CN103408932B - Water-soluble conductive polyaniline nano-fiber/lignin composite material and preparation method thereof - Google Patents

Abstract

The invention provides a water-soluble conductive polyaniline nanofiber/lignin composite material and a preparation method thereof, belonging to the field of preparation methods of conductive polymer nanomaterials. The invention solves the problems of poor electrical conductivity and water dispersion stability of the existing water-based conductive polyaniline/lignin composite material. In this method, sulfonic acid aniline is first dissolved in hydrochloric acid solution to obtain sulfonic acid functional aniline salt solution A, then ferric trichloride is dissolved in lignosulfonate aqueous solution to form solution B, and then sulfonic acid functional aniline salt solution A is obtained. The aniline salt solution A and solution B are reacted at -10～5℃, centrifuged and dried. The invention provides a water-soluble conductive polyaniline nanofiber/lignin composite material. The electrical conductivity of the water-soluble conductive polyaniline nanofiber/lignin composite material of the invention can reach 5-18 S/cm.

Description

Water-soluble conductive polyaniline nanofiber/lignin composite material and preparation method thereof

Technical field:

The invention belongs to the field of preparation methods of conductive polymer nanomaterials, and in particular relates to a water-soluble conductive polyaniline nanofiber/lignin composite material and a preparation method thereof.

technical background

Lignin, as the second most abundant natural product in nature after cellulose reserves, is regenerated at a rate of 50 billion tons every year. Due to its special nano-sized structure and large specific surface area, polyaniline nanofibers have attracted widespread attention, and the formation of polyaniline/lignin composites from lignin and polyaniline has become a research hotspot in recent years. Shao et al. (ShaoL., QiuJ.H., FengH.X., LiuM.Z., ZhangG.H., AnJ.B., GaoC.M., LiuH.L., SynthMetals, 2009, 159:1761- 1766) added small molecule sulfamic acid to the aniline solution containing sodium lignosulfonate to prepare a water-based polyaniline-lignin composite. With the addition of sulfamic acid, the lignin-modified water-based polyaniline The conductivity of aniline increases the conductivity to 5S/cm.

The synthesis of the above-mentioned water-based conductive polyaniline/lignin composite material is a composite material obtained by in-situ polymerization of aniline in the presence of lignosulfonate, so its water solubility comes from water-based lignosulfonate, and at the same time, it is insulating The specific lignosulfonate also greatly reduces the conductivity of the composite material, so the conductivity and water dispersion stability of the composite material still need to be further improved.

Contents of the invention

The object of the present invention is to provide a water-soluble conductive polyaniline nanofiber/lignin composite material and a preparation method thereof in order to solve the problems of poor conductivity and water dispersion stability of the existing water-based conductive polyaniline/lignin composite material.

The present invention firstly provides a kind of preparation method of water-soluble conductive polyaniline nanofiber/lignin composite material, comprises as follows:

Step 1: dissolving sulfonic acid aniline in hydrochloric acid solution to obtain sulfonic acid functional aniline salt solution A;

Step 2: dissolving ferric chloride in aqueous lignosulfonate solution to form solution B;

Step 3: Add the sulfonic acid group functional aniline salt solution A obtained in step 1 and the solution B obtained in step 2 into a reaction container, and react at -10 to 5°C to obtain a reaction product;

Step 4: Centrifuge and dry the reaction product obtained in Step 3 to obtain a water-soluble conductive polyaniline nanofiber/lignin composite material.

Preferably, the sulfonic aniline is selected from aniline-2,5-disulfonic acid, anthranil-4-sulfonic acid, 8-aniline-1-naphthalenesulfonic acid or 2-aminobenzenesulfonic acid One of.

Preferably, the concentration of sulfonic aniline in the sulfonic functional aniline salt solution A is 1-3 mol/L.

Preferably, the concentration of the hydrochloric acid solution is 0.5-1.5 mol/L.

Preferably, the lignosulfonate is selected from one of sodium lignosulfonate, calcium lignosulfonate, ammonium lignosulfonate and magnesium lignosulfonate.

Preferably, the concentration of iron trioxide in the solution B is 1-3 mol/L.

Preferably, the reaction time of the third step is 22-34 hours.

Preferably, the molar ratio of the sulfoaniline to iron oxide is (0.8-1.7): (1.3-2.8).

The present invention also provides the water-soluble conductive polyaniline nanofiber/lignin composite material obtained by the above-mentioned preparation method of the water-soluble conductive polyaniline nanofiber/lignin composite material.

Preferably, the electrical conductivity of the water-soluble conductive polyaniline nanofiber/lignin composite material is 5-18 S/cm.

Beneficial effects of the present invention

The present invention firstly provides a preparation method of water-soluble conductive polyaniline nanofiber/lignin composite material. In the method, sulfonic acid aniline is dissolved in hydrochloric acid solution to obtain sulfonic acid functional aniline salt solution A, and then three Ferric chloride is dissolved in lignosulfonate aqueous solution to form solution B, then the sulfonic acid group functional aniline salt solution A and solution B are reacted at -10-5°C, centrifuged and dried. Compared with the prior art, the present invention replaces aniline with sulfonic acid aniline, and reduces the usage of insulating lignosulfonate on the basis of ensuring excellent water dispersibility. Due to the structure of sulfonic acid aniline The introduction of short-chain sulfonic acid groups makes the water-based polyaniline have excellent self-doping function, thereby greatly improving the conductivity of the water-based conductive polyaniline/lignin composite material. At the same time, due to the self-doping of sulfonic acid aniline effect, and lignin sulfonate doping effect, greatly enhanced the water dispersion stability of water-based conductive polyaniline fiber, the experimental results show that: the water-soluble conductive polyaniline nanofiber/lignin composite material conductivity obtained by the method of the present invention The rate can reach 5-18S/cm, and no delamination can be seen after being placed at room temperature for 2 years.

The present invention also provides a water-soluble conductive polyaniline nanofiber/lignin composite material. The water-soluble conductive polyaniline nanofiber/lignin composite material uses ferric chloride as an oxidant, and sulfonic acid aniline is reacted in lignosulfonic acid In the presence of salt, it is prepared by in-situ polymerization. Experimental results show that the diameter of the water-soluble conductive polyaniline nanofiber is 35-67nm, and its specific surface area is as high as 68-95m ² /g.

Description of drawings

Fig. 1 is a scanning electron microscope image of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained by the preparation method of Example 1 of the present invention.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent requirements of the present invention.

The present invention firstly provides a kind of preparation method of water-soluble conductive polyaniline nanofiber/lignin composite material, comprises as follows:

Step 1: dissolving sulfonic acid aniline in hydrochloric acid solution to obtain sulfonic acid functional aniline salt solution A;

Step 2: Dissolving ferric chloride in the lignosulfonate aqueous solution to form solution B. Step 3: Adding the sulfonic acid group functional aniline salt solution A obtained in step 1 and the solution B obtained in step 2 into the reaction vessel, React at -10~5°C to obtain the reaction product;

Step 4: Centrifuge and dry the reaction product obtained in Step 3 to obtain a water-soluble conductive polyaniline nanofiber/lignin composite material.

Dissolving the sulfonic acid aniline in the hydrochloric acid solution described in the first step of the present invention to obtain the sulfonic acid functional aniline salt solution A is preferably carried out under stirring conditions, and the sulfonic acid aniline is preferably selected from aniline One of -2,5-disulfonic acid, anisole-4-sulfonic acid, 8-aniline-1-naphthalenesulfonic acid or 2-aminobenzenesulfonic acid, the sulfonic acid functional aniline The concentration of sulfoaniline in the salt solution A is preferably 1-3 mol/L, and the concentration of the hydrochloric acid solution is preferably 0.5-1.5 mol/L.

The ferric oxide described in step 2 of the present invention is used as an oxidizing agent to be dissolved in an aqueous solution of lignosulfonate to form solution B, preferably under stirring conditions, and the aqueous solution of lignosulfonate is obtained by mixing lignosulfonic The salt is dissolved in deionized water to form, and the lignosulfonate is preferably selected from one of sodium lignosulfonate, calcium lignosulfonate, ammonium lignosulfonate, magnesium lignosulfonate, and lignosulfonate The concentration is preferably 1M, and the concentration of iron trioxide in the solution B is preferably 1-3 mol/L.

Add the sulfonic acid group functional aniline salt solution A obtained in step 1 and the solution B obtained in step 2 into the reaction vessel as described in step 3 of the present invention, preferably by adding it dropwise into the reaction vessel, the described The dropping rate is preferably 20-35 mL/min. After the dropping is completed, the reaction is carried out at a reaction temperature of -10-5° C., and the reaction time is preferably 22-34 hours.

The molar ratio of the sulfoaniline to iron oxide in the present invention is preferably (0.8-1.7): (1.3-2.8).

In step 4 of the present invention, the reaction product obtained in step 3 is centrifuged and dried, preferably the reaction product is first put into a high-speed centrifuge for centrifugation, and the centrifugation speed is preferably 5000 to 7000 rpm, and the centrifugation time is preferably 30 min. Then add deionized water and methanol respectively, and carry out centrifugation until the supernatant is colorless, and vacuum-dry the product after centrifugation. The preferred drying time is 24 to 36 hours, and the water-soluble conductive polyaniline nanofiber/lignin composite material is obtained. .

The present invention also provides the water-soluble conductive polyaniline nanofiber/lignin composite material obtained by the above-mentioned preparation method of the water-soluble conductive polyaniline nanofiber/lignin composite material.

The water-soluble conductive polyaniline nanofiber/lignin composite material obtained in the present invention is poured into a polytetrafluoroethylene tray, and after natural drying, the electrical conductivity of the obtained self-supporting film is tested by a four-probe method. The electrical conductivity of the water-soluble conductive polyaniline nanofiber/lignin composite material is preferably 5-18 S/cm.

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1

Under stirring conditions, dissolve 0.8 mol of aniline-2,5-disulfonic acid in 0.5 mol/L hydrochloric acid solution to prepare aniline-2,5-disulfonic acid salt solution A with a molar concentration of 1 mol/L;

Under stirring condition, 1.3mol ferric trichloride is dissolved in the sodium lignosulfonate aqueous solution to form the sodium lignosulfonate aqueous solution B of 1mol/L;

At -10°C, add the above-mentioned aniline-2,5-disulfonate solution A and sodium lignosulfonate solution B into the reactor dropwise at a rate of 20 mL/min. After the dropwise addition is completed, stop stirring and keep The temperature of -10 ℃, standing still for 22 hours, the reaction product is obtained;

The reaction product obtained above was centrifuged with a high-speed centrifuge at 5000rpm for 30min, then deionized water and methanol were added respectively, and centrifuged until the supernatant was colorless; the centrifuged product was vacuum-dried for 24h to obtain a water-soluble conductive polymer. Aniline nanofiber/lignin composites.

The experimental results show that: the conductivity of the self-supporting film made of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained in Example 1 is 18S/cm, and with a high-speed centrifuge of 10000 revolutions, the water-soluble conductive polyaniline nanofiber The fiber/lignin composite was centrifuged for 30 minutes, and no precipitation was found, indicating excellent water dispersion stability.

Fig. 1 is the scanning electron micrograph of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained by the preparation method of Example 1 of the present invention, as can be seen from the figure, polyaniline nanofiber and lignin have been combined into a complete Overall, the present invention has successfully prepared water-soluble conductive polyaniline nanofiber/lignin composite material, the average diameter of the polyaniline nanofiber is 35nm, and its specific surface area is as high as 95m ² /g.

Example 2

Under stirring conditions, 1.7mol anthranil-4-sulfonic acid was dissolved in 1.5mol/L hydrochloric acid solution to make molar concentration of 3mol/L anthranil-4-sulfonate solution A ;

Under stirring condition, 2.8mol ferric trichloride is dissolved in the calcium lignosulfonate aqueous solution to form the calcium lignosulfonate aqueous solution B of 3mol/L;

At 5°C, add anthranilic acid-4-sulfonate solution A and calcium lignosulfonate aqueous solution B into the reactor dropwise at a rate of 35 mL/min. After the dropwise addition is completed, stop stirring and keep for 5 ℃ temperature, standing still for 34h, the reaction product is obtained;

Centrifuge the above reaction product with a high-speed centrifuge at 7000rpm for 30min, then add deionized water and methanol respectively, and centrifuge until the supernatant is colorless; vacuum-dry the product after centrifugation for 36h to obtain water-soluble conductive polyaniline nano Fiber/Lignin Composites.

The experimental results show that: the conductivity of the self-supporting film made of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained in Example 2 is 5S/cm. The fiber/lignin composite material was centrifuged for 30 minutes, and no precipitation was found, indicating excellent water dispersion stability. The average diameter of polyaniline nanofibers was 67nm, and its specific surface area was as high as 68m ² /g.

Example 3

Under stirring condition, 1.1mol 8-aniline-1-naphthalenesulfonic acid is dissolved in the hydrochloric acid solution of 1mol/L to make the 8-aniline-1-naphthalenesulfonate solution A that molar concentration is 1.5mol/L;

Under stirring conditions, 1.8mol ferric chloride oxidizing agent is dissolved in the ammonium lignosulfonate aqueous solution to form 1.5mol/L ammonium lignosulfonate aqueous solution B;

At 0°C, add 8-aniline-1-naphthalenesulfonate solution A and lignosulfonate ammonium solution B into the reactor dropwise at a rate of 25mL/min. After the dropwise addition is completed, stop stirring and keep at 0°C The temperature is placed statically for 24 hours to obtain the reaction product;

The reaction product obtained above was centrifuged with a high-speed centrifuge at 6000rpm for 30min, then deionized water and methanol were added, and centrifuged until the supernatant was colorless; the product after centrifugation was vacuum-dried for 30h to obtain a water-soluble conductive polymer. Aniline nanofiber/lignin composites.

The experimental results show that: the conductivity of the self-supporting film made of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained in Example 3 is 10S/cm. The fiber/lignin composite material was centrifuged for 30 minutes, and no precipitation was found, indicating excellent water dispersion stability. The average diameter of polyaniline nanofibers was 42nm, and its specific surface area was as high as 75m ² /g.

Example 4

Under stirring conditions, 1.5mol 2-aminobenzenesulfonic acid is dissolved in the hydrochloric acid solution of 1.2mol/L to make the 2-aminobenzenesulfonate solution A that the molar concentration is 1.3mol/L;

Under stirring condition, 2.2mol ferric chloride oxidizing agent is dissolved in the magnesium lignosulfonate aqueous solution to form the magnesium lignosulfonate aqueous solution B of 1.3mol/L;

At 5°C, add 2-aminobenzenesulfonate solution A and magnesium lignosulfonate aqueous solution B into the reactor dropwise at a rate of 30mL/min. After the dropwise addition is completed, stop stirring and keep the temperature at 5°C. Stand still for 28 hours to obtain the reaction product;

The reaction product obtained above was centrifuged with a 6500rpm high-speed centrifuge for 30 minutes, then deionized water and methanol were added, and centrifuged until the supernatant was colorless; the product after centrifugation was vacuum-dried for 35 hours to obtain a water-soluble conductive polymer. Aniline nanofiber/lignin composites.

The experimental results show that: the conductivity of the self-supporting film made of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained in Example 4 is 7S/cm. The fiber/lignin composite material was centrifuged for 30 minutes, and no precipitation was found, indicating excellent water dispersion stability. The average diameter of polyaniline nanofibers was 58nm, and its specific surface area was as high as 74m ² /g.

Example 5

Under stirring conditions, 1.4 mol of aniline-2,5-disulfonic acid was dissolved in 1 mol/L hydrochloric acid solution to prepare a sulfonic acid group functional aniline salt solution A with a molar concentration of 1 mol/L;

Under stirring conditions, 2.8mol ferric chloride oxidizing agent was dissolved in the magnesium lignosulfonate aqueous solution to form 1mol/L magnesium lignosulfonate aqueous solution B;

At -5°C, add the sulfonic acid group functional aniline salt solution A and the magnesium lignosulfonate aqueous solution B into the reactor dropwise at a rate of 22 mL/min. After the dropwise addition is completed, stop stirring and keep the temperature, standing still for 26h, the reaction product is obtained;

The reaction product obtained above was centrifuged with a high-speed centrifuge at 7000rpm for 30min, then deionized water and methanol were added respectively, and centrifuged until the supernatant was colorless; the product after centrifugation was vacuum-dried for 28h to obtain a water-soluble conductive polymer. Aniline nanofiber/lignin composites.

The experimental results show that: the conductivity of the self-supporting film made of the water-soluble conductive polyaniline nanofiber/lignin composite material obtained in Example 5 is 14S/cm. The fiber/lignin composite material was centrifuged for 30 minutes, and no precipitation was found, indicating excellent water dispersion stability. The average diameter of polyaniline nanofibers was 39nm, and its specific surface area was as high as 89m ² /g.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material, is characterized in that, comprises as follows:

Step one: be dissolved in by sulfo aniline in hydrochloric acid soln, obtains the functional aniline salt solution A of sulfonic group;

Described sulfo aniline is selected from the one in aniline-2,5-disulfonic acid, Ortho Anisidine-4-sulfonic acid, 8-aniline-1-naphthalene sulfonic aicd or 2-aniline sulfonic acid;

Step 2: iron trichloride is dissolved in lignosulfonic acid salt brine solution and forms solution B;

Step 3: the solution B that the functional aniline salt solution A of sulfonic group step one obtained and step 2 obtain joins in reaction vessel, reacts, obtains reaction product at-10 ~ 5 DEG C;

Step 4: reaction product step 3 obtained, through centrifugal, dry, namely obtains Water-soluble conductive polyaniline nano-fiber/lignin composite material.

2. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, is characterized in that, in the functional aniline salt solution A of described sulfonic group, the concentration of sulfo aniline is 1 ~ 3mol/L.

3. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, is characterized in that, the concentration of described hydrochloric acid soln is 0.5 ~ 1.5mol/L.

4. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, it is characterized in that, described sulfonated lignin are selected from the one in sodium lignosulfonate, calcium lignin sulphonate, ammonium lignosulphonate, magnesium lignosulfonate.

5. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, is characterized in that, in described solution B, the concentration of Indian red is 1 ~ 3mol/L.

6. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, is characterized in that, the reaction times of described step 3 is 22 ~ 34h.

7. the preparation method of Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 1, it is characterized in that, described sulfo aniline and the mol ratio of Indian red are (0.8 ~ 1.7): (1.3 ~ 2.8).

8. the Water-soluble conductive polyaniline nano-fiber/lignin composite material that obtains of the preparation method of the Water-soluble conductive polyaniline nano-fiber/lignin composite material of claim 1-7 described in any one.

9. Water-soluble conductive polyaniline nano-fiber/lignin composite material according to claim 8, is characterized in that, the specific conductivity of described Water-soluble conductive polyaniline nano-fiber/lignin composite material is 5 ~ 18S/cm.