RU2767683C2 - Protective coating based on fluorine-containing phthalonitrile oligomers for polymer composite materials - Google Patents

Abstract

FIELD: polymer materials.SUBSTANCE: group of inventions relates to polymer composite materials produced from phthalonitrile oligomers as a component of a polymerisable resin for protective coatings of a polymer composite matrix. Materials with phthalonitrile matrices can be applied in engine parts in the aerospace industry, for high-temperature protection of electronics, and for application in shipbuilding in manufacture of non-flammable interior elements of submarines. The phthalonitrile oligomer as a component of a polymerisable resin for protective coatings of a polymer composite matrix constitutes a compound by the formula (I)(I),or the formula (II)(II),or the formula (III)(III).Described is a method for producing a phthalonitrile oligomer, characterised by consecutive nucleophilic substitution of fluorine atoms in hexafluorobenzene and/or a nitro group in 4-nitrophthalonitrile with hydroxyl-containing aromatic compounds. Also described are a composition for preparing a thermosetting resin, including at least one compound (I) or (II) or a mixture thereof with a compound by the formula (III), and a hardener, a method for preparing a thermosetting resin, and a method for preparing a thermosetting varnish. The thermosetting resin can be applied to the surface of a composite in the form of a melt or varnish (a solution of resin in an organic solvent) to create protective coatings.EFFECT: production of a thermosetting resin based on fluorine-containing oligomers, exhibiting enhanced thermal-oxidative stability in the hardened form, as a protective coating, allowing for preservation (~90%) of the operating characteristics of PCM even after 200 h at 350°C; unlike known coatings based on phthalonitrile resins allowing, in the same conditions, for preservation of only ~70% of the initial operating characteristics of the composite; and characterised by ease of application.29 cl, 1 tbl, 56 ex

Description

Technical field

SUBSTANCE: group of inventions relates to polymer composite materials (PCM), namely to the production of coatings on polymer composite materials with phthalonitrile matrices that protect them from oxidation in air at elevated temperatures, for use in the aerospace industry in the manufacture of engine parts, for high-temperature protection electronics, as well as for use in shipbuilding in the manufacture of non-combustible parts of the interior of submarines.

State of the art

Polymer composite materials with phthalonitrile matrices are known for high temperature resistance, namely glass transition temperatures above 400°C and decomposition temperatures above 500°C. However, during prolonged exposure of PCMs with phthalonitrile matrices at temperatures above 300°C, the mechanical properties are completely lost quite quickly, limiting the possible service life of such materials. To increase the service life of PCM parts operated at high temperatures, it is necessary to create barrier coatings that block the access of oxygen to the composite.

To protect polymer composite materials (PCM) with heat-resistant matrices (polyimide, bis-maleimide) from oxidation during long-term operation at high temperatures, several inorganic protective coatings and methods for their application are known, presented below.

A known method of protecting PCM products from oxidation at high temperatures, which consists in applying a protective coating to PCM products by atomic layer deposition (EP3540002). These coatings protect PCM at temperatures up to 316°C (600 F). Composites consisting of carbon, glass, graphite, aramid, polymer, ceramic fibers or their mixtures were used as PCMs, both thermosetting and thermoplastic materials were used as a matrix, for example: bis-maleimides, cyan esters, epoxy resins, phenol-formaldehyde resins , polyetheretherketone, polyimides, and as a protective coating used Al ₂ O ₃ , CeO ₂ , MgO, NiO, TiO ₂ , V ₂ O ₅ , ZrO ₂ and mixtures thereof, and/or nitrides: AlN, HfN, InN, MgN, NbN, SiN, TaN, TiN, ZrN and mixtures thereof, and/or oxynitrides such as silicon oxynitride, SiOxNy, aluminum oxynitride, (AlN)x ⋅ (Al ₂ O ₃ )1-x, and mixtures thereof. The disadvantages of the presented coatings are low adhesion to the PCM surface and a large difference in thermal expansion coefficients, which leads to peeling and cracking of the coating.

Known protective coating of aluminum oxide, heat-resistant alloy of Nickel, chromium, aluminum and yttrium (NiCrAlY) and silicon nitride deposited on carbon fiber with a polyimide matrix by vapor deposition methods (DR Harding et al.: Oxidation protective barrier coatings for high-temperature polymer matrix composites, J. Mater, Res., Vol. 9, No. 6, Jun 1994, PP 1584-1595). Coatings based on silicon nitride during thermal aging for 200 h at 371°C showed 33-50% less weight loss than uncoated samples. Coatings based on aluminum oxide peeled off from the PCM surface immediately after deposition; coatings based on NiCrAlY peeled off PCM during aging at 371°C. Thus, the known coatings are characterized by poor adhesion to the PCM, which does not provide the protective function of the coating. Also, due to the impossibility of coating the ends of the PCM samples, it was impossible to increase the working time of the composite.

Known protective coating consisting of silver, aluminum, titanium and aluminum oxide deposited on carbon fiber with a bis-maleimide matrix by thermal and electron beam sputtering (N. An et al.: Thermo-oxidative performance of metal-coated polymers and composites, Surface & Coatings Technology 232 (2013) 166-172). Coatings with a thickness of 55-2800 nm were obtained, which also required the application of intermediate chromium layers to reduce the difference between the thermal expansion coefficients of the protective coating materials and carbon fiber with a bis-maleimide matrix. The best properties retention results were obtained for silver coatings with a thickness of 580–700 nm. Aging was carried out at 177°С, and the area of the oxidized surface of the composite turned out to be 20% lower than that of the uncoated reference sample.

However, all known protective coatings of inorganic nature for application on PCM require the application of additional layers to level the difference in the coefficients of thermal expansion of the composite (PCM) and the coating. Also, the problem of applying such layers is the complexity of their application, requiring special equipment. In this case, the coating of large parts of complex shape is difficult.

The closest to the claimed solution is a multilayer protective coating for PCM with a polyimide matrix, consisting of a protective layer of vanadium-cobalt carbide, a middle layer of a composite of vanadium-cobalt carbide and polyimide, and an inner layer consisting of polyimide, necessary to reduce the difference between the coefficients of thermal material extensions. The lower and middle layers of the coating are applied to the surface of the PCM by high-speed flame spraying, and the outer layer is applied by thermal spraying of powder in a flame, which avoids entrainment of the first two layers by a gas flow (M. Ivosevic et al .: Adhesive / Cohesive Properties of Thermally Sprayed Functionally Graded Coatings for Polymer Matrix Composites, Journal of Thermal Spray Technology Volume 14(1) March 2005-45). The thickness of the coatings is 600 µm. There is no information about the protective properties of the coating in the publication. However, it should be noted that the protective layer of vanadium-cobalt carbide, when applied to PCM with phthalonitrile matrices, will not have high adhesion to the composite material, while the difference between the thermal expansion coefficients of the materials of the protective coating and carbon fiber will be significant, which will lead to cracking of the coating. In addition, the use of this coating is limited by the complexity of application, because. methods of high-speed flame spraying and thermal spraying of powder in a flame are implemented only with the help of special robotic installations.

The technical problem solved by the claimed invention is the need to overcome the disadvantages inherent in analogs and the prototype, namely, the protection of PCM products from oxidation at high temperatures while simplifying the method of applying a protective coating on PCM by excluding additional layers from the coating that were applied in known solutions to reduce the difference between the coefficients of thermal expansion of materials.

Disclosure of invention

The technical result of the claimed group of inventions is to obtain a new compound - a fluorine-containing oligomer, which, when used in a composition for producing a thermosetting resin intended for application to the surface of a PCM with a phthalonitrile matrix, provides high adhesion of the protective layer to the matrix and a minimum difference in the thermal expansion coefficients of the coating materials and composite, which makes it possible to obtain a protective coating, which, with prolonged temperature exposure, allows maintaining performance characteristics, such as interlaminar shear strength, tensile strength, and compression strength. Due to the resistance of such a coating to oxidation at elevated temperatures, the performance characteristics of PCM are retained by ~90% even after heating for 200 h at 350°C compared to materials coated with a composition containing a non-fluorine-containing oligomer (phthalonitrile resin), which in those the same conditions make it possible to save only ~70% of the initial performance characteristics of the composite.

Also, the claimed compositions are characterized by the ease of coating the surface of the part, since they do not require the application of additional layers to reduce the difference between the coefficients of thermal expansion, and the use of complex installations.

The technical result is achieved by a phthalonitrile oligomer as a component of a polymerizable resin for protective coatings of a polymer composite matrix, which is a compound of formulas (I)

(I)

(I)

or formula (II):

(II)

(II)

or formula (III):

(III)

(III)

The technical result is also achieved by a method for producing a phthalonitrile oligomer according to claim 1, characterized in that sequential nucleophilic substitution of fluorine atoms in hexafluorobenzene and the nitro group in 4-nitrophthalonitrile with hydroxyl-containing aromatic compounds is carried out.

To obtain a compound of formula (I) for the nucleophilic substitution of fluorine atoms, hydroquinone is dissolved in a high-boiling polar aprotic solvent, taken at the rate of ~ 5-10 ml per 1 g of a mixture of soluble components, an inorganic salt is added to the solution, taken at the rate of 1-1.25 mol per 1 mol hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, and then hexafluorobenzene is added, taken at the rate of 2 molar equivalents of hexafluorobenzene per 3 molar equivalents of hydroquinone, the resulting reaction mixture is heated to 60 ± 5 ° C and left under stirring for 24 ± 2 hours, followed by heating to 110 ± 5°C and holding with stirring for 36 ± 2 hours, then the reaction mixture is added to a large excess of water at room temperature, stirred and left to precipitate, the precipitate is filtered off and washed from residues solvent, base and unreacted hydroquinone, then dried. To replace the nitro group in 4-nitrophthalonitrile, obtained after nucleophilic substitution of fluorine atoms, bisphenol is dissolved in a high-boiling polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, then an inorganic salt is added, taken from the calculation of 1- 1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, then 4-nitrophthalonitrile is added, taken at the rate of 1 mol of 4-nitrophthalonitrile per 1 mol of the hydroxyl group involved in the reaction, the reaction mixture is heated to 80 ± 5°C and left under stirring for 24 ± 2 hours, then the reaction mixture is added to a large excess of water at room temperature, stirred and left at room temperature for precipitation, the precipitate is filtered off and washed from unreacted residues and dried. In this case, N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide is used as a high-boiling aprotic solvent, and potassium fluoride, potassium carbonate, potassium phosphate are used as an inorganic salt. For precipitation, the reaction mixture after adding to water at room temperature, taken in a volume of 2.5-3.0 times the volume of the organic solvent, is kept for 2 ± 0.5 hours, and to dry the precipitate, it is placed for 12 ± 1 hours in a heated oven. up to 100°C.

To obtain a compound of formula (II) for nucleophilic substitution of fluorine atoms, 4-(3-hydroxyphenoxy)phthalonitrile or hydroquinone is dissolved in a polar aprotic solvent taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, an inorganic salt taken from calculation of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, and then hexafluorobenzene is added, taken at the rate of 1 mole equivalent of hexafluorobenzene per 1 mole equivalent of 4-(3-hydroxyphenoxy)phthalonitrile or hydroquinone, the resulting reaction mixture is heated to 30±5°C and left under stirring for 96±2 hours, then the reaction mixture is filtered through a thin layer of silica gel, the precipitate is washed, the filtrate is evaporated and flash chromatography is carried out using a mixture of methylene chloride/petroleum ether, taken in a volume ratio of 1/1. To replace the nitro group in 4-nitrophthalonitrile, the compound obtained after nucleophilic substitution of fluorine atoms, taken at the rate of 1 mol per 1 mol of the hydroxyl group participating in the reaction, is added to a solution of hydroquinone or 4-(3-hydroxyphenoxy)phthalonitrile in a polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, with the addition of an inorganic salt, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, the resulting reaction mixture is heated to 100±5°C and left under stirring for 120 ± 2 hours, then the reaction mixture is added to a large excess of water at room temperature, stirred and left (incubated) until a precipitate forms, the precipitate is filtered off and washed from unreacted residues 3 times with 10 ml of acetone and dried. In this case, acetone, N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide are used as a polar aprotic solvent, and potassium fluoride, potassium carbonate, potassium phosphate are used as an inorganic salt. To obtain a precipitate, the reaction mixture is added to water at room temperature, taken in a volume of 2.5-3.0 times the volume of the organic solvent and kept for 2 ± 0.5 hours, to dry the precipitate, it is placed for 12 ± 1 hours in an oven heated to 100 °C

To obtain a compound of formula (III), 4-(3-hydroxyphenoxy)phthalonitrile is dissolved in a polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, then an inorganic salt is added, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30±5 minutes, hexafluorobenzene is added, taken at the rate of 1 molar equivalent of hexafluorobenzene per 2 molar equivalents of 4-(3-hydroxyphenoxy)phthalonitrile, the resulting reaction mixture is heated to 60±5 °C and left under stirring for 96 ± 2 hours, then the reaction mixture is filtered through a thin layer of silica gel, the precipitate is washed 3 times with 10 ml of acetone, the filtrate is evaporated, flash chromatography is carried out using a mixture of methylene chloride/petroleum ether, taken in a volume ratio 1/1. In this case, acetone, N,N-dimethylacetamide, N,N-dimethylformamide or N-methyl-2-pyrrolidone are used as a polar aprotic solvent, potassium fluoride, potassium carbonate, potassium phosphate are used as an inorganic salt. To obtain a precipitate, the reaction mixture is added to water at room temperature, taken in a volume of 2.5-3.0 times the volume of the organic solvent and incubated for 2±0.5 hours. To dry the precipitate, it is placed for 12 ± 1 hours in an oven heated to 100°C.

The technical result is also achieved by a composition for the preparation of a thermosetting resin, comprising at least one compound of formula I-III and a hardener selected from the group including 4-(4-aminophenoxy)phthalonitrile, 4-(3-aminophenoxy)phthalonitrile, 4, 4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline, 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline taken at a concentration of 4 to 20 wt. %.

The technical result is also achieved by a method for preparing a thermosetting resin, which consists in the fact that the compound of formula I-III is melted at a temperature of 120-180°C and a hardener is added with stirring, the resulting mixture is stirred for 15-60 minutes, after which the mixture is cooled to harden.

Also, the technical result is achieved by a method for preparing a thermosetting varnish from a thermosetting resin obtained by the claimed method, which consists in dissolving the resin in a solvent selected from the group of acetone, methyl ethyl ketone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2- pyrrolidone, taken in an amount that provides a solution for application to the PCM surface.

Implementation of the invention

The inventive fluorine-containing oligomers of formula (I-III) are obtained by successive nucleophilic substitution of fluorine atoms in hexafluorobenzene (or hexafluorobenzene derivatives) and the nitro group in 4-nitrophthalonitrile with various hydroxyl-containing aromatic compounds.

To obtain a compound of formula (I) dissolve hydroquinone in a high-boiling polar aprotic solvent selected from the group including N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components. An inorganic salt is then added which acts as a base but is a weak nucleophile selected from the group consisting of K₂CO₃ or K₃PO₄, or potassium fluoride (KF) - is a strong nucleophile, but does not form by-products, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes. After that, hexafluorobenzene is added, taken at the rate of 2 molar equivalents of hexafluorobenzene per 3 equivalents of hydroquinone, the resulting reaction mixture is heated to 60±5°C and left under stirring for 24±2 hours, followed by heating to 110±5°C and keeping under stirring for within 36±2 hours. Then the reaction mixture is added to a large excess of water at room temperature (2.5-3.0 times the volume of the solvent used), stirred and left (incubated) for 2±0.5 hours at room temperature. The precipitate is filtered off and washed several times with hot water (85-95°C) to wash off the remnants of the solvent, base and unreacted hydroquinone, then placed for 12±1 hours in an oven heated to 100°C. The resulting bisphenol is dissolved in a high-boiling polar aprotic solvent selected from the group including N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components. An inorganic salt is then added which acts as a base but is a weak nucleophile selected from the group consisting of K₂CO₃ or K₃PO_4, or potassium fluoride (KF) - is a strong nucleophile, but does not form by-products, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes. After that, 4-nitrophthalonitrile is added, taken at the rate of 1 mol of 4-nitrophthalonitrile per 1 mol of the hydroxyl group involved in the reaction, the reaction mixture is heated to 80±5°C and left under stirring for 24±2 hours. Then the reaction mixture is added to a large excess of water at room temperature (2.5-3.0 times the volume of the organic solvent), stirred and kept (left) for 2±0.5 hours at room temperature. The precipitate is filtered off and washed several times with hot water (85-95°C) to wash off the remnants of the solvent or base, then placed for 12±1 hours in an oven heated to 100°C.

To obtain a compound of formula (II), dissolve 4-(3-hydroxyphenoxy)phthalonitrile in a polar aprotic solvent selected from the group consisting of acetone, N,N-dimethylacetamide, N,N-dimethylformamide, or N-methyl-2-pyrrolidone taken from calculation ~5-10 ml per 1 g of a mixture of soluble components. Then an inorganic salt is added, which acts as a base and is a weak nucleophile, for example, K ₃ PO ₄ , potassium carbonate, or KF, which is a strong nucleophile, but does not form by-products, taken at the rate of 1-1.25 mol per 1 mol involved in reaction of the hydroxyl group, after which the reaction mixture is stirred for 30±5 minutes. After that, hexafluorobenzene is added, taken at the rate of 1 molar equivalent of hexafluorobenzene per 1 equivalent of 4-(3-hydroxyphenoxy)phthalonitrile, the resulting reaction mixture is heated to 30±5°C and left under stirring for 96±2 hours. Then the reaction mixture is filtered through a thin layer of silica gel (so that inorganic compounds and unreacted 4-(3-hydroxyphenoxy)phthalonitrile remain on silica gel), the precipitate is washed 3 times with 10 ml of acetone. The filtrate is evaporated, resulting in a mixture of mono- and di-substitution products. To obtain pure target compound (4-(3-(perfluorophenoxy)phenoxy)phthalonitrile), flash chromatography is carried out (eluent mixture of methylene chloride/petroleum ether 1/1). At the second stage of the preparation process (II), hydroquinone is dissolved in a polar aprotic solvent selected from the group including acetone, N,N-dimethylacetamide, N,N-dimethylformamide or N-methyl-2-pyrrolidone, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components. Then an inorganic salt is added, acting as a base and being a weak nucleophile, for example, K ₃ PO _4, potassium carbonate or KF (strong nucleophile, but does not form by-products), taken at the rate of 1-1.25 mol per 1 mol of hydroxyl involved in the reaction group, after which the reaction mixture is stirred for 30±5 minutes. After that, 4-(3-(perfluorophenoxy)phenoxy)phthalonitrile obtained earlier, taken at the rate of 1 mol per 1 mol of the hydroxyl group involved in the reaction, is added, the reaction mixture is heated to 100±5°C and left under stirring for 120±2 hours . Then the reaction mixture is added to a large excess of water at room temperature (2.5-3.0 times the volume of the organic solvent), stirred and incubated (left for) 2±0.5 hours at room temperature. The precipitate is filtered off and washed several times with hot water (85-95°C) to wash off the remnants of the solvent, base or unreacted hydroquinone, then placed for 12±1 hours in an oven heated to 100°C.

An alternative method for obtaining compound (II) also involves the use of nucleophilic substitution reactions, but at the first stage, hydroquinone phenolate ion is used as a nucleophile instead of 4-(3-hydroxyphenoxy)phthalonitrile phenolate ion. Conversely, the second step uses 4-(3-hydroxyphenoxy)phthalonitrile phenolate ion instead of hydroquinone phenolate ion.

To obtain a compound of formula (III), 4-(3-hydroxyphenoxy)phthalonitrile is dissolved in a polar aprotic solvent selected from the group consisting of acetone, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components. Then an inorganic salt is added, which acts as a base, but is a weak nucleophile, for example, potassium carbonate, potassium phosphate, KF (strong nucleophile, but does not form by-products), taken at the rate of 1-1.25 mol per 1 mol involved in reaction of the hydroxyl group, after which the reaction mixture is stirred for 30±5 minutes. After that, hexafluorobenzene is added, taken at the rate of 1 molar equivalent of hexafluorobenzene per 2 equivalents of 4-(3-hydroxyphenoxy)phthalonitrile, the resulting reaction mixture is heated to 60±5°C and left under stirring for 96±2 hours. Then the reaction mixture is filtered through a thin layer of silica gel (so that inorganic compounds and unreacted 4-(3-hydroxyphenoxy)phthalonitrile remain on silica gel), the precipitate is washed 3 times with 10 ml of acetone. The filtrate is evaporated, resulting in a mixture of mono- and di-substitution products. To obtain pure target compound (III), flash chromatography is carried out (eluent - a mixture of methylene chloride/petroleum ether 1/1).

To prepare a thermosetting resin or varnish, fluorine-containing oligomers of formula (I-III) are mixed with hardeners. To do this, the phthalonitrile oligomer is melted at a temperature of 120-180℃ and a hardener is added with stirring, the resulting mixture is stirred for 15-60 minutes. After that, the mixture is poured into a flat metal or glass container treated with an anti-adhesive agent and left at room temperature to cool.

As a hardener, compounds selected from the group including 4-(4-aminophenoxy)phthalonitrile, 4-(3-aminophenoxy)phthalonitrile, 4,4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline are used. , 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline taken at a concentration of 4 to 20% (mass).

Coating is possible in the form of a melt, preheated to a temperature of 100-160°C, with a brush or by spraying with compressed air.

In another embodiment of the invention, thermosetting resins can be dissolved in solvents selected from the group of acetone, methyl ethyl ketone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, to obtain a varnish. The varnish is applied to the PCM surface using a molar brush or spray, evenly covering the entire PCM surface, then heated at a temperature that ensures the removal of the solvent.

The application of such coatings is possible on PCM that satisfies the following conditions: chemical similarity of the composite matrix material and coating, which ensures high adhesion and minimal difference in thermal expansion coefficients (prevents cracking of the coating); the operating temperature of PCM is comparable to the operating temperature of the coating (but not higher). These conditions are met by PCMs based on phthalonitriles.

PCM was obtained in two ways: by vacuum infusion (A) and by vacuum pressing (B). At the same time, the use of coatings is not limited to PCMs obtained by these methods; PCMs formed by other methods, but using a matrix based on phthalonitriles, can also be used.

Method A. The vacuum bag was assembled on a stainless steel tool with a silicone release coating applied to the surface. 2x2 twill carbon fabric, 200gsm² (fiber HTA-40, 3k https://www.teijincarbon.com/ru/produkci%D1%8F/uglerodn%D1%8Be-volokna-tenax%C2%AE/zzgut%D1%8B-tenax%C2%AE /) were cut into pieces 30×30 cm in size (10 layers) and laid out according to the formula [0]₁₂. Next, a vacuum bag was assembled and placed in a heating cabinet, heated to 120°C. The binder (600 g) FNI350 (http://itecma.ru/products/svyazuyushchie/do-450/46/) was degassed in a glass reactor at a temperature of 120°C and reduced pressure, then poured into a metal beaker, transferred to a heating cabinet, and placed into it the inlet tube from the package and impregnation began. After 10-15 minutes, the binder came out of the package, which meant the end of the impregnation. The package was sealed, the temperature in the cabinet was raised to 180°C at a rate of not more than 2°C/min, and kept for 8 hours. After that, the package was disassembled, the pre-cured sample was removed and post-cured in free form according to the following program: heating to 180°C at a rate not exceeding 2°C/min, 30 minutes of exposure and heating to the post-curing temperature (330-375°C) at a rate of 10 °C/h, 8 hours hold.

Method B. The bag was assembled on a stainless steel tool with a silicone release coating applied to the surface. RHT450 prepreg sheets (based on 2×2 twill carbon fabric with a density of 240 g/ ^m2 , HTA-40 fiber, 3k https://www.teijincarbon.com/ru/produkci%D1%8F/uglerodn%D1%8Be- volokna-tenax%C2%AE/zzgut%D1%8B-tenax%C2%AE/, TU 23.99.14-044-73047899-2018) were cut into pieces 30 × 30 cm in size (9 layers) and laid out on a tooling inside a silicone frames 30×30 cm so that the layer of applied binder on each of the layers is on top. From above, the prepreg sheets were covered with a dry layer of fabric and a steel plate (residue) 30 × 30 cm in size. Then, a drainage material of the brand Nialon® IP 340 A with dimensions of 45 × 55 cm was laid on top of the formed layer. A vacuum bag was assembled around the tooling, then placed in a Langzauner heat press LZT-L 250 and evacuated. The temperature of the press was raised to 140°C at a rate of 2°C/min, a pressure of 8.75 bar was applied to the sample, followed by heating to 180°C at a rate of 2°C/min, increasing the pressure to 21.8 bar, and holding for 8 hours . After that, the package was dismantled, the pre-cured sample was removed and post-cured in free form according to the following program: heating to 180°C at a rate not exceeding 2°C/min, holding for 30 minutes, and heating to a post-curing temperature (330–375°C) at a rate of 10 °C/h, 8 hours hold.

The coating can be applied to the PCM by melting and applying the melt by spraying or brushing.

In addition, varnish can be prepared from the resin by dissolving it in solvents selected from the group: dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, acetone, methyl ethyl ketone and applied to the PCM surface with a brush or spray.

After application to the composite, the varnish is cured according to the following program: heating to 180°C at a rate of no more than 2°C/min and holding for 3 hours, after which heating to a post-curing temperature (330-375°C) at a rate of 10°C/ h and exposure for 8 hours to obtain a highly heat-resistant protective coating with a thickness of 10-100 microns.

Due to the fact that fluorinated polymers have a higher thermal and oxidative stability, the coating oxidizes more slowly than the CFRP matrix.

Example 1 Preparation of 4,4'-(((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1-phenylene))bis(oxy))diphenol (1). In a single-necked flask (100 ml) equipped with a reflux condenser, 4.44 g (0.0400 mol) of hydroquinone was dissolved in 50 ml of dry N-methyl-2-pyrrolidone under argon. Potassium fluoride (3.90 g, 0.0670 mol) was then added, after which the reaction mixture was stirred for 30 minutes. After that, hexafluorobenzene (5.00 g, 0.0270 mol) was added, the reaction mixture was heated to 60°C and left under stirring for 24 hours, followed by heating to 110°C and keeping under stirring for 36 hours. The reaction mixture was added to a large excess of water (about 250 ml), stirred and left for 2 hours. The precipitate that formed was filtered off and washed several times with hot water, then placed in an oven. Flash chromatography was performed to obtain the pure title compound. The eluent used was a mixture of methylene chloride: methanol in a ratio of 60:1. Yield - 7.06 g (84.0%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 6.83 (d, J=7.41 Hz, 4 H), 7.09 (s, 4 H), 7.31 (d, J=7.89 Hz 4 H), 9.43 (s, 2 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 115.73, 115.95, 116.38, 116.52, 116.79, 129.91, 141.06, 142.70, 149.70, 152.57, 152.90, 153.64.

Elemental analysis for C ₃₀ H ₁₄ F ₈ O ₆ : Calculated values: C (57.89), H (2.27), F (24.42). Experimental values: C (57.83), H (2.31), F (24.37).

Example 2 Preparation of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1-phenylene))bis(oxy))bis(4 ,1-phenylene))bis(oxy))diphthalonitrile (I). In a single-necked flask (100 ml) equipped with a reflux condenser, 4,4'-(((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1-phenylene ))bis(oxy))diphenol (1) (4.00 g, 0.0064 mol) in 50 ml of dry N-methyl-2-pyrrolidone. Potassium fluoride (0.75 g, 0.0129 mol) was then added, after which the reaction mixture was stirred for 30 minutes. After that, 4-nitrophthalonitrile (2.23 g, 0.0129 mol) was added, the reaction mixture was heated to 80°C and left under stirring for 24 hours. The reaction mixture was added to a large excess of water (about 250 ml), stirred and left for 2.5 hours. The precipitate that formed, which represented the target product, was filtered off and washed several times with hot water, then placed in an oven. Yield - 5.42 g (96.4%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 7.04 (d, J=6.53 Hz, 4 H), 7.17 (s, 4 H), 7.30 (d, J=7.55 Hz, 4 H), 7.41 (s, 2 H), 7.76 (d, J=8.87 Hz , 2 H), 8.30 (d, J=8.53 Hz, 2 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 108.08, 110.65, 115.70, 115.93, 116.41, 116.61, 116.9, 124.7, 124.7, 124.7, 124.7, 124.7, 124.76, 124.76, 129.76, 124.76, 129.92

Elemental analysis for C ₄₆ H ₁₈ F ₈ N ₄ O ₆ : Calculated values: C (63.17), H (2.07), F (17.38), N (6.41). Experimental values: C (63.11), H (2.05), F (17.32), N (6.43).

Example 3 Preparation of 4-(3-(perfluorophenoxy)phenoxy)phthalonitrile (2). In a single-necked flask (100 ml) equipped with a reflux condenser, 4-(3-hydroxyphenoxy)phthalonitrile was dissolved under argon (the synthesis of the compound is described in A. Lyubimtsev et al.: Synthesis of novel covalently linked dimeric phthalocyanines, Eur. J. Org (12) (2007) 2000-2005) (2.54 g, 0.0108 mol) in 50 ml of dry acetone. Potassium carbonate (1.78 g, 0.0129 mol) was then added, after which the reaction mixture was stirred for 30 minutes. After that, hexafluorobenzene (2.00 g, 0.0108 mol) was added, the reaction mixture was heated to 30°C and left under stirring for 96 hours. The reaction mixture was filtered through a thin layer of silica gel, the precipitate was washed several times with acetone. After evaporating the filtrate, a mixture of target and side compounds was obtained. Flash chromatography was performed to obtain the pure title compound. A mixture of methylene chloride:petroleum ether in a ratio of 1:1 was used as an eluent. Yield - 3.51 g (82.5%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 6.98 (dd, J=8.11, 1.25 Hz, 1 H), 7.06 - 7.11 (m, 2 H), 7.42 (dd, J=8.70, 2.68 Hz, 1 H), 7.50 (t, J=8.53 Hz, 1 H), 7.83 (d, J=2.51 Hz, 1 H), 8.11 (d, J=8.70 Hz, 1 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 107.70, 108.64, 112.40, 115.29, 115.51, 115.80, 116.73, 122.31, 131.9, 122.31, 131.8, 122.34, 137.19, 136.34, 137.19

Elemental analysis for C ₂₀ H ₇ F ₅ N ₂ O ₂ : Calculated values: C (59.71), H (1.75), F (23.61), N (6.96). Experimental values: C (59.67), H (1.74), F (23.63), N (6.94).

Example 4 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1-phenylene))bis(oxy))bis(3 ,1-phenylene))bis(oxy))diphthalontrile (II). Hydroquinone (0.05 g, 0.0005 mol) was dissolved in 25 ml of dry N-methyl-2-pyrrolidone in a single-necked flask (50 ml) equipped with a reflux condenser under argon. Then potassium carbonate (0.14 g, 0.001 mol) was added, after which the reaction mixture was stirred for 35 minutes. After that, 4-(3-(perfluorophenoxy)phenoxy)phthalonitrile (2) (0.37 g, 0.0009 mol) was added, the reaction mixture was heated to 100°C, and left under stirring for 120 hours. The reaction mixture was added to a large excess of water (about 125 ml), stirred and left for 1.5 hours. The precipitate that formed, which represented the target product, was filtered off and washed several times with hot water, then placed in an oven. Yield - 0.37 g (93.2%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 7.05 (dd, J=8.13, 1.27 Hz, 2 H), 7.12 - 7.17 (m, 4 H), 7.22 (s, 4 H), 7.49 (dd, J=8.69, 2.72 Hz, 2 H), 7.57 ( t, J=8.44 Hz, 2 H), 7.90 (d, J=2.53 Hz, 2 H), 8.18 (d, J=8.70 Hz, 2 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 107.76 (s), 108.70 (s), 112.46 (s), 115.35 (s), 115.57 (s), 115.86 (s), 116.79 (s), 116.82 (s), 122.37 (s), 123.06 (s), 128.34 (s), 129.07 (s), 131.89 (s), 136.40 (s), 137.25 (s), 138.90 (s), 140.87 (s), 142.44 (s), 152.92 (s), 155.21 (s), 158.09 (s), 160.52 (s).

Elemental analysis for C ₄₆ H ₁₈ F ₈ N ₄ O ₆ : Calculated values: C (63.17), H (2.07), F (17.38), N (6.41). Experimental values: C (63.12), H (2.04), F (17.33), N (6.40).

Example 5 Preparation of 1,4-bis(perfluorophenoxy)benzene (3). This compound was obtained by the method described in the work of I.M. Tkachenko, et al. Synthesis of fluorinated poly(arylene ether)s with dibenzodioxin and spirobisindane units from new bis(pentafluorophenyl)- and bis(nonafluorobiphenyl)-containing monomers // J. Fluor. Chem. 2017 Vol. 195. P. 1-12. In a single-necked flask (250 ml) equipped with a reflux condenser, 2.00 g (0.018 mol) of hydroquinone was dissolved in 55 ml of dry N,N-dimethylformamide under an argon atmosphere. Potassium carbonate (5.00 g, 0.036 mol) was then added, after which the reaction mixture was stirred for 25 minutes. After that, hexafluorobenzene (27.00 g, 0.145 mol) was added, the reaction mixture was heated to 120°C and left under stirring for 8 hours. After cooling to room temperature, the mixture was filtered. Excess hexafluorobenzene was removed from the filtrate at atmospheric pressure, after which the remaining solution was added to an excess of cold water (250 ml). The precipitate formed was filtered off, washed several times with water. Flash chromatography was performed to obtain the pure title compound. A mixture of methylene chloride:petroleum ether in a ratio of 1:1 was used as an eluent. Yield - 6.83 g (85%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 7.15 (s, 4 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 116.76 (s), 129.01 (s), 137.15 (s), 137.61 (s), 138.79 (s), 139.26 (s), 140.83 (s), 142.49 (s), 152.86 (s).

Elemental analysis for C ₁₈ H ₄ F ₁₀ O ₂ : Calculated values: C (48.89), H (0.91), F (42.96). Experimental values: C (48.83), H (0.89), F (42.89).

Example 6 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1-phenylene))bis(oxy))bis(3 ,1-phenylene))bis(oxy))diphthalontrile (II). 4-(3-Hydroxyphenoxy)phthalonitrile (1.068 g, 0.0045 mol) was dissolved in 50 ml of dry N-methyl-2-pyrrolidone in a single-necked flask (100 ml) equipped with a reflux condenser under argon. Potassium carbonate (0.688 g, 0.0049 mol) was then added, after which the reaction mixture was stirred for 30 minutes. After that, 1,4-bis(perfluorophenoxy)benzene (3) (1.00 g, 0.0023 mol) was added, the reaction mixture was heated to 105°C and left under stirring for 122 hours. The reaction mixture was added to a large excess of water (about 250 ml), stirred and left for 1.5 hours. The precipitate that formed, which represented the target product, was filtered off and washed several times with hot water, then placed in an oven. Yield - 1.84 g (93%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 7.05 (dd, J=8.13, 1.27 Hz, 2 H), 7.12 - 7.17 (m, 4 H), 7.22 (s, 4 H), 7.49 (dd, J=8.69, 2.72 Hz, 2 H), 7.57 ( t, J=8.44 Hz, 2 H), 7.90 (d, J=2.53 Hz, 2 H), 8.18 (d, J=8.70 Hz, 2 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 107.76 (s), 108.70 (s), 112.46 (s), 115.35 (s), 115.57 (s), 115.86 (s), 116.79 (s), 116.82 (s), 122.37 (s), 123.06 (s), 128.34 (s), 129.07 (s), 131.89 (s), 136.40 (s), 137.25 (s), 138.90 (s), 140.87 (s), 142.44 (s), 152.92 (s), 155.21 (s), 158.09 (s), 160.52 (s).

Elemental analysis for C ₄₆ H ₁₈ F ₈ N ₄ O ₆ : Calculated values: C (63.17), H (2.07), F (17.38), N (6.41). Experimental values: C (63.15), H (2.09), F (17.33), N (6.37).

Example 7 4,4'-((((Perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalonitrile (III) was prepared. 4-(3-Hydroxyphenoxy)phthalonitrile (5.08 g, 0.0216 mol) was dissolved in 50 ml of dry acetone in a single-necked flask (100 ml) equipped with a reflux condenser under argon. Potassium carbonate (3.56 g, 0.0258 mol) was then added, after which the reaction mixture was stirred for 30 minutes. After that, hexafluorobenzene (2.00 g, 0.0108 mol) was added, the reaction mixture was heated to 60°C and left under stirring for 96 hours. The reaction mixture was filtered through a thin layer of silica gel, the precipitate was washed several times with acetone. After evaporating the filtrate, a mixture of target and side compounds was obtained. Flash chromatography was performed to obtain the pure title compound. A mixture of methylene chloride:petroleum ether in a ratio of 1:1 was used as an eluent. Yield - 5.46 g (82%).

¹ H NMR (600 MHz, DMSO-d ₆ ) δ ppm 7.06 (dd, J=8.11, 1.42 Hz, 2 H), 7.22 - 7.28 (m, 4 H), 7.52 (dd, J=8.78, 2.43 Hz, 2 H), 7.59 (t, J=8.11 Hz, 2 H), 7.93 (d, J=2.34 Hz, 2 H), 8.20 (d, J=8.70 Hz, 2 H).

¹³ C NMR (151 MHz, DMSO-d ₆ ) δ ppm 107.84 (s), 108.68 (s), 112.49 (s), 115.32 (s), 115.36 (s), 115.82 (s), 116.74 (s), 122.42 (s), 123.09 (s), 129.44 (s), 131.77 (s), 136.35 (s), 141.10 (s), 142.79 (s), 155.21 (s), 158.07 (s), 160.43 (s).

Elemental analysis for C ₃₄ H ₁₄ F ₄ N ₄ O ₄ : Calculated values: C (66.03), H (2.28), F (12.29), N (9.06). Experimental values: C (59.97), H (2.32), F (12.25), N (9.00).

Getting resin:

Example 8 192 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 8 g of 4-(4-aminophenoxy)phthalonitrile was added and stirred for 30 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 9 Into a 500 ml flask equipped with a magnetic stirrer, 180 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 120°C. After the substance had melted, stirring was turned on and 20 g of 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline was added and stirred for 60 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 10 170 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalontrile. The flask was heated to 180°C. After the substance had melted, stirring was turned on and 30 g of 4-(4-aminophenoxy)phthalonitrile was added and stirred for 15 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 11 160 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalontrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 40 g of 4-(3-aminophenoxy)phthalonitrile was added and stirred for 30 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 12 192 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 180°C. After the substance had melted, stirring was turned on and 8 g of 4-(3-aminophenoxy)phthalonitrile was added and stirred for 15 minutes, then 2 g of pyrolytic silica (AEROSIL 200) was added and stirred at maximum stirrer speed for 15 minutes . The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 13 192 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 140°C. After the substance had melted, the stirring was turned on and 8 g of 4-(3-aminophenoxy)phthalonitrile was added and stirred for 40 minutes, then 20 g of pyrolytic silicon oxide (AEROSIL R202) was added and mixed at maximum stirrer speed for 15 minutes . The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 14 160 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalontrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 40 g of 4-(4-aminophenoxy)phthalonitrile was added and stirred for 30 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 15 Into a 500 ml flask equipped with a mechanical stirrer, 180 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 150°C. After the substance melted, the stirring was turned on and 20 g of 4,4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline was added and stirred for 30 minutes, then 2 g of pyrolytic silicon oxide (AEROSIL 200) and stirred at maximum stirrer speed for 15 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 16 180 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 20 g of 4,4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline was added and stirred for 30 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 17 170 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 30 g of 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline was added and stirred for 30 minutes, then 10 g of pyrolytic silicon oxide (AEROSIL R202) and stirred at maximum stirrer speed for 15 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 18 96 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(4,1-phenylene))bis(oxy))diphthalonitrile and 96 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2, 3,5,6-tetrafluoro-4,1-phenylene)) bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 150°C. After the substance had melted, stirring was turned on and 8 g of 4-(4-aminophenoxy)phthalonitrile was added and stirred for 30 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Example 19 126 g of 4,4'-(((((1,4-phenylenebis(oxy))bis(2,3,5,6-tetrafluoro-4,1 -phenylene))bis(oxy))bis(3,1-phenylene))bis(oxy))diphthalonitrile and 54 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis (3,1-phenylene))bis(oxy))diphthalonitrile. The flask was heated to 170°C. After the substance had melted, stirring was turned on and 20 g of 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline was added and stirred for 60 minutes. The mixture was then poured onto a metal tray treated with a release agent and allowed to cool. An amorphous glassy resin was obtained.

Application of solvent-free polymer coatings:

Example 20 The resin obtained in Example 8 was melted at 120° C. in an open 500 ml aluminum container. The melt was applied in a thin layer with a paint brush to a PCM (Method B) post-cured at 330°C.

Example 21 The resin obtained in Example 12 was melted at 150° C. in an open 500 ml aluminum container. The melt was applied in a thin layer with a paint brush to a PCM (Method A) precured at 180°C.

Example 22 The resin obtained in Example 13 was melted at 130° C. in an open 500 ml aluminum container. The melt was applied in a thin layer with a paint brush to a PCM (Method A) post-cured at 375°C.

Example 23 The resin obtained in Example 14 was melted at 150° C. in an open 500 ml aluminum container. The melt was applied in a thin layer with a paint brush to a PCM (Method B) precured at 180°C.

Example 24 The resin obtained in Example 17 was melted at 150° C. in an open 500 ml aluminum container. The melt was applied in a thin layer with a paint brush to a PCM (method A) post-cured at 350°C.

Example 25 The resin obtained in Example 9 was melted at 150° C. in an open 500 ml aluminum container. The melt was applied in a thin layer by spraying with compressed air on PCM (method B), post-cured at 350°C.

Example 26 The resin obtained in Example 10 was melted at 150° C. in an open 500 ml aluminum container. The melt was applied in a thin layer by spraying with compressed air on PCM (method A), post-cured at 330°C.

Example 27 The resin obtained in Example 9 was melted at 160° C. in an open 500 ml aluminum container. The melt was applied in a thin layer by spraying with compressed air on PCM (method B), post-cured at 375°C.

Application of lacquer coatings:

Example 28 The resin obtained in Example 8 was dissolved in 36 ml of DMAA in an amount of 50 g. The obtained varnish was applied in a thin layer with a paint brush on PCM (method A), pre-cured at 180°C. The coating was dried in a convection oven at 170° C. for 1 hour.

Example 29 The resin obtained in Example 9 was dissolved in 42 ml of acetone in an amount of 50 g. The obtained varnish was applied in a thin layer using a paint brush on PCM (method B), post-cured at 330°C. The coating was dried in a convection oven at 60° C. for 1 hour.

Example 30 The resin obtained in Example 10 was dissolved in an amount of 50 g in 41 ml of methyl ethyl ketone. The obtained varnish was applied in a thin layer using a paint brush on PCM (method B), post-cured at 375°C. The coating was dried in a convection oven at 80° C. for 1 hour.

Example 31 The resin obtained in Example 11 was dissolved in an amount of 50 g in 32 ml of N-methyl-2-pyrrolidone. The obtained varnish was applied in a thin layer with a paint brush on PCM (method A), post-cured at 350°C. The coating was dried in a convection oven at 205° C. for 1 hour.

Example 32 The resin obtained in Example 14 was dissolved in an amount of 50 g in 35 ml of dimethylformamide. The obtained varnish was applied in a thin layer with a paint brush on PCM (method B), precured at 180°C. The coating was dried in a convection oven at 155° C. for 1 hour.

Example 33 The resin obtained in Example 16 was dissolved in 42 ml of acetone in an amount of 50 g. The obtained varnish was applied in a thin layer using a paint brush on PCM (method B), post-cured at 330°C. The coating was dried in a convection oven at 60° C. for 1 hour.

Example 34 The resin obtained in Example 8 was dissolved in 36 ml of DMAA in an amount of 50 g. The obtained varnish was applied in a thin layer by spraying with a manual spray gun on PCM (method A), pre-cured at 180°C. The coating was dried in a convection oven at 170° C. for 1 hour.

Example 35 The resin obtained in Example 9 was dissolved in 42 ml of acetone in an amount of 50 g. The resulting lacquer was applied in a thin layer by spraying with a hand sprayer onto a PCM (method B) post-cured at 330°C. The coating was dried in a convection oven at 60° C. for 1 hour.

Example 36 The resin obtained in Example 11 was dissolved in an amount of 50 g in 32 ml of N-methyl-2-pyrrolidone. The resulting lacquer was applied in a thin layer by spraying with a hand sprayer onto a PCM (method A) post-cured at 350°C. The coating was dried in a convection oven at 205° C. for 1 hour.

Example 37 96 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 4 g 4-(4-aminophenoxy)phthalonitrile and 71 ml dimethylacetamide. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method A), post-cured at 330°C. The coating was then dried in a programmable convection oven at 170° C. for 1 hour.

Example 38 90 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy ))diphthalonitrile, 10 g of 4,4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline and 65 ml of N-methyl-2-pyrrolidone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method A), post-cured at 350°C. The coating was then dried in a programmable convection oven at 205° C. for 1 hour.

Example 39 96 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy ))diphthalonitrile, 4 g of 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline and 71 ml of dimethylformamide. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method A), post-cured at 375°C. The coating was then dried in a programmable convection oven at 155° C. for 1 hour.

Example 40 Into a 250 ml flask equipped with a magnetic stirrer were placed 80 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 20 g of 4-(3-aminophenoxy)phthalonitrile and 84 ml of acetone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method A), pre-cured at 180°C. The coating was then dried in a programmable convection oven at 60° C. for 1 hour.

Example 41 Into a 250 ml flask equipped with a magnetic stirrer, 85 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 15 g of 4-(4-aminophenoxy)phthalonitrile and 83 ml of methyl ethyl ketone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method B), post-cured at 330°C. The coating was then dried in a programmable convection oven at 80° C. for 1 hour.

Example 42 90 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 10 g of 4-(3-aminophenoxy)phthalonitrile and 83 ml of methyl ethyl ketone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method B), pre-cured at 180°C. The coating was then dried in a programmable convection oven at 80° C. for 1 hour.

Example 43 90 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 10 g of 4-(4-aminophenoxy)phthalonitrile and 65 ml of N-methyl-2-pyrrolidone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer by spraying with a hand spray on PCM (method B), post-cured at 375°C. The coating was then dried in a programmable convection oven at 205° C. for 1 hour.

Example 44 Into a 250 ml flask equipped with a magnetic stirrer, 90 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy ))diphthalonitrile, 10 g of 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline and 83 ml of methyl ethyl ketone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer by spraying with a hand spray gun on the PCM (method B), post-cured at 350°C. The coating was then dried in a programmable convection oven at 80° C. for 1 hour.

Example 45 Into a 250 ml flask equipped with a magnetic stirrer were placed 16 g of 4,4'-((((perfluoro-1,4-phenylene)bis(oxy))bis(3,1-phenylene))bis(oxy )) diphthalonitrile, 64 g (4,1-phenylene))bis(oxy))diphthalonitrile, 20 g of 4-(3-aminophenoxy)phthalonitrile and 84 ml of acetone. The mixture was stirred until the components were completely dissolved in order to obtain a varnish. After that, the varnish was applied in a thin layer with a paint brush on PCM (method A), post-cured at 330°C. The coating was then dried in a programmable convection oven at 60° C. for 1 hour.

Curing Coatings:

Coated PCM samples were placed in a heating cabinet. The temperature was raised to 180°C at a rate of not more than 2°C/min and kept for 3 hours. Then the oven was heated to the post-curing temperature (330–375°C) at a rate of 10°C/h and held for 8 hours. The post-curing temperature depends on the PCM selected in each particular case. If a PCM with a specific post-cure temperature was used, the final coating treatment temperature was the same. If PCM pre-cured at 180°C was used, then the final coating treatment temperature was varied in the range of 330-375°C.

Example 46 The coated PCM from Example 20 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 330°C at a rate of 10°C/h, holding for 8 hours.

Example 47 The coated PCM from Example 22 was placed in an oven. The sample was held according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 375°C at a rate of 10°C/h, holding for 8 hours.

Example 48 The coated PCM from Example 29 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 330°C at a rate of 10°C/h, holding for 8 hours.

Example 49 The coated PCM from Example 32 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 350°C at a rate of 10°C/h, holding for 8 hours.

EXAMPLE 50 Coated PCM from Example 38 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 350°C at a rate of 10°C/h, holding for 8 hours.

Example 51 The coated PCM from Example 42 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 375°C at a rate of 10°C/h, holding for 8 hours.

To compare the effectiveness of the presented coatings, protective coatings based on non-fluorinated phthalonitrile 4,4'-(1,3-phenylenebis(oxy))diphthalonitrile mixed with a hardener 4,4'-(1,3-phenylenebis(oxy)) dianiline (a typical hardener for phthalonitrile resins) and an inorganic base.

Comparative Example 1 Into a 250 ml flask equipped with a magnetic stirrer were placed 96 g of 4,4'-(1,3-phenylenebis(oxy))diphthalonitrile, 4g of 4,4'-(1,3-phenylenebis(oxy) )dianiline and 71 ml of dimethylacetamide. The mixture was stirred until complete dissolution of the components. After that, the solution was applied in a thin layer with a paint brush on PCM (method A), post-cured at 330°C. The coating was then dried in a programmable convection oven at 170° C. for 1 hour.

Comparative Example 2 Into a 250 ml flask equipped with a magnetic stirrer were placed 96 g of 4,4'-(1,3-phenylenebis(oxy))diphthalonitrile, 4g of 4,4'-(1,3-phenylenebis(oxy) )dianiline and 71 ml of dimethylacetamide. The mixture was stirred until complete dissolution of the components. After that, the solution was applied in a thin layer by spraying with a hand spray on PCM (method B), post-cured at 375 °C. The coating was then dried in a programmable convection oven at 170° C. for 1 hour.

Comparative Example 3 198 g of phosphoric acid and 33.5 g of aluminum hydroxide were placed in a 250 ml flask equipped with a magnetic stirrer. The mixture was stirred for 15 minutes. After that, the mixture was applied in a thin layer with a paint brush on PCM (method A), post-cured at 350°C. Then the coating was dried in a programmable convection oven at 60°C for 4 hours, after which the temperature was raised to 350°C and kept for another 6 hours.

Comparative Example 4 The coated PCM of Comparative Example 1 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 330°C at a rate of 10°C/h, holding for 8 hours.

Comparative Example 5 The coated PCM of Comparative Example 2 was placed in an oven. The sample was kept according to the following program: heating to 180°C at a rate of 2°C/min, holding for 3 hours and heating to 375°C at a rate of 10°C/h, holding for 8 hours.

Aging at 350℃:

PCM samples were placed in a programmable convection oven preheated to 350°C. After the exposure time (200 or 1000 hours) the samples were removed. The results obtained are presented in the table.

Sample Weight loss after 200 h, % Residual shear strength after 200 hours of aging, % of initial Weight loss after 1000 h, % Residual shear strength after 1000 hours of aging, % of the original Untreated sample (method A), post-cured at 330°C 14.8 64 33.5 - Untreated sample (method B), post-cured at 350°C 11.9 69 36 - Example 46 2.8 89 3.1 78 Example 47 2.1 91 2.7 83 Example 48 1.9 91 2.0 80 Example 50 1.6 94 1.8 92 Comparative Example 3 4.3 76 9.3 53 Comparative Example 4 9.7 73 27.1 - Comparative Example 5 11.3 69 29.1 -

Claims (34)

1. Oligomer of phthalonitrile as a component of a polymerizable resin for protective coatings of a polymer composite matrix, which is a compound of formulas (I)

(I) or formula (II):

(II) or formula (III):

(III) 2. A method for producing a phthalonitrile oligomer according to claim 1, characterized in that sequential nucleophilic substitution of fluorine atoms in hexafluorobenzene and / or a nitro group in 4-nitrophthalonitrile with hydroxyl-containing aromatic compounds is carried out, while sequential nucleophilic substitution of fluorine atoms is carried out to obtain a compound of formula (I) in hexafluorobenzene with hydroquinone and nitro groups in 4-nitrophthalonitrile; to obtain a compound of formula (II), sequential nucleophilic substitution of fluorine atoms in hexafluorobenzene with 4-(3-hydroxyphenoxy)phthalonitrile or hydroquinone and fluorine atoms in the resulting intermediate with hydroquinone or 4-(3-hydroxyphenoxy)phthalonitrile is carried out; in order to obtain a compound of formula (III), a successive nucleophilic substitution of fluorine atoms in hexafluorobenzene with 4-(3-hydroxyphenoxy)phthalonitrile is carried out. 3. The method according to claim 2, characterized in that to obtain a compound of formula (I) for the nucleophilic substitution of fluorine atoms, hydroquinone is dissolved in a high-boiling polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, is added to the solution inorganic salt, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, and then hexafluorobenzene is added, taken at the rate of 2 mole equivalents of hexafluorobenzene per 3 mole equivalents of hydroquinone, obtained the reaction mixture is heated to 60±5°C and left under stirring for 24±2 hours, followed by heating to 110±5°C and keeping under stirring for 36±2 hours, then the reaction mixture is added to an excess of water at room temperature, taken in volume, in 2.5-3.0 exceeding the volume of the solvent used, mix and incubate for precipitation, the precipitate is filtered off and washed from about stats of solvent, base and unreacted hydroquinone, then dried. 4. The method according to claim 2, characterized in that to obtain a compound of formula (I) to replace the nitro group in 4-nitrophthalonitrile, the bisphenol obtained after the nucleophilic substitution of fluorine atoms is dissolved in a high-boiling polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, then an inorganic salt is added, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, after which 4-nitrophthalonitrile is added, taken at the rate of 1 mol 4-nitrophthalonitrile per 1 mol of the hydroxyl group involved in the reaction, the reaction mixture is heated to 80 ± 5 ° C and left under stirring for 24 ± 2 hours, then the reaction mixture is added to an excess of water at room temperature, taken in volume, in 2.5 - 3.0 greater than the volume of the solvent used, stirred and kept at room temperature for precipitation, the precipitate is filtered off and washed from impermeability. reacted residues and dried. 5. The method according to claim 3, characterized in that the reaction mixture after being added to water is kept for 2 ± 0.5 hours to precipitate a precipitate. 6. Process according to claim 3 or 4, characterized in that N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide is used as the high-boiling aprotic solvent. 7. The method according to claim 3 or 4, characterized in that potassium fluoride, potassium carbonate, potassium phosphate are used as the inorganic salt. 8. The method according to claim 3 or 4, characterized in that to obtain a precipitate, the reaction mixture is added to water at room temperature, taken in a volume 2.5-3.0 greater than the volume of the organic solvent. 9. The method according to claim 3 or 4, characterized in that to dry the precipitate, it is placed for 12 ± 1 hour in an oven heated to 100°C. 10. The method according to claim 2, characterized in that in order to obtain a compound of formula (II) for the nucleophilic substitution of fluorine atoms, 4-(3-hydroxyphenoxy)phthalonitrile or hydroquinone is dissolved in a polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, an inorganic salt is added to the solution, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group participating in the reaction, after which the reaction mixture is stirred for 30 ± 5 minutes, and then hexafluorobenzene is added, taken at the rate of 1 mole equivalent hexafluorobenzene per 1 molar equivalent of 4-(3-hydroxyphenoxy)phthalonitrile or hydroquinone, the resulting reaction mixture is heated to 30±5°C and left under stirring for 96±2 hours, then the reaction mixture is filtered through a thin layer of silica gel, the precipitate is washed, the filtrate is evaporated and perform flash chromatography. 11. The method according to claim 2, characterized in that in order to obtain a compound of formula (II) for replacing the nitro group in 4-nitrophthalonitrile, the compound obtained after the nucleophilic substitution of fluorine atoms, taken at the rate of 1 mol per 1 mol of the hydroxyl group involved in the reaction, is added to solution of hydroquinone or 4-(3-hydroxyphenoxy)phthalonitrile in a polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, with the addition of an inorganic salt, taken at the rate of 1-1.25 mol per 1 mol of hydroxyl involved in the reaction group, the resulting reaction mixture is heated to 100 ± 5°C and left under stirring for 120 ± 2 hours, then the reaction mixture is added to a large excess of water at room temperature, stirred and kept until a precipitate forms, the precipitate is filtered off and washed from unreacted residues and dried . 12. The method according to claim 10 or 11, characterized in that the reaction mixture after being added to water is kept for 2 ± 0.5 hours to precipitate. 13. The method according to claim 10 or 11, characterized in that acetone, N-methyl-2-pyrrolidone, N,N-dimethylacetamide or N,N-dimethylformamide is used as the polar aprotic solvent. 14. The method according to claim 10 or 11, characterized in that potassium fluoride, potassium carbonate, potassium phosphate are used as the inorganic salt. 15. The method according to claim 10 or 11, characterized in that to obtain a precipitate, the reaction mixture is added to water at room temperature, taken in a volume 2.5-3.0 greater than the volume of the organic solvent. 16. The method according to claim 10 or 11, characterized in that to dry the precipitate, it is placed for 12 ± 1 hour in an oven heated to 100°C. 17. The method according to claim 10 or 11, characterized in that the filtered precipitate is washed 3 times with 10 ml of acetone. 18. The method according to claim 10, characterized in that flash chromatography is carried out using a mixture of methylene chloride/petroleum ether, taken in a volume ratio of 1/1. 19. The method according to claim 2, characterized in that to obtain a compound of formula (III), 4-(3-hydroxyphenoxy)phthalonitrile is dissolved in a polar aprotic solvent, taken at the rate of ~5-10 ml per 1 g of a mixture of soluble components, then inorganic salt, taken at the rate of 1-1.25 mol per 1 mol of the hydroxyl group involved in the reaction, after which the reaction mixture is stirred for 30±5 minutes, hexafluorobenzene is added, taken at the rate of 1 mole equivalent of hexafluorobenzene per 2 mole equivalents of 4-(3- hydroxyphenoxy)phthalonitrile, the resulting reaction mixture is heated to 60±5°C and left under stirring for 96±2 hours, then the reaction mixture is filtered through a thin layer of silica gel, the precipitate is washed, the filtrate is evaporated, flash chromatography is performed. 20. The method according to claim 19, characterized in that acetone, N,N-dimethylacetamide, N,N-dimethylformamide or N-methyl-2-pyrrolidone is used as the polar aprotic solvent. 21. The method according to claim 19, characterized in that potassium fluoride, potassium carbonate, potassium phosphate are used as the inorganic salt. 22. The method according to claim 19, characterized in that the reaction mixture after being added to water is kept for 2±0.5 hours to precipitate. 23. The method according to claim 19, characterized in that to obtain a precipitate, the reaction mixture is added to water at room temperature, taken in a volume 2.5-3.0 greater than the volume of the organic solvent. 24. The method according to claim 19, characterized in that to dry the precipitate, it is placed for 12 ± 1 hour in an oven heated to 100°C. 25. The method according to claim 19, characterized in that the filtered precipitate is washed 3 times with 10 ml of acetone. 26. The method according to claim 19, characterized in that flash chromatography is carried out using a mixture of methylene chloride/petroleum ether, taken in a volume ratio of 1/1. 27. A composition for the preparation of a thermosetting resin, characterized in that it includes at least one compound of formula (I), or (II), or a mixture thereof with a compound of formula (III) according to claim 1 and a hardener selected from the group consisting of 4 -(4-aminophenoxy)phthalonitrile, 4-(3-aminophenoxy)phthalonitrile, 4,4'-((perfluoro-1,4-phenylene)bis(oxy))dianiline, 3,3'-((perfluoro-1, 4-phenylene)bis(oxy))dianiline, taken at a concentration of 4 to 20 wt.%. 28. A method for preparing a thermosetting resin, characterized in that at least one compound of formula (I), or (II), or a mixture thereof with a compound of formula (III) according to claim 1 is melted at a temperature of 120-180 ° and added with stirring hardener, the resulting mixture is stirred for 15-60 minutes, after which the mixture is cooled until solidified, while the hardener is selected from the group including 4-(4-aminophenoxy)phthalonitrile, 4-(3-aminophenoxy)phthalonitrile, 4,4'- ((perfluoro-1,4-phenylene)bis(oxy))dianiline, 3,3'-((perfluoro-1,4-phenylene)bis(oxy))dianiline, taken at a concentration of 4 to 20 wt.%. 29. A method for preparing a thermosetting varnish from a thermosetting resin obtained by the method according to claim 28, characterized in that the resin is dissolved in a solvent selected from the group of acetone, methyl ethyl ketone, dimethylformamide, dimethylacetamide, n-methylpyrrolidone, taken in an amount that provides a solution for application on the PCM surface.