Synthesis of new copolymers based on 2,3,4,5,6-pentafluorostyrene, styrene, α-methylstyrene and 4-fluoro-α-methylstyrene

2019 ◽  
Vol 60 (12) ◽  
pp. 91-95
Author(s):  
Ignat S. Dolgin ◽  
◽  
Pyotr P. Purygin ◽  
Yury P. Zarubin ◽  
◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Elevated Temperatures ◽  
Methylene Chloride ◽  
Research Work ◽  
Molar Ratio ◽  
Methyl Styrene ◽  
Derivatives Of

At the first stages of the research work, a copolymer of styrene and α methyl styrene was synthesized by the method of radical emulsion polymerization in an inert atmosphere of argon. The initiator was ammonium persulfate. The molar ratio of the initial monomers of styrene and α-methylstyrene was 70 : 30, respectively. It was found that copolymers synthesized under special controlled conditions have good values of permittivity and dielectric loss tangent. It should be noted that the choice of emulsifier directly affects the values of these indicators. It was previously shown that the most optimal emulsifier is potassium stearate, using which the best values of the dielectric constant and dielectric loss tangent were achieved. At the second stage of the research work, a number of copolymers were synthesized containing 4-methoxystyrene, 4 methyl styrene and α-methyl styrene in their structure. It was experimentally confirmed that the synthesis procedure may be applicable for the preparation of copolymers based on derivatives of styrene and α-methylstyrene. The resulting series of copolymers is highly soluble in methylene chloride; films of each copolymer sample of different thicknesses were obtained by casting from a solution. For this series of copolymer films, the dielectric constant and dielectric loss tangent were determined. It was found that the best values of permittivity and dielectric loss tangent are possessed by a sample of copolymer 4-methoxystyrene and α-methylstyrene. At the latest stage of the study, copolymers of styrene and 2,3,4,5,6-pentafluorostyrene, α-methylstyrene and 4-fluoro-α-methylstyrene, 2,3,4,5,6-pentafluorostyrene and 4-fluoro-α-methylstyrene were synthesized. These fluorine-containing derivatives of styrene and α-methylstyrene easily enough enter into the reaction of radical emulsion copolymerization. The copolymer yields are 53-76%, calculated on the weight of the starting monomers. The structure of a number of newly synthesized copolymers was confirmed by IR spectroscopy. In the future, it is planned to define the values of dielectric constant and dielectric loss tangent for these copolymer samples. It is planned to study the thermomechanical properties of the samples, since fluorine-containing polymers are a promising material for operation at elevated temperatures.

scholarly journals Investigation of the dielectric properties of copolymers based on 2,3,4,5,6-pentafluorostyrene, styrene, 4-fluoro-α-methylstyrene and α-methylstyrene

2019 ◽  
Vol 60 (12) ◽  
pp. 87-90
Author(s):  
Ignat S. Dolgin ◽  
◽  
Pyotr P. Purygin ◽  
Yury P. Zarubin ◽  
◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Signal Generator ◽  
Frequency Signal ◽  
Current Frequency ◽  
Dielectric Characteristics ◽  
Methyl Styrene

Three new copolymers based on fluorine-containing derivatives of styrene and α-methylstyrene were obtained. According to the results of the previous stages of the study, copolymers based on styrene derivatives have improved dielectric properties compared to polystyrene and a copolymer of styrene and α-methyl styrene. The dielectric constant ε and dielectric loss tangent tanδ were measured for the initial and synthesized samples of styrene – α-methyl styrene copolymer at Samara Electromechanical Plant OJ-SC (Samara city, Russia). All measurements of dielectric characteristics were carried out at an alternating current frequency of 10 GHz on a pressed copolymer tablet with a diameter of 10 and a thickness of 3 mm. During the experiment, a measuring stand was used, consisting of a high-frequency signal generator G4-83, an electronically counting frequency meter Ch3-54 with a frequency converter YaZCh-43, a measuring amplifier U2-4; low-frequency signal generator G3-109; measuring unit FKDG 418151.002. The results obtained indicate high values of the dielectric constant. For samples of copolymers of α-methylstyrene – 4-fluoro-α-methylstyrene and styrene – 4-fluoro-α-methylstyrene, values of 4.63 and 4.21, respectively, were obtained. These dielectric permittivity values are superior not only to samples previously obtained during the experiment, but also to some other compounds that are widely used in industry. In particular, the dielectric constant of lavsan, which is used in the manufacture of capacitors, is 3.1-3.3. The improved dielectric constant values are probably related to the high-quality composition of the copolymer. Samples of the copolymer containing 4-fluoro-α-methylstyrene are significantly superior to the copolymer with 2,3,4,5,6-pentafluorostyrene for this characteristic. The values of the dielectric loss tangent are in the range from 8.74∙10−4 to 37.4∙10−4. Given the dielectric characteristics of the synthesized copolymers, we can conclude that there are good prospects for the use of fluorine-containing styrene copolymers. The obtained values of permittivity and dielectric loss tangent indicate a good possible competitiveness of new materials based on new copolymers. In the future, it is planned to study a number of other physicochemical properties of these materials in order to obtain the most complete spectrum of their characteristics.

scholarly journals Dielectric and electrical properties of Cr substituted Mg ferrites

2015 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
AKM Zakaria ◽  
Faizun Nesa ◽  
MA Saeed Khan ◽  
SM Yunus ◽  
NI Khan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Lattice Parameter ◽  
Activation Energies ◽  
X Ray Diffraction ◽  
Constant E ◽  
Cr Concentration ◽  
Academy Of Sciences

The spinel ferrites MgCrxFe2-xO4 (0.0 ? × ?1.0) were prepared through the solid state reaction using conventional ceramic method at 1300°C in air. The homogeneous phase of the ferrite samples was observed from the X-ray diffraction study. Lattice parameter of the samples was found to decrease with increasing Cr concentration in the system obeying Vegard’s law. The ac electrical resistivity, measured as a function of temperature, decreases with the increase of temperature indicating the semiconducting nature of all the samples. The activation energies were calculated and found to decrease with increasing Cr content. The lower activation energies are associated with higher electrical conductivity. With the increase of temperature, dielectric constant (e`) and dielectric loss tangent are observed to be increased; while with the increase of frequency, dielectric constant (e`) and dielectric loss tangent decrease for all the samples.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 1-12, 2015

scholarly journals Design of Polymer Blends Based on Chitosan:POZ with Improved Dielectric Constant for Application in Polymer Electrolytes and Flexible Electronics

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Shujahadeen B. Aziz ◽  
M. H. Hamsan ◽  
M. F. Z. Kadir ◽  
H. J. Woo
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Flexible Electronics ◽  
Elevated Temperatures ◽  
Electric Modulus ◽  
Polymer Materials ◽  
Blend Films ◽  
Optical Micrograph ◽  
Peak Broadening

There is a considerable demand for the development and application of polymer materials in the flexible electronic- and polymer-based electrolyte technologies. Chitosan (CS) and poly(2-ethyl-2-oxazoline) (POZ) materials were blended with different ratios to obtain CS:POZ blend films using a straightforward solution cast technique. The work was involved a range of characteristic techniques, such as impedance spectroscopy, X-ray diffraction (XRD), and optical microscopy. From the XRD spectra, an enhancement in the amorphous nature in CS:POZ blend films was revealed when compared to the pure state of CS. The enhancement was verified from the peak broadening in CS:POZ blend films in relative to the one in crystalline peaks of the CS polymer. The optical micrograph study was used to designate the amorphous and crystalline regions by assigning dark and brilliant phases, respectively. Upon increasing POZ concentration, the dielectric constant was found to increase up to ɛ′ = 6.48 (at 1 MHz) at 15 wt.% of POZ, and then a drop was observed beyond this amount. The relatively high dielectric constant and dielectric loss were found at elevated temperatures. The increase of POZ concentration up to 45 wt.% made the loss tangent to shift to the lower frequency side, which is related to increasing resistivity. The increases of dielectric constant and dielectric loss with temperature were attributed to the increase of polarisation. The loss tangent peaks were found to shift to the higher frequency side as temperature elevated. Obvious relaxation peaks were observed in the imaginary part of electric modulus, and no peaks were found in the dielectric loss spectra. The concentration dependent of M″ peaks was found to follow the same trend of loss tangent peaks versus POZ content. The relaxation process was studied in terms of electric modulus parameters.

scholarly journals Dielectric Behavior of Dysprosium Substituted Magnesium Ferrite

2018 ◽  
Vol 15 (1) ◽  
pp. 48-54
Author(s):  
Jeevan S. Ghodake
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Powder Diffraction ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Dielectric Behavior ◽  
Complex Dielectric Constant ◽  
Frequency Variation ◽  
Magnesium Ferrite ◽  
X Ray

Dysprosium substituted Magnesium ferrite weresuccessfully prepared by chemical combustion method. The as synthesized powder was presintered in air at 6000C for 1hr and finally sintered at 9500C for 1hr. From X-ray powder diffraction pattern of MgDy0.03Fe1.97O4, confirmed formation of single phase cubic spinel structure. The value of crystallite size obtained from X-ray powder diffraction (311) peak , it is found to be 46.38nm.The frequency and temperature variation of dielectric parameters such as real dielectric constant (ε′), complex dielectric constant (ε") and dielectric loss tangent (tanδ) were determined using Hioki LCR - Q meter. The frequency variation of dielectric constant shows a normal dielectric behavior of spinel ferrites. The dielectric loss tangent with frequency shows similar behavior as dielectric constant. The dielectric constant and dielectric loss tangent increases with increase in temperature

Studies on Metal Oxide Nanoparticle Doped PVP Polymer Nanocomposites

2021 ◽  
pp. 1153-1169
Author(s):  
Madhu B. J.
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Ac Conductivity ◽  
Stoichiometric Composition ◽  
Magnesium Nitrate ◽  
Solution Combustion ◽  
Mgo Nanoparticles ◽  
Metal Oxide Nanoparticle

Magnesium Oxide (MgO) nanoparticles have been synthesized by solution combustion technique using stoichiometric composition of magnesium nitrate as oxidizer and urea as fuel. Structure of the MgO was studied with the X-ray diffraction (XRD) using Cu-Kα radiation. MgO/polyvinylpyrrolidone (PVP) nanocomposites have been prepared by blending MgO nanoparticles with the polyvinylpyrrolidone. MgO/PVP nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy. Frequency dependence of dielectric constant (ε′), dielectric loss tangent (tanδ) and AC conductivity studies have been undertaken on the MgO/PVP nanocomposites in the frequency range 50Hz-5MHz at room temperature. Dielectric properties such as dielectric constant (ε′) and dielectric loss tangent (tanδ) are found to decrease with the increase in the frequency. Further, AC conductivity of MgO/PVP nanocomposites was found to increase with an increase in the frequency. Observed variation in the a. c. conductivity with the frequency has been understood on the basis of electron hopping model.

MEASUREMENT OF THE DIELECTRIC PROPERTIES OF LOW LOSS MATERIALS AT MILLIMETER WAVELENGTHS

1958 ◽  
Vol 36 (12) ◽  
pp. 1672-1677
Author(s):  
A. G. Mungall
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Brewster Angle ◽  
Angle Of Incidence ◽  
Low Loss ◽  
Millimeter Wavelengths ◽  
Space Technique

Measurement at millimeter wavelengths of the dielectric properties of low loss materials by a free space technique is described. The dielectric constant is determined from the Brewster angle, and the dielectric loss tangent from the attenuation coefficient measured at the Brewster angle of incidence. Results are given for bakelite at wavelengths between 5 and 10 mm. Details of the instrument, which was specifically designed for these measurements, are also given.

scholarly journals UGCPW Structure-Based Embedded Resonator with High Quality Factor for Microwave Substrate Characterization

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 113
Author(s):  
Longzhu Cai
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Quality Factor ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Effective Dielectric Constant ◽  
Dielectric Characterization ◽  
At Resonance ◽  
Resonator Method ◽  
Microwave Substrate

In this paper, an ungrounded coplanar waveguide-based embedded resonator method for microwave substrate characterization was presented. The effective dielectric constant of the structure and the dielectric constant of microwave substrates can be calculated by the measured resonant frequency. The measured insertion losses at resonant frequencies and the 3 dB bandwidth can be used to determine the loaded and unloaded quality factors, including the dielectric quality factor which is related to dielectric loss tangent. The radiation loss and the extra length due to fringing effect caused by the open-end structure were taken into account to improve the extraction accuracy. The experimental unloaded quality factor of the proposed resonator at resonance order 1 reaches 211.3. The extracted dielectric constant and dielectric loss tangent of Taconic TLY at resonance order 1 are, respectively, 2.218 and 9.286×10−4, which are only 0.018 (relatively 0.82%) and 0.286×10−4 (relatively 3.18%) deviations from the datasheet values, respectively. The proposed resonator method is especially suitable for dielectric characterization of newly developed materials with the difficulty of realizing metal via holes, in which case substrate-integrated-waveguide (SIW) resonator methods are not applicable. When comparing with microstrip resonator methods, the proposed method is of higher quality factor, and it is more reliable and economical as well.

scholarly journals CHARGE CARRIERS TRANSPORT AND PERMITTIVITY OF SIO2 FILMS WITH INSB NANOPARTICLES

2020 ◽  
Author(s):  
Pawel Zukowsk ◽  
Tomasz Koltunowicz ◽  
Karolina Czarnacka ◽  
Alexander Fedotov ◽  
Ida Tyschenko
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Phase Angle ◽  
Exponential Decay ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Charge Carriers ◽  
Complex Dielectric Constant ◽  
Sio2 Films ◽  
The Real

A.c. current conductivity, capacitance, phase angle and dielectric loss tangent were studied for MOS SOI structures with ion-synthesized in the buried SiO2 layer InSb nanoparticles. Films conductivity nature change was detected at the temperature Т=200К. An exponential decay of the real and imaginary parts of the films complex dielectric constant was found.

scholarly journals Study of dielectric properties of 4-methylstyrene and α-methylstyrene copolymer films with different molar ratio of initial monomers

2019 ◽  
Vol 58 (6) ◽  
pp. 55-58
Author(s):  
Ignat S. Dolgin ◽  
◽  
Pyotr P. Purygin ◽  
Yury P. Zarubin ◽  
◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Methylene Chloride ◽  
Molar Ratio ◽  
Loss Angle ◽  
Electrical Capacitance ◽  
Copolymer Films ◽  
Laboratory Conditions ◽  
Dielectric Loss Angle ◽  
Material Sample

Two new copolymers of 4-methylstyrene and α-methylstyrene were obtained by the emulsion polymerization method according to the previously described and tested method in the course of the experiment in laboratory conditions. The molar ratio of the starting monomers of 4-methylstyrene and α-methylstyrene was 9: 2 and 10: 1, respectively, in each material sample. The structure of the copolymers obtained was confirmed by IR and 1H NMR spectroscopy. Under laboratory conditions, three prototypes of each copolymer film were obtained from the solution. A sample of the copolymer was dissolved in methylene chloride was applied on a smooth glass substrate. After complete evaporation of the solvent, the film was separated from the substrate. The thickness of the films for each copolymer sample was 20, 30, and 50 microns. In the course of further experimentation, these samples were examined for the values of dielectric constant and tangent of dielectric loss angle. The basis of this experiment used a resonant method of measurement. The presented method is based on the variation of conductivity due to a change in the electrical capacitance of the oscillating circuit. In this experiment, the magnitude of the electrical capacitance and the tangent of the dielectric loss angle were measured. Based on the value of the capacitance and the parameters of the film sample to be measured, it is possible to calculate the dielectric constant. From the data obtained it can be seen that with increasing film thickness, dielectric constant values decrease. However, the indicators of the tangent of dielectric loss angle increase. With an increase in the measurement frequency, a slight decrease in the dielectric constant is observed, and the value of the tangent of the dielectric loss angle decreases nonlinearly. In addition, it should be noted that the samples of 4-methylstyrene-α-methylstyrene copolymer films with a molar ratio of starting monomers of 10: 1 have a higher dielectric constant, along with lower values of the dielectric loss tangent. From this it follows that samples with a lower proportion of α-methylstyrene in their structure have better dielectric characteristics compared with their counterparts with a high content of α-methylstyrene.

Physical and Electrical Properties of Cullet-Paper Ash-Kaolin Clay Ceramic

2016 ◽  
Vol 846 ◽  
pp. 102-106
Author(s):  
Khamisah Abu Samah ◽  
Muhammad Rahim Sahar ◽  
M. Yusop
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Solid State Reaction Method ◽  
Ceramic Particle ◽  
Kaolin Clay ◽  
Dipolar Polarizability ◽  
Ceramic Density ◽  
Cullet Content

A series of (x) paper ash- (80-x) cullet – 20 Kaolin clay where 10 ≤x≤30 weight % has successfully been prepared using solid state reaction method. The ceramic density and hardness has been determined using Archimedes and Vickers hardness method respectively. The dielectric constant and dielectric loss has been determined using impedance analyzer. The obtained density is descending from 2.18 gcm-3 to 1.90 gcm-3 and hardness is increased up to 871.8 Mpa. The decrement of density and hardness as the cullet content increases is due to the non uniform vitreous areas formed in between ceramic particle. The variation of the dielectric constant and dielectric loss tangent are found to decrease with increasing of frequency which suggest the dipolar polarizability properties. It is found that the maximum value of dielectric constant is 3000 and minimum dielectric loss tangent is 0.166.

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