The Effect of Ultrasonic Treatment and Gamma Radiation on the Thermal Conductivity of TPNR Hybrid Nanocomposites

2012 ◽  
Vol 626 ◽  
pp. 29-33
Author(s):  
Mou’ad A. Tarawneh ◽  
Sahrim Haji Ahmad
Keyword(s):  
Thermal Conductivity ◽  
Gamma Radiation ◽  
Ultrasonic Treatment ◽  
Treatment Time ◽  
Laser Flash ◽  
Hybrid Nanocomposites ◽  
Hybrid Nanoparticles ◽  
Hybrid Nanocomposite ◽  
Preparation Conditions ◽  
Multi Walled Carbon Nanotubes

This paper discusses the effect of Gamma radiation and ultrasonic treatment time on hybrid nanofillers nanoclay and multi-walled carbon nanotubes (MWCNTs) as reinforcing agents to improve the thermal conductivity of TPNR. The laser flash technique was also employed to determine the thermal conductivity of the hybrid nanocomposite. The thermal conductivity of hybrid nanocomposites that were sintered at 30 to 150 °C did not show a monotonous change with MWCNTs as the filler has a high thermal conductivity compared to nanoclay by using different dose of gamma radiation or with different time of ultrasonic treatment. TEM results showed a combination of intercalated-exfoliated structure of OMMT and the dispersion of MWCNTs in the TPNR composite. The probability that hybrid nanoparticles form a network depends on the interaction between the particles, on their shape (aspect ration), preparation conditions and on their inter-particle distance will control the thermal conductivity of the hybrid nanocomposite.

Thermal Conductivity, Thermal Diffusivity and Specific Heat of TPNR Hybrid Nanocomposites at Different Temperatures

2012 ◽  
Vol 576 ◽  
pp. 296-299 ◽  
Author(s):  
Mou'ad A. Tarawneh ◽  
Sahrim H. Ahmad ◽  
Ku Zarina Ku Ahmad ◽  
Hassan Norita
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Hybrid Composites ◽  
Laser Flash ◽  
Hybrid Nanocomposites ◽  
Measured Temperature ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes

This paper discusses the inclusion of hybrid nanofillers nanoclay and multi-walled carbon nanotubes (MWNTs) as reinforcing agents to improve the thermal properties of TPNR. The laser flash technique was also employed to determine the thermal conductivity, thermal diffusivity and specific heat capacity of the nanocomposite. Two types of hybrid nanofillers were introduced into TPNR, which are untreated hybrid composites (UTH) prepared from MWNTs (without acid treatment)-nanoclay and treated hybrid composites (TH), consisting of acid treated MWNTs and nanoclay. The thermal properties of treated hybrid composites are better than untreated hybrid composites. The thermal conductivity of untreated hybrid composites that were sintered at 30 to 150 oC did not show a monotonous change with MWNTs as the filler has a high thermal conductivity compared to nanoclay. The results showed that the thermal diffusivity decreased with the increasing of temperature. The specific heat of all the measured samples increases linearly with the measured temperature from 30°C to 150°C.

scholarly journals Enhanced Functional Properties of Low-Density Polyethylene Nanocomposites Containing Hybrid Fillers of Multi-Walled Carbon Nanotubes and Nano Carbon Black

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1356 ◽  
Author(s):  
Sandra Paszkiewicz ◽  
Anna Szymczyk ◽  
Agata Zubkiewicz ◽  
Jan Subocz ◽  
Rafal Stanik ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Synergistic Effects ◽  
Hybrid Nanocomposites ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Multi Walled Carbon Nanotubes ◽  
Nano Carbon ◽  
Carbon Nanofillers ◽  
Walled Carbon Nanotubes

In this work, hybrid filler systems consisting of multi-walled carbon nanotubes (MWCNTs) and nano carbon black (nCB) were incorporated by melt mixing in low-density polyethylene (LDPE). To hybrid systems a mixture of MWCNTs and nCB a mass ratio of 1:1 and 3:1 were used. The purpose was to study if the synergistic effects can be achieved on tensile strength and electrical and thermal conductivity. The dispersion state of carbon nanofillers in the LDPE matrix has been evaluated with scanning electron microscopy. The melting and crystallization behavior of all nanocomposites was not significantly influenced by the nanofillers. It was found that the embedding of both types of carbon nanofillers into the LDPE matrix caused an increase in the value of Young’s modulus. The results of electrical and thermal conductivity were compared to LDPE nanocomposites containing only nCB or only MWCNTs presented in earlier work LDPE/MWCNTs. It was no synergistic effects of nCB in multi-walled CNTs and nCB hybrid nanocomposites regarding mechanical properties, electrical and thermal conductivity, and MWCNTs dispersion. Since LDPE/MWCNTs nanocomposites exhibit higher electrical conductivity than LDPE/MWCNTs + nCB or LDPE/nCB nanocomposites at the same nanofiller loading (wt.%), it confirms our earlier study that MWCNTs are a more efficient conductive nanofiller. The presence of MWCNTs and their concentration in hybrid nanocomposites was mainly responsible for the improvement of their thermal conductivity.

Preparation and Releasing Characteristics of Controlled Release Potassium Permanganate

2013 ◽  
Vol 743-744 ◽  
pp. 782-788
Author(s):  
Shuang Shi Dong ◽  
Jin Wang ◽  
Yan Long Wang ◽  
Jian Bin Zhang ◽  
Dan Dan Zhou ◽  
...  
Keyword(s):  
Controlled Release ◽  
Ultrasonic Treatment ◽  
Treatment Time ◽  
Weight Ratio ◽  
Radial Distance ◽  
Paraffin Wax ◽  
Sem Images ◽  
Preparation Conditions ◽  
Uniform Dispersion ◽  
Loading Amount

To extend the duration of KMnO4in the groundwater in situ remediation, controlled release oxidant was prepared by dispersing the KMnO4particles in the molten paraffin wax. Preparation conditions, including KMnO4particles size, ultrasonic treatment time and the weight ratio of KMnO4to wax (P/W) were optimized. The results showed that the average volume particle size of 13.20 μm and ultrasonic treatment of 10 min contribute to the most uniform dispersion of the KMnO4particles in the molten paraffin wax. The scanning electron microscope (SEM) images showed that the increased amount of KMnO4caused the crushed structure of paraffin wax, which resulted in the higher porosity of wax to contain more KMnO4. The KMnO4loading amount increased significantly along with the increase of the P/W. However, the loading amount almost reached saturation by 609.63 mg/g when the P/W increased to 2/1. The releasing characteristics of the samples in the distilled water and the KMnO4residual amount at different radial distance in the sample were examined by the bench scale tests. The releasing of KMnO4could be divided into four periods and stable release took place after 40 d. Controlled release KMnO4oxidant with P/W at 1/35 was used to remove COD in the leachate and 82.9% removal efficiency was obtained after 120 d treatment.

Highly thermally conductive UHMWPE/NG composites with the segregated structure and their application for heat spreader

2020 ◽  
pp. 089270572096564
Author(s):  
Xiao Wang ◽  
Hui Lu ◽  
Jun Chen
Keyword(s):  
Thermal Conductivity ◽  
Laser Flash ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Heat Spreader ◽  
Conductive Composites ◽  
Compression Direction ◽  
Thermal Analyzer ◽  
Thermally Conductive ◽  
Plane Direction

In this work, ultra-high molecular weight polyethylene (UHMWPE)/natural flake graphite (NG) polymer composites with the extraordinary high thermal conductivity were prepared by a facile mixed-heating powder method. Morphology observation and X-ray diffraction (XRD) tests revealed that the NG flakes could be more tightly coated on the surface of UHMWPE granules by mixed-heating process and align horizontally (perpendicular to the hot compression direction of composites). Laser flash thermal analyzer (LFA) demonstrated that the thermal conductivity (TC) of composites with 21.6 vol% of NG reached 19.87 W/(m·K) and 10.67 W/(m·K) in the in-plane and through-plane direction, respectively. Application experiment further demonstrated that UHMWPE/NG composites had strong capability to dissipate the heat as heat spreader. The obtained results provided a valuable basis for fabricating high thermal conductive composites which can act as advanced thermal management materials.

scholarly journals Improved thermal conductivity and stability of Na2SO4⋅10H2O PCMs system by incorporation of Al/C hybrid nanoparticles

2021 ◽  
Vol 12 ◽  
pp. 982-988
Author(s):  
Xin Liu ◽  
Jian Tie ◽  
Zhenya Wang ◽  
Yuting Xia ◽  
Chang-An Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Hybrid Nanoparticles

scholarly journals Enhancement of out-of-plane mechanical properties of carbon fiber reinforced epoxy resin composite by incorporating the multi-walled carbon nanotubes

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Seyed Ali Mirsalehi ◽  
Amir Ali Youzbashi ◽  
Amjad Sazgar
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Test ◽  
Epoxy Resin ◽  
Laminate Composite ◽  
Filament Winding ◽  
Hybrid Nanocomposites ◽  
Out Of Plane ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractIn this study, epoxy hybrid nanocomposites reinforced by carbon fibers (CFs) were fabricated by a filament winding. To improve out-of-plane (transverse) mechanical properties, 0.5 and 1.0 Wt.% multi-walled carbon nanotubes (MWCNTs) were embedded into epoxy/CF composites. The MWCNTs were well dispersed into the epoxy resin without using any additives. The transverse mechanical properties of epoxy/MWCNT/CF hybrid nanocomposites were evaluated by the tensile test in the vertical direction to the CFs (90º tensile) and flexural tests. The fracture surfaces of composites were studied by scanning electron microscopy (SEM). The SEM observations showed that the bridging of the MWCNTs is one of the mechanisms of transverse mechanical properties enhancement in the epoxy/MWCNT/CF composites. The results of the 90º tensile test proved that the tensile strength and elongation at break of nanocomposite with 1.0 Wt.% MWCNTs improved up to 53% and 50% in comparison with epoxy/CF laminate composite, respectively. Furthermore, the flexural strength, secant modulus, and elongation of epoxy/1.0 Wt.% MWCNT/CF hybrid nanocomposite increased 15%, 7%, and 9% compared to epoxy/CF laminate composite, respectively.

Thermal conduction characteristics of silicone composites including ultrasonic-treated graphite

2021 ◽  
pp. 002199832110595
Author(s):  
Weontae Oh ◽  
Jong-Seong Bae ◽  
Hyoung-Seok Moon
Keyword(s):  
Thermal Conductivity ◽  
Ultrasonic Treatment ◽  
Thermal Conduction ◽  
Light Emitting Diode ◽  
Thermal Interface Material ◽  
Ultrasonic Power ◽  
Lighting System ◽  
Thermal Interface ◽  
Light Emitting ◽  
Inorganic Oxides

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.

Hybrid nanoparticles embedded polyvinyl butyral nanocomposites for improved mechanical, thermal and microwave absorption performance

2021 ◽  
pp. 002199832110395
Author(s):  
Erdi Akman ◽  
Savas Sonmezoglu ◽  
Enes Yigit ◽  
Volkan Eskizeybek ◽  
Ahmet Avci
Keyword(s):  
Tensile Strength ◽  
Microwave Absorption ◽  
Nanocomposite Film ◽  
Arc Discharge ◽  
Synergetic Effect ◽  
Casting Process ◽  
Polyvinyl Butyral ◽  
Hybrid Nanocomposites ◽  
Hybrid Nanoparticles ◽  
Absorption Feature

Polymer-based nanocomposites have been broadly investigated to improve its specific properties such as thermal and mechanical properties to use in different application areas. In this study, we aimed to ameliorate the desired physical properties of polyvinyl butyral (PVB) by introducing various amounts of silver (Ag) and cobalt (Co) nanoparticles (NPs) in the polymer matrix. The arc-discharge method submerged in liquid nitrogen was performed to synthesize the metal NPs. To produce hybrid nanocomposites, we demonstrated embedding Ag:Co nanoparticles in the PVB matrix via easy/low-cost solution casting process without any additional materials. In the results of analysis for nanocomposites, it was observed that there were improvements in thermal, mechanical and microwave absorption characteristics of the PVB polymer with interaction of NPs with the polymer. As a result of these interactions, the hybridization of PVB with the metal NPs resulted in the improved thermal stability since the glass transition temperature was increased from 45.6 to 55.1 °C. Besides, while the tensile strength (σ) of the bare PVB film was calculated as 20.52 MPa, the strength of the corresponding tensile strength (σ) of 1.0 wt.% Ag:Co nanocomposite film was improved to 43.41 MPa. Moreover, in order to determine the effect of these changes on the radar absorption feature of nanocomposites, one-dimensional A-Scan measurements were performed on 2–18 GHz frequency band. In the results, it was observed that 1.0%.wt Ag:Co nanocomposite film absorbed approximately 90% of the incoming energy. The characterization results revealed that a positive synergetic effect raised in the case of the modification of the PVB matrix with both Ag and Co NPs. In the light of these data, it was understood that the characteristics of PVB were improved with the NPs combining, and the usage area of that will also increase thanks to this improvement. These regenerated properties made the hybrid nanocomposite a promising substrate material with considerable potential applications for various transparent, flexible, and portable surface coatings.

Influence of the preparation conditions on the thermal conductivity in metallic glasses

1991 ◽  
Vol 145 (1) ◽  
pp. 119-122 ◽  
Author(s):  
S. Welzel ◽  
H.W. Gronert ◽  
E.F. Wassermann ◽  
D.M. Herlach
Keyword(s):  
Thermal Conductivity ◽  
Metallic Glasses ◽  
Preparation Conditions

scholarly journals XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Влияние неидеальности геометрической формы образца на неопределенность измерений теплопроводности методом лазерной вспышки

2019 ◽  
Vol 53 (6) ◽  
pp. 731
Author(s):  
А.В. Асач ◽  
Г.Н. Исаченко ◽  
А.В. Новотельнова ◽  
В.Е. Фомин ◽  
К.Л. Самусевич ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Measurement Uncertainty ◽  
Conductivity Measurement ◽  
Laser Flash ◽  
Comsol Multiphysics ◽  
Flash Method ◽  
Cylindrical Shape ◽  
Plane Parallel ◽  
Coefficient Of Thermal Conductivity ◽  
Truncated Cylinder

The influence of the geometric shape of the samples on the uncertainty of the coefficient of thermal conductivity measurement of materials by the method of a laser flash has been studied. Using a method of mathematical modeling in the Comsol Multiphysics software, a model that simulates the process of measuring the coefficient of thermal conductivity of samples made of graphite, Mg2Si0.4Sn0.6 and bismuth telluride using a laser flash method has been created. Samples of cylindrical shape with plane-parallel sides and samples in the form of a truncated cylinder, as well as samples in the form of a parallelepiped with a square base, were investigated. It is shown that the measurement uncertainty of samples with plane-parallel sides and sizes up to 12.7 mm, does not exceed 2%. For samples in the form of a truncated cylinder with a diameter of 3 mm and at an angle of ϕ= 1.5°, the measurement uncertainty does not exceed 3%. With an increase in the sample diameter and the ϕ angle, the measurement uncertainty increases significantly.

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