CN117447664A - Benzoxazine and preparation method thereof, composite coating and preparation method thereof - Google Patents

Benzoxazine and preparation method thereof, composite coating and preparation method thereof Download PDF

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Publication number
CN117447664A
CN117447664A CN202311495617.0A CN202311495617A CN117447664A CN 117447664 A CN117447664 A CN 117447664A CN 202311495617 A CN202311495617 A CN 202311495617A CN 117447664 A CN117447664 A CN 117447664A
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benzoxazine
resin
organic solvent
substrate
catalyst
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邓雅君
李辉
王世斌
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Jimei University
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Jimei University
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D265/00—Heterocyclic compounds containing six-membered rings having one nitrogen atom and one oxygen atom as the only ring hetero atoms
    • C07D265/04—1,3-Oxazines; Hydrogenated 1,3-oxazines
    • C07D265/12—1,3-Oxazines; Hydrogenated 1,3-oxazines condensed with carbocyclic rings or ring systems
    • C07D265/14—1,3-Oxazines; Hydrogenated 1,3-oxazines condensed with carbocyclic rings or ring systems condensed with one six-membered ring
    • C07D265/16—1,3-Oxazines; Hydrogenated 1,3-oxazines condensed with carbocyclic rings or ring systems condensed with one six-membered ring with only hydrogen or carbon atoms directly attached in positions 2 and 4
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G14/00—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00
    • C08G14/02—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes
    • C08G14/04—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes with phenols
    • C08G14/06—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes with phenols and monomers containing hydrogen attached to nitrogen
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D161/00—Coating compositions based on condensation polymers of aldehydes or ketones; Coating compositions based on derivatives of such polymers
    • C09D161/34—Condensation polymers of aldehydes or ketones with monomers covered by at least two of the groups C09D161/04, C09D161/18 and C09D161/20
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/08—Anti-corrosive paints

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Phenolic Resins Or Amino Resins (AREA)

Abstract

The present disclosure provides benzoxazines and methods of making the same, composite coatings and methods of making the same. The benzoxazine comprises curcumin, paraformaldehyde or formaldehyde, a compound containing primary amine groups and a catalyst as raw materials. The composite coating comprises a first resin and a second resin; the first resin is a polybenzoxazine phenolic resin obtained after the benzoxazine is polymerized; the second resin is at least one of oily resin and aqueous resin. The benzoxazine resin disclosed by the disclosure has a lower curing temperature, and the benzoxazine composite coating disclosed by the disclosure has excellent mechanical properties and corrosion resistance.

Description

Benzoxazine and preparation method thereof, composite coating and preparation method thereof
Technical Field
The present disclosure relates to the field of metal corrosion, in particular to the field of resins, and more particularly to benzoxazines and methods of preparing the same, composite coatings and methods of preparing the same.
Background
Metal corrosion is a global problem which afflicts humans for many years, and has a wide range of influence, and is easy to cause huge economic loss. In the eastern coastal region of China, annual rainfall is large, and a large amount of salt particles exist in the air under the action of sea wind. In such a humid and salty environment, the metal is easily corroded, and thus the service life of metal-containing articles such as metal members, ships, bridges, etc. is shortened, and even safety accidents are caused. The metal corrosion prevention technology can greatly slow down the metal corrosion rate, so that a series of adverse effects caused by the metal corrosion are reduced.
At present, the exploration of metal corrosion prevention technology is advanced, the metal structure is changed so that the metal has corrosion prevention performance, a cathode protection method of a sacrificial anode, a protection method of impressed current, and the metal surface is coated with a coating to isolate the metal from a corrosion medium, and the like are all effective metal corrosion prevention technologies. The change of the metal structure can indeed obtain unusual corrosion resistance, but the density is generally larger and the manufacturing cost is high. Both electrochemical protection methods are inherently costly and have many complex circumstances to consider, requiring frequent maintenance. The method for coating the coating on the metal surface has high economic cost performance, long service period and easy realization of the process technology in the construction process, and is a simple and efficient method. Benzoxazines as a thermosetting resin with a high glass transition temperature T g The characteristics of good mechanical property, excellent dielectric property, high molecular design flexibility and the like are superior to other thermosetting resins, and the thermosetting resin can be used as a coating material to achieve excellent corrosion resistance on metal materials, but the traditional polybenzoxazine has the defects of high curing temperature, high brittleness and the like, so that the improvement of the defects and the improvement of the related properties are very important.
Disclosure of Invention
In order to solve the problems in the background art, the present disclosure provides benzoxazines and methods of preparing the same, composite coatings and methods of preparing the same.
The benzoxazine provided by the present disclosure, the raw materials of which include curcumin, paraformaldehyde or formaldehyde, a compound containing a primary amine group, and a catalyst.
In some embodiments, the molar ratio of curcumin, paraformaldehyde, primary amine group-containing compound is (0.01 to 20): (0.02-20): (0.01-20).
The preparation method of the benzoxazine provided by the disclosure comprises the following steps: step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering; step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution; step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; and after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain the benzoxazine concentrated solution containing the catalyst.
In some embodiments, the catalyst comprises at least one of a lewis acid, a lewis base.
In some embodiments, the mass ratio of the catalyst to benzoxazine monomer is (0.001-20): (0.001-20).
The composite coating provided by the disclosure comprises a first resin and a second resin; the resin I is the benzoxazine phenolic resin obtained by polymerizing the benzoxazine according to any one of claims 1-3; the second resin is at least one of oily resin and aqueous resin.
In some embodiments, the second resin is at least one of an acrylic resin, an epoxy resin, a polyester resin, a polyamide resin, and a polyurethane resin.
The preparation method of the composite coating provided by the disclosure comprises the following steps: step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering; step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution; step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain benzoxazine concentrated solution containing the catalyst; step S4, adding bisphenol A epoxy resin into the benzoxazine concentrate, uniformly stirring, then adding bisphenol A epoxy resin curing agent, uniformly stirring again, and applying the mixture on the surface of a substrate; and S5, heating and curing the surface of the substrate treated in the step S4 to form a composite coating comprising the polybenzoxazine phenolic resin.
In some embodiments, the substrate comprises at least one of a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, and a composite substrate formed from the foregoing substrates.
In some embodiments, in step 3, the mass ratio of bisphenol a epoxy resin to benzoxazine is (0.01-10): (0.01-10).
In some embodiments, in step S4, the temperature of the heat cure is 10 to 300 ℃ and the time of the heat cure is 0.1 to 120 hours.
The beneficial effects of the present disclosure are: the benzoxazine resin disclosed by the disclosure has a lower curing temperature, and the benzoxazine composite coating disclosed by the disclosure has excellent mechanical properties and corrosion resistance.
Drawings
Fig. 1 is an infrared spectrum of the composite polybenzoxazine phenolic resin coating of examples 1-6, where curves a-F are the sample spectrum curves of examples 1-6, respectively.
Fig. 2 is a graph of the morphology of the composite polybenzoxazine phenolic resin coating of examples 1-6 after adhesion testing, where a-F are the morphology of the samples of examples 1-6, respectively.
FIG. 3 is a bar graph of adhesion values for examples 1-6, wherein 1-6 are the sample adhesion force profiles for examples 1-6, respectively.
FIG. 4 is a graph of electrochemical corrosion performance test for examples 1-6, wherein carbon steel represents the corrosion performance curves for carbon steel and A-F are the corrosion performance curves for the samples of examples 1-6, respectively.
Detailed Description
It is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms and that the specific details of the disclosure should not be construed as limiting, but merely as a basis for the claims to teach one of ordinary skill in the art to practice the disclosure in various ways. In the description of the present disclosure, terms and specialized words not explicitly described are common general knowledge to those skilled in the art, and methods not explicitly described are conventional methods known to those skilled in the art.
No endpoints of the ranges and any values disclosed in this disclosure are limited to the precise range or value, and such ranges or values are to be understood as encompassing values close to the range or value, and for numerical ranges, one or more new numerical ranges may be obtained by combining each other between the endpoints of each range, between the endpoints of each range and the individual point values, and between the individual point values, and such numerical ranges are to be considered as specifically disclosed herein.
[ benzoxazine ]
Compared with the traditional epoxy resin and phenolic resin, the benzoxazine has the advantages of low water absorption, high modulus, high thermal stability, high cost performance and the like, but has high curing temperature (about 250 ℃), high processing cost and complex molding process, and limits the application range. Researchers have found that the curing temperature of benzoxazines can be reduced by reacting them with a catalyst, thereby expanding their range of applications.
The benzoxazine disclosed herein comprises raw materials including curcumin, paraformaldehyde or formaldehyde, a compound containing a primary amine group, and a catalyst.
In some embodiments, the catalyst comprises at least one of a lewis acid, a lewis base. In some embodiments, the lewis acid comprises copper chloride, aluminum chloride, ferric chloride, ferrous chloride, zinc chloride. In some embodiments, the lewis base comprises potassium thiocyanate, lead thiocyanate, guanidine thiocyanate.
In some embodiments, the primary amine group-containing compound includes a primary amine group-containing silane coupling agent, preferably gamma-aminopropyl triethoxysilane.
In some embodiments, the molar ratio of curcumin, paraformaldehyde, primary amine group-containing compound is (0.01 to 20): (0.02-20): (0.01-20).
[ method for producing benzoxazine ]
The preparation of the benzoxazine can be realized by reacting the benzoxazine with a catalyst in an organic solvent, and separating reaction products to obtain the benzoxazine with different crosslinking structures, thereby achieving the purpose of reducing the curing temperature of the benzoxazine.
In some embodiments, the methods of preparing benzoxazines of the present disclosure include the steps of:
step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering;
step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution;
step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; and after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain the benzoxazine concentrated solution containing the catalyst.
The preparation method of the benzoxazine can greatly reduce the curing temperature of the treated benzoxazine while keeping the original performance of the benzoxazine as much as possible, and is simple and convenient to operate and easy to realize.
In some embodiments, in steps S1 to S3, the organic solvent is selected from at least one of methanol, chloroform, dimethylformamide, xylene, tetrahydrofuran, toluene, and methylene chloride.
In some embodiments, in step S3, the reaction temperature is 5 to 120 ℃ and the reaction time is 2 to 24 hours. In some embodiments, in step S2, the reaction temperature is 40-100deg.C and the reaction time is 4-12 hours.
In some embodiments, in step S3, the catalyst comprises at least one of a lewis acid, a lewis base. In some embodiments, the lewis acid comprises copper chloride, aluminum chloride, ferric chloride, ferrous chloride, zinc chloride. In some embodiments, the lewis base comprises potassium thiocyanate, lead thiocyanate, guanidine thiocyanate.
In some embodiments, in step S3, the mass ratio of the catalyst to benzoxazine monomer is (0.001-20): (0.001-20).
[ composite coating ]
In some embodiments, the composite coating of the present disclosure includes a first resin and a second resin; the first resin is a polybenzoxazine phenolic resin obtained by polymerizing the benzoxazine disclosed by the disclosure; the second resin is at least one of oily resin and aqueous resin.
Researchers find that the coating obtained by blending the polybenzoxazine phenolic resin and the epoxy resin disclosed by the disclosure has more excellent performance than the coating prepared by the polybenzoxazine phenolic resin and the epoxy resin, so that the curing temperature of the coating is reduced, and the performance of the coating is enhanced.
In some embodiments, the second resin is at least one of an acrylic resin, an epoxy resin, a polyester resin, a polyamide resin, and a polyurethane resin.
[ method for producing composite coating ]
In some embodiments, a method of preparing a composite coating of the present disclosure includes the steps of:
step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering;
step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution;
step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain benzoxazine concentrated solution containing the catalyst;
step S4, adding bisphenol A epoxy resin into the benzoxazine concentrate, uniformly stirring, then adding bisphenol A epoxy resin curing agent, uniformly stirring again, and applying the mixture on the surface of a substrate;
and S5, heating and curing the surface of the substrate treated in the step S4 to form a composite coating comprising the polybenzoxazine phenolic resin.
In some embodiments, in step S3, the mass ratio of bisphenol a epoxy resin to benzoxazine is (0.01-10): (0.01-10). In some embodiments, in step S3, the mass ratio of bisphenol a epoxy resin to benzoxazine is (0.01-8): (0.01-8). In some embodiments, in step S3, the mass ratio of bisphenol a epoxy resin to benzoxazine is (0.01-5): (0.01-5).
In some embodiments, in step S4, the temperature of the heat cure is 10 to 300 ℃ and the time of the heat cure is 0.1 to 120 hours. In some embodiments, in step S4, the temperature of the heat cure is 20 to 200 ℃ and the time of the heat cure is 0.1 to 72 hours. In some embodiments, in step S4, the temperature of the heat cure is 40 to 160 ℃ and the time of the heat cure is 0.1 to 48 hours.
In some embodiments, the heating and curing are performed in a gradient heating mode, and the whole system cross-linked network structure of the coating can be more compact in a gradient heating mode, so that the corrosion resistance of the coating can be improved.
The material of the substrate is not particularly limited in the present disclosure. In some embodiments, in step S5, the substrate comprises at least one of a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, and a composite substrate formed from the above substrates.
The composite coating may be attached to the substrate of the article or at least a portion of the surface of the substrate by the methods described above to enhance the corrosion protection properties of the article.
Examples (example)
The disclosure is further illustrated below in conjunction with the examples. In the examples and comparative examples described below, the reagents, materials and apparatus used, unless otherwise specified, were either commercially available or prepared by methods known in the art.
Example 1
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous copper chloride (0.0028 mol,0.379 g), adding the anhydrous copper chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (2.25 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (0.75 g) is added, and then the mixture is fully stirred again, and then spin-coated on the surface of clean glass sheets or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating A is obtained by curing at 40 ℃ for 20min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, then at 100 ℃ for 20min and finally at 120 ℃ for 1.5 h.
Example 2
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous copper chloride (0.0028 mol,0.379 g), adding the anhydrous copper chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A type epoxy resin (3.75 g) was added to the treated benzoxazine monomer, and after the mixture was thoroughly stirred, bisphenol A type epoxy resin curing agent (1.25 g) was added. Then, stirring again fully, and spin-coating on the clean glass sheet or carbon steel surface for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating B is obtained by curing at 40 ℃ for 20min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, at 100 ℃ for 20min and at 120 ℃ for 1.5 h.
Example 3
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous zinc chloride (0.0028 mol, 0.3832 g), adding the anhydrous zinc chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (2.25 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (0.75 g) is added, and then the mixture is fully stirred again, and then spin-coated on the surface of clean glass sheets or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating C is obtained by curing at 40 ℃ for 20min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, then at 100 ℃ for 20min and finally at 120 ℃ for 1.5 h.
Example 4
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous zinc chloride (0.0028 mol, 0.3832 g), adding the anhydrous zinc chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (3.75 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (1.25 g) is added, so that the mass of the epoxy resin accounts for 50wt% of the total mass. Then, stirring again fully, and spin-coating on the clean glass sheet or carbon steel surface for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating D is obtained by curing at 40 ℃ for 20min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, then at 100 ℃ for 20min and finally at 120 ℃ for 1.5 h.
Example 5
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous copper chloride (0.0028 mol,0.379 g), adding the anhydrous copper chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; after the reaction is finished, removing redundant organic solvent by spin evaporation, and then spin-coating on the surface of clean glass sheets or carbon steel for curing treatment, wherein the curing process is as follows: the polybenzoxazine coating E was obtained by curing at 40℃for 20min, then at 60℃for 20min, then at 80℃for 20min, then at 100℃for 20min, and finally at 120℃for 1.5 h.
Example 6
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of tetrahydrofuran to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous zinc chloride (0.0028 mol, 0.3832 g), adding the anhydrous zinc chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; after the reaction is finished, removing redundant organic solvent by spin evaporation, and then spin-coating on the surface of clean glass sheets or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating F is obtained by curing at 40 ℃ for 20min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, then at 100 ℃ for 20min and finally at 120 ℃ for 1.5 h.
Example 7
Curcumin (0.07 mol,25 g) and paraformaldehyde (0.985 mol,30 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.225 mol,25 g) and 300mL chloroform are added, and the mixture is reacted in an oil bath pot at 85 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 100mL of chloroform to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous copper chloride (0.0185 mol,2.5 g), adding the anhydrous copper chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (12.6 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (4.2 g) is added, so that the mass ratio of the benzoxazine monomer to the epoxy resin is 2:1, then stirring thoroughly again, and spin-coating on the surface of clean glass sheet or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating G is obtained by curing at 40 ℃ for 30min, then at 60 ℃ for 20min, then at 80 ℃ for 20min, then at 100 ℃ for 20min and finally at 120 ℃ for 2h.
Example 8
Curcumin (0.01 mol,3.68 g) and paraformaldehyde (0.04 mol,1.22 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.04 mol,4.42 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath at 80 ℃ for 8 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by spin evaporation, and then spin-coating on the surface of a clean glass sheet or carbon steel for curing treatment, wherein the curing process is as follows: the polybenzoxazine coating H is obtained by curing for 1H at 60 ℃, then for 2H at 180 ℃, then for 2H at 200 ℃ and finally for 2H at 220 ℃.
Example 9
Curcumin (0.05 mol,18.4 g) and paraformaldehyde (0.262 mol,8 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.036 mol,4 g) and 60mL tetrahydrofuran are added, and the mixture is reacted in an oil bath pot at 90 ℃ for 12 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of chloroform to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous zinc chloride (0.0044 mol,0.6 g), adding the anhydrous zinc chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (5.25 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (1.75 g) is added, so that the mass ratio of the benzoxazine monomer to the epoxy resin is 4:1, then, fully stirring again, and then spin-coating on the surface of a clean glass sheet or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating I is obtained by curing at 60 ℃ for 30min, at 80 ℃ for 20min, at 100 ℃ for 20min and at 120 ℃ for 1 h.
Example 10
Curcumin (0.011mol, 4 g) and paraformaldehyde (0.328 mol,10 g) are weighed into a 250mL three-neck flask, gamma-aminopropyl triethoxysilane (0.023 mol,2.5 g) and 60mL chloroform are added, and the mixture is reacted in an oil bath pot at 70 ℃ for 6 hours; after the reaction is finished, filtering the obtained mixture solution, removing redundant organic solvents by rotary evaporation to obtain a benzoxazine monomer, adding 15mL of chloroform to dissolve the benzoxazine monomer, adding 2mL of methanol to dissolve anhydrous copper chloride (0.0014 mol,0.2 g), adding the anhydrous copper chloride and the benzoxazine monomer into a single-neck flask together, and then reacting for 2 hours in an oil bath pot at 60 ℃; and after the reaction is finished, removing redundant organic solvent by rotary evaporation to obtain the treated benzoxazine monomer.
Bisphenol A epoxy resin (2.85 g) is added into the treated benzoxazine monomer, and after the mixture is fully stirred and uniformly mixed, bisphenol A epoxy resin curing agent (0.95 g) is added, so that the mass ratio of the benzoxazine monomer to the epoxy resin is 3:1, then, fully stirring again, and then spin-coating on the surface of a clean glass sheet or carbon steel for curing treatment, wherein the curing process is as follows: the composite polybenzoxazine coating J is obtained by curing at 40 ℃ for 30min, then at 60 ℃ for 30min, then at 80 ℃ for 30min, then at 100 ℃ for 20min and finally at 120 ℃ for 1.5 h.
The parameters of the materials involved in the test of examples 1 to 10 and the highest curing temperatures of the samples obtained are shown in Table 1. For ease of illustration, the symbols are used in table 1 to denote the substances:
a1: curcumin;
a2: gamma-aminopropyl triethoxysilane;
a3: paraformaldehyde;
b1: copper chloride;
b2: zinc chloride;
c1: bisphenol a type epoxy resin;
c2: bisphenol A type epoxy resin curing agent.
The relevant samples finally obtained in the above examples were then subjected to infrared tests, mechanical tests and corrosion tests.
1. Infrared test
The absorbance test was performed by scanning with an infrared spectrometer FT-IR (IS-50) for the polybenzoxazine phenolic resin-epoxy resin composite coatings obtained in examples 1 to 6, respectively, and the scanning results are shown in fig. 1.
2. Mechanical testing
The samples of the polybenzoxazine phenolic resin-epoxy resin composite coating obtained in examples 1-6 are respectively subjected to adhesion test in a mode of drawing by using a drawing tester PosiTest AT, the appearance is observed, the appearance diagram of the sample is shown in figure 2, and the adhesion test result is shown in figure 3.
3. Corrosion resistance test
Respectively taking the polybenzoxazine phenolic resin-epoxy resin composite coating obtained in the examples 1-6 and blank carbon steel for electrochemical corrosion performance test, wherein an Ag/AgCl electrode is used as a reference electrode, a platinum electrode is used as an auxiliary electrode in the electrochemical test, a three-electrode test environment with a sample as a working electrode is adopted, a 3.5wt% NaC1 solution is used as a test solvent, and the Protection Efficiency (PE) is tested:wherein I is corr,bare And I corr,coated Representing the current densities of carbon steel and resin, respectively. The test results are shown in table 2 and fig. 4, respectively, wherein table 2 shows the electrochemical corrosion performance test results; FIG. 4 shows a Tafel test plot of electrochemical corrosion performance.
Table 1 examples 1-10 parameters of matter involved in the test procedure and the highest cure temperature of the resulting samples
Note that: -means not added.
As can be seen from Table 1, the curing temperature of the samples was as high as 220℃in the case where the catalysts copper chloride and zinc chloride were not added, whereas the curing temperature of the samples was reduced to 120℃in the case where the catalysts copper chloride and zinc chloride were used.
Table 2 polarization parameters of the coating after 0.5h immersion in 3.5% NaCl solution
Note that: * Taking the value as a reference value.
As can be seen from FIG. 1, 1511 cm and 1581cm -1 Typical bands at these are due to C=C vibrations in the aromatic ring, 1260 and 1076cm -1 The characteristic peak is benzoxazine ringC-O-C stretching vibration of middle symmetry and asymmetry, 1365 and 3365cm -1 respectively-CH in oxazine ring 2 From the above, it is clear that the characteristic peaks of different functional groups of the benzoxazine are successfully detected, which is enough to prove that the benzoxazine is successfully prepared.
As can be seen from the test results of table 2 and fig. 4, the polybenzoxazine phenolic resin-epoxy resin composite coating layer shows excellent corrosion resistance after being coated on the surface of the substrate, and is suitable for simulating the brine environment of the ocean, compared with the blank substrate.
As can be seen from table 2, fig. 2 and fig. 3, the benzoxazine phenolic resin-epoxy resin composite coating added with zinc chloride and copper chloride has excellent mechanical properties and also has unusual corrosion resistance.
The above description is merely exemplary of the disclosure, and not intended to limit the disclosure in any way, and although the disclosure has been described above with reference to the preferred embodiments, it is not intended to limit the disclosure, but rather to cover all modifications and equivalents of the disclosed embodiments without departing from the scope of the disclosure.

Claims (11)

1. The benzoxazine is characterized in that the benzoxazine comprises curcumin, paraformaldehyde or formaldehyde, a compound containing primary amine groups and a catalyst as raw materials.
2. The benzoxazine according to claim 1, wherein the molar ratio of curcumin, paraformaldehyde, primary amine group-containing compound is (0.01 to 20): (0.02-20): (0.01-20).
3. A method for preparing benzoxazine, which is characterized by comprising the following steps:
step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering;
step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution;
step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; and after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain the benzoxazine concentrated solution containing the catalyst.
4. A method of preparing a benzoxazine according to claim 3, wherein said catalyst comprises at least one of a lewis acid, a lewis base.
5. The method for producing benzoxazine according to claim 3, wherein the mass ratio of the catalyst to the benzoxazine monomer is (0.001 to 20): (0.001-20).
6. A composite coating, which is characterized by comprising a first resin and a second resin; the resin I is the benzoxazine phenolic resin obtained by polymerizing the benzoxazine according to any one of claims 1-2; the second resin is at least one of oily resin and aqueous resin.
7. The composite coating of claim 6, wherein the second resin is at least one of an acrylic resin, an epoxy resin, a polyester resin, a polyamide resin, and a polyurethane resin.
8. The preparation method of the composite coating is characterized by comprising the following steps:
step S1, curcumin, paraformaldehyde or formaldehyde and a compound containing primary amine groups react in an organic solvent to obtain a benzoxazine monomer, and then filtering;
step S2, spin-evaporating the filtered solution to remove redundant organic solvent, and then dissolving benzoxazine monomer in the organic solvent to obtain a first solution;
step S3, adding an organic solvent containing a catalyst into the first solution, and then stirring and reacting for 1-48 h at the temperature of 5-180 ℃; after the reaction is finished and cooled, removing redundant organic solvent by rotary evaporation to obtain benzoxazine concentrated solution containing the catalyst;
step S4, adding bisphenol A epoxy resin into the benzoxazine concentrate, uniformly stirring, then adding bisphenol A epoxy resin curing agent, uniformly stirring again, and applying the mixture on the surface of a substrate;
and S5, heating and curing the surface of the substrate treated in the step S4 to form a composite coating comprising the polybenzoxazine phenolic resin.
9. The method of claim 8, wherein the substrate comprises at least one of a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, and a composite substrate formed from the above substrates.
10. The method for producing a composite coating according to claim 8, wherein in step 3, the mass ratio of bisphenol a type epoxy resin to benzoxazine is (0.01 to 10):
(0.01～10)。
11. the method of preparing a composite coating according to claim 8, wherein in the step S4, the temperature of the heat curing is 10 to 300 ℃ and the time of the heat curing is 0.1 to 120 hours.
CN202311495617.0A 2023-11-10 2023-11-10 Benzoxazine and preparation method thereof, composite coating and preparation method thereof Pending CN117447664A (en)

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