scholarly journals An Experimental Study on the Dielectric Properties of Rubber Materials

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2908
Author(s):  
Hailong Chen ◽  
Yudong Xu ◽  
Mengqi Liu ◽  
Tao Li
Keyword(s):  
Experimental Study ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
Peak Frequency ◽  
Mixing Process ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Internal Mixing ◽  
Dielectric Constant And Loss

According to specific formulas, the mixing of rubber samples occurs by two methods: open mixing and internal mixing. The effects of frequency, mixing process, carbon black (CB) content, zinc oxide (ZnO) content, and stearic acid (SA) content on the dielectric properties of rubber materials were studied. The results showed that the effects of the mixing process on the dielectric properties of the rubber samples cannot be ignored, and the appropriate mixing process should be selected when preparing the required rubber materials. The dielectric constant and loss factor of the rubber samples vary depending on the frequency. The dielectric constant had a peak and valley value, while the loss factor only had a peak. The dielectric constant and loss factor of rubber samples were significantly affected by the content of CB, ZnO, and SA. The peak frequency decreased with the increase in CB content, however, the dielectric constant increased with an increase in CB content. The higher the ZnO content, the lower the peak frequency. In addition, the dielectric constant and loss factor increased with an increase in ZnO content. The higher the SA content, the greater the peak frequency. In addition, the dielectric constant and loss factor decreased with an increase in SA content. It is hoped that the experimental results obtained can provide guidance for the study of the dielectric properties, microwave absorption properties, and microwave heating characteristics of rubber polymers.

scholarly journals Microwave absorption properties of steelmaking dusts: effects of temperature on the dielectric constant (ε′) and loss factor (ε′′) at 1064 MHz and 2423 MHz

RSC Advances ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 6859-6870 ◽  
Author(s):  
Mamdouh Omran ◽  
Timo Fabritius ◽  
Guo Chen ◽  
Aoxi He
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Absorption ◽  
Loss Factor ◽  
Effect Of Temperature ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Effects Of Temperature

The effect of temperature on the dielectric properties was found to be minor at temperatures below 600 °C. Above this temperature, sharp rises in the values of both the dielectric constant and the loss factor were observed.

Dielectric Properties Measurements and Data

1990 ◽  
Vol 189 ◽  
Author(s):  
Joseph A. Carpenter
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
Intelligent Design ◽  
Elevated Temperatures ◽  
Measurement Techniques ◽  
Materials Processing ◽  
Microwave Range ◽  
Solid Materials ◽  
Dielectric Constant And Loss

ABSTRACTThis paper reviews measurement techniques and sources of data for the dielectric constant and loss factor of solid materials. Accurate values of such properties are basic to intelligent design of materials processing schemes utilizing electromagnetic energy. Emphasis is on techniques and data for these properties in the “microwave” range of frequencies of roughly 108 to 1011 Hz and at elevated temperatures.

Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Bulk Density ◽  
Water Activity ◽  
Free Space ◽  
Loss Factor ◽  
Dielectric Loss Factor ◽  
List Type

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.

Phase Development and Dielectric Properties of 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3 Ceramic

2011 ◽  
Vol 700 ◽  
pp. 58-62
Author(s):  
Rachanusorn Roongtao ◽  
Supagorn Rugmai ◽  
Wanwilai C. Vittayakorn
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Phase Development ◽  
Scanning Electron

The 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3ceramics has been synthesized through a conventional mixed-oxide by using BT nanopowder and BMN micropowder. The phase purity of the powders and the ceramics was examined using X-ray diffraction (XRD). The 0.98BT-0.02BMN powders were sintered to 92% of the theoretical density at a temperature of 1300 °C for 2 h. The microstructure of the sintered surface was investigated using scanning electron microscopy (SEM). The dielectric constant (εr) and loss factor (tanδ) of the sintered pellets at Curie temperture were 3000 and 0.015, respectively.

Broadband Dielectric Characterization of Aluminum Oxide (Al2O3)

2008 ◽  
Vol 5 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Khalid Z. Rajab ◽  
Mira Naftaly ◽  
Edmund H. Linfield ◽  
Juan C. Nino ◽  
Daniel Arenas ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Aluminum Oxide ◽  
Time Domain ◽  
Measurement Techniques ◽  
Thz Spectroscopy ◽  
Dielectric Characterization ◽  
Dielectric Constant And Loss ◽  
Ir Frequencies ◽  
Cofired Ceramics

Applications for low-temperature cofired ceramics (LTCC) and high-temperature cofired ceramics (HTCC) are advancing to higher frequencies. In order to design ceramic microsystems and electronic packages, the electrical properties of materials must be well characterized over a broad frequency range. In this study, the dielectric properties of commercial aluminum oxide (Al2O3) with different glass loadings are characterized using three different measurement techniques: the split-post cavity, terahertz (THz) time-domain spectroscopy, and Fourier transform IR spectroscopy (FTIR). Specifically, the dielectric properties will be characterized from 10 GHz to IR frequencies. A split-post cavity was employed for determination of dielectric properties in the 10 GHz range. A broadband THz spectroscopy technique was used to characterize the specimens using measured time-domain transmission data. The dielectric constant and loss were extracted from the sample's frequency-domain transmission characteristics, providing data between 100 GHz and 2 THz. Additionally, FTIR was used to characterize the samples from ~33 to 3300 cm−1 (~1–100 THz). The measurements from the three techniques are compared, and dielectric constant and loss data will be presented for commercial and experimental ceramic systems from 10 GHz to IR frequencies.

scholarly journals Dielectric Properties of Substrates for InkJet Technology in GHz Area

2019 ◽  
Vol 63 (1) ◽  
pp. 9-15
Author(s):  
Tibor Rovensky ◽  
Peter Lukacs ◽  
Alena Pietrikova
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Inkjet Printing ◽  
Measuring Method ◽  
Flexible Substrates ◽  
Network Analyzer ◽  
Dielectric Constant And Loss ◽  
Inkjet Printing Technology ◽  
Specific Material ◽  
Frequency Area

This paper is focused on investigation of dielectric properties of various substrates for InkJet printing technology. In addition this paper included investigation of dielectric properties' homogeneity. Dielectric constant and loss tangent of polymeric flexible substrates (Polyimide DuPont Kapton HN, PET Mylar A, PEN Teonex Q51) and insulation paper (Nomex 410) were measured in GHz frequency area. Measurements were done by combination of vector network analyzer and split cylinder resonator. This measuring method provides dielectric properties at frequency around 10 GHz, the exact value of frequency may vary depends on specific material and its resonant frequency. Experiments included two types of samples, 6 x 6 cm which is recommended area for measurements of dielectric properties by split cylinder resonator and 12 x 12 cm for measurements of dielectric properties' homogeneity (one sheet contains 9 overlapping measuring areas 6 x 6 cm). All measured values of dielectric constant and dielectric losses were statistically processed and depicted by SigmaPlot software. The paper shows values of dielectric properties at GHz frequency area as they are lacking in datasheets from manufacturers and evaluate homogeneity of measured substrates.

Synthesis and Characteristics of MgO Coated BST-Mg2TiO4 Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1180-1183
Author(s):  
Qian Qian Jia ◽  
Hui Ming Ji ◽  
Shan Liu ◽  
Xiao Lei Li ◽  
Zheng Guo Jin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Phase Shifters ◽  
Precipitation Method ◽  
Composite Ceramics ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Bst Ceramics

The (Ba, Sr)TiO3 (hereafter BST) ceramics are promising candidate for applying in tunable devices. MgO coated BST-Mg2TiO4 (BSTM-MT) composite ceramics were prepared to obtain the low dielectric constant, low dielectric loss, good dielectric constant temperature stability, and high tunability of BST ceramics. The Ba0.55Sr0.40Ca0.05TiO3 nanoparticles were coated with MgO using the precipitation method and then mixed with Mg2TiO4 powders to fabricate BSTM-MT composite ceramics. The morphologies, phases, elements, and dielectric properties of the sintered ceramics were investigated. The core-shell structure of BST powder wrapped with MgO was clearly observed from the TEM image. After sintered at 1100 °C for 2 h, the composite ceramics expressed dense microstructures from SEM images and two main phases BST and Mg2TiO4 were detected in the XRD patterns. The dielectric constant and loss tangent were both reduced after the coating. The reduced dielectric constant and loss tangent of BSTM-MT were 190, 0.0011 (2MHz), respectively. The ceramics exhibited the diffuse phase transition near the Curie temperature and the Curie temperature shifted from 10 °C to 5 °C after the coating. Since the continuous Ti-O bonds were disconnected with the MgO coating, the tunability was reduced to 15.14 % under a DC bias field of 1.1 kV/mm. The optimistic dielectric properties made it useful for the application of tunable capacitors and phase shifters.

Investigations on the Structural, Optical and Dielectric Properties of Ball-Milled ZnO–Fe2O3 Nanocomposites

2020 ◽  
Vol 19 (04) ◽  
pp. 1950034
Author(s):  
V. Balachandar ◽  
J. Brijitta ◽  
K. Viswanathan ◽  
R. Sampathkumar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Ball Milling ◽  
High Energy ◽  
X Ray Diffraction ◽  
Dielectric Constant And Loss ◽  
Energy Ball ◽  
Uv Visible ◽  
Ball Milling Technique ◽  
Xrd Patterns

In this study, ZnO–Fe2O3 nanocomposites were prepared by high-energy ball milling technique and characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV–visible spectroscopy and dielectric spectroscopy. The amount of Fe2O3 in the ZnO–Fe2O3 nanocomposites was varied at the rates of 1[Formula: see text]wt.%, 3[Formula: see text]wt.% and 5[Formula: see text]wt.% in order to investigate its influence on the structural, optical and dielectric properties of the nanocomposites. XRD patterns of nanocomposites revealed no shift in peak positions and hence confirmed the formation of composites after ball milling. Further, it was observed from FESEM analysis that Fe2O3 particles were distributed randomly on the ZnO matrix of the nanocomposites. ZnO–Fe2O3 nanocomposites reveal extended optical absorption in the range of 400–600[Formula: see text]nm from UV studies. The dielectric constant and loss of the nanocomposites decrease exponentially with increase in frequency. The composition and frequency dependences of the dielectric constant, dielectric loss and AC conductivity are explained based on the Maxwell–Wagner effect and Koop’s theory.

Study on the Properties of Microwave Curing Epoxy Resin/Nano-Fe Composite Materials

2010 ◽  
Vol 26-28 ◽  
pp. 356-359 ◽  
Author(s):  
Xiao Feng Sun ◽  
Shi Ning Ma ◽  
Jia Wu He ◽  
Nai Shu Zhu
Keyword(s):  
Composite Materials ◽  
Microwave Irradiation ◽  
Epoxy Resin ◽  
Loss Factor ◽  
Mechanical Analysis ◽  
Resin Matrix ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Microwave Curing ◽  
Scanning Electron

Nano-Fe particles were selected as microwave-absorber, and added in the epoxy resin. Epoxy resin/nano-Fe composite materials were cured by microwave irradiation and heating. Vector network analysis, dynamic mechanical analysis(DMA) and scanning electron microscope(SEM) were used to study the curing behaviors of composite materials under the different curing ways. Results show that the dielectric constant(εr) and the dielectric loss factor(tanδ) of the epoxy resin increased obviously when nano-Fe particles were added, and microwave absorption properties of epoxy resin/nano-Fe composite materials improved greatly with increasing contents of nano-Fe particles. DMA results indicate that the storage modulus (E’) and glass transition temperature(Tg) of epoxy resin samples with nano-Fe particles were higher than those without nano-Fe particles. The microstructure and phase composition of the samples were studied by SEM and EDX. Results show that nano-Fe particles were homogeneously dispersed in the epoxy resin matrix under microwave irradiation, which implies improved strength and toughness of epoxy resin/nano-Fe composite materials.

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