scholarly journals Surfactant Incorporated Co Nanoparticles Polymer Composites with Uniform Dispersion and Double Percolation

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Tajamal Hussain ◽  
Mirza Nadeem Ahmad ◽  
Aneela Nawaz ◽  
Adnan Mujahid ◽  
Farrukh Bashir ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Polymer Matrix ◽  
Threshold Value ◽  
Filler Concentration ◽  
Physical Interaction ◽  
Uniform Dispersion ◽  
Uv Visible ◽  
Filler Particles ◽  
Lcr Meter ◽  
Co Nanoparticles

Series of Cobalt nanoparticles incorporated polymethylmethacrylate composites in the presence and absence of dodecyl-benzene-sulphonic acid (DBSA-CoNPs/PMMA and CoNPs/PMMA, resp.) were synthesized by solution mixing methodology. UV-visible and FTIR techniques were used to confirm the formation of nanocomposite. UV-visible spectra of the composites showed the incorporation of filler particles in the polymer matrix. On the other hand, FTIR spectra indicated the physical interaction between the two phases of the composite. Moreover, the electrical nature of the composites was studied by plotting graphs between electrical conductivity (measured using LCR meter at 100 kHz) and contents of the filler particles as introduced in the polymer matrix. An increase in electrical conductivity was first observed with increasing filler concentration up to the critical percolation threshold value (0.5% for DBSA-CoNPs/PMMA and 1% for CoNPs/PMMA), which then dropped upon further increments in the filler content. However, at higher concentrations, a second jump in the conductivity was observed in case of DBSA-CoNPs/PMMA composites.

scholarly journals Dielectrical properties of composites LDPE+CB

2010 ◽  
Vol 64 (3) ◽  
pp. 187-191
Author(s):  
Blanka Skipina ◽  
Dusko Dudic ◽  
Dusan Kostoski ◽  
Jablan Dojcilovic
Keyword(s):  
Electrical Conductivity ◽  
Polymer Composites ◽  
Conductive Polymer ◽  
Dissipation Factor ◽  
Filler Concentration ◽  
Electrical Insulator ◽  
Conductive Polymer Composites ◽  
Wide Range ◽  
Filler Particles ◽  
Dielectrical Properties

There is currently great interest in the technological properties of conductive polymer composites because their cost-performance balance. They have a wide range of industrial applications -in anti-static materials, self regulating heaters, current overload and overheating protection devices, and materials for electromagnetic radiation shielding. Measurements of the electrical properties of polymer composites are one of the most convenient and sensitive methods for studying polymer structure. A polymer composite differs substantially from a free polymer in a wide range of properties. The presence of filler affects both the electrical, as well as mechanical properties. One of the most important characteristics of conductive polymer composites is that their electrical conductivity increases nonlinearly with the increase of the concentration of filler particles. When the concentration of filler particles reaches a certain critical value, a drastic transition from an electrical insulator to a conductor is exhibited. This conductivity behavior resulting in a sudden insulator-conductor transition is ascribed to a percolation process, and the critical filler concentration at which the conductivity jump occurs is called ?percolation threshold?. In the past few years, a lot of studies have been carried out to analyze the percolation phenomenon and mechanisms of the conductive behavior in conductive polymer composites. It has been established that the electrical conductivity of conductive polymer composites uncommonly depends on the temperature. Some of such composites show a sharp increase and/or decrease in electrical conductivity at specific temperatures. The conductive temperature coefficient (CTC) of conductive polymer composites has been widely investigated. In these work we investigated how concentration of the CB affects the dielectrical properties of the composite LDPE+CB. The ac electrical conductivity, ?ac, for such composites was measured. The temperature and frequency dependence of the dissipation factor were analyzed. It was found that the ac conductivity and dissipation factor were highly affected by the concentration of the filler.

scholarly journals PLA/Graphene/MWCNT Composites with Improved Electrical and Thermal Properties Suitable for FDM 3D Printing Applications

2019 ◽  
Vol 9 (6) ◽  
pp. 1209 ◽  
Author(s):  
Evgeni Ivanov ◽  
Rumiana Kotsilkova ◽  
Hesheng Xia ◽  
Yinghong Chen ◽  
Ricardo Donato ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Thermal Properties ◽  
3D Printing ◽  
Filler Content ◽  
Hybrid Composites ◽  
Filler Concentration ◽  
Fused Deposition ◽  
Aspect Ratios ◽  
Uniform Dispersion

In this study, the structure, electrical and thermal properties of ten polymer compositions based on polylactic acid (PLA), low-cost industrial graphene nanoplates (GNP) and multi-walled carbon nanotubes (MWCNT) in mono-filler PLA/MWCNT and PLA/GNP systems with 0–6 wt.% filler content were investigated. Filler dispersion was further improved by combining these two carbon nanofillers with different geometric shapes and aspect ratios in hybrid bi-filler nanocomposites. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy exhibited uniform dispersion of nanoparticles in a polymer matrix. The obtained results have shown that for the mono-filler systems with MWCNT or GNP, the electrical conductivity increased with decades. Moreover, a small synergistic effect was observed in the GNP/MWCNT/PLA bi-filler hybrid composites when combining GNP and CNT at a ratio of 3% GNP/3% CNT and 1.5% GNP:4.5% CNT, showing higher electrical conductivity with respect to the systems incorporating individual CNTs and GNPs at the same overall filler concentration. This improvement was attributed to the interaction between CNTs and GNPs limiting GNP aggregation and bridging adjacent graphene platelets thus, forming a more efficient network. Thermal conductivity increases with higher filler content; this effect was more pronounced for the mono-filler composites based on PLA and GNP due to the ability of graphene to better transfer the heat. Morphological analysis carried out by electron microscopy (SEM, TEM) and Raman indicated that the nanocomposites present smaller and more homogeneous filler aggregates. The well-dispersed nanofillers also lead to a microstructure which is able to better enhance the electron and heat transfer and maximize the electrical and thermal properties. The obtained composites are suitable for the production of a multifunctional filament with improved electrical and thermal properties for different fused deposition modelling (FDM) 3D printing applications and also present a low production cost, which could potentially increase the competitiveness of this promising market niche.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

scholarly journals Experimental Investigation on Stability, Viscosity, and Electrical Conductivity of Water-Based Hybrid Nanofluid of MWCNT-Fe2O3

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 136
Author(s):  
Solomon O. Giwa ◽  
Mohsen Sharifpur ◽  
Mohammad H. Ahmadi ◽  
S. M. Sohel Murshed ◽  
Josua P. Meyer
Keyword(s):  
Electrical Conductivity ◽  
Visual Inspection ◽  
Volume Concentration ◽  
Working Fluid ◽  
Hybrid Nanofluid ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Hybrid Nanofluids ◽  
Uv Visible ◽  
The Stability

The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-Fe2O3 (20:80) nanofluids at temperatures and volume concentrations ranging from 15 °C to 55 °C and 0.1–1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV–visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-Fe2O3/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of Fe2O3/water, which was good for engineering applications as the pumping power would be reduced.

Percolation Theory Applied to Study the Effect of Shape and Size of the Filler Particles in Thermal Interface Materials

2000 ◽  
Author(s):  
Amit Devpura ◽  
Patrick E. Phelan ◽  
Ravi S. Prasher
Keyword(s):  
Percolation Theory ◽  
Flip Chip ◽  
Filler Concentration ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Chip Technology ◽  
The Matrix ◽  
Different Shapes ◽  
Filler Particles ◽  
Interface Materials

Abstract An important aspect in electronic packaging is the heat dissipation. Flip-chip technology is widely being used to increase the rate of heat transfer from the chip. A method to further enhance the thermal conductivity is by the use of a thermal interface material between the device and the heat sink attached to it in the flip-chip technology. Percolation theory holds a key to understanding the behavior of thermal interface materials. Percolation, used widely in electrical engineering, is a physical phenomenon in which the highly conducting particles distributed randomly in the matrix form at least one continuous chain connecting the opposite faces of the matrix. This phenomenon was simulated using the matrix method, to study the effect of different shapes and size of the filler particles. The different shapes considered were spherical, vertical or horizontal rods, and flakes in horizontal or vertical orientation. The effect of the size of these particles was also examined. The results indicate that the composites with particles having the largest side in the direction of heat flow will always have a better conductivity than the particles oriented normal to it. Also, from the results, we can choose the best filler size in the composite if we know the filler concentration we are aiming at.

Random Lasers Based on Organic-Inorganic Hybrids

2002 ◽  
Vol 726 ◽  
Author(s):  
E.P. Giannelis ◽  
A. Stasinopoulos ◽  
M. Psyllaki ◽  
G. Zacharakis ◽  
R. N. Das ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Light Trapping ◽  
Fluorescence Emission ◽  
Laser Action ◽  
Threshold Value ◽  
Flat Panel Displays ◽  
Inorganic Nanocomposites ◽  
Modified Zno Nanoparticles ◽  
Surface Modified ◽  
Strong Scattering

AbstractLaser action is demonstrated in organic/inorganic nanocomposites consisting of pristine and surface-modified ZnO nanoparticles dispersed in an optically inert polymer matrix. The semiconductor particles feature simultaneously gain behavior and strong scattering ability, whereas the polymer matrix provides better processability and mechanical robustness. When excited by a laser pulse of appropriately short duration (pico- to nanoseconds), the composites give off fluorescence emission, which is strongly amplified as a result of light trapping due to multiple scattering. This laser action is manifested as a dramatic increase in the emitted light intensity accompanied by a significant spectral and temporal narrowing above a threshold value of the pumping laser intensity. Applications may include brighter flat-panel displays, inexpensive lasers for communications, military countermeasures, and lasers for search and rescue operations.

scholarly journals Влияние концентрации примеси магния на электрические свойства кристаллов LiNbO-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (10) ◽  
pp. 1566
Author(s):  
А.В. Яценко ◽  
С.В. Евдокимов ◽  
В.Ф. Шульгин ◽  
М.Н. Палатников ◽  
Н.В. Сидоров ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Absorption Spectra ◽  
Impurity Content ◽  
Threshold Value ◽  
Ir Absorption ◽  
Temperature Range ◽  
Polar Direction ◽  
Ir Absorption Spectra ◽  
Mg Content

Using the results of studying the electrical conductivity in the temperature range of ~ 295-460 K and the IR absorption spectra of a series of LiNbO3: Mg crystals, it is shown that as the Mg content in the sample increases, the mobility of H+ ions sharply decreases when moving along the polar direction. This effect is most clearly manifested in the samples of LiNbO3: Mg crystals with a high (above threshold value) impurity content.

scholarly journals The effect of additives metal on the D.C conductivity of epoxy resin

2011 ◽  
Vol 8 (1) ◽  
pp. 168-174
Author(s):  
Baghdad Science Journal
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Epoxy Resin ◽  
Filler Content ◽  
Experimental Results ◽  
Filler Concentration ◽  
Effect Of Additives

The present studies are focused on the modification of the properties of epoxy resin with different additives namely aluminum, copper by preparing of composites systems with percentage (20%, 40% and 50%) of the above additives. The experimental results show that the D.C of conductivity on wt% filler content at ( 293-413 ) K electrical conductivity of all above composites increased with temperature for composites with filler contact and find the excellent electrical conductivity of copper and lie between (2.6*10-10 - 2.1*10-10)?.cm . The activation energy of the electrical conductivity is determined and found to decrease with increasing the filler concentration.

Synthesis and Electrical Conductivity of N-(3-(Trifluoromethyl)Benzylidine)Thiosemicarbazide towards Dyes Sensitized Solar Cell

2018 ◽  
Vol 382 ◽  
pp. 364-368
Author(s):  
Uwaisulqarni M. Osman ◽  
Azieda Syafika N. Farizal ◽  
Nurhayati Ishak ◽  
Mohd Hasmizam Razali ◽  
M.I.N. Isa
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Light Intensity ◽  
Indium Tin Oxide ◽  
Spectroscopic Technique ◽  
Ito Glass ◽  
Maximum Conductivity ◽  
Ft Ir ◽  
Uv Visible ◽  
Conductivity Of Thin Films

Organic compound containing thiosemicarbazide moiety has been successfully synthesized. The new synthesized dyes, N-(3-(Trifluoromethylbenzaldehyde)benzylidine thiosemi- carbazide (3-TFT) was characterized by spectroscopic technique namely, CHNS elemental analysis, Fourier Transform Infra-Red analysis (FT-IR), UV-Visible analysis (UV-Vis),1H and13C Nuclear Magnetic Resonance (NMR). The thin films of this dye have been prepared using a spin coating technique and deposited on indium tin oxide (ITO) glass substrate. The main highlight was an electrical conductivity of thin films which was measured using four point probing system in a range of light intensity, 25 Wm-2until 200Wm-2. The potential electrical conductivity of 3-TFT dye was found gradually increased until reached the maximum conductivity values of 0.1489 Scm-1at light intensity of 100 Wm-2in the most diluted concentration at 1x10-5M.

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