CN102936339A - Polypyrrole/ferrite/multi-wall carbon nanotube composite material preparation method - Google Patents

Abstract

The present invention relates to a polypyrrole/ferrite/multi-wall carbon nanotube composite material preparation method, which comprises adopting a sol-gel method to prepare a BaFe12O19-Ni0.8Zn0.2Fe2O4 material, and then adopting an in situ polymerization method to prepare the polypyrrole/ferrite/multi-wall carbon nanotube composite material. According to the prepared polypyrrole/BaFe12O19-Ni0.8Zn0.2Fe2O4/multi-wall carbon nanotube composite material, polypyrrole, a carrier multi-wall carbon nanotube with characteristics of large specific surface area, good electrical conductivity, good dispersion and stable performance, and a hard magnetic and soft magnetic composite material BaFe12O19-Ni0.8Zn0.2Fe2O are compounded to increase a wave absorption performance of the material, wherein the polypyrrole adopted as the wave absorption material has advantages of low specific gravity, good compatibility and good electrical conductivity; and a chemical oxidation method is adopted to carry out polypyrrole in situ polymerization on the surface of the different amounts of the BaFe12O19-Ni0.8Zn0.2Fe2O4/multi-wall carbon nanotubes so as to achieve adjustable electromagnetic parameters, such that important significances are provided for widening of composite material microwave absorption frequency bands and preparation of novel wave absorption materials.

Description

The preparation method of a kind of polypyrrole/ferrite/multi-wall carbon nano-tube composite material

Technical field

The invention belongs to the preparation method of ferrite composite wave-suction material, be specifically related to the preparation method of a kind of polypyrrole/ferrite/multi-wall carbon nano-tube composite material, be specially a kind of ferrite, conduction high polymer, carbon nano tube compound material---polypyrrole/BaFe ₁₂O _19-Ni _0.8Zn _0.2Fe ₂O ₄The preparation method of/multi-wall carbon nano-tube composite material.

Background technology

Microwave absorbing material has wide application background at commercial and military aspect.Development structure is stable, bandwidth, specific absorption are high, low density novel wave-absorbing material is the nowadays key point in electromagnetic absorption field.Normally used microwave absorbing material comprises ferrite, conduction high polymer, carbon nanomaterial etc.Ferrite such as Z 250, barium ferrite, although nickel-zinc ferrite etc. have higher saturation magnetization and magnetic loss, its density is large, dielectric loss is low, has greatly limited being widely used of it.Conduction high polymer such as polyaniline, polypyrrole, polyphenylacetylene etc. since being found, just because the structure of their uniquenesses, good electroconductibility, potential functionalization prospect and receiving much concern.Such as carbon nanotube and Graphene, high specific surface area is arranged in the carbon nanomaterial, special electronic conduction mode, satisfactory stability are the ideal choses of solid support material.Conduction high polymer and carbon nanomaterial are mainly the electrical loss material when being used for microwave absorbing, if can form electricity, magnetic loss shaped material with the magnetic particle compound, and obtain stable, efficient absorbing property.Document " " Applied surface science ", 259 (2012) pp.486-493 " has openly adopted situ aggregation method to synthesize PPy-BaFe ₁₂O ₁₉/ Ni _0.8Zn _0.2Fe ₂O ₄Nano composite material.By the analysis of vector network instrument, it is inhaled ripple and is lost in the I of 10.7GHz and reaches-21.5dB.

But, the PPy-BaFe for preparing in the document ₁₂O ₁₉/ Ni _0.8Zn _0.2Fe ₂O ₄Has following deficiency: inhale ripple loss less (being that absorbing property is not good enough) at 8.2-12.4GHz, this is because the specific conductivity of matrix material is lower, electrical loss is less, and by adding 5% carbon nanotube, its suction ripple is lost in 8.9GHz and can reaches-25.46dB, has improved preferably its absorbing property.This is because the adding of carbon nanotube can increase the specific conductivity of matrix material, can form polaron when the main chain oxidation, and the position of polaron in molecule can displacement under the effect of electromagnetic field, thereby forms conductive current.Because the vibration of electromagnetic field forms eddy current at the conductive network of composite inner, electric energy conversion is that heat energy loses, thereby has increased electrical loss, has improved absorbing property.

Summary of the invention

The technical problem that solves

For fear of the deficiencies in the prior art part, the present invention proposes the preparation method of a kind of polypyrrole/ferrite/multi-wall carbon nano-tube composite material, at first adopts sol-gel method to prepare BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Material adopts situ aggregation method to prepare polypyrrole/BaFe then ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material.

Technical scheme

The preparation method of a kind of polypyrrole/ferrite/multi-wall carbon nano-tube composite material is characterized in that step is as follows:

Step 1 adopts sol-gel method to prepare BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder: be the citric acid of 217:76:4:1:6 with mol ratio, iron nitrate, nickelous nitrate, zinc nitrate and nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs; Then the ethylene glycol that with mol ratio is 2 times of citric acids joins in the solution, and regulates pH to 7 with quadrol; Under the magnetic agitation, gained solution is heated to 75-80 ℃, transpiring moisture is to gel formation; With gel dry 12-36h in 120-140 ℃ baking oven at first, be transferred to then that calcining obtains BaFe in the retort furnace ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder;

Step 2 pair multi-walled carbon nano-tubes is processed: multi-walled carbon nano-tubes at 550-650 ℃ of tubular type kiln roasting 2-2.5h, then is transferred in the mixed solution of sulfuric acid and nitric acid and reacts 4-5h; By centrifugal or filter to isolate multi-walled carbon nano-tubes after, with deionized water wash; At the dry 12-36h of 50-60 ℃ vacuum drying oven, obtain carboxylated multi-walled carbon nano-tubes at last, the sulfuric acid of described mixed solution and the volume ratio of nitric acid are 3:1;

Step 3 original position is synthesized polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material: be pyrrole monomer, the BaFe of 2:1:0.05-3 with mass ratio ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the deionized water with multi-walled carbon nano-tubes, after ultra-sonic dispersion is complete, add FeCl ₃6H ₂The aqueous solution of O carries out oxypolymerization; Be transferred to 50-60 ℃ the dry 12-36h of vacuum drying oven behind the precipitation repetitive scrubbing that the gained mixed solution obtains after filtration, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material; FeCl in the aqueous solution of described FeCl36H2O ₃6H ₂O and pyrroles's mol ratio is 2.33:1.

Beneficial effect

The preparation method of a kind of polypyrrole/ferrite that the present invention proposes/multi-wall carbon nano-tube composite material, the polypyrrole/BaFe of preparation ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material is with polypyrrole and the carrier multi-walled carbon nano-tubes with bigger serface, satisfactory electrical conductivity and dispersiveness and stable performance and hard, soft-magnetic composite material BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O is compound, to improve the absorbing property of material.Polypyrrole has the advantage of little, compatible good, the good conductivity of proportion as absorbing material.Adopt chemical oxidization method, at the BaFe of difference amount ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes in situ Polymerization polypyrrole realizes that electromagnetic parameter is adjustable, for widen the Composite Microwave absorption band, the preparation novel wave-absorbing material significant.

The invention has the beneficial effects as follows: adopt situ aggregation method to prepare polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes composite wave-suction material.But the polypyrrole well loaded is in multi-walled carbon nano-tubes and BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄The surface participates in microwave absorbing; Polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes composite wave-suction material has good absorbing property.

Description of drawings

Fig. 1 is polypyrrole/BaFe among the embodiment 2 ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes XRD figure;

Polypyrrole/BaFe among Fig. 2 embodiment 2 ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes TEM figure

Polypyrrole/BaFe among Fig. 3 embodiment 2 ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes reflection loss curve.

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

Embodiment 1:

(1) BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Preparation:

(a) with mol ratio be the citric acid of 217:76:4:1:6, iron nitrate, nickelous nitrate, zinc nitrate, nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs;

(b) be that the ethylene glycol of 2 times of citric acids joins in the solution with mol ratio, then regulate pH to 7 with quadrol;

(c) under the magnetic agitation, gained solution is heated to 75 ℃, transpiring moisture is to gel formation;

(d) with gel dry 24h in 120 ℃ baking oven at first, then be transferred to 400 ℃ retort furnace presintering 3h, at 1100 ℃ of lower calcining 2h, obtain BaFe at last ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder.

(2) multi-walled carbon nano-tubes is processed:

(a) with multi-walled carbon nano-tubes at first at 600 ℃ tubular type kiln roasting 2h;

(b) being transferred to sulfuric acid and nitric acid volume ratio is in the mixed solution of 3:1, and 60 ℃ are stirred 4h;

(c) centrifugation goes out precipitation, and is extremely neutral with deionized water wash;

(d) put that dry 24h. obtains carboxylated multi-walled carbon nano-tubes to 60 ℃ the baking oven.

(3) in-situ polymerization polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material:

(a) BaFe of 1g ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the 200ml deionized water ultra-sonic dispersion 1h with 2% multi-walled carbon nano-tubes;

(b) under 0 ℃, add the 2ml pyrrole monomer, ultrasonic 1h is uniformly dispersed;

(c) dropwise adding contains 18.2g FeCl ₃6H ₂O (FeCl ₃6H ₂O and pyrroles's mol ratio is 2.33:1) 100ml aqueous solution chlorination polymerization 12h, with the gained sedimentation and filtration, with behind deionized water and the ethanol repetitive scrubbing in 60 ℃ of vacuum drying ovens dry 24h, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube pipe powder.

Product among the embodiment 1 is mixed take mass ratio as 2:5 with paraffin, be pressed into the rectangle of 22.86mm * 10.16mm with mould, adopt vector network analyzer at its electromagnetic parameter of 8.2GHz-12.4GHz scope build-in test: magnetic permeability real part (μ '), magnetic permeability imaginary part (μ "), real part of permittivity (ε '), imaginary part of dielectric constant (ε ").By complex permeability μ _r=μ '-j μ ", complex permittivity ε _r=ε '-j ε ", and formula $Z_{\mathrm{in}}=\sqrt{\frac{{\mathrm{\μ}}_r}{{\mathrm{\ϵ}}_r}}\tanh \left(j\frac{2\mathrm{\πfd}}{c}\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}\right),$

Finally simulate the reflectivity R (dB) of sample.Record product at the reflection loss of 8.8-10.3GHz less than-10dB, be up under the 9GHz-20.6dB.

Embodiment 2:

(1) BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Preparation:

(a) with mol ratio be the citric acid of 217:76:4:1:6, iron nitrate, nickelous nitrate, zinc nitrate, nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs;

(b) be that the ethylene glycol of 2 times of citric acids joins in the solution with mol ratio, then regulate pH to 7 with quadrol;

(c) under the magnetic agitation, gained solution is heated to 75 ℃, transpiring moisture is to gel formation;

(d) with gel dry 24h in 120 ℃ baking oven at first, then be transferred to 400 ℃ retort furnace presintering 3h, at 1100 ℃ of lower calcining 2h, obtain BaFe at last ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder.

(2) multi-walled carbon nano-tubes is processed:

(a) with multi-walled carbon nano-tubes at first at 600 ℃ tubular type kiln roasting 2h;

(b) being transferred to sulfuric acid and nitric acid volume ratio is in the mixed solution of 3:1, and 60 ℃ are stirred 4h;

(c) centrifugation goes out precipitation, and is extremely neutral with deionized water wash;

(d) put that dry 24h. obtains carboxylated multi-walled carbon nano-tubes to 60 ℃ the baking oven.

(3) in-situ polymerization polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material:

(a) BaFe of 1g ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the 200ml deionized water ultra-sonic dispersion 1h with 5% multi-walled carbon nano-tubes;

(b) under 0 ℃, add the 2ml pyrrole monomer, ultrasonic 1h is uniformly dispersed;

(c) dropwise adding contains 18.2g FeCl ₃6H ₂O (FeCl ₃6H ₂O and pyrroles's mol ratio is 2.33:1) 100ml aqueous solution chlorination polymerization 12h, with the gained sedimentation and filtration, with behind deionized water and the ethanol repetitive scrubbing in 60 ℃ of vacuum drying ovens dry 24h, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube pipe powder.

Product among the embodiment 2 is mixed take mass ratio as 2:5 with paraffin, be pressed into the rectangle of 22.86mm * 10.16mm with mould, adopt vector network analyzer at its electromagnetic parameter of 8.2GHz-12.4GHz scope build-in test: magnetic permeability real part (μ '), magnetic permeability imaginary part (μ "), real part of permittivity (ε '), imaginary part of dielectric constant (ε ").By complex permeability μ _r=μ '-j μ ", complex permittivity ε _r=ε '-j ε ", and formula $Z_{\mathrm{in}}=\sqrt{\frac{{\mathrm{\μ}}_r}{{\mathrm{\ϵ}}_r}}\tanh \left(j\frac{2\mathrm{\πfd}}{c}\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}\right),$

Finally simulate the reflectivity R (dB) of sample.Record product at the reflection loss of 8.5-10.3GHz less than-10dB, be up under the 8.9GHz-25.46dB.

Embodiment 3:

(1) BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Preparation:

(a) with mol ratio be the citric acid of 217:76:4:1:6, iron nitrate, nickelous nitrate, zinc nitrate, nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs;

(b) be that the ethylene glycol of 2 times of citric acids joins in the solution with mol ratio, then regulate pH to 7 with quadrol;

(c) under the magnetic agitation, gained solution is heated to 75 ℃, transpiring moisture is to gel formation;

(d) with gel dry 24h in 120 ℃ baking oven at first, then be transferred to 400 ℃ retort furnace presintering 3h, at 1100 ℃ of lower calcining 2h, obtain BaFe at last ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder.

(2) multi-walled carbon nano-tubes is processed:

(a) with multi-walled carbon nano-tubes at first at 600 ℃ tubular type kiln roasting 2h;

(b) being transferred to sulfuric acid and nitric acid volume ratio is in the mixed solution of 3:1, and 60 ℃ are stirred 4h;

(c) centrifugation goes out precipitation, and is extremely neutral with deionized water wash;

(d) put that dry 24h. obtains carboxylated multi-walled carbon nano-tubes to 60 ℃ the baking oven.

(3) in-situ polymerization polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material:

(a) BaFe of 1g ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the 200ml deionized water ultra-sonic dispersion 1h with 10% multi-walled carbon nano-tubes;

(b) under 0 ℃, add the 2ml pyrrole monomer, ultrasonic 1h is uniformly dispersed;

(c) dropwise adding contains 18.2g FeCl ₃6H ₂O (FeCl ₃6H ₂O and pyrroles's mol ratio is 2.33:1) 100ml aqueous solution chlorination polymerization 12h, with the gained sedimentation and filtration, with behind deionized water and the ethanol repetitive scrubbing in 60 ℃ of vacuum drying ovens dry 24h, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube pipe powder.

Product among the embodiment 3 is mixed take mass ratio as 2:5 with paraffin, be pressed into the rectangle of 22.86mm * 10.16mm with mould, adopt vector network analyzer at its electromagnetic parameter of 8.2GHz-12.4GHz scope build-in test: magnetic permeability real part (μ '), magnetic permeability imaginary part (μ "), real part of permittivity (ε '), imaginary part of dielectric constant (ε ").By complex permeability μ _r=μ '-j μ ", complex permittivity ε _r=ε '-j ε ", and formula $Z_{\mathrm{in}}=\sqrt{\frac{{\mathrm{\μ}}_r}{{\mathrm{\ϵ}}_r}}\tanh \left(j\frac{2\mathrm{\πfd}}{c}\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}\right),$

Finally simulate the reflectivity R (dB) of sample.Record product at the reflection loss of 10.7-11.3GHz less than-10dB, be up under the 10.8GHz-23.9dB.

Case study on implementation 4:

(1) BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Preparation:

(a) with mol ratio be the citric acid of 217:76:4:1:6, iron nitrate, nickelous nitrate, zinc nitrate, nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs;

(b) be that the ethylene glycol of 2 times of citric acids joins in the solution with mol ratio, then regulate pH to 7 with quadrol;

(c) under the magnetic agitation, gained solution is heated to 75 ℃, transpiring moisture is to gel formation;

(d) with gel dry 24h in 120 ℃ baking oven at first, then be transferred to 400 ℃ retort furnace presintering 3h, at 1100 ℃ of lower calcining 2h, obtain BaFe at last ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder.

(2) multi-walled carbon nano-tubes is processed:

(a) with multi-walled carbon nano-tubes at first at 600 ℃ tubular type kiln roasting 2h;

(b) being transferred to sulfuric acid and nitric acid volume ratio is in the mixed solution of 3:1, and 60 ℃ are stirred 4h;

(c) centrifugation goes out precipitation, and is extremely neutral with deionized water wash;

(d) put dry 24h to 60 ℃ the baking oven, obtain carboxylated multi-walled carbon nano-tubes.

(3) in-situ polymerization polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material:

(a) BaFe of 1g ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the 200ml deionized water ultra-sonic dispersion 1h with 20% multi-walled carbon nano-tubes;

(b) under 0 ℃, add the 2ml pyrrole monomer, ultrasonic 1h is uniformly dispersed;

(c) dropwise adding contains 18.2g FeCl ₃6H ₂O (FeCl ₃6H ₂O and pyrroles's mol ratio is 2.33:1) 100ml aqueous solution chlorination polymerization 12h, with the gained sedimentation and filtration, with behind deionized water and the ethanol repetitive scrubbing in 60 ℃ vacuum drying oven dry 24h, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube pipe powder.

Product among the embodiment 4 is mixed take mass ratio as 2:5 with paraffin, be pressed into the rectangle of 22.86mm * 10.16mm with mould, adopt vector network analyzer at its electromagnetic parameter of 8.2GHz-12.4GHz scope build-in test: magnetic permeability real part (μ '), magnetic permeability imaginary part (μ "), real part of permittivity (ε '), imaginary part of dielectric constant (ε ").By complex permeability μ _r=μ '-j μ ", complex permittivity ε _r=ε '-j ε ", and formula $Z_{\mathrm{in}}=\sqrt{\frac{{\mathrm{\μ}}_r}{{\mathrm{\ϵ}}_r}}\tanh \left(j\frac{2\mathrm{\πfd}}{c}\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}\right),$ Finally simulate the reflectivity R (dB) of sample.Record product at the reflection loss of 11.2-11.7GHz less than-10dB, be up under the 11.3GHz-22.5dB.

Case study on implementation 5:

(1) BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Preparation:

(a) with mol ratio be the citric acid of 217:76:4:1:6, iron nitrate, nickelous nitrate, zinc nitrate, nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs;

(b) be that the ethylene glycol of 2 times of citric acids joins in the solution with mol ratio, then regulate pH to 7 with quadrol;

(c) under the magnetic agitation, gained solution is heated to 75 ℃, transpiring moisture is to gel formation;

(d) with gel dry 24h in 120 ℃ baking oven at first, then be transferred to 400 ℃ retort furnace presintering 3h, at 1100 ℃ of lower calcining 2h, obtain BaFe at last ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder.

(2) multi-walled carbon nano-tubes is processed:

(a) with multi-walled carbon nano-tubes at first at 600 ℃ tubular type kiln roasting 2h;

(b) being transferred to sulfuric acid and nitric acid volume ratio is in the mixed solution of 3:1, and 60 ℃ are stirred 4h;

(c) centrifugation goes out precipitation, and is extremely neutral with deionized water wash;

(d) put dry 24h to 60 ℃ the baking oven, obtain carboxylated multi-walled carbon nano-tubes.

(3) in-situ polymerization polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material:

(a) BaFe of 1g ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the 200ml deionized water ultra-sonic dispersion 1h with 30% multi-walled carbon nano-tubes;

(b) under 0 ℃, add the 2ml pyrrole monomer, ultrasonic 1h is uniformly dispersed;

(c) dropwise adding contains 18.2g FeCl ₃6H ₂O (FeCl ₃6H ₂O and pyrroles's mol ratio is 2.33:1) 100ml aqueous solution chlorination polymerization 12h, with the gained sedimentation and filtration, with behind deionized water and the ethanol repetitive scrubbing in 60 ℃ vacuum drying oven dry 24h, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube pipe powder.

Product among the embodiment 5 is mixed take mass ratio as 2:5 with paraffin, be pressed into the rectangle of 22.86mm * 10.16mm with mould, adopt vector network analyzer at its electromagnetic parameter of 8.2GHz-12.4GHz scope build-in test: magnetic permeability real part (μ '), magnetic permeability imaginary part (μ "), real part of permittivity (ε '), imaginary part of dielectric constant (ε ").By complex permeability μ _r=μ '-j μ ", complex permittivity ε _r=ε '-j ε ", and formula $Z_{\mathrm{in}}=\sqrt{\frac{{\mathrm{\μ}}_r}{{\mathrm{\ϵ}}_r}}\tanh \left(j\frac{2\mathrm{\πfd}}{c}\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}\right),$

Finally simulate the reflectivity R (dB) of sample.Record product at the reflection loss of 11.2-11.7GHz less than-10dB, be up under the 11.3GHz-28dB.

By the test result of above embodiment as can be known, 5% multi-wall carbon nano-tube composite material has excellent absorbing property than other ratios., be up under the 8.9GHz-25.46dB less than-10dB at the reflection loss of 8.5-10.3GHz, illustrate polypyrrole //BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes can be used for the stealth material field.Fig. 1 is the XRD figure of embodiment 2, has clearly show the crystal face of each material among the figure.Fig. 2 is embodiment 2TEM figure, shows polypyrrole and BaFe among the figure ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄In-situ polymerization has formed polypyrrole/BaFe on the multi-wall carbon nano-tube tube-surface ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-walled carbon nano-tubes microwave absorbing system.

Claims (1)

1. the preparation method of polypyrrole/ferrite/multi-wall carbon nano-tube composite material is characterized in that step is as follows:

Step 1 adopts sol-gel method to prepare BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder: be the citric acid of 217:76:4:1:6 with mol ratio, iron nitrate, nickelous nitrate, zinc nitrate and nitrate of baryta are dissolved in the deionized water, and the room temperature lower magnetic force stirs; Then the ethylene glycol that with mol ratio is 2 times of citric acids joins in the solution, and regulates pH to 7 with quadrol; Under the magnetic agitation, gained solution is heated to 75-80 ℃, transpiring moisture is to gel formation; With gel dry 12-36h in 120-140 ℃ baking oven at first, be transferred to then that calcining obtains BaFe in the retort furnace ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Ferrite powder;

Step 2 pair multi-walled carbon nano-tubes is processed: multi-walled carbon nano-tubes at 550-650 ℃ of tubular type kiln roasting 2-2.5h, then is transferred in the mixed solution of sulfuric acid and nitric acid and reacts 4-5h; By centrifugal or filter to isolate multi-walled carbon nano-tubes after, with deionized water wash; At the dry 12-36h of 50-60 ℃ vacuum drying oven, obtain carboxylated multi-walled carbon nano-tubes at last, the sulfuric acid of described mixed solution and the volume ratio of nitric acid are 3:1;

Step 3 original position is synthesized polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material: be pyrrole monomer, the BaFe of 2:1:0.05-3 with mass ratio ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄Join in the deionized water with multi-walled carbon nano-tubes, after ultra-sonic dispersion is complete, add FeCl ₃6H ₂The aqueous solution of O carries out oxypolymerization; Be transferred to 50-60 ℃ the dry 12-36h of vacuum drying oven behind the precipitation repetitive scrubbing that the gained mixed solution obtains after filtration, obtain polypyrrole/BaFe ₁₂O ₁₉-Ni _0.8Zn _0.2Fe ₂O ₄/ multi-wall carbon nano-tube composite material; FeCl in the aqueous solution of described FeCl36H2O ₃6H ₂O and pyrroles's mol ratio is 2.33:1.

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