CN116589754A - A kind of high loading nanostructure polyaniline composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of a high-load nano-structure polyaniline composite material, which comprises the steps of using pulp fibers as a substrate, using phytic acid as a doping agent, using alizarin red S as a regulating agent, dispersing pulp fibers and aniline monomers in a solution dissolved with the doping agent and the regulating agent, then dropwise adding an oxidant into the mixed dispersion liquid, coating nano-structure polyaniline on the surface of the pulp fibers through an in-situ oxidative polymerization process, and finally filtering, washing and drying to obtain the high-load nano-structure polyaniline composite material. The polyaniline composite material with the high-loading nano-structure obtained by the preparation method has the characteristics of high active material loading, excellent electrochemical performance and the like; the invention has simple process, high utilization rate of raw materials, no need of complex equipment and suitability for large-scale industrial production; the raw material pulp fiber used in the invention has wide sources, is degradable and renewable; the cost is low, the environment is protected, and the method is green and safe, and has important significance for environmental protection and promotion of development of flexible energy storage materials.

Description

A kind of high loading nanostructure polyaniline composite material and preparation method thereof

technical field

The invention relates to the technical field of polyaniline composite materials, in particular to a high-load nanostructure polyaniline composite material and a preparation method thereof.

Background technique

Conductive polymers, such as polyaniline, polypyrrole, etc., are a new class of polymer functional materials, which can realize their unique conductive functions through their own conductivity or doping with other materials. Among these conductive polymers, polyaniline has received great attention due to its low cost, facile preparation, and unique doping behavior. At the same time, polyaniline also has a high theoretical specific capacitance, and has broad application prospects in the field of energy storage. As an energy storage material, polyaniline can undergo reversible n-type, p-type doping and dedoping redox reactions during charging and discharging, so that charges are stored in the polymer chains, thereby generating Faraday capacitance. Since the phase transition of the electrode material basically does not change during the entire charging and discharging process, its energy storage has good reversibility. In addition, polyaniline is the most studied intrinsically conductive polymer because it has excellent electrochemical and optical properties, is easy to synthesize, has high operating voltage, and has good plasticity. When polyaniline is in the semi-oxidized and semi-reduced state, its molecular structure is a benzo-quinone alternating structure that can be converted into a conductor by proton acid doping, which is called the emerald green intermediate oxidation state, and the conductivity of polyaniline is maximum at this time. However, polyaniline has the disadvantages of being unable to form a film and poor machinability, so it is difficult to be directly applied, and it can only be compounded with other materials to obtain sheet or film materials.

Pulp fiber is the most common material in the pulp and paper industry. It has the advantages of wide source, low cost and machinability, and is an excellent base material. Using pulp fiber as the base material of polyaniline can improve the machinability of polyaniline, prepare low-cost and high-performance energy storage materials, expand the application field of polyaniline, and promote the industrial application of polyaniline.

At present, the loading of polyaniline on pulp fibers mostly adopts the in-situ polymerization method, which can completely maintain the porosity of the paper and ensure the uniform distribution of polyaniline on the surface and inside of the paper. However, during the in-situ polymerization process, the amount of polyaniline deposited on pulp fibers is limited, and it is difficult to obtain high-load polyaniline composites. Studies have shown that increasing the amount of reactants such as aniline monomer and oxidant can increase the loading capacity of polyaniline. However, this will not only increase the cost, but also increase the difficulty of wastewater treatment, and the polyaniline in the prepared composite material will also produce serious agglomeration, resulting in a decline in the overall performance of the composite material.

Because it is necessary to propose a new high-loading nanostructure polyaniline composite material and its preparation method to solve the above problems.

Contents of the invention

The technical problem to be solved by the present invention is that in the in-situ polymerization process, the amount of polyaniline deposited on the pulp fiber is limited, and it is difficult to obtain high-load polyaniline composite materials, and a high-load nanostructure polymer is proposed. Aniline composite materials and methods for their preparation.

The preparation method of the high-load nanostructure polyaniline composite material includes: performing enzyme pretreatment on pulp fibers, then using sulfosalicylic acid as a dopant, ammonium persulfate as an oxidant, and alizarin red S as a shape control agent, and prepared high-loading nanostructured polyaniline composites through an in-situ polymerization process.

The preparation method specifically comprises the following steps:

Step 1. Pretreatment of pulp fibers:

At room temperature, put the pulp fibers in a sealed bag; add cellulase solution, and then quickly add acetic acid-sodium acetate buffer solution with a pH of 4.8, knead for 1-2 minutes to disperse the fibers evenly, seal the above sealed bag and put Stand in a water bath for a period of time; take it out and wash away impurities with ethanol, and you can get rapid enzyme pretreated pulp fiber;

Further, the absolute dry mass of the pulp is 0.5 g; the amount of the cellulase solution is 0.05-0.3 mL, and the concentration is 3.5 EGU/mL; the amount of the buffer solution is 50 mL. The temperature of the water bath is 10-50°C, and the standing time is 1-20min.

Step 2. Prepare high-capacity nanostructured polyaniline composites:

Put the rapid enzyme pretreated pulp fiber in a round bottom flask and place it in an ice-water bath; add sulfosalicylic acid and alizarin red S solution into the flask and perform mechanical stirring for 20 minutes; add aniline monomer and continue stirring for 30 minutes; Then add ammonium persulfate solution dropwise, and continue to stir for a period of time under ice-water bath conditions; after the reaction is over, filter and wash until the filtrate becomes colorless to remove impurities; High-loading nanostructured polyaniline composites were obtained.

Further, the dosage of sulfosalicylic acid is 100mL, the concentration is 0.1-0.8mol/L; the dosage of Alizarin Red S is 50mL, the concentration is 0.1-0.8mol/L; the dosage of aniline monomer is 0.1-1mL; The dosage of ammonium persulfate is 50mL, and the concentration is 1-10mmol/L. Stirring time in ice water bath is 1-6h.

Principle of the present invention:

In order to increase the loading capacity of polyaniline in the polyaniline composite material, the present invention activates the reactive groups on the surface of the pulp by performing rapid enzyme pretreatment on the paper-based fibers, increases the specific surface area of the pulp fibers, and provides a more stable environment for the deposition of polyaniline. More active sites can promote the efficient in-situ deposition of polyaniline on pulp fibers, thereby achieving the purpose of increasing the loading capacity of polyaniline.

At the same time, alizarin red S was introduced as a morphology regulator to regulate the microscopic morphology of high-loaded polyaniline. On the one hand, Alizarin Red S contains a sulfonic acid group, which can be used as a dopant to enter the polyaniline polymer chain. The agglomeration between aniline particles; on the other hand, Alizarin Red S contains hydroxyl groups, which can endow the polymer chain with hydrophilicity, improve its dispersion performance in the water phase, and reduce the agglomeration between particles. Alizarin red S was used to control the microscopic morphology of polyaniline, avoiding the agglomeration of high-load polyaniline, and promoting the formation of nanostructures of polyaniline. Finally, high-capacity nanostructured polyaniline composites were obtained through rapid enzyme pretreatment and alizarin red S doping regulation.

Implement the present invention, have following beneficial effect:

The invention discloses a preparation method of a high-load nanostructure polyaniline composite material, which has simple process, high raw material utilization rate, no complicated equipment and is suitable for large-scale industrial production;

The raw material pulp fiber used in the present invention has a wide range of sources, is degradable and renewable;

The high-load nanostructure polyaniline composite material prepared by the invention has low cost, is green and safe, and has great significance for environmental protection and promotion of the development of flexible energy storage materials.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the scanning electron microscope picture of the high-capacity nanostructure polyaniline composite material that makes in embodiment 3;

Fig. 2 is the scanning electron microscope picture of the high-capacity nanostructure polyaniline composite material that makes in embodiment 4;

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

Put 0.5g of pulp fiber in a round bottom flask and place it in an ice-water bath; add 100mL of sulfosalicylic acid with a concentration of 0.1mol/L and 50mL of alizarin red S solution with a concentration of 0.1mol/L into the flask and Perform mechanical stirring for 20 minutes; add 0.5 mL of aniline monomer, and continue stirring for 30 minutes; then add ammonium persulfate solution dropwise, the amount of ammonium persulfate is 50 mL, the concentration is 1 mmol/L, and continue stirring for 1 h under ice-water bath conditions; After the end, filter and wash until the filtrate becomes colorless to remove impurities; the resulting composite material is then suction filtered, pressed, and dried to obtain a high-load nanostructure polyaniline composite material.

Example 2

At room temperature, put 0.5 g of pulp fiber in a sealed bag; add 0.1 mL of cellulase solution with a concentration of 3.5 EGU/mL, and then quickly add 50 mL of acetic acid-sodium acetate buffer solution with a pH of 4.8, knead for 2 minutes to make the fiber Disperse evenly, seal the above-mentioned sealed bag and put it in a 50°C water bath for 5 minutes; take it out and wash it with ethanol to remove impurities, and you can get the rapid enzyme pretreated pulp fiber;

Put the rapid enzyme pretreated pulp fibers in a round bottom flask and put them in an ice-water bath; add 100 mL of sulfosalicylic acid with a concentration of 0.1 mol/L and 50 mL of alizarin red S solution with a concentration of 0.1 mol/L The flask was mechanically stirred for 20 min; 0.5 mL of aniline monomer was added, and the stirring was continued for 30 min; then ammonium persulfate solution was added dropwise, the amount of ammonium persulfate was 50 mL, and the concentration was 1 mmol/L, and stirring was continued for 1 h in an ice-water bath After the reaction, filter and wash until the filtrate becomes colorless to remove impurities; the obtained composite material is then suction filtered, pressed and dried to obtain a high-load nanostructure polyaniline composite material.

Example 3

At room temperature, put 0.5 g of pulp fiber in a sealed bag; add 0.1 mL of cellulase solution with a concentration of 3.5 EGU/mL, and then quickly add 50 mL of acetic acid-sodium acetate buffer solution with a pH of 4.8, knead for 2 minutes to make the fiber Disperse evenly, seal the above-mentioned sealed bag and put it in a 50°C water bath for 10 minutes; take it out and wash it with ethanol to remove impurities, and the rapid enzyme pretreated pulp fiber can be obtained;

Put the rapid enzyme pretreated pulp fibers in a round bottom flask and put them in an ice-water bath; add 100 mL of sulfosalicylic acid with a concentration of 0.1 mol/L and 50 mL of alizarin red S solution with a concentration of 0.1 mol/L The flask was mechanically stirred for 20 min; 0.5 mL of aniline monomer was added, and the stirring was continued for 30 min; then ammonium persulfate solution was added dropwise, the amount of ammonium persulfate was 50 mL, and the concentration was 1 mmol/L, and stirring was continued for 1 h in an ice-water bath After the reaction, filter and wash until the filtrate becomes colorless to remove impurities; the obtained composite material is then suction filtered, pressed and dried to obtain a high-load nanostructure polyaniline composite material.

Example 4

At room temperature, put 0.5 g of pulp fiber in a sealed bag; add 0.1 mL of cellulase solution with a concentration of 3.5 EGU/mL, and then quickly add 50 mL of acetic acid-sodium acetate buffer solution with a pH of 4.8, knead for 2 minutes to make the fiber Disperse evenly, seal the above-mentioned sealed bag and put it in a 50°C water bath for 10 minutes; take it out and wash it with ethanol to remove impurities, and the rapid enzyme pretreated pulp fiber can be obtained;

Put the rapid enzyme pretreated pulp fiber in a round bottom flask and place it in an ice-water bath; add 100 mL of sulfosalicylic acid with a concentration of 0.1 mol/L into the flask and perform mechanical stirring for 20 min; add 0.5 mL of aniline monomer, Continue to stir for 30min; then add ammonium persulfate solution dropwise, the amount of ammonium persulfate is 50mL, the concentration is 1mmol/L, and continue to stir for 1h under ice-water bath conditions; after the reaction is completed, filter and wash until the filtrate becomes free Color to remove impurities; the resulting composite material is then suction filtered, pressed, and dried to obtain a high-load nanostructure polyaniline composite material.

The experimental result of embodiment 1-4 please refer to the table below:

Experimental parameters and result comparison table of table 1 embodiment 1-4

It can be seen from Table 1 that, compared with Example 1 without pretreatment, the loading capacity of Examples 2-4 after rapid enzyme pretreatment of pulp fibers is significantly increased, and the resistivity is also significantly decreased. However, the resistivity of Examples 2 and 3 in which Alizarin Red S was added was lower than that in Example 4 in which Alizarin Red S was not added. That is to say: rapid enzymatic pretreatment of pulp fibers can significantly increase the loading capacity of polyaniline, while reducing the resistivity of the composite material, while prolonging the enzyme pretreatment time has little effect on the loading capacity of polyaniline and the resistivity of the composite material Obviously; the addition of alizarin red S can reduce the resistivity of the material, which may be related to the change of the microstructure of polyaniline.

Electron microscope characterization of the high-capacity nanostructure polyaniline composite material obtained in Examples 3 and 4, please refer to Figures 1-2, Figure 1 is the scanning electron microscope of the high-capacity nanostructure polyaniline composite material obtained in Example 3 Picture; FIG. 2 is a scanning electron microscope picture of the high-capacity nanostructured polyaniline composite material prepared in Example 4.

From the scanning electron microscope pictures, it can be seen that the polyaniline in sample 3 is in a better dispersed state, the nanoparticles are small in size and have a porous structure, while the polyaniline in sample 4 has a very obvious agglomeration phenomenon, and there is basically no pore structure. Therefore, the addition of Alizarin Red S is also beneficial to reduce the size of polyaniline particles in the composite material and reduce the agglomeration phenomenon.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (6)

1. The preparation method of the high-loading nano-structure polyaniline composite material is characterized by comprising the following steps of: enzyme pretreatment is carried out on paper pulp fibers, sulfosalicylic acid is taken as a doping agent, ammonium persulfate is taken as an oxidant, alizarin red S is taken as a morphology regulator, and the high-loading nano-structure polyaniline composite material is prepared through an in-situ polymerization process.

2. The method for preparing the high-loading nano-structured polyaniline composite material according to claim 1, comprising the following steps:

step one, preprocessing pulp fibers:

placing pulp fibers in a sealed bag at room temperature; adding cellulase solution, rapidly adding acetic acid-sodium acetate buffer solution with pH of 4.8, kneading for 1-2min to disperse fiber uniformly, sealing the sealed bag, and standing in water bath for a period of time; taking out, washing impurities with ethanol, and obtaining the rapid enzyme pretreatment pulp fiber;

step two, preparing a high-load nano-structure polyaniline composite material:

placing the rapid enzyme pretreated pulp fiber in a round bottom flask and placing in an ice water bath; adding sulfosalicylic acid and alizarin red S solution into the flask, and mechanically stirring for 20min; adding aniline monomer, and continuing stirring for 30min; then dropwise adding ammonium persulfate solution, and continuously stirring for a period of time under the ice water bath condition; filtering and washing after the reaction is finished until the filtrate becomes colorless to remove impurities; the obtained composite material is subjected to suction filtration, squeezing and drying to obtain the polyaniline composite material with the high-loading nano-structure.

3. The method of preparing a high loading nanostructured polyaniline composite according to claim 2, wherein the oven dry mass of the pulp in step one is 0.5g; the dosage of the cellulase solution is 0.05-0.3mL, and the concentration is 3.5EGU/mL; the buffer was used in an amount of 50mL.

4. The method for preparing a high-loading nano-structured polyaniline composite material according to claim 3, wherein the water bath temperature in the first step is 10-50 ℃ and the standing time is 1-20min.

5. The method for preparing the high-loading nano-structure polyaniline composite material according to claim 3, wherein the sulfosalicylic acid in the second step is used in an amount of 100mL and the concentration is 0.1-0.8mol/L; the dosage of alizarin red S is 50mL, and the concentration is 0.1-0.8mol/L; the dosage of the aniline monomer is 0.1-1mL; the dosage of ammonium persulfate is 50mL, and the concentration is 1-10mmol/L.

6. The method for preparing a high-loading nano-structured polyaniline composite according to claim 5, wherein the stirring time in the ice-water bath in the second step is 1-6h.