Graphene modified flame-retardant polyurethane material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses a graphene modified flame-retardant polyurethane material and a preparation method thereof.The graphene modified flame-retardant polyurethane material is obtained by adding graphene modified polyurethane, a sodium hydroxysulfonate polymer and epoxy nano-silica into a twin-screw extruder and conducting blending extrusion. In the blending extrusion process, hydroxyl groups of the graphene modified polyurethane and the sodium hydroxysulfonate polymer are subjected to ring-opening reaction with epoxy groups of the epoxy nano silicon dioxide, stable chemical crosslinking is formed by the graphene modified polyurethane, the sodium hydroxysulfonate polymer and the epoxy groups of the epoxy nano silicon dioxide, the interfacial compatibility among the three components is increased, and the mechanical property of the graphene modified polyurethane and the sodium hydroxysulfonate polymer is improved. Phosphorus, triazinyl and sodium sulfonate groups in the graphene modified polyurethane and the sodium hydroxysulfonate polymer have good flame retardance and jointly form a flame retardant system, and graphene has good flame retardance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a graphene-modified flame-retardant polyurethane material and a preparation method thereof. Background Art

[0002] Polyurethane is a block copolymer with both plasticity and elasticity. Its molecular chain contains ester, ether, carbamate, urea and other groups. It has high mechanical strength, elasticity and good low-temperature compliance. It is widely used in plastics, rubber, leather and other fields. However, its poor flame retardant performance affects its use in many fields. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent CN114395160B discloses a graphene-modified polyurethane composite material and its preparation method. The method provided by the invention is simple to operate, low in cost, widely used, and the prepared composite material has good comprehensive properties such as thermal stability and mechanical properties, but its flame retardant effect is not improved. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a graphene-modified flame-retardant polyurethane material and a preparation method thereof, which have good flame-retardant and stretching effects.

[0004] (II) Technical solution To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a graphene-modified flame-retardant polyurethane material, wherein the graphene-modified flame-retardant polyurethane material comprises the following components by weight: 20-40 parts by weight of graphene-modified polyurethane, 80-100 parts by weight of sodium hydroxysulfonate polymer, and 2-6 parts by weight of epoxy nano-silica.

[0005] Preferably, the preparation method of the graphene-modified polyurethane is: (1) Ultrasonic dispersion of 5-7 parts by weight of graphene oxide in 75-110 parts by weight of thionyl chloride, after uniform dispersion, reacting at 55-80° C. for 4-8 hours to obtain modified graphene; then, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is added, reacting at 75-90° C. for 4-6 hours, and after the reaction, suction filtration, washing, and drying are performed to obtain intermediate 1; (2) Add intermediate 1 to a reactor containing N,N-dimethylformamide, then heat it, and after it is completely dissolved, add 2,4-dihydroxybenzaldehyde to it and stir to react for 8-10 hours, continue to add diethyl phosphite, and react at 70-85°C for 6-12 hours. After the reaction, reduce pressure and concentrate, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate as a catalyst, react at 50-80°C for 2-4 hours to perform prepolymerization, then add a triazine-based chain extender, stir to continue the chain extension reaction, and after the reaction is completed, cool and discharge the material to obtain graphene-modified polyurethane.

[0006] Preferably, the mass ratio of the modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine in (1) is 1.5-2.3:1.

[0007] Preferably, the mass ratio of the intermediate 1, 2,4-dihydroxybenzaldehyde, and diethyl phosphite in (2) is 1:1.4-1.6:2.1-2.4.

[0008] Preferably, the mass ratio of the polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and triazine chain extender in (3) is 1.2-1.3:1:0.01-0.03:0.6-0.9.

[0009] Preferably, the preparation method of the sodium hydroxysulfonate polymer is: S1. Add intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 2-5%, react at 60-95° C. for 8-14 hours, and after the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; S2. Add 3-6 parts by weight of sodium sulfonate modified triazine-based graphene, 4-9 parts by weight of sodium methyl propylene sulfonate, and 2-5 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, add 0.4-0.6 parts by weight of ammonium persulfate initiator after dissolution, heat and react for 3-6 hours, remove the solvent by distillation under reduced pressure after the reaction, filter, wash and dry to obtain sodium hydroxysulfonate polymer.

[0010] Preferably, the mass ratio of the intermediate 1 to propenyl-1,3-sultone in S1 is 1:2.2-2.5.

[0011] Preferably, the preparation method of the graphene-modified flame-retardant polyurethane material is: adding graphene-modified polyurethane, sodium hydroxysulfonate polymer, and epoxy nano-silica into a twin-screw extruder, with a blending temperature of 180-190° C. and an extrusion temperature of 170-180° C. to obtain the graphene-modified flame-retardant polyurethane material.

[0012] 3. Beneficial technical effects The invention obtains the graphene-modified flame-retardant polyurethane material by adding graphene-modified polyurethane, sodium hydroxysulfonate polymer and epoxy nano-silica into a twin-screw extruder for co-mixing and extrusion.

[0013] The acyl chloride group in the modified graphene reacts with the amino group in 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to obtain intermediate 1; the amino group in intermediate 1 and the aldehyde group in 2,4-dihydroxybenzaldehyde undergo condensation reaction, and then undergo addition reaction with diethyl phosphite to introduce hydroxyl groups, thereby obtaining a triazine-based chain extender; the polyether diol is dehydrated and mixed evenly with hexamethylene diisocyanate, and then a dibutyltin dilaurate catalyst is added dropwise to perform prepolymerization, and then a triazine-based chain extender is added to react, thereby obtaining graphene-modified polyurethane; the amino group in intermediate 1 reacts with allyl-1,3-sultone to introduce alkenyl groups, thereby obtaining sodium sulfonate-modified triazine-based graphene; sodium sulfonate-modified triazine-based graphene, sodium methacrylic sulfonate, and allyl alcohol are polymerized to obtain sodium hydroxysulfonate polymer, and the degree of substitution of the sodium sulfonate group is increased at the same time.

[0014] During the co-extrusion process, the hydroxyl groups of graphene-modified polyurethane and sodium hydroxysulfonate polymers will undergo a ring-opening reaction with the epoxy groups of epoxy nano-silica, forming a stable chemical cross-linking between the three, and increasing the interfacial compatibility between each other, thereby improving their mechanical properties. The phosphorus element, triazine group, and sodium sulfonate group in graphene-modified polyurethane and sodium hydroxysulfonate polymers all have good flame retardancy, and together they form a flame retardant system. Graphene itself has good flame retardancy, while reducing the aggregation of graphene. DETAILED DESCRIPTION

[0015] Example 1 (1) Ultrasonic dispersion of 5 parts by weight of graphene oxide in 75 parts by weight of thionyl chloride, after uniform dispersion, reacting at 55° C. for 4 hours to obtain modified graphene; then adding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, wherein the mass ratio of modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is 1.5:1, reacting at 75° C. for 4 hours, and after the reaction, filtering, washing, and drying to obtain intermediate 1; (2) Add intermediate 1 into a reactor filled with N,N-dimethylformamide, then heat it, add 2,4-dihydroxybenzaldehyde to it after it is completely dissolved, stir and react for 8 hours, continue to add diethyl phosphite, wherein the mass ratio of intermediate 1, 2,4-dihydroxybenzaldehyde and diethyl phosphite is 1:1.4:2.1, react at 70°C for 6 hours, concentrate under reduced pressure after completion, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate catalyst, react at 50°C for 2h to perform prepolymerization, then add triazine-based chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and triazine-based chain extender is 1.2:1:0.01:0.6, stir to continue chain extension reaction, and after the reaction is completed, cool and discharge to obtain graphene-modified polyurethane; (4) adding intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, wherein the mass ratio of intermediate 1 to propenyl-1,3-sultone is 1:2.2, then dropping a 2% sodium hydroxide solution, reacting at 60° C. for 8 h, and concentrating under reduced pressure to remove the solvent after the reaction, and recrystallizing the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; (5) adding 3 parts by weight of sodium sulfonate modified triazine-based graphene, 4 parts by weight of sodium methyl propylene sulfonate, and 2 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, adding 0.4 parts by weight of ammonium persulfate initiator after dissolution, heating to react for 3 hours, and removing the solvent by reduced pressure distillation after the reaction, filtering, washing and drying to obtain sodium hydroxysulfonate polymer; (6) 20 parts by weight of graphene-modified polyurethane, 80 parts by weight of sodium hydroxysulfonate polymer, and 2 parts by weight of epoxy nano-silica were added into a twin-screw extruder at a blending temperature of 180° C. and an extrusion temperature of 170° C. to obtain a graphene-modified flame-retardant polyurethane material.

[0016] Example 2

[0017] (1) Ultrasonic dispersion of 7 parts by weight of graphene oxide in 110 parts by weight of thionyl chloride, after uniform dispersion, reacting at 80° C. for 8 h to obtain modified graphene; then adding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, wherein the mass ratio of modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is 2.3:1, reacting at 90° C. for 6 h, and after the reaction, filtering, washing, and drying to obtain intermediate 1; (2) Add intermediate 1 to a reactor containing N,N-dimethylformamide, then heat it, add 2,4-dihydroxybenzaldehyde to it after it is completely dissolved, stir and react for 8-10 hours, continue to add diethyl phosphite, wherein the mass ratio of intermediate 1, 2,4-dihydroxybenzaldehyde and diethyl phosphite is 1:1.6:2.4, react at 85°C for 12 hours, concentrate under reduced pressure after completion, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate catalyst, react at 80°C for 4 hours to perform prepolymerization, and then add triazine-based chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and triazine-based chain extender is 1.3:1:0.03:0.9, stir to continue chain extension reaction, and after the reaction is completed, cool and discharge to obtain graphene-modified polyurethane; (4) adding intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, wherein the mass ratio of intermediate 1 to propenyl-1,3-sultone is 1:2.5, then dropping a 5% sodium hydroxide solution, reacting at 95° C. for 14 h, and concentrating under reduced pressure to remove the solvent after the reaction, and recrystallizing the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; (5) adding 6 parts by weight of sodium sulfonate modified triazine-based graphene, 9 parts by weight of sodium methyl propylene sulfonate, and 5 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, adding 0.6 parts by weight of ammonium persulfate initiator after dissolution, heating to react for 6 hours, and removing the solvent by reduced pressure distillation after the reaction, filtering, washing and drying to obtain sodium hydroxysulfonate polymer; (6) 40 parts by weight of graphene-modified polyurethane, 100 parts by weight of sodium hydroxysulfonate polymer, and 6 parts by weight of epoxy nano-silica were added into a twin-screw extruder at a blending temperature of 190°C and an extrusion temperature of 180°C to obtain a graphene-modified flame-retardant polyurethane material.

[0018] Example 3

[0019] (1) ultrasonically dispersing 6 parts by weight of graphene oxide into 85 parts by weight of thionyl chloride, after being evenly dispersed, reacting at 70° C. for 6 hours to obtain modified graphene; then continuing to add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, wherein the mass ratio of modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is 1.8:1, reacting at 82° C. for 5 hours, and after the reaction, filtering, washing, and drying to obtain intermediate 1; (2) Add intermediate 1 into a reactor filled with N,N-dimethylformamide, then heat it, add 2,4-dihydroxybenzaldehyde to it after it is completely dissolved, stir and react for 9 hours, continue to add diethyl phosphite, wherein the mass ratio of intermediate 1, 2,4-dihydroxybenzaldehyde and diethyl phosphite is 1:1.5:2.3, react at 80°C for 9 hours, concentrate under reduced pressure after completion, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate catalyst, react at 65°C for 3 hours to perform prepolymerization, and then add triazine-based chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and triazine-based chain extender is 1.25:1:0.02:0.8, stir to continue chain extension reaction, and after the reaction is completed, cool and discharge to obtain graphene-modified polyurethane; (4) adding intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, wherein the mass ratio of intermediate 1 to propenyl-1,3-sultone is 1:2.4, then dropping a 3% sodium hydroxide solution, reacting at 82° C. for 12 h, and concentrating under reduced pressure to remove the solvent after the reaction, and recrystallizing the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; (5) adding 4 parts by weight of sodium sulfonate modified triazine-based graphene, 6 parts by weight of sodium methyl propylene sulfonate, and 3 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, adding 0.5 parts by weight of ammonium persulfate initiator after dissolution, heating to react for 4 hours, and removing the solvent by reduced pressure distillation after the reaction, filtering, washing and drying to obtain sodium hydroxysulfonate polymer; (6) 30 parts by weight of graphene-modified polyurethane, 90 parts by weight of sodium hydroxysulfonate polymer, and 4 parts by weight of epoxy nano-silica were added into a twin-screw extruder at a blending temperature of 185° C. and an extrusion temperature of 175° C. to obtain a graphene-modified flame-retardant polyurethane material.

[0020] Example 4

[0021] (1) Ultrasonic dispersion of 5 parts by weight of graphene oxide in 75 parts by weight of thionyl chloride, after uniform dispersion, reacting at 55° C. for 4 hours to obtain modified graphene; then adding 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, wherein the mass ratio of modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is 1.5:1, reacting at 75° C. for 4 hours, and after the reaction, filtering, washing, and drying to obtain intermediate 1; (2) Add intermediate 1 into a reactor filled with N,N-dimethylformamide, then heat it, add 2,4-dihydroxybenzaldehyde to it after it is completely dissolved, stir and react for 8 hours, continue to add diethyl phosphite, wherein the mass ratio of intermediate 1, 2,4-dihydroxybenzaldehyde and diethyl phosphite is 1:1.4:2.1, react at 70°C for 6 hours, concentrate under reduced pressure after completion, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate catalyst, react at 80°C for 4 hours to perform prepolymerization, and then add triazine-based chain extender, wherein the mass ratio of polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst, and triazine-based chain extender is 1.3:1:0.03:0.9, stir to continue chain extension reaction, and after the reaction is completed, cool and discharge to obtain graphene-modified polyurethane; (4) adding intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, wherein the mass ratio of intermediate 1 to propenyl-1,3-sultone is 1:2.5, then dropping a 5% sodium hydroxide solution, reacting at 95° C. for 14 h, and concentrating under reduced pressure to remove the solvent after the reaction, and recrystallizing the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; (5) adding 4 parts by weight of sodium sulfonate modified triazine-based graphene, 6 parts by weight of sodium methyl propylene sulfonate, and 3 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, adding 0.5 parts by weight of ammonium persulfate initiator after dissolution, heating to react for 4 hours, and removing the solvent by reduced pressure distillation after the reaction, filtering, washing and drying to obtain sodium hydroxysulfonate polymer; (6) 30 parts by weight of graphene-modified polyurethane, 90 parts by weight of sodium hydroxysulfonate polymer, and 4 parts by weight of epoxy nano-silica were added into a twin-screw extruder at a blending temperature of 185° C. and an extrusion temperature of 175° C. to obtain a graphene-modified flame-retardant polyurethane material.

[0022] Comparative Example 1 30 parts by weight of polyurethane, 90 parts by weight of sodium hydroxysulfonate polymer and 4 parts by weight of epoxy nano-silica were added into a twin-screw extruder at a blending temperature of 185° C. and an extrusion temperature of 175° C. to obtain a flame-retardant polyurethane material.

[0023] Comparative Example 2 30 parts by weight of graphene-modified polyurethane and 4 parts by weight of epoxy nano-silica were added into a twin-screw extruder, with a blending temperature of 185° C. and an extrusion temperature of 175° C. to obtain a graphene-modified flame-retardant polyurethane material.

[0024] The tensile properties of the material were tested using an electronic universal testing machine. The test results are shown in Table 1.

[0025] Table 1: Tensile properties tested.

[0026] project Tensile properties (MPa) Example 1 41.5 Example 2 43.8 Example 3 42.9 Example 4 41.3 Comparative Example 1 20.3 Comparative Example 2 18.5 It can be seen from Table 1 that the material examples 1-4 prepared by the present invention have better tensile properties than the comparative examples 1-2.

[0027] Use an oxygen index tester to test the oxygen index of the material, and use a horizontal and vertical combustion tester to test the combustion grade of the material.

[0028] Table 2: Flame retardancy tests.

[0029] project Oxygen index (%) UL-94 Example 1 32 V-0 Example 2 33 V-0 Example 3 32 V-0 Example 4 31 V-0 Comparative Example 1 20 V-1 Comparative Example 2 21 V-1 It can be seen from Table 2 that Examples 1-4 of the present invention have better flame retardant effects than Comparative Examples 1-2.

[0030] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A graphene-modified flame-retardant polyurethane material, characterized in that: The graphene-modified flame-retardant polyurethane material comprises the following components by weight: 20-40 parts by weight of graphene-modified polyurethane, 80-100 parts by weight of sodium hydroxysulfonate polymer, and 2-6 parts by weight of epoxy nano-silicon dioxide.

2. The graphene-modified flame-retardant polyurethane material according to claim 1, characterized in that: The preparation method of the graphene-modified polyurethane is: (1) Ultrasonic dispersion of 5-7 parts by weight of graphene oxide in 75-110 parts by weight of thionyl chloride, after uniform dispersion, reacting at 55-80° C. for 4-8 hours to obtain modified graphene; then, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is added, reacting at 75-90° C. for 4-6 hours, and after the reaction, suction filtration, washing, and drying are performed to obtain intermediate 1; (2) Add intermediate 1 to a reactor containing N,N-dimethylformamide, then heat it, and after it is completely dissolved, add 2,4-dihydroxybenzaldehyde to it and stir to react for 8-10 hours, continue to add diethyl phosphite, and react at 70-85°C for 6-12 hours. After the reaction, reduce pressure and concentrate, wash, and recrystallize the crude product to obtain a triazine-based chain extender; (3) After removing water from the polyether diol, mix it evenly with hexamethylene diisocyanate, introduce nitrogen, then drop dibutyltin dilaurate as a catalyst, react at 50-80°C for 2-4 hours to perform prepolymerization, then add a triazine-based chain extender, stir to continue the chain extension reaction, and after the reaction is completed, cool and discharge the material to obtain graphene-modified polyurethane.

3. The graphene-modified flame-retardant polyurethane material according to claim 2, characterized in that: The mass ratio of the modified graphene to 2,4,6-tris(4-aminophenyl)-1,3,5-triazine in (1) is 1.5-2.3:

1.

4. The graphene-modified flame-retardant polyurethane material according to claim 2, characterized in that: The mass ratio of the intermediate 1, 2,4-dihydroxybenzaldehyde and diethyl phosphite in (2) is 1:1.4-1.6:2.1-2.

4.

5. The graphene-modified flame-retardant polyurethane material according to claim 2, characterized in that: The mass ratio of the polyether diol, hexamethylene diisocyanate, dibutyltin dilaurate catalyst and triazine chain extender in (3) is 1.2-1.3:1:0.01-0.03:0.6-0.

9.

6. The graphene-modified flame-retardant polyurethane material according to claim 1, characterized in that: The preparation method of the sodium hydroxysulfonate polymer is: S1. Add intermediate 1 and propenyl-1,3-sultone to acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 2-5%, react at 60-95° C. for 8-14 hours, and after the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain sodium sulfonate modified triazine-based graphene; S2. Add 3-6 parts by weight of sodium sulfonate modified triazine-based graphene, 4-9 parts by weight of sodium methyl propylene sulfonate, and 2-5 parts by weight of acryl alcohol to N,N-dimethylformamide solvent, add 0.4-0.6 parts by weight of ammonium persulfate initiator after dissolution, heat and react for 3-6 hours, remove the solvent by distillation under reduced pressure after the reaction, filter, wash and dry to obtain sodium hydroxysulfonate polymer.

7. The graphene-modified flame-retardant polyurethane material according to claim 6, characterized in that: The mass ratio of the intermediate 1 to propenyl-1,3-sultone in S1 is 1:2.2-2.

5.

8. A method for preparing a graphene-modified flame-retardant polyurethane material according to any one of claims 1 to 7, characterized in that: The preparation method of the graphene modified flame retardant polyurethane material is as follows: adding graphene modified polyurethane, sodium hydroxysulfonate polymer and epoxy nano-silica into a twin-screw extruder, with a blending temperature of 180-190° C. and an extrusion temperature of 170-180° C. to obtain the graphene modified flame retardant polyurethane material.