CN103524733B - A kind of cerous nitrate (III) doped polyaniline/argentum nano composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of cerous nitrate (III) doped polyaniline/argentum nano composite material and preparation method thereof, this matrix material is the ternary organic combination consisted of on polyaniline chain conjugation Coordination Adsorption cerous nitrate (III) and nanometer silver, preparation method is first by reduction method for preparing nanometer silver, pass through the polymerization of aniline again by nanometer silver and cerous nitrate (III) compound, to obtain final product; This preparation method is simple, cost is low, productive rate is high, can suitability for industrialized production, and obtained matrix material thermostability, electroconductibility and corrosion resistance nature improving a lot all than polyaniline/argentum binary composite, have a wide range of applications potentiality.

Description

A kind of cerium nitrate (Ⅲ) doped polyaniline/silver nanocomposite material and preparation method thereof

technical field

The invention relates to a polyaniline/silver nanocomposite material doped with cerium (III) nitrate and a preparation method thereof, belonging to the field of conductive polymer-based composite materials.

Background technique

Polyaniline is one of the more popular conductive polymers in current research and application. The simple synthesis, good environmental stability, and good electrochemical performance make it have broad application prospects in the fields of electrode materials, energy storage, electromagnetic shielding, sensors, and corrosion resistance. In the current research on nanocomposites, the study of polyaniline/metal nanocomposites has also attracted much attention. Such as polyaniline/palladium, polyaniline/gold, polyaniline/copper, polyaniline/platinum and other nanomaterials are also extensively studied. As one of them, polyaniline/silver nanocomposite material not only combines the original characteristics of polyaniline but also retains the unique properties of silver, such as high conductivity, bactericidal, and high sensitivity of silver. Therefore, the study of polyaniline/silver nanocomposites has also attracted extensive attention from scholars at home and abroad.

Doping is an important means and main way for polyaniline to obtain higher conductivity and better electrochemical performance. At present, the main forms of polyaniline doping are proton acid doping, iodine doping, photooxidation doping and ion implantation doping. Among them, protonic acid doped polyaniline is the most common. The protonic acid used may be inorganic acids such as hydrochloric acid, nitric acid, perchloric acid, etc., or p-toluenesulfonic acid, camphorsulfonic acid, dodecylbenzenesulfonic acid, etc. In these different types of doped polyaniline, the electrical conductivity of polyaniline has been improved to varying degrees, but the thermal stability and environmental stability of the material are not guaranteed. The prepared doped polyaniline still has great deficiencies in steel anti-corrosion, alloy anti-corrosion, capacitor application and so on. Therefore, the development of doped polyaniline with high conductivity, high stability and electrochemical performance is of great practical significance and application value.

Contents of the invention

The present invention aims to provide a kind of nitric acid with good heat resistance, high electrical conductivity and good corrosion resistance, aiming at the disadvantages of poor thermal stability, limited improvement of electrical conductivity and limited application of the doped polyaniline material in the prior art. Cerium(III)-doped polyaniline/silver nanocomposites.

Another object of the present invention is to provide a method for preparing polyaniline/silver nanocomposite materials doped with cerium nitrate (III) with simple process, convenient operation, low cost and high yield.

The invention provides a cerium (III) nitrate-doped polyaniline/silver nanocomposite material, which is a ternary organic bond formed by cerium (III) nitrate and nano-silver adsorbed on the polyaniline chain through conjugate coordination. body; the ternary organic combination is dispersed by aniline and cerium (III) nitrate in the sodium dodecylbenzenesulfonate microemulsion containing nano-silver, polyaniline is generated by the polymerization of aniline and cerium (III) and nitrate Nano-silver is compounded; wherein, the molar ratio of aniline, nano-silver and cerium (III) nitrate is 2.5-3.5:1:0.5-3.

The molar ratio of said aniline: nano silver: cerium (III) nitrate is preferably 3:1:0.5-3.

The sodium dodecylbenzenesulfonate microemulsion containing nanometer silver is obtained by adding silver nitrate to the sodium dodecylbenzenesulfonate microemulsion containing sodium hypophosphite for reduction reaction.

The present invention also provides a preparation method of polyaniline/silver nanocomposite material doped with cerium (III) nitrate. The preparation method is to add silver nitrate solution dropwise to sodium hypophosphite In the sodium dodecylbenzenesulfonate microemulsion, a reduction reaction occurs at 30-50°C to prepare a nano-silver-containing micro-emulsion; after adding aniline and cerium nitrate (Ⅲ) to the obtained nano-silver-containing micro-emulsion, Ultrasonic dispersion, and then add the initiator dropwise at a rate of 15-20 drops/min under stirring conditions, and polymerize at 0-5°C; after the polymerization is completed, break the emulsion, wash, and dry; among them, aniline : Silver nitrate: cerium nitrate (III) molar ratio is 2.5～3.5:1:0.5～3.

The molar ratio of aniline:silver nitrate:cerium(III) nitrate is preferably 3:1:0.5-3.

The molar ratio of sodium hypophosphite to silver nitrate is 1-1.5:2.

The silver nitrate concentration is 0.5M/L.

The mass percent concentration of sodium dodecylbenzenesulfonate in the sodium dodecylbenzenesulfonate microemulsion is 0.5-3%.

The initiator is an aqueous solution of ammonium persulfate with a concentration of 1.5-2.5 g/mL.

The reduction reaction time is 60-120 minutes.

The polymerization reaction time is 10-14 hours.

The preparation method of the cerium (III) nitrate doped polyaniline/silver nanocomposite material of the present invention comprises the following steps:

1) Preparation of nano-silver microemulsion: Dissolve sodium hypophosphite in a small amount of water and add it to a microemulsion of sodium dodecylbenzenesulfonate with a mass percentage concentration of 0.5-3%. After adding a small amount of nitric acid, stir and disperse for 10 ~20min, heat the system to 30~50°C, add 0.5M/L silver nitrate solution at a rate of 15~20 drops/min for reduction reaction for 60~120min, and prepare microemulsion containing nano-silver; among them, sodium hypophosphite The molar ratio with silver nitrate is 1～1.5:2;

2) Preparation of cerium (Ⅲ) nitrate-doped polyaniline/silver nanocomposite: add aniline and cerium (Ⅲ) nitrate in succession to the sodium dodecylbenzenesulfonate microemulsion containing nano-silver obtained in step 1) , ultrasonically disperse for 5-15 minutes, and then under the condition of stirring, control the temperature at 0-5°C, add dropwise an aqueous solution of ammonium persulfate with a concentration of 1.5-2.5 g/mL at a rate of 15-20 drops/min to initiate a polymerization reaction , and reacted for 10-14 hours. After the reaction was completed, excess acetone was added to break the emulsion. After the product was washed repeatedly with ethanol and distilled water, it was dried at 60-70°C for 10-14 hours to obtain cerium (Ⅲ) doped polyaniline/ The silver nanocomposite material, wherein, the reaction molar ratio of aniline:silver nitrate:cerium (III) nitrate is 2.5-3.5:1:0.5-3, and the molar ratio of aniline and ammonium persulfate is 1:1.

Beneficial effects of the present invention: the present invention adopts step-by-step in-situ composite technology for the first time to prepare nano-silver in microemulsion, and then generate polyaniline through the polymerization of aniline to conjugate and adsorb cerium (Ⅲ) and nano-silver on the polyaniline. On the aniline chain, the cerium nitrate (Ⅲ) doped polyaniline/silver nanocomposite material with good thermal stability, high conductivity and excellent electrochemical performance was prepared. The present invention firstly prepares nano-silver in the microemulsion of sodium dodecylbenzene sulfonate by reduction method, effectively prevents the agglomeration of generated nano-silver, and then directly adds polymerized monomer aniline and cerium (III) nitrate on this basis, After ultrasonic dispersion, aniline is polymerized, and cerium (III) nitrate and nano-silver are mainly adsorbed on the nitrogen atoms of the main chain of polyaniline through conjugated coordination, forming free electrons in nano-silver particles and cerium nitrate ions and polyaniline. The ternary organic combination of N atoms through conjugated coordination, that is, polyaniline/silver nanocomposites doped with cerium nitrate (Ⅲ), nano-silver and cerium nitrate (Ⅲ) uniformly dispersed in polyaniline constitutes a relatively A good conductive channel greatly increases the conductivity of the composite material, and it is found that the introduction of nano-silver and cerium nitrate (Ⅲ) in a certain proportion can greatly improve the thermal stability of the composite material; a large number of experimental studies have found that; when Aniline: nano-silver: cerium (III) nitrate in a molar ratio of 2.5-3.5:1:0.5-3 composite material not only exhibits excellent thermal stability and electrical conductivity, but also greatly improves corrosion resistance; especially when aniline : Silver nitrate: cerium nitrate (III) The composite material prepared with a molar ratio of 3:1:0.5～3 has excellent corrosion resistance, and the corrosion current density can be reduced to 0.81mA/cm ² , and its thermal stability is better than other doped and Composite polyaniline is significantly improved (as shown in Figure 4); and when the ratio of nano-silver and cerium (Ⅲ) is too high or too small, it will lead to poor composite effect with polyaniline, which will affect the thermal and chemical stability of the composite material. properties (such as Comparative Example 2); so the three components can only be obtained in strict accordance with the reasonable ratio of the present invention to obtain composite doped polyaniline with good thermal stability, high electrical conductivity, and excellent corrosion resistance. Composite material; in addition, the preparation method of the present invention has simple process, convenient operation, low cost and high yield, and can be industrialized.

Description of drawings

【Figure 1】The TEM image and XRD image of the prepared silver nanoparticles: Among them: the crystal plane indices (111), (200), (220) and (311) correspond to the standard PDF card of silver.

[Figure 2] is the XRD pattern of the cerium (III) nitrate-doped polyaniline/silver nanocomposite material prepared in Example 2.

[Figure 3] is the FT-IR image of cerium (Ⅲ) doped polyaniline/silver nanocomposite: a is aniline: silver molar ratio = 3:1, b is aniline: nano silver: cerium nitrate molar ratio = 3 :1:1.

[ FIG. 4 ] is an SEM image of the cerium (III) nitrate-doped polyaniline/silver nanocomposite prepared in Example 2.

[Figure 5] is the TG comparison chart of cerium (Ⅲ) doped polyaniline/silver nanocomposite material and polyaniline and polyaniline/silver material: a is polyaniline, b is polyaniline/silver (aniline: nano silver mole Ratio = 3:1), c is polyaniline/silver doped with cerium nitrate (aniline: nano silver: cerium nitrate molar ratio = 3:1:1).

Detailed ways

The following specific examples are intended to further illustrate the present invention, rather than limit the protection scope of the present invention.

Example 1

Nanocomposites prepared when the molar ratio of aniline: silver nitrate: cerium(Ⅲ) nitrate is 3:1:0.5

Dissolve 0.44g of sodium hypophosphite in 10mL of distilled water and add it to 100mL of 1% microemulsion of sodium dodecylbenzenesulfonate, then add 10mL of 0.5M/L nitric acid and stir for 15 minutes. Afterwards, the temperature of the reaction system was raised to 40° C., and 50 mL of silver nitrate solution containing 1.42 g was added dropwise, and the dropping rate was controlled at 15-20 drops/min. The reaction time is 90 minutes.

On the basis of the silver nanoparticle microemulsion, 2.50g of aniline and 1.80g of cerium nitrate (Ⅲ) were successively added, and ultrasonically dispersed for 10 minutes. Afterwards, under electric stirring conditions, 30 mL of an aqueous solution containing 5.71 g of ammonium persulfate was added dropwise to the reaction system to initiate aniline polymerization. The dropping rate is 15-20 drops/min, the reaction temperature is controlled at 0-5°C, and the reaction time is 12 hours. The reaction product is demulsified with excess acetone, washed three times with distilled water, ethanol and distilled water successively, and then dried at 60-70° C. for 12 hours to obtain a composite material. The electrical conductivity of the composite material was tested by the four-probe method, and the test results showed that the electrical conductivity of the composite material was 7.67S/cm. The polarization curve test results show that the corrosion current density of the composite material obtained in this example is lower than that of polyaniline/silver (1.49 mA/cm ² ), and can be reduced to 1.39 mA/cm ² .

Example 2

Nanocomposites prepared when the molar ratio of aniline: silver nitrate: cerium(Ⅲ) nitrate is 3:1:1

Dissolve 0.44g of sodium hypophosphite in 10mL of distilled water and add it to 100mL of 1% microemulsion of sodium dodecylbenzenesulfonate, then add 10mL of 0.5M/L nitric acid and stir for 15 minutes. Afterwards, the temperature of the reaction system was raised to 40° C., and 50 mL of silver nitrate solution containing 1.42 g was added dropwise, and the dropping rate was controlled at 15-20 drops/min. The reaction time is 90 minutes.

On the basis of the silver nanoparticle microemulsion, 2.50g of aniline and 3.60g of cerium (Ⅲ) nitrate were successively added, and ultrasonically dispersed for 10 minutes. Afterwards, under electric stirring conditions, 30 mL of an aqueous solution containing 5.71 g of ammonium persulfate was added dropwise to the reaction system to initiate aniline polymerization. The dropping rate is 15-20 drops/min, the reaction temperature is controlled at 0-5°C, and the reaction time is 12 hours. The reaction product is demulsified with excess acetone, washed three times with distilled water, ethanol and distilled water successively, and then dried at 60-70° C. for 12 hours to obtain a composite material. The electrical conductivity of the composite material was tested by the four-probe method, and the test results showed that the electrical conductivity of the composite material was 8.25S/cm. The polarization curve test results show that the corrosion current density of the composite material obtained in this example is lower than that of polyaniline/silver (1.49 mA/cm ² ), and can be reduced to 0.81 mA/cm ² .

It can be seen from the infrared image (Figure 3) that the NH stretching vibration peak moves from 3438cm ^-1 to 3502cm ^-1 , and the CN stretching vibration peak moves from 1113cm ^-1 to 1151cm ^-1 ; these two peaks can be attributed to the silver nanoparticles Conjugate polyaniline with cerium nitrate.

Example 3

Nanocomposites prepared when the molar ratio of aniline: silver nitrate: cerium(Ⅲ) nitrate is 3:1:3

Dissolve 0.44g of sodium hypophosphite in 10mL of distilled water and add it to 100mL of 1% microemulsion of sodium dodecylbenzenesulfonate, then add 10mL of 0.5M/L nitric acid and stir for 15 minutes. Afterwards, the temperature of the reaction system was raised to 40° C., and 50 mL of silver nitrate solution containing 1.42 g was added dropwise, and the dropping rate was controlled at 15-20 drops/min. The reaction time is 90 minutes.

On the basis of the silver nanoparticle microemulsion, 2.50g of aniline and 10.80g of cerium nitrate (Ⅲ) were successively added, and ultrasonically dispersed for 10 minutes. Afterwards, under electric stirring conditions, 30 mL of an aqueous solution containing 5.71 g of ammonium persulfate was added dropwise to the reaction system to initiate aniline polymerization. The dropping rate is 15-20 drops/min, the reaction temperature is controlled at 0-5°C, and the reaction time is 12 hours. The reaction product is demulsified with excess acetone, washed three times with distilled water, ethanol and distilled water successively, and then dried at 60-70° C. for 12 hours to obtain a composite material. The electrical conductivity of the composite material was tested by the four-probe method, and the test results showed that the electrical conductivity of the composite material was 9.05S/cm. The polarization curve test results show that the corrosion current density of the composite material obtained in this example is lower than that of polyaniline/silver (1.49 mA/cm ² ), and can be reduced to 0.86 mA/cm ² .

Comparative Example 1

Binary composites prepared when the molar ratio of aniline:silver nitrate is 3:1

Dissolve 0.44g of sodium hypophosphite in 10mL of distilled water and add it to 100mL of 1% microemulsion of sodium dodecylbenzenesulfonate, then add 10mL of 0.5M/L nitric acid and stir for 15 minutes. Afterwards, the temperature of the reaction system was raised to 40° C., and 50 mL of silver nitrate solution containing 1.42 g was added dropwise, and the dropping rate was controlled at 15-20 drops/min. The reaction time is 90 minutes.

On the basis of the silver nanoparticle microemulsion, 2.50 g of aniline was added. After ultrasonic dispersion for 10 minutes, 30 mL of an aqueous solution containing 5.71 g of ammonium persulfate was added dropwise to the reaction system under electric stirring to initiate aniline polymerization. The dropping rate is 15-20 drops/min, the reaction temperature is controlled at 0-5°C, and the reaction time is 12 hours. The reaction product is demulsified with excess acetone, washed three times with distilled water, ethanol and distilled water successively, and then dried at 60-70° C. for 12 hours to obtain a composite material. The electrical conductivity of the composite material was tested by the four-probe method, and the test results showed that the electrical conductivity of the composite material was 5.26S/cm. The polarization curve test results show that the corrosion current density of the composite material obtained in this embodiment is (1.49 mA/cm ² ).

Comparative Example 2

Nanocomposites prepared when the molar ratio of aniline: silver nitrate: cerium(Ⅲ) nitrate is 3:1:9

Dissolve 0.44g of sodium hypophosphite in 10mL of distilled water and add it to 100mL of 1% microemulsion of sodium dodecylbenzenesulfonate, then add 10mL of 0.5M/L nitric acid and stir for 15 minutes. Afterwards, the temperature of the reaction system was raised to 40° C., and 50 mL of silver nitrate solution containing 1.42 g was added dropwise, and the dropping rate was controlled at 15-20 drops/min. The reaction time is 90 minutes.

On the basis of the silver nanoparticle microemulsion, 2.50g of aniline and 32.40g of cerium nitrate (Ⅲ) were successively added, and ultrasonically dispersed for 10 minutes. Afterwards, under electric stirring conditions, 30 mL of an aqueous solution containing 5.71 g of ammonium persulfate was added dropwise to the reaction system to initiate aniline polymerization. The dropping rate is 15-20 drops/min, the reaction temperature is controlled at 0-5°C, and the reaction time is 12 hours. The reaction product is demulsified with excess acetone, washed three times with distilled water, ethanol and distilled water successively, and then dried at 60-70° C. for 12 hours to obtain a composite material. The electrical conductivity of the composite material was tested by the four-probe method, and the test results showed that the electrical conductivity of the composite material was 4.61S/cm. The polarization curve test results show that the corrosion current density of the composite material obtained in this example is lower than that of polyaniline/silver (1.49 mA/cm ² ), and can be reduced to 0.92 mA/cm ² .

Claims (10)

1. cerous nitrate (III) doped polyaniline/argentum nano composite material, is characterized in that, the ternary organic combination consisted of on polyaniline chain conjugation Coordination Adsorption cerous nitrate (III) and nanometer silver; Described ternary organic combination is dispersed in the Sodium dodecylbenzene sulfonate microemulsion containing nanometer silver by aniline and cerous nitrate (III), generates polyaniline cerous nitrate (III) and nanometer silver compound are obtained by the polymerization of aniline; Wherein, the mol ratio of aniline, nanometer silver and cerous nitrate (III) is 2.5 ~ 3.5:1:0.5 ~ 3.

2. cerous nitrate (III) doped polyaniline/argentum nano composite material as claimed in claim 1, is characterized in that, described aniline: nanometer silver: the mol ratio of cerous nitrate (III) is 3:1:0.5 ~ 3.

3. cerous nitrate (III) doped polyaniline/argentum nano composite material as claimed in claim 1 or 2, it is characterized in that, the described Sodium dodecylbenzene sulfonate microemulsion containing nanometer silver adds Silver Nitrate in containing the Sodium dodecylbenzene sulfonate microemulsion of sodium hypophosphite to carry out reduction reaction and obtain.

4. the preparation method of cerous nitrate (III) doped polyaniline/argentum nano composite material, it is characterized in that, silver nitrate solution is added drop-wise in the Sodium dodecylbenzene sulfonate microemulsion containing sodium hypophosphite with the speed of 15 ~ 20/min, raw reduction reaction is issued, the obtained microemulsion containing nanometer silver at 30 ~ 50 DEG C; Contain to gained after adding aniline and cerous nitrate (III) in the microemulsion of nanometer silver, ultrasonic disperse, then drip initiator with the speed of 15 ~ 20/min under agitation, polyreaction at 0 ~ 5 DEG C; After polyreaction completes, breakdown of emulsion, washing, after drying, to obtain final product; Wherein, aniline: Silver Nitrate: the mol ratio of cerous nitrate (III) is 2.5 ~ 3.5:1:0.5 ~ 3.

5. preparation method as claimed in claim 4, is characterized in that, described aniline: Silver Nitrate: the mol ratio of cerous nitrate (III) is 3:1:0.5 ~ 3.

6. preparation method as claimed in claim 4, it is characterized in that, described sodium hypophosphite and the mol ratio of Silver Nitrate are 1 ~ 1.5:2.

7. preparation method as claimed in claim 4, it is characterized in that, in described Sodium dodecylbenzene sulfonate microemulsion, the mass percentage concentration of Sodium dodecylbenzene sulfonate is 0.5 ~ 3%.

8. preparation method as claimed in claim 4, is characterized in that, the aqueous solution of described initiator to be concentration the be ammonium persulphate of 1.5 ~ 2.5g/mL.

9. the preparation method as described in any one of claim 4 ~ 8, is characterized in that, the described reduction reaction time is 60 ~ 120min.

10. the preparation method as described in any one of claim 4 ~ 8, is characterized in that, described polymerization reaction time is 10 ~ 14h.