Dielectric analysis of polypropylene (PP) and polylactic acid (PLA) blends reinforced with halloysite nanotubes

2017 ◽  
Vol 31 (8) ◽  
pp. 1042-1053 ◽  
Author(s):  
Krishna Prasad Rajan ◽  
Ahmed Al-Ghamdi ◽  
Selvin P Thomas ◽  
Aravinthan Gopanna ◽  
Murthy Chavali
Keyword(s):  
Dielectric Properties ◽  
Polylactic Acid ◽  
Loss Factor ◽  
Halloysite Nanotubes ◽  
Dynamic Mechanical Properties ◽  
Dielectric Analysis ◽  
Melt Mixing ◽  
Microelectronic Devices ◽  
Base Matrix ◽  
Tan Δ

Polypropylene (PP) and polylactic acid were blended in the ratio 80:20 by weight and compatibilized with 3 wt% of maleic anhydride-grafted-PP. The compatibilized blend was chosen as the base matrix for reinforcement with halloysite nanotubes (HNTs). The nanotube content varied from 0 to 10 wt%. Blend and the nanocomposites were prepared by melt mixing technique. Dielectric analysis of the base matrix and the nanocomposites was carried out using interdigitated electrode sensor in a DEA 288 Epsilon-dielectric analyser. The dielectric properties of the composites were measured at temperatures from 30 to 120°C at various frequencies ranging from 1 Hz to 1 kHz. Permittivity values slightly decreased as the HNT content increased from 0 to 2 wt%. It increased at 4 wt% of HNT and again slightly decreased at 6 wt% of HNT, and with further increase in HNT (HNT 8 and HNT 10) led to increase in permittivity values. Loss factor values decreased slightly as the HNT content in the composites increased from 0 to 4 wt%; but with further increase in HNT, the loss factor showed a sharp increase. Loss tangent (tan δ) values decreased up to 4 wt% of HNT (HNT 4) and then increased up to 8 wt% (HNT 8) of HNT and then decreased slightly (for HNT 10). Analysing the different dielectric properties, consistent properties were shown by 6 wt% of HNT similar to static and dynamic mechanical properties. The analysis showed that the composites can be utilized in microelectronic devices or in microelectronic packaging applications.

Cu0.5K0.25Tl0.25Ba2Ca3Cu4O12-δ SUPERCONDUCTOR AND ITS DIELECTRIC PROPERTIES

2010 ◽  
Vol 24 (32) ◽  
pp. 3097-3107
Author(s):  
ADNAN YOUNIS ◽  
NAWAZISH ALI KHAN
Keyword(s):  
Dielectric Properties ◽  
Loss Factor ◽  
Dielectric Constants ◽  
Negative Capacitance ◽  
Test Frequency ◽  
Ceramic Superconductor ◽  
Thermal Agitation ◽  
Metal Electrodes ◽  
Low Frequencies ◽  
Tan Δ

Cu 0.5 K 0.25 Tl 0.25 Ba 2 Ca 3 Cu 4 O 12-δ superconductor samples were synthesized and their dielectric properties were measured between 80 K and 290 K by means of capacitance (C) and conductance (G) measurements with the test frequency (f) in the range of 10 KHz to 4 MHz. A negative capacitance (NC) occurrence was observed, which most likely arose from the superior Fermi level of ceramic superconductor samples than metal electrodes. Also the NC may be due to the space charge situated at the multiple insulator–superconductor interfaces (grain boundaries) in the materials. The negative dielectric constant (ε′) and loss factor ( tan δ) show strong dispersion at low frequencies. The lower thermal agitation at 80 K may boost the polarizability and hence the dielectric constants (ε′ and ε″).

Effect of thermal plasma heating on the dielectric properties of Al-Zr composites

2002 ◽  
Vol 216 (2) ◽  
pp. 127-132
Author(s):  
D R Sahu ◽  
B K Roul ◽  
S K Singh ◽  
R N P Chaudhury
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Thermal Plasma ◽  
Loss Factor ◽  
Gas Flow ◽  
Plasma Heating ◽  
Sintered Sample ◽  
Dielectric Measurement ◽  
Sintering Time ◽  
Tan Δ

A low-cost extended arc thermal plasma heating (EATPH) source has been used for the sintering of Al-Zr high-temperature ceramic oxides, and their dielectric properties have been studied. Pellets of Al-Zr composites were sintered using optimum sintering parameters such as sintering time, plasma power and plasmagen gas flow rate in an EATPH reactor. Samples of similar composites were also sintered using a conventional resistive heating furnace at 1500°C for 20 h, and their dielectric properties were studied and compared with the plasma sintered sample. Sintered pellets were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and dielectric measurement, carried out as a function of frequency and temperature. Highly dense sintered products were obtained by the plasma heating route within a very short sintering time compared with the conventional sintering schedule. Dielectric measurements (both dielectric constant and loss factor) showed a significant reduction in the dielectric constant, K, at room temperature under different test frequencies and also as a function of temperature. However, the change in dielectric loss factor, tan Δ, was not as pronounced as the change in K. The behaviour of the K and tan Δ curves changes drastically compared with the conventional sintered material. The reduction in K and the crossover behaviour of tan Δ in the plasma sintered specimen may be due to the action of non-reactive Ar plasmagen gas during plasma sintering, which favours mobile oxygen for the polarization network under the influence of frequency and temperature.

scholarly journals Combination of Self-Healing Butyl Rubber and Natural Rubber Composites for Improving the Stability

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 443
Author(s):  
Kunakorn Chumnum ◽  
Ekwipoo Kalkornsurapranee ◽  
Jobish Johns ◽  
Karnda Sengloyluan ◽  
Yeampon Nakaramontri
Keyword(s):  
Natural Rubber ◽  
Dynamic Mechanical Properties ◽  
Attenuated Total Reflection ◽  
Rubber Matrix ◽  
Self Healing ◽  
Mechanical And Electrical Properties ◽  
Natural Rubber Composites ◽  
Tan Δ ◽  
The Stability ◽  
Physical And Chemical

The self-healing composites were prepared from the combination of bromobutyl rubber (BIIR) and natural rubber (NR) blends filled with carbon nanotubes (CNT) and carbon black (CB). To reach the optimized self-healing propagation, the BIIR was modified with ionic liquid (IL) and butylimidazole (IM), and blended with NR using the ratios of 70:30 and 80:20 BIIR:NR. Physical and chemical modifications were confirmed from the mixing torque and attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR). It was found that the BIIR/NR-CNTCB with IL and IM effectively improved the cure properties with enhanced tensile properties relative to pure BIIR/NR blends. For the healed composites, BIIR/NR-CNTCB-IM exhibited superior mechanical and electrical properties due to the existing ionic linkages in rubber matrix. For the abrasion resistances, puncture stress and electrical recyclability were examined to know the possibility of inner liner applications and Taber abrasion with dynamic mechanical properties were elucidated for tire tread applications. Based on the obtained Tg and Tan δ values, the composites are proposed for tire applications in the future with a simplified preparation procedure.

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.

Effect of Sintering Temperature on Structure and Dielectric Properties of Lead Free K0.5Na0.5NbO3 Prepared via Hot Isostatic Pressing

2017 ◽  
Vol 888 ◽  
pp. 42-46 ◽  
Author(s):  
Fatin Khairah Bahanurdin ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Hot Isostatic Pressing ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Tangent Loss ◽  
Isostatic Pressing ◽  
Tan Δ

In this research, alkaline niobate known as K0.5Na0.5NbO3 (KNN) lead-free piezoelectric ceramic was synthesis by solid state reaction method which pressing at different sintering temperatures (1000 °C and 1080 °C) prepared via hot isostatic pressing (HIP)). The effect of sintering temperature on structure and dielectric properties was studied. The optimum sintering temperature (at 1080 °C for 30 minutes) using hot isostatic pressing (HIP) was successfully increase the density, enlarge the particle grain size in the range of 0.3 µm – 2.5 µm and improves the dielectric properties of K0.5Na0.5NbO3 ceramics. The larger grain size and higher density ceramics body will contribute the good dielectric properties. At room temperature, the excellent relative permittivity and tangent loss recorded at 1 MHz (ɛr = 5517.35 and tan δ = 0.954), respectively for KNN1080HIP sample. The KNN1080HIP sample is also exhibits highest relative density which is 4.485 g/cm3. The ɛr depends upon density and in this work, the density increase as the sintering temperature increase, which resulting the corresponding ɛr value also increases.

Effects of Various Types of Modified Nanoclay on The Physical, Mechanical, and Viscoelastic Characteristics of Lignocellulosic Filler-Reinforced PVC Composites

2021 ◽  
Author(s):  
Mohammad Dahmardeh Ghalehno ◽  
Behzad Kord ◽  
Laleh Adlnasab
Keyword(s):  
Wood Flour ◽  
Dynamic Mechanical Properties ◽  
Clay Nanoparticles ◽  
Plastic Composites ◽  
Different Types ◽  
Higher Temperature ◽  
Viscoelastic Characteristics ◽  
Tan Δ ◽  
Lignocellulosic Filler ◽  
Double Hydroxide

Abstract The objective of this research was to comprehensively compare the effects of two different types of nanoclay, namely layered double hydroxide (LDH) and halloysite nanotube (HNT) on the physical, mechanical, and dynamic mechanical properties of compression-molded composite panels fabricated from wood flour (WF) and polyvinyl chloride (PVC). To achieve the desired properties in the composites, the clay nanoparticles were modified with surfactant (mLDH and mHNT) before usage. The results showed that the composite specimens with mLDH exhibited higher tensile and flexural properties (strength and moduli) than with mHNT at low content. However, at high content, the composite specimens with mHNT presented greater hydrophobicity. The DMTA results indicated that the composite specimens with mLDH demonstrated better molecular restriction and larger storage modulus than with mHNT. Besides, the loss-tangent (tan δ) peak was shifted to a higher temperature for the samples including both mLDH and mHNT than without ones. Morphological observations showed that the nanoparticles were predominantly dispersed uniformly within the polymer matrix. Overall, it is found that the addition of 3 phc mLDH clay was the most effective in the composite formulation; it has significantly enhanced the properties of the wood-plastic composites.

Halloysite nanotubes (HNT) as reinforcement for compatibilized blends of polypropylene (PP) and polylactic acid (PLA)

2021 ◽  
Vol 28 (10) ◽  
Author(s):  
Krishna Prasad Rajan ◽  
Aravinthan Gopanna ◽  
Emad A. M. Abdelghani ◽  
Selvin P. Thomas
Keyword(s):  
Polylactic Acid ◽  
Halloysite Nanotubes ◽  
Compatibilized Blends

Determination of Relative Damping at Various Prestresses

1960 ◽  
Vol 33 (2) ◽  
pp. 282-301
Author(s):  
Th Kempermann ◽  
R. Clamroth
Keyword(s):  
Energy Loss ◽  
Phase Angle ◽  
Loss Factor ◽  
Short Review ◽  
The Other ◽  
Simple Function ◽  
History Of ◽  
Tan Δ ◽  
Special Case

Abstract After a short review of the history of the development of the concept of damping, the definitions—one in words, the other in the form of an equation—given in DIN 53513 are discussed, and their usefulness for measurements at various values of prestress is investigated. It is evident that the mathematical definition given in the Standard applies only in the special case when prestress and alternating stress are equal. For the complete range of prestress, the phase angle δ or some simple function of δ, such as the loss factor, tan δ, should be measured. If it is desired not to relinquish the percentage statement of the energy loss, then a new definition for the relative damping is proposed which is independent of the prestress, just as is tan δ. The dependence upon the prestress of the damping values under discussion is demonstrated in an experimental section, for various types of elastomers.

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