Naphthyl branched polymer as well as preparation method and application thereof

Abstract

The invention discloses a naphthyl branched polymer as well as a preparation method and application thereof. The naphthyl branched polymer is obtained by reacting the following components: (a) polyether amine; (b) terephthalaldehyde; (c) melamine; and (d) naphthaldehyde. The preparation method of the naphthyl branched polymer comprises the following steps: adding polyether amine and terephthalaldehyde into a flask, then adding an organic solvent, uniformly stirring, then adding melamine and naphthaldehyde, carrying out ultrasonic dispersion and reaction, and cooling to room temperature to obtain the naphthyl branched polymer. The naphthyl branched polymer has a good dispersion effect on carbon black, carbon nanotubes and graphene, and can be used for dispersing a carbon material in a new energy battery.

Description

Technical Field

[0001] The invention belongs to the technical field of dispersants, and in particular relates to a naphthyl branched polymer and a preparation method and application thereof. Background Art

[0002] The positive electrode slurry system of lithium-ion batteries includes active materials, binders, conductive agents and solvents. The uniformity and stability of the positive electrode slurry have an important impact on battery performance. In the positive electrode slurry system, the polar surface energy and dispersion surface energy of different components are different, which will affect the interaction strength between particles.

[0003] Commonly used conductive agents include conductive graphite, conductive carbon black, carbon nanotubes, etc. Conductive agents have the following main functions: 1) The normal charging and discharging process of lithium batteries requires the participation of lithium ions and electrons. This requires that the electrodes of lithium-ion batteries must be mixed conductors of ions and electrons, and the electrode reaction can only occur at the junction of the electrolyte, conductive agent, and active material; 2) The electrode active materials are mostly transition metal oxides or transition metal phosphates, which are semiconductors or insulators with poor conductivity. Conductive agents must be added to improve the conductivity; 3) The conductivity of negative electrode graphite materials is slightly better, but during multiple charging and discharging, the expansion and contraction of graphite materials reduces the contact between graphite particles, increases the gap, and even some of them are separated from the collector and become dead active materials. They no longer participate in the electrode reaction, so conductive agents are also needed to maintain the stability of the conductivity of negative electrode materials during the cycle. Since the particles of carbon black conductive agents are tens of nanometers, the particles of conductive graphite are several microns, and the particles of carbon nanotubes and graphene are only a few nanometers, it is difficult to disperse evenly inside the electrode and it is difficult to meet the growing performance requirements of power batteries.

[0004] Existing dispersants include surfactants and polymer stabilizers such as sodium dodecylbenzene sulfonate (SDBS), gum arabic, and polyvinyl pyrrolidone (PVP); there are also some self-synthesized complex organic small molecules and polymers with surface activity. However, these dispersants still have many limitations. On the one hand, the amount of dispersant used is relatively large, often reaching several times, dozens of times, or even higher than the mass of graphite; on the other hand, the dispersant has limited ability to disperse graphene. After ultrasonic treatment, the graphene concentration in the obtained dispersion is usually less than 0.5 mg·mL -1 , the dispersion performance is poor, which greatly limits its application in practice. In addition, the dispersant will generally remain in the graphene composite material as an ineffective component, which has a great impact on the final performance of the material.

[0005] A large number of domestic and foreign literature and patent reports can be used to disperse CNTs by non-covalent treatment, that is, using a dispersant with a special structure to interact with CNTs to achieve directional arrangement and stable distribution, and enhance the dispersibility of CNTs in the dispersion medium. Chinese patent application CN101773801A proposes to disperse carbon nanotubes with biomolecules, which can achieve the dispersion of CNTs without destroying the structure of carbon nanotubes. However, the production process of such bio-based dispersants is complicated, difficult to obtain, and expensive. Chinese patent application CN106587013A designs a switch-type dispersant that can disperse CNTs in an aqueous solution, but the dispersant needs to be introduced with nitrogen, air or heated and decomposed during use. The method of use is complicated, and it can only be dispersed in an aqueous solution, and the application conditions are relatively limited. Chinese patent application CN113248739A discloses a carbon-olefin material dispersion and its application, and the carbon-olefin material dispersion includes: carbon-olefin material, dispersant, and solvent. The olefin-carbon material dispersion can be used for olefin-carbon composite aramid fiber, which is low-cost, green and environmentally friendly, simple in process, and has excellent dispersion effect. It is greatly beneficial to the preparation of olefin-carbon composite aramid fiber, improve the comprehensive performance of aramid fiber, and accelerate the upgrading and innovation of the aramid industry. However, the dispersant has limited dispersion effect on graphene, carbon nanotubes, etc., and there is room for further improvement; and the dispersant is mainly used in the preparation of aramid fiber composite materials, and whether it can be applied to lithium-ion batteries remains to be discussed. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a naphthyl branched polymer and a preparation method and use thereof. The naphthyl branched polymer has a good dispersing effect on carbon black, carbon nanotubes and graphene, and can be used for dispersing carbon materials in new energy batteries.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A naphthyl branched polymer obtained by reacting the following components:

[0009] (a) polyetheramines;

[0010] (b) terephthalaldehyde;

[0011] (c) melamine;

[0012] (d) Naphthaldehyde.

[0013] The naphthyl branched polymer M n 3000-100000.

[0014] Preferably, the (a) is a single-terminal primary amino polyether, and its structural formula is R-(CH2CH2O) y (CH2CHCH3O) x-NH2; wherein x is an integer from 0 to 100; y is an integer from 0 to 100; x+y≥20, and R is a straight-chain alkyl group having 1 to 18 carbon atoms.

[0015] Preferably, the (a) is a single-terminal primary amino polyether, and its structural formula is R-(CH2CH2O) y (CH2CHCH3O) x -NH2; wherein x is an integer from 20 to 80; y is an integer from 0 to 70; x+y≥20, and R is a straight-chain alkyl group having 1 to 18 carbon atoms.

[0016] Preferably, the molar ratio of (a), (b), (c) and (d) is 1:1:1:2.

[0017] The present invention also protects a method for preparing the naphthyl branched polymer as described above, comprising the following steps:

[0018] Add polyetheramine and terephthalaldehyde into a flask, then add an organic solvent, stir evenly, then add melamine and naphthaldehyde, disperse by ultrasonic, react, and cool to room temperature to obtain the naphthyl branched polymer.

[0019] Preferably, the organic solvent is one or more of N-methylpyrrolidone, dimethyl sulfoxide, and N,N-dimethylacetamide.

[0020] Preferably, the reaction temperature is 180-220° C. and the reaction time is 10-20 h.

[0021] More preferably, the reaction temperature is 180-200° C. and the reaction time is 15-20 h.

[0022] In the present invention, the reaction temperature can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, and the reaction time can be 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h.

[0023] Preferably, the ultrasonic dispersion time is 10-20 min.

[0024] More preferably, the ultrasonic dispersion time is 15-20 min.

[0025] The present invention also protects the use of the naphthyl branched polymer as described above in dispersing carbon black, carbon nanotubes and graphene.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The naphthyl branched polymer provided by the present invention uses polyetheramine, trimesic acid, melamine and naphthaldehyde as raw materials, and utilizes the Schiff base reaction principle to generate the naphthyl branched polymer in one step. The naphthyl branched polymer contains abundant aromatic rings, naphthalene rings, triazine rings and amide bond structures. Since the benzene rings, naphthalene rings, amide bonds and triazine rings have good affinity for carbon, the carbon material can be effectively dispersed evenly. At the same time, the introduced polyether chain segments can provide dispersibility and lithium ion complexing ability, making the naphthyl branched polymer very suitable for the dispersion of carbon materials in new energy batteries.

[0028] (2) The naphthyl branched polymer provided by the present invention has a simple preparation method, and the raw materials used are easily available, which is suitable for industrial production and has good application prospects. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The polyetheramines are Huntsman M1000, Huntsman M2070 and Huntsman M3085, all of which were purchased from Hubei Maidehao Chemical Co., Ltd.

[0031] Example 1

[0032] A method for preparing a naphthyl branched polymer comprises the following steps:

[0033] 100 g of polyetheramine M2070 (molecular weight 2070) and 6.47 g of terephthalaldehyde were added to a flask, followed by 500 mL of N-methylpyrrolidone, and then 6.09 g of melamine and 7.54 g of naphthaldehyde were added after stirring. The mixture was ultrasonically dispersed for 15 min, reacted at 200° C. for 18 h, and cooled to room temperature to obtain the naphthyl branched polymer. The naphthyl branched polymer M n is 13000.

[0034] Example 2

[0035] A method for preparing a naphthyl branched polymer comprises the following steps:

[0036] 90g polyetheramine M3085 (molecular weight 3085) and 3.91g terephthalaldehyde were added to a flask, followed by 500mL dimethyl sulfoxide, stirred evenly, and then 3.68g melamine and 4.55g naphthaldehyde were added, ultrasonically dispersed for 15min, reacted at 210°C for 16h, and cooled to room temperature to obtain the naphthyl branched polymer. The naphthyl branched polymer M nis 25000.

[0037] Example 3

[0038] A method for preparing a naphthyl branched polymer comprises the following steps:

[0039] 100g polyetheramine M2070 (molecular weight 2070) and 6.47g terephthalaldehyde were added to a flask, followed by 500mL N,N-dimethylacetamide, stirred evenly, and then 6.09g melamine and 7.54g naphthaldehyde were added, ultrasonically dispersed for 10min, reacted at 190°C for 20h, and cooled to room temperature to obtain the naphthyl branched polymer. The naphthyl branched polymer M n is 8000.

[0040] Example 4

[0041] A method for preparing a naphthyl branched polymer comprises the following steps:

[0042] 100 g of polyetheramine M1000 (molecular weight 1000) and 13.4 g of terephthalaldehyde were added to a flask, followed by 500 mL of N-methylpyrrolidone, and then 12.6 g of melamine and 15.6 g of naphthaldehyde were added after stirring evenly, and ultrasonic dispersion was performed for 15 min, and the mixture was reacted at 200° C. for 17 h, and cooled to room temperature to obtain the naphthyl branched polymer. n is 7000.

[0043] Example 5

[0044] A method for preparing a naphthyl branched polymer comprises the following steps:

[0045] 100 g of polyetheramine M2070 (molecular weight 2070) and 6.47 g of terephthalaldehyde were added to a flask, followed by 500 mL of N-methylpyrrolidone, and then 6.09 g of melamine and 7.54 g of naphthaldehyde were added after stirring. The mixture was ultrasonically dispersed for 20 min, reacted at 220° C. for 11 h, and cooled to room temperature to obtain the naphthyl branched polymer. The naphthyl branched polymer M n is 10000.

[0046] Comparative Example 1

[0047] A method for preparing a naphthyl branched polymer comprises the following steps:

[0048] 100 g of polyetheramine M2070 (molecular weight 2070) and 6.47 g of terephthalaldehyde were added to a flask, followed by 500 mL of N-methylpyrrolidone. After stirring evenly, ultrasonic dispersion was performed for 15 min, the mixture was reacted at 200° C. for 15 h, and cooled to room temperature to obtain the branched polymer.

[0049] Compared with Example 1, no melamine or naphthaldehyde was added to this comparative example.

[0050] Comparative Example 2

[0051] A method for preparing a naphthyl branched polymer comprises the following steps:

[0052] 6.47 g of terephthalaldehyde was added to a flask, followed by 500 mL of N-methylpyrrolidone. After stirring evenly, 6.09 g of melamine and 7.54 g of naphthaldehyde were added. Ultrasonic dispersion was performed for 15 minutes, the mixture was reacted at 200° C. for 15 hours, and the mixture was cooled to room temperature to obtain the naphthyl branched polymer.

[0053] Compared with Example 1, no polyetheramine was added in this comparative example.

[0054] The naphthyl branched polymers prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to a dispersion test on carbon nanotubes. The test conditions were: ambient humidity of 75% and ambient temperature of 25°C. The dispersion method was as follows: 50g carbon nanotubes, 5g naphthyl branched polymers, and 945g N-methylpyrrolidone were first dispersed uniformly at 2000rpm and then added to a 1000mL desktop nano grinder and ground at 25°C for 3 hours. The prepared slurry was tested for particle size and viscosity using a Malvern particle size analyzer and a viscometer, respectively. The evaluation results are shown in Table 1:

[0055] Table 1 Evaluation results of carbon nanotube dispersion slurry

[0056] Group Carbon nanotube particle size / nm Slurry viscosity / mPas Apparent state after 60 days of static storage Example 1 236 285 Evenly dispersed Example 2 282 327 Evenly dispersed Example 3 261 309 Evenly dispersed Example 4 279 312 Evenly dispersed Example 5 254 298 Evenly dispersed Comparative Example 1 683 961 Layered, with sediment at the bottom Comparative Example 2 892 2466 Layered, with a lot of sediment at the bottom

[0057] As can be seen from Table 1, the naphthyl branched polymer prepared in the present invention can stably and uniformly disperse carbon nanotubes into a high-concentration dispersion, and the particle size of the carbon nanotubes and the viscosity of the slurry are lower than those in the comparative example, indicating that the naphthyl branched polymer obtained in the embodiment of the present invention has a good dispersion effect on carbon nanotubes and excellent performance.

[0058] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A naphthyl branched polymer, characterized in that Obtained by the reaction of the following components: (a) polyetheramines; (b) terephthalaldehyde; (c) melamine; (d) Naphthaldehyde.

2. The naphthyl branched polymer according to claim 1, characterized in that The naphthyl branched polymer M n 3000-100000.

3. The naphthyl branched polymer according to claim 1, characterized in that The (a) is a single-terminal primary amino polyether, and its structural formula is R-(CH2CH2O) y (CH2CHCH3O) x -NH2; wherein x is an integer from 0 to 100; y is an integer from 0 to 100; x+y≥20, and R is a straight-chain alkyl group having 1 to 18 carbon atoms.

4. The naphthyl branched polymer according to claim 3, characterized in that The (a) is a single-terminal primary amino polyether, and its structural formula is R-(CH2CH2O) y (CH2CHCH3O) x -NH2; wherein x is an integer from 20 to 80; y is an integer from 0 to 70; x+y≥20, and R is a straight-chain alkyl group having 1 to 18 carbon atoms.

5. The naphthyl branched polymer according to claim 1, characterized in that The molar ratio of (a), (b), (c) and (d) is 1:1:1:

2.

6. A method for preparing a naphthyl branched polymer as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Add polyetheramine and terephthalaldehyde into a flask, then add an organic solvent, stir evenly, then add melamine and naphthaldehyde, disperse by ultrasonic, react, and cool to room temperature to obtain the naphthyl branched polymer.

7. The preparation method according to claim 6, characterized in that: The organic solution is one or more of N-methylpyrrolidone, dimethyl sulfoxide, and N,N-dimethylacetamide.

8. The preparation method according to claim 6, characterized in that: The reaction temperature is 180-220° C. and the reaction time is 10-20 h.

9. The preparation method according to claim 6, characterized in that: The ultrasonic dispersion time is 10-20 min.

10. Use of the naphthyl branched polymer according to any one of claims 1 to 5 in dispersing carbon black, carbon nanotubes and graphene.