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study of attenuation of microwaves by ppy-doped pvc films.

by:Top-In     2020-07-28
Brief introduction in recent years, the research and development of sound wave absorbing materials has aroused considerable interest to eliminate or reduce the false radiation present in the environment caused by technological advances in the telecom field.
In order to allow all these various devices used in telecom to coexist without creating harmful emc interference, it is necessary to develop new emc shielding and absorption materials for high performance and large work bands.
Microwaves are waves in the frequency range from 300MHz to 300 GHz, corresponding to the wavelength range from l m to 1mm.
In this part of the spectrum, there are frequencies used for mobile phones, radar, TV sets, satellite communications, etc. 1].
The interaction of an electric field with a substance may produce several responses, and microwaves may be reflected, absorbed, and/or transmitted by matter.
Microwave-absorbing materials are designed to provide an electro-magnetic shielding and absorption with potential applications in commercial, civilian and many other electronic devices.
If the material is composed of a dielectric or magnetic or a mixture of these [s], the simulated electric radiation interaction on the material is different2].
The important properties of microwave absorbing materials are related to their complex dielectric constants ([[epsilon]. sup. *])
And magnetic flux ([[mu]. sup. *])[3].
According to the microwave absorption properties, the materials are divided into three categories, namely :(i)
Microwave-absorbing body or high dielectric loss material ,(ii)
Microwave by attenuation of very small transparent or low electrical loss materials and (iii)
Opaque or conductor reflecting microwave [4].
In addition, the dielectric properties of these materials are mainly affected by the operating temperature and microwave frequency used.
The penetration of radiation to the material and the attenuation of the surface electric field are also important parameters that determine the microwave absorption performance of the material [5-7].
Organic conductive polymers, also known as synthetic metals, belong to a class of materials that combine the chemical and mechanical properties of polymers with the electrical properties of metals and semiconductors [8,9].
In addition, conductive polymers have special properties compared to other materials, they not only reflect but also can selectively absorb [10].
These properties make them potential applications for microwave absorbing materials [1]3]. Polypyrrole (PPy)
It has received a lot of attention due to some properties of conductive polymer such as environmental stability, low cost, considerable conductivity and commercial availability;
However, the polymer lacks mechanical strength.
Here, poly (PPy)
In the current work, it has been selected as a conductive polymer.
On the other hand, with polymerization vinyl chlorine (PVC)
Materials with good weather resistance and mechanical strength are selected as insulating polymer matrix.
In this study, a free standing polyplatinum composite PVC film was prepared by a technique called Mixed oxidation polymerization [2]11].
Trying to study the attenuation of microwave (8. 2-12. 4 GHz)
PVC film by doping.
Depth of skin ([delta])
Strong penetration depth ([D. sub. p])
Absorption index (k)
Has been evaluated. The frequency-
The dependence of the above parameters with the concentration of py percentage in PVC film was studied.
PVC experimental materials (PVC)(
Average molecular weight 62,000g [mol. sup. -1])
Provided by Sigma
Aldrich is used as an insulation matrix.
The pyrrole monomer is used by Spectrochem India.
Four fluorine hydrocarbons purchased from high performance liquid chromatography are used as solvents, and no-water Iron Chloride purchased from Otto chemical is used as an antioxidant for pyrol monomer polymerization.
Sample preparation, Pure PVC and Poly yr in this work (PPy)
PVC film with different weight percentage concentration (
6, 11, 16, 14, 20%)
Polyplatinum was prepared at room temperature by a technology called Mixed oxidation polymerization [11].
The film was prepared by solution casting technology at room temperature (24[degrees]C).
The thickness of the film is measured by a thousand-meter gauge.
The average thickness of these films is within the range of 550 [micro]m.
Representation Technology X
Ray diffraction (XRD)
Research using Bruker AXSD8 X-
Ray diffraction.
X-ray spectrum was recorded in 2 [theta]range of 3-60[degrees]
The step size is 0. 02[degrees]
Step Time 64 SEC using Cu K [alpha]radiation ([lambda]= 1. 5406 A).
Film review of morphology using scanning electron microscopy (JEOL JSM6360)
Use an acceleration voltage of 25 kV.
Microwave measurements measured the dielectric properties of PVC and polyphosphorus-doped PVC Films in the frequency range of 8. 2-12.
4 GHz using a network analyzer (
Agilent Technology E8361C).
Sample size 2 cm x 2 cm placed in X-
Rectangular wave guide.
Complex dielectric constant ([[epsilon]. sup. *]= [epsilon]\' -i [epsilon]\")
Therefore, it is extracted from the amplitude and phase shift measurements of the scattering parameters [S. sub. 11]([omega])and[S. sub. 21]([omega])
Use the 85071 material measurement software.
The dielectric properties of the material largely control the behavior of the material under the action of radio frequency or microwave field [12].
Absorption induction magnetic energy is defined as the energy absorbed per unit volume and the decay distance or skin depth ([delta])
, Indicating the size of the magnetic energy inside the material.
A plane wave that periodically changes with frequency f and advances in the direction of X through space, presenting a complex propagation factor [? ? ]given as [13]: [? ? ]= j[omega][Square root][epsilon]. sup. *][[mu]. sup. *]]=[alpha]+ j[beta](1)where [alpha]
Is the attenuation factor and [beta]
Is the phase factor.
The attenuation factor and phase factor are related to the dielectric properties of the medium as follows [14]: [alpha]= 2[pi]/[lambda]o [Square root ()[epsilon]\'/2([Square root ()1 + [tan. sup. 2][delta]-1))])](2)[beta]= 2[pi]/[lambda]o [Square root ()[epsilon]\'/2([Square root ()1 + [tan. sup. 2][delta]-1))])](3)Where [[lambda]. sub. o]
= Free space wavelength [epsilon]
Real part of complex dielectric constant tan [delta]
= Loss tangent of AC conductivity [[sigma]. sub. ac]
Using Equation [evaluation][sigma]. sub. ac]= 2[pi]f [[epsilon]. sub. o][epsilon]\" (4)
The attenuation produced by the dielectric material is expressed as the attenuation distance or the skin depth ([delta])
And is defined as the decay of field strength (1/e)i. e.
37% of the original value.
What is given in mathematics is [1]: [delta]= 1/[alpha]= c/[omega][Square root ()2/[epsilon]\'([
1 square root [tan. sup. 2][delta]-1)])](5)where E-mail: vaishali. b. bhavsar@gmail.
Promoter of contract award: DST-FIST (Level-I)and DRS(SAP)Program. DOI 10. 1002/pen. 24388----------
Please note: some tables or numbers are omitted in this article.
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