Synthesis process and application of hyperbranched polyarylamide grafted graphene

Abstract

The invention relates to the technical field of graphene and discloses a synthesis process and application of hyperbranched polyarylamide grafted graphene. N,N-bis(β-methoxycarbonylethyl)aniline and diethylenetriamine are used as polymerization monomers to obtain amino-terminated hyperbranched polyarylamide. Then, under the condensation reaction conditions of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, the amino-terminated hyperbranched polyarylamide and carboxylated graphene are subjected to an amidation reaction to obtain amino-terminated hyperbranched polyarylamide grafted graphene. The obtained product is chemically bonded to a polyurethane molecular chain, thereby enhancing the interfacial bonding force between the two, improving the dispersibility of the graphene in the polyurethane, and enhancing the comprehensive properties of the polyurethane, such as mechanical strength.

Description

Technical Field

[0001] The present invention relates to the technical field of graphene, in particular to a synthesis process and application of hyperbranched polyaramid grafted graphene. Background Art

[0002] Hyperbranched polymers are multifunctional polymer materials, including hyperbranched polyanhydride-type hyperbranched polymers, carboxyl-terminated hyperbranched polymers, hyperbranched polyesters, hyperbranched polyaromatics, etc. Among them, hyperbranched polyaromatics have excellent mechanical properties, thermal stability and good flame retardancy, and are widely used in polymers. The document "Synthesis of Phosphorus-Containing Hyperbranched Polyaromatics and Toughening of Nylon-6" reports the synthesis of hyperbranched polyaromatics containing triphenylphosphine structure using isophthaloyl chloride and tris(3-aminophenyl)phosphine oxide as monomers, which improves the tensile strength and other mechanical properties of nylon-6.

[0003] Polyurethane is a polymer made from raw materials such as polyisocyanates, polyols, and chain extenders or crosslinking agents. However, polyurethane suffers from poor heat resistance and mechanical strength, leading to a need to improve its mechanical strength and other properties. For example, the document "Study on WPU / Graphene Nanocomposite Emulsions Modified with PEI" reports on the use of hyperbranched polyethyleneimine to modify graphene oxide to produce a modified graphene oxide dispersion. This dispersion is then introduced in situ during the emulsification process of an aqueous polyurethane and reduced to produce an aqueous polyurethane / modified graphene nanocomposite emulsion. The prepared modified graphene oxide is uniformly dispersed in the aqueous polyurethane film, improving the mechanical and electrical properties of the polyurethane. This invention synthesizes a novel hyperbranched polyarylamide-grafted graphene to improve the mechanical strength and other properties of polyurethane. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the deficiencies of the prior art, the present invention provides a hyperbranched polyaramid grafted graphene, which is applied to polyurethane to improve the mechanical strength of polyurethane.

[0006] (2) Technical solution

[0007] A synthesis process of hyperbranched polyarylamide grafted graphene, the synthesis process comprising:

[0008] (1) Synthesis of amino-terminated hyperbranched polyarylamide: N,N-di(β-methoxycarbonylethyl)aniline and diethylenetriamine were added dropwise to N,N-dimethylacetamide, stirred for reaction, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain amino-terminated hyperbranched polyarylamide;

[0009] (2) Synthesis of hyperbranched polyarylamide grafted graphene: Carboxylated graphene oxide was added to deionized water and subjected to ultrasonic dispersion treatment. N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added thereto and stirred at room temperature to dissolve them. Then, amino-terminated hyperbranched polyarylamide was added and subjected to ultrasonic reaction. The reaction was carried out at 20-35°C for 10-18 hours. Finally, the product was centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene.

[0010] Preferably, the reaction molar ratio of (1) N,N-di(β-methoxycarbonylethyl)aniline and diethylenetriamine is 1-1.3:1.

[0011] Preferably, the reaction in (1) is first heated to 100-130°C for 1-3 hours, and then heated to 135-150°C for 6-12 hours.

[0012] Preferably, the mass ratio of carboxylated graphene oxide, N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and hyperbranched polyaromatic amide in (2) is 1:4.5-7:6-10:8-20.

[0013] Preferably, the polyol and diisocyanate are dried and added to a flask, heated to 70-80° C. and stirred for reaction for 1-2 hours, and then the hyperbranched polyarylamide grafted graphene is added and reacted for 1-2 hours to obtain an emulsion of modified polyurethane.

[0014] Preferably, the reaction molar ratio of the polyol to the diisocyanate in the step is 1:1.5-2.5.

[0015] Preferably, the polyol comprises polytetramethylene glycol, polycarbonate glycol, polyethylene glycol or polyester polyol.

[0016] Preferably, the diisocyanate includes toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate.

[0017] Preferably, the content of hyperbranched polyaramid grafted graphene in the modified polyurethane is 1-10%.

[0018] (3) Beneficial technical effects

[0019] Using N,N-bis(β-methoxycarbonylethyl)aniline and diethylenetriamine as polymerization monomers and regulating the reaction ratio, a polymerization reaction is performed to obtain amino-terminated hyperbranched polyarylamide. Then, under the condensation reaction conditions of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, the amino-terminated hyperbranched polyarylamide is amidated with carboxylated graphene to obtain amino-terminated hyperbranched polyarylamide grafted graphene, which is used in polyurethane.

[0020] During the polymerization reaction of polyol and diisocyanate, hyperbranched polyarylamide grafted graphene with terminal amino groups is added, and the terminal isocyanate groups of the generated polyurethane prepolymer are used to react with the terminal amino groups of the hyperbranched polyarylamide grafted graphene, so that polyurethane is in situ grafted and polymerized on the surface of the hyperbranched polyarylamide grafted graphene to obtain a modified polyurethane, thereby chemically bonding the hyperbranched polyarylamide grafted graphene to the polyurethane molecular chain, enhancing the interfacial bonding force between the two and improving the dispersibility of the graphene in the polyurethane. The hyperbranched polyarylamide has excellent mechanical properties, thermal stability and other properties, and the graphene nanoparticles also have excellent mechanical strength. Under the synergistic modification effect, the mechanical strength and other comprehensive properties of the polyurethane are enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the synthetic reaction formula for amino-terminated hyperbranched polyarylamide. DETAILED DESCRIPTION

[0022] The preparation method of N,N-bis(β-methoxycarbonylethyl)aniline refers to the journal "Dyes and Colorants" Vol. 40 No. 6, December 2003, the article "Preparation of High-quality N,N-bis(β-methoxycarbonylethyl)aniline":

[0023] Place aniline, methyl acrylate, acetic acid, and hydroquinone in a flask at 90-120°C and reflux for 20 hours. After the reaction is complete, recover the excess methyl acrylate and acetic acid by vacuum distillation to obtain N,N-bis(β-methoxycarbonylethyl)aniline. The structural formula is: .

[0024] Example 1

[0025] (1) 0.35 mol of N,N-di(β-methoxycarbonylethyl)aniline and 0.3 mol of diethylenetriamine were added dropwise to N,N-dimethylacetamide, heated to 120°C, stirred and reacted for 2 h, then heated to 140°C, stirred and reacted for 14 h, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain amino-terminated hyperbranched polyarylamide;

[0026] (2) Add 200 mg of carboxylated graphene oxide to deionized water and perform ultrasonic dispersion treatment. Then add 1000 mg of N-hydroxysuccinimide and 1600 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride thereto and stir to dissolve them at room temperature. Then add 21000 mg of hyperbranched polyarylamide and perform ultrasonic reaction. The reaction is carried out at 20°C for 14 hours. Finally, the product is centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene.

[0027] (3) 2 mol of polycarbonate diol and 3 mol of 1,6-hexamethylene diisocyanate were dried and added to a flask, heated to 75°C and stirred for 2 h, and then hyperbranched polyarylamide grafted graphene was added and reacted for 2 h to obtain an emulsion of modified polyurethane, wherein the content of hyperbranched polyarylamide grafted graphene in the modified polyurethane was 1%.

[0028] Example 2

[0029] (1) 0.3 mol of N,N-di(β-methoxycarbonylethyl)aniline and 0.3 mol of diethylenetriamine were added dropwise to N,N-dimethylacetamide, heated to 100°C, stirred and reacted for 1 hour, then heated to 135°C, stirred and reacted for 12 hours, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain amino-terminated hyperbranched polyarylamide;

[0030] (2) Add 200 mg of carboxylated graphene oxide to deionized water and perform ultrasonic dispersion treatment. Then add 1400 mg of N-hydroxysuccinimide and 1200 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride thereto and stir to dissolve them at room temperature. Then add 1600 mg of hyperbranched polyarylamide and perform ultrasonic reaction. The reaction is carried out at 35°C for 18 hours. Finally, the product is centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene.

[0031] (3) 2 mol of polytetramethylene glycol and 3 mol of toluene diisocyanate were dried and added to a flask, heated to 70°C and stirred for reaction for 1 hour, and then hyperbranched polyarylamide grafted graphene was added and reacted for 1 hour to obtain an emulsion of modified polyurethane, wherein the content of hyperbranched polyarylamide grafted graphene in the modified polyurethane was 4%.

[0032] Example 3

[0033] (1) 0.39 mol of N,N-di(β-methoxycarbonylethyl)aniline and 0.3 mol of diethylenetriamine were added dropwise to N,N-dimethylacetamide, first heated to 130°C, stirred and reacted for 3 h, then heated to 150°C, stirred and reacted for 12 h, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain amino-terminated hyperbranched polyarylamide;

[0034] (2) Add 200 mg of carboxylated graphene oxide to deionized water and perform ultrasonic dispersion treatment. Then add 900 mg of N-hydroxysuccinimide and 1200 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride thereto and stir to dissolve them at room temperature. Then add 1600 mg of hyperbranched polyarylamide and perform ultrasonic reaction. The reaction is carried out at 35°C for 18 hours. Finally, the product is centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene.

[0035] (3) 2 mol of polyethylene glycol and 4 mol of diphenylmethane diisocyanate were dried and added to a flask, heated to 75°C and stirred for reaction for 1.5 h, and then hyperbranched polyarylamide grafted graphene was added and reacted for 1.5 h to obtain an emulsion of modified polyurethane, wherein the content of hyperbranched polyarylamide grafted graphene in the modified polyurethane was 7%.

[0036] Example 4

[0037] (1) 0.35 mol of N,N-di(β-methoxycarbonylethyl)aniline and 0.3 mol of diethylenetriamine were added dropwise to N,N-dimethylacetamide, heated to 120°C, stirred and reacted for 2 h, then heated to 140°C, stirred and reacted for 12 h, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and dried in vacuum to obtain amino-terminated hyperbranched polyarylamide;

[0038] (2) Add 200 mg of carboxylated graphene oxide to deionized water and perform ultrasonic dispersion treatment. Then add 1000 mg of N-hydroxysuccinimide and 1800 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride thereto and stir to dissolve them at room temperature. Then add 1600 mg of hyperbranched polyarylamide and perform ultrasonic reaction. The reaction is carried out at 35°C for 14 hours. Finally, the product is centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene.

[0039] (3) 2 mol of polyester polyol and 5 mol of isophorone diisocyanate were dried and added to a flask, heated to 80 °C and stirred for 2 h, and then hyperbranched polyarylamide grafted graphene was added and reacted for 2 h to obtain an emulsion of modified polyurethane, wherein the content of hyperbranched polyarylamide grafted graphene in the modified polyurethane was 10%.

[0040] Comparative Example 1

[0041] (1) 2 mol of polyester polyol and 4 mol of diphenylmethane diisocyanate were dried and added to a flask, heated to 80°C and stirred for 2 h, and then carboxylated graphene was added and mixed for 1 h to obtain an emulsion of modified polyurethane, wherein the content of carboxylated graphene in the modified polyurethane was 1%.

[0042] Comparative Example 2

[0043] (1) 0.33 mol of N,N-di(β-methoxycarbonylethyl)aniline and 0.3 mol of diethylenetriamine were added dropwise to N,N-dimethylacetamide, heated to 100°C, stirred and reacted for 2 h, then heated to 130°C, stirred and reacted for 12 h, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and dried in vacuum to obtain amino-terminated hyperbranched polyarylamide;

[0044] (2) 2 mol of polyethylene glycol and 5 mol of toluene diisocyanate were dried and added to a flask, heated to 70°C and stirred for 1.5 h, and then amino-terminated hyperbranched polyarylamide was added and reacted for 1.5 h to obtain an emulsion of modified polyurethane, wherein the content of hyperbranched polyarylamide in the modified polyurethane was 1%.

[0045] The hyperbranched polyarylamide grafted graphene modified polyurethane was thermally cured to form a film, which was then pressed into a dumbbell-shaped specimen with a length of 60 mm and a width of 2 mm using a mold. The test was performed using an electronic universal material testing machine with a tensile rate of 120 mm / min. The sample was repeated three times and the average value was taken.

[0046] According to GB / T6739-1996, the pencil hardness of the paint film is tested; according to GB / T1732-93, the impact resistance of the paint film is tested.

[0047] Tensile strength / MPa Pencil hardness Impact resistance Example 1 16.5 3H No falling off, no cracking Example 2 19.5 4H No falling off, no cracking Example 3 30.6 3H No falling off, no cracking Example 4 23.7 3H Minor cracking, no falling off Comparative Example 1 14.0 H Minor cracking, no falling off Comparative Example 2 12.2 H Obvious cracking, no falling off

[0048] The tensile strength of the hyperbranched polyarylamide grafted graphene modified polyurethane paint film prepared in Example 3 is the largest, reaching 30.6 MPa. The pencil hardness of the modified polyurethane paint film prepared in Example 2 is the best, reaching 4H grade. The polyurethane paint films prepared in each example show good impact resistance.

[0049] In Comparative Example 1, polyurethane was modified using carboxylated graphene, and the obtained polyurethane paint film had a tensile strength of only 14.0 MPa and a pencil hardness of only H.

[0050] In Comparative Example 2, hyperbranched polyarylamide was used to modify polyurethane, and the obtained polyurethane paint film showed poor performance in terms of tensile strength, pencil hardness, and impact resistance.

Claims

1. A synthesis process for hyperbranched polyarylamide grafted graphene, characterized in that: The synthesis process is: (1) Synthesis of amino-terminated hyperbranched polyarylamide: N,N-di(β-methoxycarbonylethyl)aniline and diethylenetriamine were added dropwise to N,N-dimethylacetamide, stirred for reaction, cooled after the reaction, added with ethanol for precipitation, filtered, washed with ethanol, and vacuum dried to obtain amino-terminated hyperbranched polyarylamide; (2) Synthesis of hyperbranched polyarylamide grafted graphene: Carboxylated graphene oxide was added to deionized water and subjected to ultrasonic dispersion treatment. N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added thereto and stirred at room temperature to dissolve them. Then, amino-terminated hyperbranched polyarylamide was added and subjected to ultrasonic reaction. The reaction was carried out at 20-35°C for 10-18 hours. Finally, the product was centrifuged, washed with anhydrous ethanol, and vacuum dried to obtain hyperbranched polyarylamide grafted graphene. The reaction molar ratio of N,N-di(β-methoxycarbonylethyl)aniline and diethylenetriamine in (1) is 1-1.3:1; The mass ratio of carboxylated graphene oxide, N-hydroxysuccinimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and amino-terminated hyperbranched polyarylamide in (2) is 1:4.5-7:6-10:8-20.

2. A synthesis process for hyperbranched polyaramid grafted graphene according to claim 1, characterized in that: In the step (1), the reaction is first heated to 100-130°C for 1-3 hours, and then heated to 135-150°C for 6-12 hours.

3. The application of the hyperbranched polyarylamide grafted graphene in polyurethane prepared by the synthesis process according to claim 1, characterized in that: After drying, polyol and diisocyanate are added to a flask, heated to 70-80°C and stirred for reaction for 1-2 hours, and then hyperbranched polyarylamide grafted graphene is added and reacted for 1-2 hours to obtain a modified polyurethane emulsion; The reaction molar ratio of the polyol and diisocyanate in the step is 1:1.5-2.5; The polyol includes polytetramethylene glycol, polycarbonate glycol, polyethylene glycol or polyester polyol.

4. The use according to claim 3, characterized in that: The diisocyanate includes toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate.

5. The use according to claim 3, characterized in that: The content of the hyperbranched polyaramid grafted graphene in the modified polyurethane is 1-10%.

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