TPU material with high gas barrier property and preparation method thereof

Abstract

The invention discloses a TPU material with high gas barrier property and a preparation method thereof, and relates to the technical field of high polymer materials. When the TPU material with the high gas barrier property is prepared, 1, 10-phenanthroline-4, 7-diamine and di (2-chloroethyoxyl) phosphorus-based benzene are polymerized and coated on a boron nitride nanosheet to prepare a pre-modified boron nitride nanosheet; reacting the pre-modified boron nitride nanosheet, europium chloride hexahydrate and n-hexanoic acid to prepare a modified boron nitride nanosheet; the preparation method comprises the following steps: reacting 3, 5-diamino-1, 2, 4-triazole with vanillin to prepare a vanillin Schiff base triazole monomer; the preparation method comprises the following steps: reacting vanillin Schiff base triazole monomer with N-chloroethyl maleimide to prepare a bio-based flame retardant; mixing polyurethane, a bio-based flame retardant and the modified boron nitride nanosheets, and performing extrusion molding to obtain the TPU material with high gas barrier property. The TPU material with high gas barrier property prepared by the invention has excellent gas barrier property, anti-aging property and flame retardant property.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer materials, in particular to a high-gas-barrier TPU material and a preparation method thereof. BACKGROUND

[0002] TPU, namely thermoplastic polyurethane, is a high polymer material with both rubber elasticity and engineering plastic strength, and is widely used in the tire manufacturing industry. Compared with traditional rubber tires, TPU is lighter, stronger in impact resistance and tensile resistance, and has excellent puncture resistance, which can effectively reduce the risk of tire burst caused by gravel and branches during mountain biking. Secondly, TPU tread material does not contain carbon black and rubber filling oil, so it will not pollute the air and soil during the wear process, which meets the modern environmental protection concept.

[0003] The high strength and environmental protection performance of the TPU material make it applicable in the tire manufacturing field, but in actual use, the problems of poor durability and insufficient air tightness generally exist, the TPU inner tube generally has a slow air leakage problem, the air tightness caused by the glue bonding process is much lower than that of the butyl rubber inner tube, and frequent air supplement is needed; the TPU material is easily affected by the environment, and will be oxidized and blackened during long-term use, and ultraviolet rays, moisture and rubber debris residues will accelerate aging. In view of the above problems, it is necessary to invent a TPU material with anti-aging and high gas barrier properties. SUMMARY

[0004] The purpose of the application is to provide a high-gas-barrier TPU material and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the application provides the following technical scheme: A high-gas-barrier TPU material, the high-gas-barrier TPU material is modified boron nitride nanosheet prepared by reacting pre-modified boron nitride nanosheet, europium trichloride hexahydrate and n-hexanoic acid; a bio-based flame retardant is prepared by reacting vanillin Schiff base triazole monomer and N-chloroethyl maleimide; and the high-gas-barrier TPU material is prepared by mixing polyurethane, the bio-based flame retardant and the modified boron nitride nanosheet and extruding; The pre-modified boron nitride nanosheet is prepared by coating 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy) phosphorbenzene on the boron nitride nanosheet; The vanillin Schiff base triazole monomer is prepared by reacting 3,5-diamino-1,2,4-triazole and vanillin; The polyurethane is prepared by polymerizing polyether glycol, 2,5-furandimethanol and isophorone diisocyanate, and chain extending with 1,4-butanediol.

[0006] The application discloses a preparation method of a high-gas-barrier TPU material. (1) a pre-modified boron nitride nanosheet, europium trichloride hexahydrate, n-hexanoic acid and anhydrous ethanol are uniformly mixed according to a mass ratio of 1:(3-4):(8-10):(30-40), ammonia water solution is used to adjust the pH to 6, stirring is carried out at room temperature and at a speed of 300-400 r / min for 4-5 h, filtration is carried out, the modified boron nitride nanosheet is washed with anhydrous ethanol for 5 times, and drying is carried out under a vacuum condition at 50-60 DEG C for 12-14 h; (2) vanillin Schiff base triazole monomers and N-chloroethyl maleimide are mixed according to a molar ratio of 1:2, 0.05-0.06 times the mass of the vanillin Schiff base triazole monomers of tetrabutylammonium bromide is added, stirring is carried out at 80 DEG C and at a speed of 200-300 r / min for 12-13 h, the temperature is lowered to 60 DEG C, 0.6-0.7 times the mass of a 40% mass fraction sodium hydroxide aqueous solution of the vanillin Schiff base triazole monomers is uniformly added at a speed within 15 min, after the addition is completed, stirring is continuously carried out for 5-6 h, washing is carried out with deionized water for 5 times, and drying is carried out under a vacuum condition at 50-60 DEG C for 10-12 h, so as to obtain a bio-based flame retardant; (3) polyether diol, 2,5-furandimethanol and N,N-dimethylformamide are uniformly mixed according to a mass ratio of 1:(0.4-0.5):(14-16), stirring is carried out at 55-65 DEG C and at a speed of 200-300 r / min for 20-30 min, 2-2.4 times the mass of the polyether diol of isophorone diisocyanate is added, 0.04-0.06 times the mass of the polyether diol of dibutyltin dilaurate is added, the temperature is raised to 88-92 DEG C, stirring is continuously carried out for 2-3 h, the temperature is lowered to 70-80 DEG C, 0.1-0.2 times the mass of isophorone diisocyanate of 1,4-butanediol is added, stirring is continuously carried out for 50-60 min, and drying is carried out under a vacuum condition at 60-70 DEG C for 14-16 h, so as to obtain a polyurethane; (4) the polyurethane, the bio-based flame retardant and the modified boron nitride nanosheet are mixed and extruded into a high-gas-barrier TPU material in a double-screw extruder.

[0007] As optimization, the preparation method of the pre-modified boron nitride nanosheet in step (1) is as follows: boron nitride nanosheet, 1,10-phenanthroline-4,7-diamine, and triethylamine are weighed according to a mass ratio of 1:(3-4):(0.06-0.08); 1,10-phenanthroline-4,7-diamine and bis(2-chloroethoxy) phosphorophenyl are added into toluene in a molar ratio of 1:(1.2-1.4), and mixed uniformly to prepare a reaction solution; triethylamine and toluene are mixed uniformly according to a mass ratio of 1:(5-6) to prepare a catalyst solution; the boron nitride nanosheet and toluene are mixed uniformly according to a mass ratio of 1:(20-24), and the reaction solution and the catalyst solution are added at a constant speed under the conditions of 50-60℃ and 200-300r / min stirring within 20min; after the addition is completed, the stirring is continued for 3-4h; filtration, washing with anhydrous ethanol and deionized water for 3 times, and drying at 50-60℃ under vacuum for 8-10h to obtain the pre-modified boron nitride nanosheet.

[0008] As optimization, the CAS number of the bis(2-chloroethoxy) phosphorophenyl is 13547-39-2, and the structural formula is as follows: .

[0009] As optimization, the preparation method of the vanillin Schiff base triazole monomer in step (2) is as follows: 3,5-diamino-1,2,4-triazole and vanillin are added into anhydrous ethanol in a molar ratio of 1:2, and deionized water is added in an amount of 8-10 times the mass of vanillin; stirring is carried out at 50-60℃ and 300-500r / min for 2-3h; and drying is carried out at 50-60℃ under vacuum for 8-10h to obtain the vanillin Schiff base triazole monomer.

[0010] As optimization, the CAS number of the N-chloroethyl maleimide in step (2) is 35889-79-3, and the structural formula is as follows: .

[0011] As optimization, the synthesis mechanism of the bio-based flame retardant in step (2) is as follows: .

[0012] As optimization, the molecular weight of the polyether diol in step (3) is 1000.

[0013] As optimization, the amounts of the polyurethane, the bio-based flame retardant, and the modified boron nitride nanosheet in step (4) are as follows: the polyurethane is 90-92 parts by mass, the bio-based flame retardant is 7-8 parts by mass, and the modified boron nitride nanosheet is 4-5 parts by mass.

[0014] As optimization, the process parameters of the extrusion forming in step (4) are as follows: the extrusion temperature of the double-screw extruder is 190-210 DEG C, the extrusion pressure is 20-24 MPa, and the screw rotation speed is 50-60 r / min.

[0015] Compared with the prior art, the present application has the following beneficial effects: In the preparation of the high gas barrier TPU material, first, 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy) phosphorus-based phenyl polymer are coated on boron nitride nanosheets to obtain pre-modified boron nitride nanosheets, the phosphorus element and 1,10-phenanthroline structure are introduced on the surface of the pre-modified boron nitride nanosheets, the introduction of the phosphorus element can improve the flame retardant performance of the high gas barrier TPU material; the pre-modified boron nitride nanosheets, europium chloride hexahydrate and n-hexanoic acid are reacted to obtain modified boron nitride nanosheets; the 1,10-phenanthroline structure introduced on the pre-modified boron nitride nanosheets reacts with the europium chloride hexahydrate and the n-hexanoic acid to form a rare earth europium complex, the rare earth europium complex has excellent photoluminescence characteristics and will emit strong red light under ultraviolet light excitation; the rare earth europium complex can absorb more ultraviolet rays than a single rare earth element ion itself, and the absorbed ultraviolet energy can be effectively transferred to the rare earth ion through intramolecular organic ligand, thereby improving the anti-aging performance of the high gas barrier TPU material, and the structure of the generated rare earth europium complex is as follows: ; Meanwhile, the boron nitride nanosheet is an inorganic two-dimensional sheet-shaped nanomaterial, and has gas impermeability by itself, the addition of the boron nitride nanosheet can prolong the diffusion path required for gas molecules to pass through the polymer material, thereby improving the gas barrier performance of the material.

[0016] Secondly, vanillin Schiff base triazole monomers are prepared by reacting 3,5-diamino-1,2,4-triazole and vanillin; bio-based flame retardants are prepared by reacting the vanillin Schiff base triazole monomers and N-chloroethylmaleimide, and maleimide groups are introduced at both ends of the bio-based flame retardants, the addition of the bio-based flame retardants can improve the flame retardant performance of the high gas barrier TPU material, and the maleimide groups at both ends can undergo D-A reaction with furan groups introduced on the polyurethane main chain to form a thermally reversible crosslinking structure, the crosslinking can reduce the movement ability of the polyurethane molecular chain and improve the gas barrier performance of the material.

[0017] Finally, polyurethane is prepared by polymerizing polyether diol, 2,5-furandimethanol and isophorone diisocyanate and chain extending with 1,4-butanediol; and furan groups are introduced on the polyurethane main chain, due to the polarity of the furan ring and the nonlinearity of the furan ring structure, the furan ring is difficult to flip, which further limits the beta relaxation behavior, the movement of the polyurethane molecular chain is hindered, the diffusion rate of the gas molecules is reduced, and the gas barrier performance of the material is improved. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0019] Embodiment 1: A preparation method of a high gas barrier TPU material, the preparation method of the high gas barrier TPU material comprising the following preparation steps: (1) Boron nitride nanosheets, 1,10-phenanthroline-4,7-diamine, and triethylamine are weighed according to a mass ratio of 1:3:0.06; 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy) phosphorophenyl are added into toluene with a mass of 16 times that of 1,10-phenanthroline-4,7-diamine according to a molar ratio of 1:1.2, and mixed uniformly to prepare a reaction solution; triethylamine and toluene are mixed uniformly according to a mass ratio of 1:5 to prepare a catalyst solution; the boron nitride nanosheets and toluene are mixed uniformly according to a mass ratio of 1:20, and the reaction solution and the catalyst solution are added at a constant speed under the conditions of 50℃ and 200r / min stirring within 20min; after the addition is completed, the stirring reaction is continued for 4h; filtration is performed, and the product is washed with anhydrous ethanol and deionized water for 3 times each; and the product is dried at 50℃ under vacuum conditions for 10h to prepare pre-modified boron nitride nanosheets; the pre-modified boron nitride nanosheets, europium chloride hexahydrate, n-hexanoic acid, and anhydrous ethanol are mixed uniformly according to a mass ratio of 1:3:8:30, and the pH is adjusted to 6 with an ammonia solution; the stirring reaction is performed at room temperature and at a speed of 300r / min for 5h; filtration is performed, and the product is washed with anhydrous ethanol for 5 times; and the product is dried at 50℃ under vacuum conditions for 14h to prepare modified boron nitride nanosheets; (2) 3,5-diamino-1,2,4-triazole and vanillin are added into anhydrous ethanol with a mass of 10 times that of vanillin according to a molar ratio of 1:2, and deionized water with a mass of 8 times that of vanillin is further added; the stirring reaction is performed at 50℃ and at a speed of 300r / min for 3h; and the product is dried at 50℃ under vacuum conditions for 10h to prepare a vanillin Schiff base triazole monomer; the vanillin Schiff base triazole monomer and N-chloroethylmaleimide are mixed according to a molar ratio of 1:2, and tetrabutylammonium bromide with a mass of 0.05 times that of the vanillin Schiff base triazole monomer is added; the stirring reaction is performed at 80℃ and at a speed of 200r / min for 13h; the temperature is lowered to 60℃, and sodium hydroxide aqueous solution with a mass fraction of 40% and a mass of 0.6 times that of the vanillin Schiff base triazole monomer is added at a constant speed within 15min; after the addition is completed, the stirring reaction is continued for 6h; the product is washed with deionized water for 5 times; and the product is dried at 50℃ under vacuum conditions for 12h to prepare a bio-based flame retardant; (3) Polyether diol, 2,5-furandiethanol and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.4:14. The mixture was stirred at 55°C and 200 r / min for 30 min. Isophorone diisocyanate with a mass of 2 times that of polyether diol and dibutyltin dilaurate with a mass of 0.04 times that of polyether diol were added. The mixture was heated to 88°C and stirred for 3 h. The mixture was then cooled to 70°C and 1,4-butanediol with a molar mass of 0.1 times that of isophorone diisocyanate were added. The mixture was stirred for 60 min and dried at 60°C under vacuum for 16 h to obtain polyurethane. (4) Weigh 90 parts of polyurethane, 7 parts of bio-based flame retardant, and 4 parts of modified boron nitride nanosheets by mass. Mix the polyurethane, bio-based flame retardant, and modified boron nitride nanosheets and extrude them in a twin-screw extruder. Set the extrusion temperature of the twin-screw extruder to 190°C, the extrusion pressure to 20 MPa, and the screw speed to 50 r / min to obtain a high gas barrier TPU material.

[0020] Example 2: A method for preparing a high gas barrier TPU material, the method comprising the following steps: (1) Weigh boron nitride nanosheets, 1,10-phenanthroline-4,7-diamine, and triethylamine in a mass ratio of 1:3.5:0.07; add 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphobenzene in a molar ratio of 1:1.3 to 17 times the mass of 1,10-phenanthroline-4,7-diamine in toluene, and mix well to prepare a reaction solution; mix triethylamine and toluene in a mass ratio of 1:5.5 to prepare a catalyst solution; mix boron nitride nanosheets and toluene in a mass ratio of 1:22, and stir at 55℃ and 250 r / min for 2... The reaction solution and catalyst solution were added dropwise at a uniform rate within 0 min. After the addition was complete, the reaction was stirred for 3.5 h. The mixture was filtered, washed three times each with anhydrous ethanol and deionized water, and dried at 55 °C for 9 h under vacuum to obtain pre-modified boron nitride nanosheets. The pre-modified boron nitride nanosheets, europium trichloride hexahydrate, hexanoic acid, and anhydrous ethanol were mixed evenly in a mass ratio of 1:3.5:9:35. The pH was adjusted to 6 with ammonia solution, and the mixture was stirred at 350 r / min for 4.5 h at room temperature. The mixture was filtered, washed five times with anhydrous ethanol, and dried at 55 °C for 13 h under vacuum to obtain modified boron nitride nanosheets. (2) 3,5-Diamino-1,2,4-triazole and vanillin were added to anhydrous ethanol at a molar ratio of 1:2, which was 11 times the mass of vanillin. Then, deionized water at a molar ratio of 9 times the mass of vanillin was added. The mixture was stirred at 55°C and 400 r / min for 2.5 h, and then dried at 55°C under vacuum for 9 h to obtain vanillin Schiff base triazole monomer. Vanillin Schiff base triazole monomer and N-chloroethyl maleimide were mixed at a molar ratio of 1:2 and added to anhydrous ethanol. A bio-based flame retardant was prepared by reacting 0.055 times the mass of vanillin Schiff base triazole monomer with tetrabutylammonium bromide at 80℃ and 250 r / min for 12.5 h with stirring. The mixture was then cooled to 60℃, and 0.65 times the mass of vanillin Schiff base triazole monomer with a 40% sodium hydroxide aqueous solution was added dropwise over 15 min at a uniform rate. After the addition was complete, the mixture was stirred for another 5.5 h. The mixture was washed 5 times with deionized water and dried at 55℃ for 11 h under vacuum to obtain the bio-based flame retardant. (3) Polyether diol, 2,5-furandiethanol and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.45:15. The mixture was stirred at 250 r / min for 25 min at 60 °C. Isophorone diisocyanate was added at 2.2 times the mass of polyether diol and dibutyltin dilaurate at 0.05 times the mass of polyether diol. The mixture was heated to 90 °C and stirred for 2.5 h. The mixture was then cooled to 75 °C and 1,4-butanediol at 0.15 times the molar mass of isophorone diisocyanate was added. The mixture was stirred for 55 min and dried at 65 °C for 15 h under vacuum to obtain polyurethane. (4) Weigh 91 parts of polyurethane, 7.5 parts of bio-based flame retardant, and 4.5 parts of modified boron nitride nanosheets by mass. Mix the polyurethane, bio-based flame retardant, and modified boron nitride nanosheets and extrude them in a twin-screw extruder. Set the extrusion temperature of the twin-screw extruder to 200℃, the extrusion pressure to 22MPa, and the screw speed to 55r / min to obtain a high gas barrier TPU material.

[0021] Example 3: A method for preparing a high gas barrier TPU material, the method comprising the following steps: (1) Weigh boron nitride nanosheets, 1,10-phenanthroline-4,7-diamine, and triethylamine in a mass ratio of 1:4:0.08; add 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphobenzene in a molar ratio of 1:1.4 to 18 times the mass of 1,10-phenanthroline-4,7-diamine in toluene, and mix thoroughly to prepare a reaction solution; mix triethylamine and toluene in a mass ratio of 1:6 to prepare a catalyst solution; mix boron nitride nanosheets and toluene in a mass ratio of 1:24, and stir at 60℃ and 300 r / min. The reaction solution and catalyst solution were added dropwise at a uniform rate over 20 min. After the addition was complete, the reaction was stirred for 3 h. The mixture was then filtered, washed three times each with anhydrous ethanol and deionized water, and dried at 60 °C for 8 h under vacuum to obtain pre-modified boron nitride nanosheets. The pre-modified boron nitride nanosheets, europium trichloride hexahydrate, hexanoic acid, and anhydrous ethanol were mixed evenly in a mass ratio of 1:4:10:40. The pH was adjusted to 6 with ammonia solution, and the mixture was stirred at 400 r / min for 4 h at room temperature. The mixture was then filtered, washed five times with anhydrous ethanol, and dried at 60 °C for 12 h under vacuum to obtain modified boron nitride nanosheets. (2) 3,5-Diamino-1,2,4-triazole and vanillin were added to anhydrous ethanol at a molar ratio of 1:2, which was 12 times the mass of vanillin. Then, deionized water at a molar ratio of 10 times the mass of vanillin was added. The mixture was stirred at 60°C and 500 r / min for 2 h. The mixture was then dried at 60°C under vacuum for 8 h to obtain vanillin Schiff base triazole monomer. Vanillin Schiff base triazole monomer and N-chloroethyl maleimide were mixed at a molar ratio of 1:2. Add 0.06 times the mass of vanillin Schiff base triazole monomer to tetrabutylammonium bromide, stir at 300 r / min for 12 h at 80 °C, cool to 60 °C, and add 0.7 times the mass of vanillin Schiff base triazole monomer to a 40% sodium hydroxide aqueous solution at a uniform rate over 15 min. After the addition is complete, continue stirring for 5 h, wash 5 times with deionized water, and dry at 60 °C for 10 h under vacuum to obtain a bio-based flame retardant. (3) Polyether diol, 2,5-furandiethanol and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:0.5:16. The mixture was stirred at 300 r / min for 20 min at 65 °C. Isophorone diisocyanate was added at 2.4 times the mass of polyether diol and dibutyltin dilaurate at 0.06 times the mass of polyether diol. The temperature was raised to 92 °C and the reaction was stirred for 2 h. The temperature was lowered to 80 °C and 1,4-butanediol at 0.2 times the molar mass of isophorone diisocyanate was added. The reaction was stirred for 50 min. The mixture was dried at 70 °C for 14 h under vacuum to obtain polyurethane. (4) Weigh 92 parts of polyurethane, 8 parts of bio-based flame retardant, and 5 parts of modified boron nitride nanosheets by mass. Mix the polyurethane, bio-based flame retardant, and modified boron nitride nanosheets and extrude them in a twin-screw extruder. Set the extrusion temperature of the twin-screw extruder to 210℃, the extrusion pressure to 24MPa, and the screw speed to 60r / min to obtain a high gas barrier TPU material.

[0022] Comparative Example 1: The difference between the preparation method of the high gas barrier TPU material in Comparative Example 1 and Example 2 lies in the difference in step (1). In step (1), the following steps are modified: boron nitride nanosheets, 1,10-phenanthroline-4,7-diamine, and triethylamine are weighed in a mass ratio of 1:3.5:0.07; 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphobenzene are added in a molar ratio of 1:1.3 to toluene at 17 times the mass of 1,10-phenanthroline-4,7-diamine, and mixed. A uniform reaction solution was prepared. Triethylamine and toluene were mixed uniformly at a mass ratio of 1:5.5 to prepare a catalyst solution. Boron nitride nanosheets and toluene were mixed uniformly at a mass ratio of 1:22. Under stirring conditions of 250 r / min at 55℃, the reaction solution and catalyst solution were added dropwise at a uniform rate over 20 min. After the addition was complete, the reaction was stirred for another 3.5 h. The mixture was filtered, washed three times each with anhydrous ethanol and deionized water, and dried under vacuum at 55℃ for 9 h to obtain modified boron nitride nanosheets. The remaining steps were the same as in Example 2.

[0023] Comparative Example 2: The preparation method of the high gas barrier TPU material in Comparative Example 2 differs from that in Example 2 in that step (1) is omitted, and step (4) is modified as follows: 91 parts of polyurethane, 7.5 parts of bio-based flame retardant, and 4.5 parts of boron nitride nanosheets are weighed by mass; the polyurethane, bio-based flame retardant, and boron nitride nanosheets are mixed and extruded in a twin-screw extruder. The extrusion temperature of the twin-screw extruder is set to 200℃, the extrusion pressure to 22MPa, and the screw speed to 55r / min to obtain the high gas barrier TPU material. The remaining steps are the same as in Example 2.

[0024] Comparative Example 3: The preparation method of the high gas barrier TPU material in Comparative Example 3 differs from that in Example 2 in that step (1) is omitted, and step (4) is modified as follows: 91 parts of polyurethane and 7.5 parts of bio-based flame retardant are weighed by mass; the polyurethane and bio-based flame retardant are mixed and extruded in a twin-screw extruder. The extrusion temperature of the twin-screw extruder is set to 200℃, the extrusion pressure to 22MPa, and the screw speed to 55r / min to obtain the high gas barrier TPU material. The remaining steps are the same as in Example 2.

[0025] Comparative Example 4: The preparation method of the high gas barrier TPU material in Comparative Example 4 differs from that in Example 2 in that step (2) is omitted, and step (4) is modified as follows: 91 parts of polyurethane and 4.5 parts of modified boron nitride nanosheets are weighed by mass; the polyurethane and modified boron nitride nanosheets are mixed and extruded in a twin-screw extruder. The extrusion temperature of the twin-screw extruder is set to 200℃, the extrusion pressure to 22MPa, and the screw speed to 55r / min to obtain the high gas barrier TPU material. The remaining steps are the same as in Example 2.

[0026] Comparative Example 5: The difference between the preparation method of the high gas barrier TPU material in Comparative Example 5 and Example 2 lies in step (3). Step (3) is modified as follows: Polyether diol, 1,6-hexanediol, and N,N-dimethylformamide are mixed evenly at a mass ratio of 1:0.45:15, stirred at 250 r / min for 25 min at 60 °C, and then isophorone diisocyanate (2.2 times the mass of polyether diol) and dibutyltin dilaurate (0.05 times the mass of polyether diol) are added. The temperature is raised to 90 °C, and the reaction is continued with stirring for 2.5 h. The temperature is then lowered to 75 °C, and 1,4-butanediol (0.15 times the molar mass of isophorone diisocyanate) is added. The reaction is continued with stirring for 55 min, and the mixture is dried at 65 °C for 15 h under vacuum to obtain polyurethane. The remaining steps are the same as in Example 2.

[0027] Test Example 1 Gas barrier performance testing Test method: The examples and comparative examples were prepared into sheet-shaped samples with a thickness of 1 mm. The samples were tested using a VAC-V2 gas permeability tester. The test method was the differential pressure method, and the test atmosphere was nitrogen. The temperature was maintained at a constant 23 ± 0.5 ℃ during the test. A vacuum was required for 10 h before the test. The results are shown in Table 1.

[0028] Table 1

[0029] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 1 reveals that the high gas barrier TPU material prepared by this invention has excellent gas barrier properties.

[0030] By comparison, the gas permeability coefficients of Examples 1-3 are less than those of Comparative Example 3, indicating that boron nitride nanosheets, as an inorganic two-dimensional sheet-like nanomaterial, are inherently gas-impermeable. The addition of boron nitride nanosheets can extend the diffusion path required for gas molecules to pass through the polymer material, thereby improving the gas barrier performance of the material.

[0031] By comparison, the gas permeability coefficients of Examples 1-3 are less than those of Comparative Example 4, indicating that the vanillin Schiff base triazole monomer is prepared by reacting 3,5-diamino-1,2,4-triazole and vanillin; the bio-based flame retardant is prepared by reacting the vanillin Schiff base triazole monomer and N-chloroethyl maleimide; and maleimide groups are introduced at both ends of the bio-based flame retardant. The maleimide groups at both ends can undergo a DA reaction with the furan groups introduced on the polyurethane backbone to form a thermally reversible cross-linked structure. Cross-linking can reduce the mobility of polyurethane molecular chains and improve the gas barrier performance of the material.

[0032] By comparison, the gas permeability coefficients of Examples 1-3 are less than those of Comparative Example 5, indicating that polyurethane is prepared by polymerizing polyether diol, 2,5-furandiethanol, and isophorone diisocyanate, and then extending the chain with 1,4-butanediol; and by introducing furan groups into the polyurethane backbone. Due to the polarity of the furan ring and the nonlinearity of the furan ring structure, the furan ring flipping is difficult, which further restricts the β-relaxation behavior, hinders the movement of the polyurethane molecular chain, reduces the diffusion rate of gas molecules, and improves the gas barrier performance of the material.

[0033] Test Example 2 Anti-aging performance test Test method: Standard specimens were prepared according to GB / T1040.3 based on the examples and comparative examples. The tensile strength X of the standard specimens was tested using an electronic universal testing machine. The standard specimens were irradiated under a 200W UV lamp with a wavelength of 365nm for 15 days. After the irradiation, the tensile strength Y of the standard specimens was tested. The performance degradation rate of the standard specimens after UV aging was calculated. Performance degradation rate = (XY / X) × 100%. The results are shown in Table 2.

[0034] Table 2

[0035] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 2 reveals that the high gas barrier TPU material prepared by this invention has good anti-aging properties.

[0036] By comparison, the performance degradation rate of Examples 1-3 was less than that of Comparative Examples 1-3, indicating that pre-modified boron nitride nanosheets were prepared by polymerizing and coating 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphobenzene onto boron nitride nanosheets, and a 1,10-phenanthroline structure was introduced onto the surface of the pre-modified boron nitride nanosheets. Modified boron nitride nanosheets were prepared by reacting the pre-modified boron nitride nanosheets, europium trichloride hexahydrate, and hexanoic acid. The 1,10-phenanthroline structure introduced on the pre-modified boron nitride nanosheets reacted with europium trichloride hexahydrate and hexanoic acid to form a rare earth europium complex. The rare earth europium complex has excellent photoluminescence properties and emits strong red light under ultraviolet light excitation. The rare earth europium complex can absorb more ultraviolet light than the single rare earth element ions themselves, and the absorbed ultraviolet energy can be effectively transferred to rare earth ions through intramolecular organic ligands, thereby improving the anti-aging performance of high gas barrier TPU materials.

[0037] Test Example 3 Flame retardant performance testing Test method: Standard samples were prepared according to GB / T2406-93 for the examples and comparative examples, and the limiting oxygen index of the standard samples was tested. The results are shown in Table 3.

[0038] Table 3

[0039] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 3 reveals that the high gas barrier TPU material prepared by this invention has good flame retardant properties.

[0040] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Examples 2-3, indicating that pre-modified boron nitride nanosheets are prepared by polymerizing and coating 1,10-phenanthroline-4,7-diamine and bis(2-chloroethoxy)phosphorylbenzene onto boron nitride nanosheets. The introduction of phosphorus element on the surface of pre-modified boron nitride nanosheets can improve the flame retardant properties of high gas barrier TPU materials.

[0041] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Example 4, indicating that the vanillin Schiff base triazole monomer is prepared by reacting 3,5-diamino-1,2,4-triazole and vanillin; and the bio-based flame retardant is prepared by reacting the vanillin Schiff base triazole monomer and N-chloroethyl maleimide. The addition of the bio-based flame retardant can improve the flame retardant performance of high gas barrier TPU materials.

[0042] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high gas barrier TPU material, characterized in that, The high gas barrier TPU material is prepared by reacting pre-modified boron nitride nanosheets, europium trichloride hexahydrate, and hexanoic acid to obtain modified boron nitride nanosheets; reacting vanillin Schiff base triazole monomer and N-chloroethyl maleimide to obtain a bio-based flame retardant; and mixing polyurethane, bio-based flame retardant, and modified boron nitride nanosheets, followed by extrusion molding to obtain the high gas barrier TPU material. The pre-modified boron nitride nanosheets are prepared by polymerizing and coating 1,10-phenanthroline-4,7-diamine and bis(2-chloroethoxy)phosphobenzene onto boron nitride nanosheets; The vanillin Schiff base triazole monomer is prepared by reacting 3,5-diamino-1,2,4-triazole with vanillin. The polyurethane is prepared by polymerizing polyether diol, 2,5-furandiethanol, and isophorone diisocyanate, and then extending the chain with 1,4-butanediol.

2. A method for preparing a high gas barrier TPU material, characterized in that, The preparation method of the high gas barrier TPU material includes the following preparation steps: (1) Mix pre-modified boron nitride nanosheets, europium trichloride hexahydrate, hexanoic acid and anhydrous ethanol evenly, adjust the pH to 6 with ammonia solution, react at room temperature for 4-5 h, filter, wash and dry to obtain modified boron nitride nanosheets; (2) Mix vanillin Schiff base triazole monomer and N-chloroethyl maleimide, add tetrabutylammonium bromide, react at 80℃ for 12-13h, cool down to 60℃, add sodium hydroxide aqueous solution dropwise, continue to react for 5-6h after the addition is complete, wash, dry, and obtain bio-based flame retardant. (3) Mix polyether diol, 2,5-furandiethanol and N,N-dimethylformamide evenly, stir at 55~65℃ for 20~30min, add isophorone diisocyanate and dibutyltin dilaurate, heat to 88~92℃, continue to react for 2~3h, cool to 70~80℃, add 1,4-butanediol, continue to react for 50~60min to obtain polyurethane; (4) Polyurethane, bio-based flame retardant and modified boron nitride nanosheets are mixed and extruded in a twin-screw extruder to obtain a high gas barrier TPU material.

3. The method for preparing a high gas barrier TPU material according to claim 2, characterized in that, The preparation method of the pre-modified boron nitride nanosheets in step (1) is as follows: 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphobenzene are added to toluene and mixed evenly to prepare a reaction solution; triethylamine and toluene are mixed evenly to prepare a catalyst solution; boron nitride nanosheets and toluene are mixed evenly, and the reaction solution and catalyst solution are added dropwise at a temperature of 50~60℃. After the addition is completed, the reaction continues for 3~4h, filtered, washed, and dried to obtain the pre-modified boron nitride nanosheets.

4. The method for preparing a high gas barrier TPU material according to claim 3, characterized in that, The mass ratio of the boron nitride nanosheets, 1,10-phenanthroline-4,7-diamine, and triethylamine is 1:(3~4):(0.06~0.08); the molar ratio of the 1,10-phenanthroline-4,7-diamine and di(2-chloroethoxy)phosphorylbenzene is 1:(1.2~1.4).

5. The method for preparing a high gas barrier TPU material according to claim 2, characterized in that, The preparation method of vanillin Schiff base triazole monomer in step (2) is as follows: 3,5-diamino-1,2,4-triazole and vanillin are added to anhydrous ethanol, then deionized water is added, and the mixture is reacted at 50~60℃ for 2~3h to obtain vanillin Schiff base triazole monomer.

6. The method for preparing a high gas barrier TPU material according to claim 2, characterized in that, In step (2), the molar ratio of vanillin Schiff base triazole monomer and N-chloroethyl maleimide is 1:2; the mass fraction of the sodium hydroxide aqueous solution is 40%.

7. The method for preparing a high gas barrier TPU material according to claim 2, characterized in that, The amounts of polyurethane, bio-based flame retardant, and modified boron nitride nanosheets in step (4) are as follows: by mass parts, 90-92 parts of polyurethane, 7-8 parts of bio-based flame retardant, and 4-5 parts of modified boron nitride nanosheets.

8. The method for preparing a high gas barrier TPU material according to claim 2, characterized in that, The extrusion molding process parameters in step (4) are as follows: the extrusion temperature of the twin-screw extruder is set to 190~210℃, the extrusion pressure is set to 20~24MPa, and the screw speed is set to 50~60r / min.

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