Formula for synthesizing high-molecular-weight PBI resin and preparation method of high-molecular-weight PBI resin

Abstract

The invention relates to the technical field of synthetic high-molecular-weight PBI resin, and discloses a formula and a preparation method of synthetic high-molecular-weight PBI resin, and the formula comprises the following raw materials by mass: 25-35 parts of a quaternary amine monomer, 18-22 parts of composite aromatic dibasic acid, 4-6 parts of a eugenol derivative, 1-3 parts of carboxylated o-carborane, 0.1-0.5 part of a catalyst, and 120-150 parts of a solvent. Under the irradiation of ultraviolet light, the composite aromatic binary acid and the eugenol derivative are subjected to double-bond copolymerization, and then a large number of flexible long chains are introduced into the PBI resin, so that the PBI resin can be endowed with better flexibility, and the molecular weight of the PBI resin is increased; the carboxylated o-carborane contains a stable cage structure, has relatively high thermal resistance and thermal stability, and can improve the heat-resistant stability of the PBI resin.

Description

Technical Field

[0001] The invention relates to the technical field of synthetic high molecular weight PBI resin, in particular to a formula and a preparation method of a synthetic high molecular weight PBI resin. Background Art

[0002] PBI (polybenzimidazole) resin is a high-performance engineering plastic. It is an amorphous linear heterocyclic polymer with benzimidazole as a repeating unit. Its fully aromatic main chain gives PBI resin an extremely high glass transition temperature, excellent chemical stability and mechanical stability. PBI resin can be used as a high-temperature structural adhesive and has high bonding strength to stainless steel and titanium alloys. Its fibers can be used as flame-resistant fabrics and ablative materials. It has good prospects in aerospace, such as heat-resistant films, diaphragms, reinforced plastics, foam materials, etc.

[0003] PBI resin has good mechanical properties and chemical corrosion resistance, and is an engineering plastic with excellent performance. These excellent properties make it have broad application prospects in many fields. However, the rigidity of the main chain of PBI resin is strong, resulting in its poor flexibility; and the molecular weight of the synthesized PBI resin is low, which affects the thermal stability and mechanical properties of the resin. Summary of the invention

[0004] The invention provides a formula and a preparation method for synthesizing a high molecular weight PBI resin, which solves the problem that the PBI resin has poor flexibility and low molecular weight, resulting in poor thermal stability and mechanical properties of the PBI resin.

[0005] The technical solution of the present invention:

[0006] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 25-35 parts of a tetraamine monomer, 18-22 parts of a composite aromatic dibasic acid, 4-6 parts of a eugenol derivative, 1-3 parts of a carboxylated o-carborane, 0.1-0.5 parts of a catalyst, and 120-150 parts of a solvent;

[0007] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0008] The tetraamine monomer, catalyst, composite aromatic dibasic acid and solvent are mixed, stirred at 80-120°C for 30-35 minutes under a nitrogen atmosphere, heated to 190-200°C, stirred for reaction for 10-15 hours, cooled to room temperature, irradiated with ultraviolet light, injected with cold distilled water, crushed, soaked, washed, filtered and dried to obtain a high molecular weight PBI resin.

[0009] The composite aromatic dibasic acid is obtained by reacting 6,7-dihydroxycoumarin with glycidyl methacrylate, and then reacting with terephthalic acid and carboxylated o-carborane;

[0010] The eugenol derivative is obtained by mixed reaction of eugenol, hydroxyethyl methacrylate and carboxylated o-carborane.

[0011] Furthermore, the solvent is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone.

[0012] Furthermore, the catalyst is phosphorus pentoxide.

[0013] Furthermore, the tetraamine monomer is selected from one or more of 3,3',4,4'-tetraaminodiphenylmethane, 3,3',4,4'-tetraaminodiphenyl sulfone and 3,3',4,4'-tetraaminodiphenyl ether.

[0014] Furthermore, the UV irradiation power is 35-45W, the wavelength is 300-400nm, the temperature is 35-45℃, and the light intensity is 30-40mW / cm 2 The irradiation time is 18-22min.

[0015] Furthermore, the composite aromatic dibasic acid is specifically prepared by the following steps:

[0016] A1. Add 6,7-dihydroxycoumarin to N,N-dimethylacetamide, stir evenly, add 10-13 mol / L ammonia and glycidyl methacrylate, stir, distill under reduced pressure, filter, wash, and dry to obtain a coumarin derivative;

[0017] A2. Add coumarin derivatives and terephthalic acid to N,N-dimethylformamide, stir evenly, add tetrabutyl titanate, heat to 150-160°C, stir to react for 2-4 hours, cool to room temperature, stand for 10-20 minutes, filter, wash and dry to obtain a composite aromatic dibasic acid.

[0018] Furthermore, in the above-mentioned reaction process A1, in the organic solvent N,N-dimethylacetamide, ammonia water is used as a catalyst, so that the two hydroxyl groups contained in 6,7-dihydroxycoumarin can undergo a ring-opening reaction with the epoxy group in glycidyl methacrylate, so that glycidyl methacrylate is grafted on 6,7-dihydroxycoumarin to obtain a coumarin derivative.

[0019] Furthermore, in the above reaction process A2, the two hydroxyl groups produced by the ring-opening reaction in the coumarin derivative can react with the carboxyl groups in terephthalic acid to achieve the grafting of terephthalic acid onto the modified 6,7-dihydroxycoumarin as a composite aromatic dibasic acid.

[0020] Furthermore, in step A1, the amount ratio of 6,7-dihydroxycoumarin, N,N-dimethylacetamide, ammonia water, and glycidyl methacrylate is (3-4) g: (16-20) mL: (1.2-1.4) mL: (7-8) mL.

[0021] Furthermore, in step A2, the ratio of the coumarin derivative, terephthalic acid, N,N-dimethylformamide and tetrabutyl titanate is (1-2) g:(1-1.4) g:(15-25) mL:(0.5-0.6) g.

[0022] Furthermore, the eugenol derivative is specifically prepared by the following steps:

[0023] B1. Add 4-ethynyltoluene and o-carborane to tetrahydrofuran, stir evenly, add N,N-dimethylaniline, stir, let stand, take out the organic phase, remove the water and solvent in the organic phase to obtain a solid, add the solid and chromium trioxide to ethanol, stir to react, add thionyl chloride, stir, filter, wash, and dry to obtain carboxylated o-carborane;

[0024] B2. Add eugenol and carboxylated o-carborane to ethanol, stir evenly, add sodium hydroxide, stir and react at 60-70°C for 8-12 min, add hydroxyethyl methacrylate, stir and react for 8-12 min, heat to 80-90°C, stir, take out the solid, wash and dry to obtain a eugenol derivative.

[0025] Furthermore, in the above-mentioned B1 reaction process, N,N-dimethylaniline is used as an activator to allow the alkyne group of 4-ethynyltoluene to undergo an alkyne insertion reaction with o-carborane, thereby grafting 4-ethynyltoluene onto the o-carborane monomer, and chromium trioxide is used as chromium trioxide to oxidize the methyl group of 4-ethynyltoluene grafted onto the o-carborane monomer into a carboxyl group, and thionyl chloride is used as an activator to activate the carboxyl group of o-carborane, thereby synthesizing carboxylated o-carborane.

[0026] Furthermore, in the above-mentioned B2 reaction process, in the organic solvent ethanol, sodium hydroxide is used as a catalyst to allow the hydroxyl group of eugenol to undergo an esterification reaction with the carboxyl group of carboxylated o-carborane, so that the carboxylated o-carborane is grafted onto eugenol, and the carboxyl group contained in the eugenol grafted with the carboxylated o-carborane can react with the hydroxyl group of hydroxyethyl methacrylate, thereby synthesizing a eugenol derivative.

[0027] Furthermore, in step B1, the amount ratio of 4-ethynyltoluene, o-carborane, tetrahydrofuran, and N,N-dimethylaniline is (2-3) g: (1-2) g: (45-55) mL: (0.3-0.7) g.

[0028] Furthermore, in step B1, the ratio of the solid, chromium trioxide, ethanol and thionyl chloride is (2-3) g: (0.1-0.3) g: (25-35) mL: (0.05-0.15) g.

[0029] Furthermore, in step B2, the amount ratio of eugenol, carboxylated o-carborane, ethanol, sodium hydroxide, and hydroxyethyl methacrylate is (3-4) g: (1.1-1.3) g: (15-25) mL: (0.2-0.4) g: (4-6) mL.

[0030] The present invention has the following beneficial effects:

[0031] (1) In the technical scheme of the present invention, glycidyl methacrylate is grafted onto 6,7-dihydroxycoumarin to give the reactive functional group a double bond, which is beneficial to the introduction of a flexible chain into the polybenzimidazole resin; the coumarin derivative contains two hydroxyl groups produced by the ring-opening reaction, which can react with the carboxyl group in terephthalic acid, thereby realizing the grafting of terephthalic acid onto the modified 6,7-dihydroxycoumarin. As a composite aromatic dibasic acid, it can undergo a condensation reaction with a tetraamine monomer to form a PBI resin, so that 6,7-dihydroxycoumarin is grafted onto the PBI resin, thereby increasing the molecular weight of the PBI resin and improving the mechanical properties and thermal stability of the PBI resin.

[0032] (2) In the technical scheme of the present invention, the hydroxyl group of eugenol can undergo an esterification reaction with the carboxyl group of carboxylated o-carborane, so that the carboxylated o-carborane is grafted on the eugenol, and the carboxyl group contained in the eugenol grafted with the carboxylated o-carborane can react with the hydroxyl group of hydroxyethyl methacrylate to synthesize the eugenol derivative. The formed eugenol derivative can undergo double bond copolymerization with a complex aromatic dibasic acid under ultraviolet light irradiation, and then the eugenol derivative is grafted into the PBI resin, wherein the carboxylated o-carborane contains a stable cage structure, has high thermal resistance and thermal stability, and can improve the heat stability of the PBI resin.

[0033] (3) In the technical solution of the present invention, during the synthesis of PBI resin, under ultraviolet light, the composite aromatic dibasic acid and the eugenol derivative undergo double bond copolymerization, thereby introducing a large number of flexible long chains into the PBI resin, which can give the PBI resin better flexibility, better mechanical properties, and increase the molecular weight of the PBI resin. The tetraamine monomer 3,3',4,4'-tetraaminodiphenyl ether has a high purity. In the system of solvent polyphosphoric acid and catalyst phosphorus pentoxide, it is further polymerized with the composite aromatic dibasic acid to obtain a high molecular weight PBI resin, the molecular weight of which can reach 300,000, thereby improving the mechanical properties and thermal stability of the PBI resin. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The raw materials used in the examples of the present invention are as follows, and all reagents used are of analytical grade.

[0036] The solvent is N,N-dimethylacetamide.

[0037] The catalyst is phosphorus pentoxide.

[0038] The tetraamine monomer is 3,3',4,4'-tetraaminodiphenylmethane.

[0039] Example 1

[0040] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 25 parts of 3,3',4,4'-tetraaminodiphenylmethane, 18 parts of a composite aromatic dibasic acid, 4 parts of a eugenol derivative, 1 part of a carboxylated o-carborane, 0.1 parts of phosphorus pentoxide, and 120 parts of N,N-dimethylacetamide.

[0041] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0042] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent are mixed, stirred at 80°C for 30 minutes under a nitrogen atmosphere, heated to 190°C, stirred for 10 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants clump and stick to the stirring rod, and after being broken, they are soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power is 35W, the wavelength is 300nm, the temperature is 35°C, and the light intensity is 30mW / cm 2 , the irradiation time is 18min.

[0043] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0044] A1. Add 3 g of 6,7-dihydroxycoumarin to 16 mL of N,N-dimethylacetamide, stir evenly, add 1.2 mL of 10 mol / L ammonia water and 7 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0045] A2. Add 1g of coumarin derivative and 1g of terephthalic acid to 15mL of N,N-dimethylformamide, stir evenly, add 0.5g of tetrabutyl titanate, heat to 150℃, stir and react for 2h, cool to room temperature, stand for 10min, filter, wash with deionized water 3 times, and dry in an oven at 70℃ for 8min to obtain a composite aromatic dibasic acid.

[0046] The eugenol derivatives are specifically prepared by the following steps:

[0047] B1. Add 2 g of 4-ethynyltoluene and 1 g of o-carborane to 45 mL of tetrahydrofuran, stir evenly, add 0.3 g of N,N-dimethylaniline, stir and react for 25 min, let stand for 10 min, take out the organic phase, add 0.5 g of anhydrous magnesium sulfate to the organic phase to remove the moisture in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 2 g of the solid and 0.1 g of chromium trioxide to 25 mL of ethanol, stir, after the reaction is complete, add 0.05 g of thionyl chloride for activation, filter, wash with ethanol 3 times, and dry in an oven at 85 ° C for 10 min to obtain carboxylated o-carborane;

[0048] B2. Add 3 g of eugenol and 1.1 g of carboxylated o-borane to 15 mL of ethanol, stir evenly, add 0.2 g of sodium hydroxide, stir and react at 60 °C for 8 min, add 4 mL of hydroxyethyl methacrylate, continue stirring and react for 8 min, heat to 80 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0049] Example 2

[0050] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by mass: 30 parts of 3,3',4,4'-tetraaminodiphenylmethane, 20 parts of a composite aromatic dibasic acid, 5 parts of a eugenol derivative, 2 parts of carboxylated o-carborane, 0.3 parts of phosphorus pentoxide, and 130 parts of N,N-dimethylacetamide.

[0051] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0052] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 100°C for 33 minutes under a nitrogen atmosphere, heated to 195°C, stirred for 13 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 40W, the wavelength was 350nm, the temperature was 40°C, and the light intensity was 35mW / cm 2 , the irradiation time is 20min.

[0053] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0054] A1. Add 3.6 g of 6,7-dihydroxycoumarin to 18 mL of N,N-dimethylacetamide, stir evenly, add 1.3 mL of 12 mol / L ammonia water and 7.5 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0055] A2. Add 1.5 g of coumarin derivative and 1.2 g of terephthalic acid into 20 mL of N,N-dimethylformamide, stir evenly, add 0.54 g of tetrabutyl titanate, heat to 155°C, stir to react for 3 hours, cool to room temperature, stand for 15 minutes, filter, wash with deionized water three times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0056] The eugenol derivatives are specifically prepared by the following steps:

[0057] B1. Add 2.5 g of 4-ethynyltoluene and 1.5 g of o-carborane to 50 mL of tetrahydrofuran, stir evenly, add 0.5 g of N,N-dimethylaniline, stir and react for 25 min, let stand for 10 min, take out the organic phase, add 0.5 g of anhydrous magnesium sulfate to the organic phase to remove the moisture in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 2.5 g of the solid and 0.2 g of chromium trioxide to 30 mL of ethanol, stir, after the reaction is complete, add 0.1 g of thionyl chloride for activation, filter, wash with ethanol 3 times, and dry in an oven at 85 ° C for 10 min to obtain carboxylated o-carborane;

[0058] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-carborane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 65 °C for 10 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 10 min, heat to 85 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0059] Example 3

[0060] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a composite aromatic dibasic acid, 6 parts of a eugenol derivative, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0061] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0062] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0063] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0064] A1. Add 4 g of 6,7-dihydroxycoumarin to 20 mL of N,N-dimethylacetamide, stir evenly, add 1.4 mL of 13 mol / L ammonia water and 8 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0065] A2. Add 2 g of coumarin derivative and 1.4 g of terephthalic acid into 25 mL of N,N-dimethylformamide, stir evenly, add 0.6 g of tetrabutyl titanate, heat to 160°C, stir and react for 4 hours, cool to room temperature, stand for 20 minutes, filter, wash with deionized water 3 times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0066] The eugenol derivatives are specifically prepared by the following steps:

[0067] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0068] B2. Add 3.5 g of eugenol and 1.3 g of carboxylated o-carborane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0069] Comparative Example 1

[0070] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a composite aromatic dibasic acid, 6 parts of a eugenol derivative, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0071] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0072] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0073] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0074] Add 2 g of 6,7-dihydroxycoumarin and 1.4 g of terephthalic acid into 25 mL of N,N-dimethylformamide, stir evenly, add 0.6 g of tetrabutyl titanate, heat to 160°C, stir and react for 4 hours, cool to room temperature, stand for 20 minutes, filter, wash with deionized water 3 times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0075] The eugenol derivatives are specifically prepared by the following steps:

[0076] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0077] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-borane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0078] Comparative Example 2

[0079] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a mixture of a coumarin derivative and terephthalic acid, 6 parts of a eugenol derivative, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0080] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0081] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0082] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0083] A1. Add 4 g of 6,7-dihydroxycoumarin to 20 mL of N,N-dimethylacetamide, stir evenly, add 1.4 mL of 13 mol / L ammonia water and 8 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0084] A2. Mix 2 g of a coumarin derivative and 1.4 g of terephthalic acid to obtain a mixture of a coumarin derivative and terephthalic acid.

[0085] The eugenol derivatives are specifically prepared by the following steps:

[0086] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0087] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-borane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0088] Comparative Example 3

[0089] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of terephthalic acid, 6 parts of eugenol derivatives, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0090] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0091] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0092] The eugenol derivatives are specifically prepared by the following steps:

[0093] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0094] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-borane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0095] Comparative Example 4

[0096] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by mass: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a composite aromatic dibasic acid, 6 parts of eugenol, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0097] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0098] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0099] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0100] A1. Add 4 g of 6,7-dihydroxycoumarin to 20 mL of N,N-dimethylacetamide, stir evenly, add 1.4 mL of 13 mol / L ammonia water and 8 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0101] A2. Add 2 g of coumarin derivative and 1.4 g of terephthalic acid into 25 mL of N,N-dimethylformamide, stir evenly, add 0.6 g of tetrabutyl titanate, heat to 160°C, stir and react for 4 hours, cool to room temperature, stand for 20 minutes, filter, wash with deionized water 3 times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0102] Comparative Example 5

[0103] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a composite aromatic dibasic acid, 6 parts of a eugenol derivative, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0104] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0105] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent were mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, stirred for 15 hours, cooled to room temperature, and injected with cold distilled water into the three-necked flask after ultraviolet irradiation. The reactants agglomerated and adhered to the stirring rod, and after being broken, they were soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin. The ultraviolet irradiation power was 45W, the wavelength was 400nm, the temperature was 45°C, and the light intensity was 40mW / cm 2 , the irradiation time is 22min.

[0106] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0107] A1. Add 4 g of 6,7-dihydroxycoumarin to 20 mL of N,N-dimethylacetamide, stir evenly, add 1.4 mL of 13 mol / L ammonia water and 8 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0108] A2. Add 2 g of coumarin derivative and 1.4 g of terephthalic acid into 25 mL of N,N-dimethylformamide, stir evenly, add 0.6 g of tetrabutyl titanate, heat to 160°C, stir and react for 4 hours, cool to room temperature, stand for 20 minutes, filter, wash with deionized water 3 times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0109] The eugenol derivatives are specifically prepared by the following steps:

[0110] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0111] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-borane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0112] Comparative Example 6

[0113] A formula for synthesizing a high molecular weight PBI resin comprises the following raw materials in parts by weight: 35 parts of 3,3',4,4'-tetraaminodiphenylmethane, 22 parts of a composite aromatic dibasic acid, 6 parts of a eugenol derivative, 3 parts of carboxylated o-carborane, 0.5 parts of phosphorus pentoxide, and 150 parts of N,N-dimethylacetamide.

[0114] A method for preparing a synthetic high molecular weight PBI resin comprises the following preparation steps:

[0115] In a three-necked flask equipped with a nitrogen tube, a stirrer, a thermometer, and a condenser, a tetraamine monomer, a catalyst, a complex aromatic dibasic acid, and a solvent are mixed, stirred at 120°C for 35 minutes under a nitrogen atmosphere, heated to 200°C, and stirred for reaction for 15 hours, then cooled to room temperature, and cold distilled water is injected into the three-necked flask. The reactants clump and stick to the stirring rod. After being broken, they are soaked in sodium bicarbonate, washed with water until neutral, filtered, and dried in an oven at 80°C for 10 minutes to obtain a high molecular weight PBI resin.

[0116] The composite aromatic dibasic acid is specifically prepared by the following steps:

[0117] A1. Add 4 g of 6,7-dihydroxycoumarin to 20 mL of N,N-dimethylacetamide, stir evenly, add 1.4 mL of 13 mol / L ammonia water and 8 mL of glycidyl methacrylate, stir at room temperature for 12 h, distill under reduced pressure until crystals precipitate, filter, wash with deionized water three times, and dry in an oven at 60 ° C for 10 min to obtain a coumarin derivative;

[0118] A2. Add 2 g of coumarin derivative and 1.4 g of terephthalic acid into 25 mL of N,N-dimethylformamide, stir evenly, add 0.6 g of tetrabutyl titanate, heat to 160°C, stir and react for 4 hours, cool to room temperature, stand for 20 minutes, filter, wash with deionized water 3 times, and dry in an oven at 70°C for 8 minutes to obtain a composite aromatic dibasic acid.

[0119] The eugenol derivatives are specifically prepared by the following steps:

[0120] B1. Add 3g 4-ethynyltoluene and 2g o-carborane to 55mL tetrahydrofuran, stir evenly, add 0.7g N,N-dimethylaniline, stir and react for 25min, let stand for 10min, take out the organic phase, add 2.5g anhydrous magnesium sulfate to the organic phase to remove the water in the organic phase, remove the solvent by rotary evaporator to obtain a solid, add 3g solid and 0.3g chromium trioxide to 35mL ethanol, stir, after the reaction is complete, add 0.15g thionyl chloride for activation, filter, wash 3 times with ethanol, and dry in an oven at 85°C for 10min to obtain carboxylated o-carborane;

[0121] B2. Add 3.5 g of eugenol and 1.2 g of carboxylated o-borane to 20 mL of ethanol, stir evenly, add 0.3 g of sodium hydroxide, stir and react at 70 °C for 12 min, add 5 mL of hydroxyethyl methacrylate, continue stirring and reacting for 12 min, heat to 90 °C and stir until the organic solvent evaporates, take out the solid, wash with deionized water until the pH of the washing liquid is neutral, and dry in an oven at 60 °C for 10 min to obtain a eugenol derivative.

[0122] The performance of the high molecular weight PBI resins prepared in Examples 1-3 and Comparative Examples 1-6 was tested.

[0123] Heat resistance test: A Mettler Toledo SDTA-854 thermogravimetric analyzer was used with a temperature of 30-800°C and a heating rate of 10°C / min. The test was conducted in a nitrogen atmosphere with a nitrogen flow rate of 100 mL / min to perform thermogravimetric analysis on the high molecular weight PBI resin prepared above.

[0124] Mechanical properties test: tested by WDW-5 micro-controlled electronic universal testing machine (Changchun Kexin Experiment Co., Ltd.), the tensile rate is 5mm / min. The test temperature is 23°C, the indoor relative humidity is 23%, the high molecular weight PBI resin prepared above forms a film, and the film is made into a length of 25mm, a width of 3mm, and a thickness of 0.3mm. The test standard is GB / 13022-1991, and the breaking strength and breaking elongation are tested.

[0125] Viscosity test: The viscosity was measured using a JLABO-VISCOME-16G viscosity test system (ULABO Technology Co., Ltd.). 0.05 g of the high molecular weight PBI resin prepared above was weighed and prepared into 25 mL of dimethyl sulfoxide solution. The test temperature was 25° C. and the shear rate was 1001 / s.

[0126] Molecular weight determination of high molecular weight PBI resin: The molecular weight of the high molecular weight PBI resin prepared above was determined by gel permeation chromatography. The PBI resin passes through the gel chromatography column and performs a reciprocating motion of "entering the gel micropores-diffusion between the gel particles", continuously entering and diffusing, so that the sample flows out in order from large to small volume. Connect the molecular weight test instrument and record the measurement results of the relative molecular weight. As shown in Table 1 below.

[0127] Table 1 Performance test of high molecular weight PBI resin prepared in Examples 1-3 and Comparative Examples 1-6

[0128]

[0129]

[0130] It can be seen from the data in Table 1 that the high molecular weight PBI resin prepared in Examples 1-3 has a high molecular weight, mechanical strength and thermal stability. In Comparative Example 1, the coumarin derivative was replaced with a composite aromatic dibasic acid prepared by 6,7-dihydroxycoumarin, and added to the high molecular weight PBI resin, and its mechanical strength and thermal stability decreased, proving that the composite aromatic dibasic acid synthesized by the reaction of 6,7-dihydroxycoumarin with glycidyl methacrylate and terephthalic acid can be grafted on the PBI resin, increase the molecular weight of the PBI resin, and improve the mechanical properties and thermal stability of the PBI resin.

[0131] In Comparative Example 2, the complex aromatic dibasic acid was replaced by a mixture of coumarin derivatives and terephthalic acid and added to the high molecular weight PBI resin, and its mechanical strength and thermal stability decreased, proving that coumarin derivatives and terephthalic acid can be used as dibasic acid monomers through chemical grafting, participate in the synthesis of PBI resin, increase the molecular weight of PBI resin, and improve mechanical strength and thermal stability.

[0132] In Comparative Example 3, the complex aromatic dibasic acid is replaced with terephthalic acid and added to the high molecular weight PBI resin, and its mechanical strength and thermal stability decrease, indicating that 6,7-dihydroxycoumarin and glycidyl methacrylate are grafted on the PBI resin. Under ultraviolet light, the complex aromatic dibasic acid and the eugenol derivative are double-bonded copolymerized, thereby introducing a large number of flexible long chains into the PBI resin, which can give the PBI resin better mechanical properties and a higher molecular weight.

[0133] In Comparative Example 4, the eugenol derivative was replaced with eugenol and added to the high molecular weight PBI resin, and its mechanical strength and thermal stability decreased, proving that the eugenol derivative formed on carboxylated o-carborane, hydroxyethyl methacrylate, and eugenol can undergo double bond copolymerization with the complex aromatic dibasic acid under ultraviolet light, and then the eugenol derivative is grafted into the PBI resin to increase the molecular weight. In addition, the carboxylated o-carborane contains a stable cage structure and has high thermal resistance and thermal stability.

[0134] The mechanical strength and thermal stability of the eugenol derivative prepared without adding hydroxyethyl methacrylate in Comparative Example 5 were reduced when added to the high molecular weight PBI resin, proving that under ultraviolet light, the double bonds contained in hydroxyethyl methacrylate in the eugenol derivative copolymerized, and then the eugenol derivative was grafted into the PBI resin, thereby increasing the molecular weight, and improving the mechanical strength and thermal stability of the PBI resin.

[0135] In Comparative Example 6, during the synthesis of the high molecular weight PBI resin, no ultraviolet irradiation was performed, and the mechanical strength and thermal stability of the synthesized high molecular weight PBI resin decreased, proving that under ultraviolet irradiation, the complex aromatic dibasic acid and the eugenol derivative underwent double bond copolymerization, thereby introducing a large number of flexible long chains into the PBI resin, increasing the molecular weight, and improving the mechanical strength and thermal stability of the PBI resin.

[0136] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0137] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A formula for synthesizing high molecular weight PBI resin, characterized in that: The method comprises the following raw materials by weight: 25-35 parts of a tetraamine monomer, 18-22 parts of a composite aromatic dibasic acid, 4-6 parts of a eugenol derivative, 1-3 parts of a carboxylated o-carborane, 0.1-0.5 parts of a catalyst, and 120-150 parts of a solvent; The composite aromatic dibasic acid is obtained by reacting 6,7-dihydroxycoumarin with glycidyl methacrylate, and then reacting with terephthalic acid and carboxylated o-carborane; The eugenol derivative is obtained by mixed reaction of eugenol, hydroxyethyl methacrylate and carboxylated o-carborane.

2. A formulation for synthesizing a high molecular weight PBI resin according to claim 1, characterized in that: The composite aromatic dibasic acid is specifically prepared by the following steps: A1. Add 6,7-dihydroxycoumarin to N,N-dimethylacetamide, stir evenly, add 10-13 mol / L ammonia and glycidyl methacrylate, stir, distill under reduced pressure, filter, wash, and dry to obtain a coumarin derivative; A2. Add coumarin derivatives and terephthalic acid to N,N-dimethylformamide, stir evenly, add tetrabutyl titanate, heat to 150-160°C, stir to react for 2-4 hours, cool to room temperature, stand for 10-20 minutes, filter, wash and dry to obtain a composite aromatic dibasic acid.

3. A formulation for synthesizing a high molecular weight PBI resin according to claim 2, characterized in that: In step A1, the usage ratio of 6,7-dihydroxycoumarin, N,N-dimethylacetamide, aqueous ammonia, and glycidyl methacrylate is (3-4) g:(16-20) mL:(1.2-1.4) mL:(7-8) mL.

4. A formulation for synthesizing a high molecular weight PBI resin according to claim 2, characterized in that: In step A2, the ratio of the coumarin derivative, terephthalic acid, N,N-dimethylformamide and tetrabutyl titanate is (1-2) g:(1-1.4) g:(15-25) mL:(0.5-0.6) g.

5. A formulation for synthesizing a high molecular weight PBI resin according to claim 1, characterized in that: The eugenol derivative is specifically prepared by the following steps: B1. Add 4-ethynyltoluene and o-carborane to tetrahydrofuran, stir evenly, add N,N-dimethylaniline, stir, let stand, take out the organic phase, remove the water and solvent in the organic phase to obtain a solid, add the solid and chromium trioxide to ethanol, stir to react, add thionyl chloride, stir, filter, wash, and dry to obtain carboxylated o-carborane; B2. Add eugenol and carboxylated o-carborane to ethanol, stir evenly, add sodium hydroxide, stir and react at 60-70°C for 8-12 min, add hydroxyethyl methacrylate, stir and react for 8-12 min, heat to 80-90°C, stir, take out the solid, wash and dry to obtain a eugenol derivative.

6. A formulation for synthesizing a high molecular weight PBI resin according to claim 5, characterized in that: In step B1, the amount ratio of 4-ethynyltoluene, o-carborane, tetrahydrofuran, and N,N-dimethylaniline is (2-3) g: (1-2) g: (45-55) mL: (0.3-0.7) g; the amount ratio of the solid, chromium trioxide, ethanol, and thionyl chloride is (2-3) g: (0.1-0.3) g: (25-35) mL: (0.05-0.15) g.

7. A formulation for synthesizing a high molecular weight PBI resin according to claim 5, characterized in that: In step B2, the amount ratio of eugenol, carboxylated o-carborane, ethanol, hydroxyethyl methacrylate, and sodium hydroxide is (3-4) g: (1.1-1.3) g: (15-25) mL: (4-6) mL: (0.2-0.4) g.

8. The formulation of a synthetic high molecular weight PBI resin according to claim 1, characterized in that: The solvent is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone.

9. The formula of a molecular weight PBI resin according to claim 1, characterized in that: The catalyst is phosphorus pentoxide; the tetraamine monomer is selected from one or more of 3,3',4,4'-tetraaminodiphenylmethane, 3,3',4,4'-tetraaminodiphenyl sulfone and 3,3',4,4'-tetraaminodiphenyl ether.

10. A method for preparing a synthetic high molecular weight PBI resin as claimed in any one of claims 1 to 9, characterized in that: The method comprises the following preparation steps: The tetraamine monomer, catalyst, composite aromatic dibasic acid and solvent are mixed, stirred at 80-120°C for 30-35 minutes under a nitrogen atmosphere, heated to 190-200°C, stirred for reaction for 10-15 hours, cooled to room temperature, irradiated with ultraviolet light, injected with cold distilled water, crushed, soaked, washed, filtered and dried to obtain a high molecular weight PBI resin.

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