Flame-retardant functionalized graphene modified nitrile rubber and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses flame-retardant functionalized graphene modified nitrile rubber, which is characterized in that organic flame-retardant macromolecules are grafted and introduced on the surface of graphene, and the interlayer spacing among graphene molecules is increased, so that the agglomeration phenomenon among graphene can be inhibited, and the flame-retardant functionalized graphene modified nitrile rubber is prepared. According to the present invention, by adding the graphene, the graphene sheet layer and the matrix molecular chain member can participate in the friction effect, such that the loss modulus of the system is increased so as to provide the wear resistance effect, and the introduction of the high strength graphene sheet layer can provide the reinforcing effect so as to provide the wear resistance effect; the surface of the graphene contains groups such as active hydroxyl and the like, so that a hydrogen bond network can be formed, the nitrile rubber is reinforced and toughened, the nitrile rubber is endowed with good flame retardant property by the introduced flame retardant macromolecules, the comprehensive performance of the nitrile rubber is more excellent, and the nitrile rubber has a wide application prospect.

Description

Technical Field

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

[0002] With the continuous development of society, people's requirements for product quality are constantly improving, so the requirements for materials are also getting higher and higher. As a base material that can be used to prepare automotive dynamic sealing materials, the quality of nitrile rubber can directly affect the performance of various materials prepared from nitrile rubber. Therefore, in today's increasingly competitive market, improving product quality is also an effective means to improve product competitiveness. The wear resistance of nitrile rubber itself is poor, so there are many studies on the wear-resistant modification of nitrile rubber. Among them, inorganic rigid particle modified nitrile rubber is a more common modification method. Another way to improve wear resistance is to improve wear resistance by coating a protective coating.

[0003] There are many studies on the modification of nitrile rubber. In the Chinese patent "CN104130436B, a method for preparing a self-lubricating and wear-resistant nitrile rubber" discloses a nitrile rubber prepared with erucic acid amide as a lubricant and high wear-resistant carbon black as a wear-resistant reinforcing agent. Graphene, as an inorganic nanomaterial with excellent performance, also has excellent wear resistance and mechanical properties. Therefore, it can also be used as a reinforcing agent to modify nitrile rubber. However, graphene itself is prone to agglomeration, so the wear-resistant modification performance is relatively poor when directly added. Organic modification of graphene grafted macromolecules can effectively inhibit the agglomeration of graphene itself. In addition, the flame retardant performance of ordinary nitrile rubber is relatively poor, which is difficult to meet the application in the field of high flame retardant performance. Grafting nitrogen-phosphorus flame retardants can also improve the flame retardant effect of nitrile rubber. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a flame retardant functionalized graphene modified nitrile rubber and a preparation method thereof, which solves the problems that graphene is prone to agglomeration in the nitrile rubber matrix and the nitrile rubber has poor wear resistance and flame retardancy.

[0005] To achieve the above object, the present invention provides the following technical solution: A method for preparing a flame retardant functionalized graphene-modified nitrile rubber comprises the following steps: (1) dispersing graphene in N,N-dimethylformamide solvent, then adding 3-chloropropyltrimethoxysilane, stirring and reacting at 20-40° C. for 24-48 hours, after the reaction is completed, centrifuging, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Adding chloropropyl graphene to anhydrous ethanol solvent, adding diethanolamine under a nitrogen atmosphere, heating to 45-65°C, reacting in a water bath for 8-16 hours, and after the reaction is completed, centrifuging, washing with anhydrous ethanol, and vacuum drying to obtain diethanolamine-modified graphene; (3) adding diethyl phenylphosphonate into a reaction vessel, then adding diethanolamine modified graphene, stirring and dispersing, then adding dibutyltin dilaurate, heating for pre-reaction, then adding diethanolamine, stirring for polymerization reaction, after the reaction is completed, centrifugation, acetone washing, and vacuum drying to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) Add nitrile rubber, nitrogen-phosphorus polyether diol flame-retardant modified graphene, vulcanization activator zinc oxide, accelerator dibenzothiazole disulfide, sulfur, antioxidant A and antioxidant 4010 into a stirring device in sequence, stir and mix for 2-4 hours, and then use a flat vulcanizer to vulcanize in a mold at 45-65°C for 24-36 hours to obtain flame-retardant functionalized graphene modified nitrile rubber.

[0006] Preferably, in step (1), the mass fractions of N,N-dimethylformamide are 3000-9000 parts, the mass fractions of graphene are 100 parts, and the mass fractions of 3-chloropropyltrimethoxysilane are 260-600 parts.

[0007] Preferably, in step (2), the mass fractions of anhydrous ethanol are 3500-8000 parts, the mass fractions of chloropropyl graphene are 100 parts, and the mass fractions of diethanolamine are 10-30 parts.

[0008] Preferably, in step (3), the mass fractions of diethyl phenylphosphonate are 80-320 parts, the diethanolamine-modified graphene is 100 parts, the dibutyltin dilaurate is 2-5 parts, and the diethanolamine is 60-145 parts.

[0009] Preferably, the pre-reaction temperature in step (3) is 140-160° C., the reaction time is 0.5-1.5 h, and the polymerization reaction time is 6-12 h.

[0010] Preferably, in the step (4), the mass fraction of nitrile rubber is 100 parts, the mass fraction of nitrogen-phosphorus polyether diol flame-retardant modified graphene is 0.5-2.5 parts, the mass fraction of vulcanization activator zinc oxide is 2-4 parts, the mass fraction of accelerator dibenzothiazole disulfide is 0.5-1.5 parts, the mass fraction of sulfur is 1-2.5 parts, the mass fraction of antioxidant A is 0.5-2 parts, and the mass fraction of antioxidant 4010 is 1-2.5 parts.

[0011] Compared with the prior art, the present invention has the following experimental principles and beneficial technical effects: The flame retardant functionalized graphene modified nitrile rubber comprises the following steps: firstly, graphene is chloropropylated with 3-chloropropyltrimethoxysilane to obtain chloropropyl graphene, then the chloropropyl group reacts with the imine group on diethanolamine to obtain diethanolamine modified graphene, then the active hydroxyl group on the surface of the diethanolamine modified graphene is pre-reacted with diethyl phenyl phosphate, then diethanolamine is added to polymerize the diethanolamine and diethyl phenyl phosphate on the surface of the graphene in situ, the flame retardant macromolecule is grafted on the surface of the graphene to obtain nitrogen-phosphorus polyether diol flame retardant modified graphene, then the nitrogen-phosphorus polyether diol flame retardant modified graphene is reacted with nitrile rubber, a vulcanization accelerator, a vulcanization activator, etc. The flame retardant functionalized graphene modified nitrile rubber is obtained by mixing and vulcanizing the additives. Organic flame retardant macromolecules are introduced by grafting on the graphene surface to increase the interlayer distance of the graphene molecules, thereby inhibiting the agglomeration of the graphene molecules, so that the graphene has good dispersion in the nitrile rubber. Due to the addition of graphene, the graphene sheets can participate in the friction with the matrix molecular chain, so that the system shows an increase in the loss modulus, thereby achieving a wear-resistant effect. At the same time, the introduction of high-strength graphene sheets can also play a reinforcing role. Since the graphene surface contains active hydroxyl groups and other groups, a hydrogen bond network can be formed, thereby enhancing and toughening the nitrile rubber.

[0012] The flame-retardant functionalized graphene-modified nitrile rubber introduces flame-retardant macromolecules on the graphene surface, which can not only increase the interlayer spacing between graphene sheets and inhibit the agglomeration of graphene itself, but also effectively perform flame-retardant modification on nitrile rubber with poor flame-retardant performance. The nitrile rubber has an excellent flame-retardant effect under the synergistic flame-retardant effect of N and P. When the nitrile rubber burns, phosphoric acid, polyphosphoric acid and other components are formed to promote the carbonization of the nitrile rubber. At the same time, nitrogen-containing flame-retardant gas is formed to play the role of expansion barrier, thereby giving the nitrile rubber good flame-retardant performance, making the comprehensive performance of the nitrile rubber more excellent, and having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Reaction diagram for preparing diethanolamine-modified graphene; Figure 2 Reaction diagram for preparing flame-retardant modified graphene with nitrogen-phosphorus polyether diol. DETAILED DESCRIPTION

[0014] A method for preparing flame-retardant functionalized graphene-modified nitrile rubber, characterized in that it comprises the following steps: (1) Dispersing 0.5 g of graphene in 15-40 g of N,N-dimethylformamide solvent, then adding 1.3-3 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 20-40 ° C for 24-48 hours, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 50-100 ml of anhydrous ethanol solvent, add 0.1-0.3 g of diethanolamine under a nitrogen atmosphere, heat to 45-65° C., react in a water bath for 8-16 hours, and after the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 1.6-6.4g of diethyl phenylphosphonate into a reaction container, then add 2g of diethanolamine-modified graphene, stir and disperse, then add 0.04-0.05g of dibutyltin dilaurate, heat to 140-160°C for pre-reaction for 0.5-1.5h, then add 1.2-2.8g of diethanolamine, stir and polymerize for 6-12h, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) Add 200 g of nitrile rubber, 1-5 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 2-8 g of vulcanization activator zinc oxide, 1-3 g of accelerator dibenzothiazole disulfide, 2-5 g of sulfur, 1-4 g of antioxidant A and 2-5 g of antioxidant 4010 into a stirring device in sequence, stir and mix for 2-4 h, and then use a flat vulcanizer to vulcanize at 45-65 ° C in a mold for 24-36 h to obtain flame-retardant functionalized graphene modified nitrile rubber. Example 1

[0015] (1) Dispersing 0.5 g of graphene in 15 g of N,N-dimethylformamide solvent, then adding 1.3 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 20 ° C for 24 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 50 ml of anhydrous ethanol solvent, add 0.1 g of diethanolamine under a nitrogen atmosphere, heat to 45°C, react in a water bath for 8 hours, and after the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 1.6 g of diethyl phenylphosphonate into a reaction vessel, then add 2 g of diethanolamine-modified graphene, stir and disperse, then add 0.04 g of dibutyltin dilaurate, heat to 140 ° C for pre-reaction for 0.5 h, then add 1.2 g of diethanolamine, stir and polymerize for 6 h, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) Add 200 g of nitrile rubber, 1 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 2 g of vulcanization activator zinc oxide, 1 g of accelerator dibenzothiazole disulfide, 2 g of sulfur, 1 g of antioxidant A and 2 g of antioxidant 4010 into a stirring device in sequence, stir and mix for 2 h, and then use a flat vulcanizer to vulcanize at 45 ° C in a mold for 24 h to obtain flame-retardant functionalized graphene modified nitrile rubber. Example 2

[0016] (1) Dispersing 0.5 g of graphene in 18 g of N,N-dimethylformamide solvent, then adding 1.6 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 25 °C for 28 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 60 ml of anhydrous ethanol solvent, add 0.15 g of diethanolamine under a nitrogen atmosphere, heat to 50°C, and react in a water bath for 10 hours. After the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 2.6 g of diethyl phenylphosphonate into a reaction container, then add 2 g of diethanolamine-modified graphene, stir and disperse, then add 0.04 g of dibutyltin dilaurate, heat to 145 ° C for pre-reaction for 1 hour, then add 1.8 g of diethanolamine, stir and polymerize for 8 hours, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) 200 g of nitrile rubber, 2 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 4 g of vulcanization activator zinc oxide, 1.5 g of accelerator dibenzothiazole disulfide, 3 g of sulfur, 2 g of antioxidant A and 2.5 g of antioxidant 4010 were added into a stirring device in sequence, stirred and mixed for 2 h, and then vulcanized at 50 ° C for 28 h in a mold using a flat vulcanizer to obtain flame-retardant functionalized graphene modified nitrile rubber. Example 3

[0017] (1) Dispersing 0.5 g of graphene in 30 g of N,N-dimethylformamide solvent, then adding 1.9 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 30 ° C for 36 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 70 ml of anhydrous ethanol solvent, add 0.2 g of diethanolamine under a nitrogen atmosphere, heat to 55°C, and react in a water bath for 12 hours. After the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 3.6 g of diethyl phenylphosphonate into a reaction container, then add 2 g of diethanolamine-modified graphene, stir and disperse, then add 0.045 g of dibutyltin dilaurate, heat to 150 ° C for pre-reaction for 1 hour, then add 2 g of diethanolamine, stir and polymerize for 10 hours, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) 200 g of nitrile rubber, 3 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 4 g of vulcanization activator zinc oxide, 2 g of accelerator dibenzothiazole disulfide, 4 g of sulfur, 3 g of antioxidant A and 3 g of antioxidant 4010 were added into a stirring device in sequence, stirred and mixed for 3 h, and then vulcanized at 55 °C for 30 h in a mold using a flat vulcanizer to obtain flame-retardant functionalized graphene modified nitrile rubber. Example 4

[0018] (1) Dispersing 0.5 g of graphene in 35 g of N,N-dimethylformamide solvent, then adding 2.4 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 35 °C for 40 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 60 ml of anhydrous ethanol solvent, add 0.25 g of diethanolamine under a nitrogen atmosphere, heat to 60°C, and react in a water bath for 14 h. After the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 6 g of diethyl phenylphosphonate into a reaction container, then add 2 g of diethanolamine-modified graphene, stir and disperse, then add 0.045 g of dibutyltin dilaurate, heat to 155 ° C for pre-reaction for 1.2 h, then add 2.6 g of diethanolamine, stir and polymerize for 10 h, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) 200 g of nitrile rubber, 4 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 6 g of vulcanization activator zinc oxide, 3 g of accelerator dibenzothiazole disulfide, 4 g of sulfur, 3 g of antioxidant A and 5 g of antioxidant 4010 were added into a stirring device in sequence, stirred and mixed for 4 h, and then vulcanized at 65 ° C in a mold for 36 h using a flat vulcanizer to obtain flame-retardant functionalized graphene modified nitrile rubber. Example 5

[0019] (1) Dispersing 0.5 g of graphene in 40 g of N,N-dimethylformamide solvent, then adding 1.8 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 40 ° C for 48 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 100 ml of anhydrous ethanol solvent, add 0.3 g of diethanolamine under a nitrogen atmosphere, heat to 65°C, react in a water bath for 16 hours, and after the reaction is completed, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) Add 6.4 g of diethyl phenylphosphonate into a reaction container, then add 2 g of diethanolamine-modified graphene, stir and disperse, then add 0.05 g of dibutyltin dilaurate, heat to 160 ° C for pre-reaction for 1.5 h, then add 2.8 g of diethanolamine, stir and polymerize for 12 h, after the reaction is completed, centrifuge, wash with acetone, and vacuum dry to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) 200 g of nitrile rubber, 5 g of nitrogen-phosphorus polyether diol flame-retardant modified graphene, 6 g of vulcanization activator zinc oxide, 3 g of accelerator dibenzothiazole disulfide, 5 g of sulfur, 4 g of antioxidant A and 5 g of antioxidant 4010 were added into a stirring device in sequence, stirred and mixed for 4 h, and then vulcanized at 65 ° C in a mold for 36 h using a flat vulcanizer to obtain flame-retardant functionalized graphene modified nitrile rubber.

[0020] Comparative Example 1 (1) Dispersing 0.5 g of graphene in 35 g of N,N-dimethylformamide solvent, then adding 1.8 g of 3-chloropropyltrimethoxysilane, stirring and reacting at 30 ° C for 36 h, after the reaction is completed, centrifugation, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Add 1 g of chloropropyl graphene to 80 ml of anhydrous ethanol solvent, add 0.2 g of diethanolamine under a nitrogen atmosphere, heat to 60°C, react in a water bath for 12 h, and after the reaction is complete, centrifuge, wash with anhydrous ethanol, and vacuum dry to obtain diethanolamine-modified graphene; (3) 200 g of nitrile rubber, 3 g of diethanolamine-modified graphene, 4 g of vulcanization activator zinc oxide, 2 g of accelerator dibenzothiazole disulfide, 3 g of sulfur, 2 g of antioxidant A and 3 g of antioxidant 4010 were added into a stirring device in sequence, stirred and mixed for 4 h, and then vulcanized at 50 ° C for 30 h in a mold using a flat vulcanizer to obtain graphene-modified nitrile rubber.

[0021] The nitrile rubbers prepared in Examples 1-5 and Comparative Example 1 are compared as follows: The nitrile rubbers prepared in the embodiment and the comparative example were respectively made into standard tensile specimens, and the tensile strength and elongation at break were tested using an XDS-10 tensile testing machine, and the test standard was GB / T 528-2009.

[0022]

[0023] The nitrile rubbers prepared in the embodiment and the comparative example were respectively made into wear-resistant specimens, and the wear resistance was tested using an HLS-8003 Axon abrasion tester, and the test standard was GB / T 1689-2014.

[0024]

[0025] The limiting oxygen index of the nitrile rubber prepared in the embodiment and the comparative example was tested using a BXT-JF-3 oxygen index tester, and the test standard was GB / T 2406.1-2008.

[0026]

Claims

1. A flame retardant functionalized graphene modified nitrile rubber, characterized in that: The method for preparing a flame retardant functionalized graphene modified nitrile rubber comprises the following steps: (1) dispersing graphene in N,N-dimethylformamide solvent, then adding 3-chloropropyltrimethoxysilane, stirring and reacting at 20-40° C. for 24-48 hours, after the reaction is completed, centrifuging, washing with toluene, and vacuum drying to obtain chloropropyl graphene; (2) Adding chloropropyl graphene to anhydrous ethanol solvent, adding diethanolamine under a nitrogen atmosphere, heating to 45-65°C, reacting in a water bath for 8-16 hours, and after the reaction is completed, centrifuging, washing with anhydrous ethanol, and vacuum drying to obtain diethanolamine-modified graphene; (3) adding diethyl phenylphosphonate into a reaction vessel, then adding diethanolamine modified graphene, stirring and dispersing, then adding dibutyltin dilaurate, heating for pre-reaction, then adding diethanolamine, stirring for polymerization reaction, after the reaction is completed, centrifugation, acetone washing, and vacuum drying to obtain nitrogen-phosphorus polyether diol flame-retardant modified graphene; (4) Add nitrile rubber, nitrogen-phosphorus polyether diol flame-retardant modified graphene, vulcanization activator zinc oxide, accelerator dibenzothiazole disulfide, sulfur, antioxidant A and antioxidant 4010 into a stirring device in sequence, stir and mix for 2-4 hours, and then use a flat vulcanizer to vulcanize in a mold at 45-65°C for 24-36 hours to obtain flame-retardant functionalized graphene modified nitrile rubber.

2. The flame retardant functionalized graphene modified nitrile rubber according to claim 1, characterized in that: In the step (1), the mass fractions of N,N-dimethylformamide are 3000-9000 parts, the mass fractions of graphene are 100 parts, and the mass fractions of 3-chloropropyltrimethoxysilane are 260-600 parts.

3. The flame retardant functionalized graphene modified nitrile rubber according to claim 1, characterized in that: In the step (2), the mass fractions of anhydrous ethanol are 3500-8000 parts, the mass fractions of chloropropyl graphene are 100 parts, and the mass fractions of diethanolamine are 10-30 parts.

4. The flame retardant functionalized graphene modified nitrile rubber according to claim 1, characterized in that: In the step (3), the mass fractions of diethyl phenylphosphonate are 80-320 parts, the diethanolamine-modified graphene is 100 parts, the dibutyltin dilaurate is 2-5 parts, and the diethanolamine is 60-145 parts.

5. The flame retardant functionalized graphene modified nitrile rubber according to claim 1, characterized in that: The temperature of the pre-reaction in step (3) is 140-160° C., the reaction time is 0.5-1.5 h, and the polymerization reaction time is 6-12 h.

6. The flame retardant functionalized graphene modified nitrile rubber according to claim 1, characterized in that: In the step (4), the mass fraction of nitrile rubber is 100 parts, the mass fraction of nitrogen-phosphorus polyether diol flame-retardant modified graphene is 0.5-2.5 parts, the mass fraction of vulcanization activator zinc oxide is 2-4 parts, the mass fraction of accelerator dibenzothiazole disulfide is 0.5-1.5 parts, the mass fraction of sulfur is 1-2.5 parts, the mass fraction of antioxidant A is 0.5-2 parts, and the mass fraction of antioxidant 4010 is 1-2.5 parts.

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