019] The steps of providing a high-temperature corrosion inhibitor may include reacting at least one polycyclic aromatic carboxylic acid compound with at least one crosslinking agent to form a crosslinked polymer. The reaction between the polycyclic aromatic carboxylic acid compound and the crosslinking agent proceeds rapidly until the crosslinking agent is depleted. Gelation may occur due to the formation of over-crosslinked portions that quickly lose their solubility. Therefore, the reaction must be carefully controlled to avoid gelation of the product. Strategies for controlling the reaction include modifying the molecular weight of the synthesized crosslinked polymer to reduce the occurrence of gelation. Another exemplary strategy is to determine the gelation point based on variations in the amount of polycyclic aromatic carboxylic acid compound, the amount of crosslinking agent, and the reaction temperature. Determining the gelation point chemically allows for the establishment of a detection point at which the reaction stops some time before the gelation point.

[0020] During the refining process of hydrocarbon feedstocks, high-temperature corrosion inhibitors may be particularly useful for corrosion inhibition in high-temperature geothermal wells, atmospheric distillation towers, or coking units. However, it should be understood that high-temperature corrosion inhibitors can be injected into a variety of metal equipment or parts to address corrosion problems, including but not limited to wellbore fittings, pipes, wellheads, production pipelines, downhole equipment, process equipment, process tanks and conduits, and storage tanks.

[0021] High-temperature corrosion inhibitors can be delivered in concentrated form. For wellbore application, the concentrated form can be injected into the affected area via capillary tubes, chemical injection plungers, or other treatment chemical delivery mechanisms. For application to surface-based equipment or facilities, the concentrated high-temperature corrosion inhibitor can be applied by pumping, spraying, immersion, or otherwise contacting the equipment / facilities with the high-temperature corrosion inhibitor.

[0022] Alternatively, the high-temperature corrosion inhibitor may be mixed with a suitable carrier fluid and pumped into the wellbore or pumped via surface-based equipment and facilities. The carrier fluid may be water, brine, or another aqueous solution. In some embodiments, the high-temperature corrosion inhibitor is mixed into the carrier fluid at a concentration ranging from about 1 ppm to about 10,000 ppm (high-temperature corrosion inhibitor / carrier fluid). In other embodiments, the concentration range is between about 10 ppm and about 3,000 ppm.

[0023] I. Implementation Example—Settings

[0024] Various tests were conducted to measure the corrosion rate of metal samples (tests) immersed in a corrosive environment (Equation 1), in both the presence of a high-temperature corrosion inhibitor (treatment group) and the absence of a high-temperature corrosion inhibitor (control group). The performance of the high-temperature corrosion inhibitor was evaluated by comparing the corrosion rates of the treated and control samples, and the difference was expressed as inhibition % (Equation 2). A good high-temperature corrosion inhibitor was defined as one with a high inhibition % (Equation 2). The tests were conducted under conditions close to the intended application environment.

[0025]

[0026] in:

[0027] W = Metal loss (g)

[0028] A = Surface area of ​​the sample (cm²) 2 )

[0029] ρ = alloy density (g / cm³) 3 )

[0030] T = Test duration (hours)

[0031] K = 3.45 × 10 6 (Unit: mils or mpy per year)

[0032]

[0033] in:

[0034] CR 对照 =Corrosion rate of the control group (i.e., without inhibitor)

[0035] CR 抑制剂 =Corrosion rate of the treatment group (i.e., using inhibitors)

[0036] A measured amount of commercially available naphthenic acid (NA) with a nominal total acid number (TAN) and heavy, highly refined mineral oil were added to a test vessel. NA was added to the mineral oil in a specific ratio to obtain a TAN of approximately 9 mg KOH / g to 10 mg KOH / g. The test vessel was then equipped with a paddle stirrer, thermocouple, condenser, inlet tube, and two samples. Once the vessel was sealed, the test fluid (treatment or control group) was stirred at approximately 400 rpm, and nitrogen was continuously passed through the test fluid for 30 to 60 minutes to remove oxygen. Afterward, a mixture of 1% H₂S in nitrogen was passed through the test fluid to provide H₂S, and a degassed environment was maintained during the test. After 20 hours, the samples were removed, cleaned, and weighed. The difference between the initial and final mass of each sample provided a direct measurement of metal loss during the test. Finally, the metal loss recorded for the samples was used to calculate the corrosion rate.

[0037] II. Example I

[0038] A series of tests were conducted to evaluate Benzene-1,2,4,5-Tetracarboxylic Acid (BTCA) crosslinked via direct ethoxylation in propylene carbonate. For these tests, a mixture of 80 g BTCA, 6 g N,N-dimethyloctadecamide (DMOA), and 130 g propylene carbonate was charged into a pressure reactor. The mixture was mechanically stirred and heated to 110 °C, followed by dehydration via N2 jet. Samples were periodically removed from the mixture to check the water content until Karl Fischer < 0.1%. After dehydration, approximately 12 equivalents of ethylene oxide per BTCA molecule were charged into the reactor, and the reaction was carried out at 110 °C for 2 hours. After the reaction was complete, the reactor was cooled to 70 °C, and N2 jet was applied again to remove any residual unreacted ethylene oxide. The reactor was further cooled to room temperature to discharge the product. This sample was tested as a high-temperature corrosion inhibitor without further modification.

[0039] III. Example II

[0040] Further tests were conducted to observe the crosslinking of BTCA with ethylene oxide in the presence of tall oil fatty acid (TOFA) dimer acid, with DMOA as a catalyst and aromatic 100 as a solvent. The procedure in Example I was repeated, but with the following modifications. Initially, a mixture of 100 g BTCA, 82.5 g TOFA dimer acid, 5.54 g DMOA, and 67.5 g aromatic 100 was charged into a pressure reactor. After dehydration, 165 g ethylene oxide was charged into the reactor. Before testing as a high-temperature corrosion inhibitor, the final product was diluted with propylene glycol carbonate to 70% of the activity of the reaction product.

[0041] IV. Example III

[0042] Further tests were conducted to observe the crosslinking of BTCA with ethylene oxide in the presence of trimeric acid, with DMOA as a catalyst and propylene glycol carbonate and aromatic 100 as solvents. The procedure of Example I was repeated, but with the following modifications. Initially, a mixture of 80 g BTCA, 60 g maleic oleic trimeric acid, 4.60 g DMOA, 60 g propylene glycol carbonate, and 40 g aromatic 100 was charged into a pressure reactor. After dehydration, 80 g ethylene oxide was charged into the reactor. Before testing as a high-temperature corrosion inhibitor, the final product was diluted with propylene glycol carbonate to 70% of the activity of the reaction product.

[0043] V. Example IV

[0044] Additional tests were conducted to evaluate BTCA, which is crosslinked with ethylene oxide in the presence of trimeric acid and catalyzed by Baker Hughes' commercial product CRO111, with propylene glycol carbonate and aromatic 100 as solvents. The procedure of Example I was repeated, but with the following modifications. Initially, a mixture of 80 g BTCA, 80 g maleic oleic trimeric acid, 19.2 g CRO111 (tall oil, a reaction product with diethylenetriamine), 60 g propylene glycol carbonate, and 20 g aromatic 100 was charged into a pressure reactor. After dehydration, 80 g ethylene oxide was charged into the reactor. The final product was diluted with propylene glycol carbonate to 70% of the activity of the reaction product before testing as a high-temperature corrosion inhibitor.

[0045] VI. Example V

[0046] Additional tests were conducted on BTCA, which is produced by reacting ethylene glycol or ethylene oxide at C2000 ppm. 12 -C 80 It was obtained by crosslinking alkenyl succinic anhydride (i.e., alkenyl succinic anhydride having between 12 and 80 carbon atoms) (ASA) and polyisobutylene succinic anhydride. In a specific example, 80 g of an alkenyl succinic anhydride mixture (containing 48 wt.% C) was used. 16 ASA, 32wt.% C 18 ASA and 20wt.% C 20 -C 2427.31 g of ASA, 20 g of ethylene glycol, 20 g of aromatic 100, and 1 g of dodecylbenzenesulfonic acid were placed in a three-necked flask. The mixture was purged with a gentle stream of N2 and heated to 160 °C until approximately 3.8 g of water was removed. The temperature was then lowered to 100 °C, and pyromellitic dianhydride (PMDA)—the dianhydride form of BTCA—was added to the homogenized solution, and the mixture was stirred at 140 °C for 4 hours. As the PMDA completely disappeared from the reactor vessel, a viscous product formed. Before testing as a high-temperature corrosion inhibitor, the final product (5,317 Daltons by mass) was diluted with propylene glycol carbonate to 90% of the activity of the reaction product.

[0047]

[0048] In the foregoing description, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and alterations may be made thereto without departing from the broader scope of the invention as set forth in the appended claims. Therefore, this specification should be considered exemplary rather than restrictive. For example, polycyclic aromatic carboxylic acid compounds and crosslinking agents, fatty acid compounds, solvents, etching processes, proportions, dosages, temperatures, and amounts not specifically identified or described in the disclosure or evaluated in particular embodiments are still contemplated within the scope of the invention.

[0049] As used herein, the range of concentration ratios should be interpreted to include any and all ratios within the specified range. For example, embodiments in which the ratio of the polycyclic aromatic carboxylic acid compound to the crosslinking agent is expressed as being in the range of 1:1 to 1:4 should be interpreted to also include discrete intermediate concentration ratios of 1:2 and 1:3 (polycyclic aromatic carboxylic acid compound: crosslinking agent) and fractional ratios between them (e.g., 1:1.1 and 1:3.5). It should be understood that, as used herein, the range of X wt.% to Y wt.% will be interpreted to include the disclosure of each discrete integer value between X and Y (e.g., X, X+1, X+2…Y-1, Y).

[0050] This invention may suitably include, consist of, or substantially consist of the disclosed elements, and may be practiced in the absence of undisclosed elements. As used herein, the singular forms “an,” “a,” and “the” are intended to also include the plural forms, unless the context clearly indicates otherwise. As used herein, the term “about” with respect to a given parameter includes the stated value and has a meaning determined by the context (e.g., it includes the degree of error associated with the measurement of the given parameter). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

Claims

1. A high-temperature corrosion inhibitor, wherein the high-temperature corrosion inhibitor comprises: Crosslinked polymer, wherein the crosslinked polymer comprises: At least one polycyclic aromatic carboxylic acid compound; and At least one crosslinking agent.

2. The high-temperature corrosion inhibitor according to claim 1, wherein the at least one polycyclic aromatic carboxylic acid compound is selected from the group consisting of: benzene-1,2,4,5-tetracarboxylic acid, anhydrides of benzene-1,2,4,5-tetracarboxylic acid, and combinations thereof.

3. The high-temperature corrosion inhibitor according to claim 2, wherein the at least one crosslinking agent is selected from the group consisting of: alkylene oxides, alkylene glycols, alkylene carbonates, and combinations thereof.

4. The high-temperature corrosion inhibitor according to claim 3, wherein the at least one crosslinking agent is ethylene oxide.

5. The high-temperature corrosion inhibitor according to claim 4, wherein the crosslinked polymer comprises: Polycyclic aromatic carboxylic acid compounds ranging from about 0.5 wt.% to about 50 wt.%; and Ethylene oxide ranging from about 0.5 wt.% to about 50 wt.%.

6. The high-temperature corrosion inhibitor according to claim 5, wherein the crosslinked polymer comprises: Approximately 25 wt.% of polycyclic aromatic carboxylic acid compounds; and Approximately 25 wt.% ethylene oxide.

7. The high-temperature corrosion inhibitor according to claim 3, wherein the alkylene glycol, if present, is selected from the group consisting of: ethylene glycol, polyethylene glycol, propylene glycol, butanediol, hexanediol, homopolymers and oligomers and polymers of one or more of the previously listed diols, glycerol and any combination thereof.

8. The high-temperature corrosion inhibitor according to claim 1, wherein the concentration ratio of the polycyclic aromatic carboxylic acid compound in the crosslinking polymer to the crosslinking agent is in the range of about 1:1 to about 1:

20.

9. The high-temperature corrosion inhibitor according to claim 1, wherein the concentration ratio of the polycyclic aromatic carboxylic acid compound in the crosslinking polymer to the crosslinking agent is in the range of 1:2 to about 1:

10.

10. The high-temperature corrosion inhibitor according to claim 1, wherein the high-temperature corrosion inhibitor further comprises at least one fatty acid compound selected from the group consisting of natural and synthetic fatty acids, fatty acid derivatives and combinations thereof.

11. The high-temperature corrosion inhibitor according to claim 10, wherein the high-temperature corrosion inhibitor comprises: Polycyclic aromatic carboxylic acid compounds ranging from about 5 wt.% to about 30 wt.%; Crosslinking agent between approximately 10 wt.% and approximately 40 wt.%; and The fatty acid compounds are between about 10 wt.% and about 50 wt.%, wherein the fatty acid compounds are selected from the group consisting of: C5-C 80 Alkyl succinic acid, C5-C 80 Alkenyl succinic acid, diol esters of polyisobutylene succinic acid, and mixtures thereof.

12. The high-temperature corrosion inhibitor according to claim 10, wherein the at least one crosslinking agent is an epoxy alkane, and the high-temperature corrosion inhibitor comprises: Polycyclic aromatic carboxylic acid compounds ranging from about 10 wt.% to about 50 wt.%; Epoxides ranging from about 0.5 wt.% to about 50 wt.%; and Fatty acid compounds ranging from about 0.5 wt.% to about 40 wt.%.

13. The high-temperature corrosion inhibitor according to claim 10, wherein the high-temperature corrosion inhibitor comprises: Polycyclic aromatic carboxylic acid compounds ranging from about 5 wt.% to about 30 wt.%; Between approximately 10 wt.% and approximately 40 wt.% of alkyl oxides; and Fatty acid compounds ranging from approximately 10 wt.% to approximately 50 wt.%.

14. The high-temperature corrosion inhibitor according to claim 10, wherein the high-temperature corrosion inhibitor comprises: Polycyclic aromatic carboxylic acid compounds ranging from about 5 wt.% to about 25 wt.%; Between approximately 5 wt.% and approximately 25 wt.% of alkyl oxides; and Fatty acid compounds ranging from approximately 10 wt.% to approximately 50 wt.%.

15. The high-temperature corrosion inhibitor according to claim 1, wherein the high-temperature corrosion inhibitor further comprises a solvent selected from the group consisting of alkylene carbonates, glycols, glycol ethers, aromatic solvents, alcohols, mineral oils, water, and combinations thereof.

16. The high-temperature corrosion inhibitor according to claim 15, wherein the solvent is propylene glycol carbonate.

17. The high-temperature corrosion inhibitor of claim 15, wherein the high-temperature corrosion inhibitor comprises a solvent between about 10 wt.% and about 40 wt.%.

18. A method for reducing naphthenic acid corrosion at high temperatures, the method comprising the following steps: Provide a high-temperature corrosion inhibitor, wherein the high-temperature corrosion inhibitor comprises a crosslinked polymer; and The high-temperature corrosion inhibitor was used to treat crude oil containing naphthenic acids.

19. A method according to claim 18, wherein the step of providing the high-temperature corrosion inhibitor further comprises the following steps: At least one polycyclic aromatic carboxylic acid compound is reacted with at least one crosslinking agent to form the crosslinked polymer.

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