scholarly journals Multistage Mechanical Activation of Multilayer Carbon Nanotubes in Creation of Electric Heaters with Self-Regulating Temperature

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4654
Author(s):  
Alexandr Viktorovich Shchegolkov ◽  
Sung-Hwan Jang ◽  
Aleksei Viktorovich Shchegolkov ◽  
Yuri Viktorovich Rodionov ◽  
Olga Anatolievna Glivenkova
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Field ◽  
Mechanical Activation ◽  
Thermal Effect ◽  
Supply Voltage ◽  
Mechanical Energy ◽  
Mechanical Action ◽  
Multilayer Carbon Nanotubes ◽  
Starting Current ◽  
Paddle Mixer

The article deals with research related to the issues of nanomodification of elastomers as a basis of electric heaters with self-regulating temperature. The effect of multistage mechanical activation of multilayer carbon nanotubes (MCNTs) with graphite on the uniformity of the temperature field distribution on the surface of nanomodified organosilicon elastomer has been studied. The influence of the stages of mechanical action on the parameters of MCNTs is revealed. It has been ascertained that for the MCNTs/graphite bulk material, which has passed the stage of mechanical activation in the vortex layer apparatus, a more uniform distribution of the temperature field and an increase in temperature to 57.1 °C at the supply voltage of 100 V are typical. The distribution of the temperature field in the centrifugal paddle mixer “WF-20B” for mixing MCNTs with graphite has been investigated. It has been found that there is also a thermal effect in addition to the mechanical action on the MCNTs in the paddle mixer “WF-20B”. The thermal effect is associated with the transfer of the mechanical energy of friction of the binary mixture MCNTs/graphite on the paddle and the walls of the vessel. The multiplicity of the starting current Ip to the nominal In (Ip/In) is 5 for the first sample, 7.5 for the second sample, and 10 for the third sample at the supply voltage of 100 V. The effect of reducing the starting current and stabilizing the temperature indicates the presence of self-regulation, which is expressed in maintaining a certain level of temperature.

scholarly journals Self-regulating electric heater based on elastomer, modified with multilayer carbon nanotubes

2018 ◽  
Vol 80 (3) ◽  
pp. 341-345 ◽  
Author(s):  
V. S. Yagubov ◽  
A. V. Shchegolkov
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Field ◽  
Supply Voltage ◽  
Electric Heating ◽  
Heating Element ◽  
Electric Heater ◽  
Heater Surface ◽  
Electrically Conductive ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The review of modern approaches to the development of electric heating materials makes it possible to conclude that the studies of electrically conductive composites are based on using elastomers modified with nanoscale carbon materials. In the manufacturing of electric heaters, temperature self-regulation is the main property that increases their characteristics. However, researchers engaged in studying such heaters, face difficulties associated with the magnitude of supply voltage and power. In this regard, the tasks of the present work were as follows: to study the modifier characteristics for nanomodified heaters, and to select a modifier that is best dispersed in the elastomer, which will ensure the maximum magnitude of the supply voltage and the high value of the specific power of the heater. To develop an electric heater, silicone rubber modified with carbon nanotubes was used as an elastomer. The method for manufacturing the heating element nanomodified material was described. Multi-walled carbon nanotubes synthesized through the CVD method were employed as an electrically conductive modifier. Before modifying the elastomer, the carbon nanotubes were processed in a mill at a rotational speed of working blades of 25,000 rpm. Then, the nanotubes were thermally treated in a furnace until the temperature of 110 °C was reached. After that, the nanotubes and the elastomer were mixed using a BRABENDER mixer, followed by pressing and obtaining plates of the electric heating material. To ensure contact between the heater and the power source, aluminum foil, inserted into the punches before pressing, was used. The electrical conductivity of the elastic heater nanomodified material was studied using a setup (facility) constructed especially for that purpose. Based on the results obtained, a conclusion can be made on the expediency of using different multi-walled carbon nanotubes as elastomer modifiers, which form electrically conductive networks inside the elastomer and are capable of releasing heat when connected to an electrical voltage source. Employing a non-contact method of measuring the temperature field on the electric heater surface, thermograms were recorded. It was found that the temperature field is uniformly distributed on the heater surface and is stabilized at a certain time after achieving a thermal balance with the environment. From the data obtained, it can be concluded that the heating element connected to an alternating current network with a voltage of 220 V is efficient.

scholarly journals Carbon Nanotube-Based Composite Filaments for 3D Printing of Structural and Conductive Elements

2021 ◽  
Vol 11 (3) ◽  
pp. 1272
Author(s):  
Bartłomiej Podsiadły ◽  
Piotr Matuszewski ◽  
Andrzej Skalski ◽  
Marcin Słoma
Keyword(s):  
Carbon Nanotubes ◽  
Fused Deposition Modeling ◽  
Supply Voltage ◽  
Acrylonitrile Butadiene Styrene ◽  
Structural Elements ◽  
Filling Fraction ◽  
Fused Deposition ◽  
Structural Electronics ◽  
Measured Sample ◽  
Deposition Modeling

In this publication, we describe the process of fabrication and the analysis of the properties of nanocomposite filaments based on carbon nanotubes and acrylonitrile butadiene styrene (ABS) polymer for fused deposition modeling (FDM) additive manufacturing. Polymer granulate was mixed and extruded with a filling fraction of 0.99, 1.96, 4.76, 9.09 wt.% of CNTs (carbon nanotubes) to fabricate composite filaments with a diameter of 1.75 mm. Detailed mechanical and electrical investigations of printed test samples were performed. The results demonstrate that CNT content has a significant influence on mechanical properties and electrical conductivity of printed samples. Printed samples obtained from high CNT content composites exhibited an improvement in the tensile strength by 12.6%. Measurements of nanocomposites’ electrical properties exhibited non-linear relation between the supply voltage and measured sample resistivity. This effect can be attributed to the semiconductor nature of the CNT functional phase and the occurrence of a tunnelling effect in percolation network. Detailed I–V characteristics related to the amount of CNTs in the composite and the supply voltage influence are also presented. At a constant voltage value, the average resistivity of the printed elements is 2.5 Ωm for 4.76 wt.% CNT and 0.15 Ωm for 9.09 wt.% CNT, respectively. These results demonstrate that ABS/CNT composites are a promising functional material for FDM additive fabrication of structural elements, but also structural electronics and sensors.

Influence of carbon nanotubes on the dissipation of disturbances in a magnetic fluid layer

2021 ◽  
Vol 57 (2) ◽  
pp. 273-280
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Properties ◽  
Magnetic Fluid ◽  
Fluid Layer ◽  
Viscous Friction ◽  
Multilayer Carbon Nanotubes

In this paper, processes of dissipation of disturbances of pressure and velocity in a magnetic fluid layer are experimentally studied. It is shown that the introduction of multi-layer carbon nanotubes (MCNT) up to 2wt.% into a magnetic fluid substantially increases the dissipation of disturbances due to increasing viscous friction and elastic properties of multilayer carbon nanotubes. Figs 9, Refs 9.

scholarly journals Solid phase synthesis of calcium stearate on a modified screw equipment

2019 ◽  
Vol 58 (4) ◽  
pp. 127-132
Author(s):  
Alexander A. Momziakov ◽  
◽  
Timur R. Deberdeev ◽  
Rustam Ya. Deberdeev ◽  
Eugeny A. Pecheny ◽  
...  
Keyword(s):  
Solid Phase ◽  
Metal Salt ◽  
Mechanical Energy ◽  
Mechanical Action ◽  
Calcium Stearate ◽  
Chemical Additives ◽  
Metal Carboxylates ◽  
New Approach ◽  
Solution Methods ◽  
Full Factorial

Metal stearates are widely used in various industries: as a thickener, lubricants, auxiliary desiccant, emulsifier for cosmetics, chemical additives to synthetic rubbers and a stabilizing component in polyolefins (PE, PP), ABS plastic, polystyrene, polyamide and polyvinyl chloride ( PVC). The greatest interest in using the metal salt of stearic acid is stabilization of PVC. At present, technologies for the synthesis of divalent metal carboxylates have evolved in three directions: synthesis technology in solution, in the melt and in the solid phase. The latter was the most laborious at the end of the last century due to the lack of equipment that allowed the imposition of mechanical energy on the material in sufficient quantity to initiate chemical transformation. In the literature, experiments are carried out on planetary mills, attritors, rollers and Bridgman anvils. In devices of a similar design, the best conditions for the chemical process between the components of the reaction mixture are created. The chemical reaction proceeds as a result of the creation and subsequent relaxation of the stress field when applying a mechanical action to the reaction mixture. However, they did not give a high selectivity for the target product; therefore, the chemical industry of stabilizing additives focused on solution methods for producing metal carboxylates. The authors of the article have developed a new approach for the synthesis of calcium stearate in the solid phase on a modified screw apparatus. Screw machines, in turn, provide an increase in the number of contacts between reagents and, more significantly, the area of the contact interface. In addition, heat generation due to friction in the contact area can further intensify the process. The influence of the temperature range inside the material cylinder - the reactor, the screw rotation speed on the technical characteristics and the yield of calcium stearate was investigated. Mathematical processing of the results of the full factorial experiment was carried out. A comparison of the adequacy of the obtained linear equation and experimental data is carried out.

Modification of Multilayer Carbon Nanotubes for the Removal of Arsenate

2016 ◽  
Vol 16 (4) ◽  
pp. 3835-3840
Author(s):  
Libing Liao ◽  
Gin-Lung Liu ◽  
Jiin-Shuh Jean ◽  
Wei-Teh Jiang ◽  
Zhaohui Li
Keyword(s):  
Carbon Nanotubes ◽  
Contact Time ◽  
Carbon Adsorbent ◽  
Superior Performance ◽  
Solution Ph ◽  
Nano Composite ◽  
X Ray ◽  
Multilayer Carbon Nanotubes ◽  
Removal Of Arsenic ◽  
Composite Carbon

The aim of this study was to explore a new nano-composite carbon adsorbent material for the removal of arsenic from water. The multilayer carbon nanotubes (MCNTs) were treated with different acids and/or modified with iron to create more surface COOH sites or Fe-impregnated MCNTs for the enhanced uptake of As(V). Tests were conducted as a function of initial As(V) concentrations, contact time, and solution pH. The coverage of ferric hydroxides on MCNTs and the uptake of As on Fe-MCNTs were independently confirmed by field emission scanning electron microscope and energy dispersive X-ray spectroscopy analyses. With an As(V) uptake capacities of 27 mg/g on Fe-MCNTs and 14 mg/g on acid-MCNTs, the material showed superior performance for As(V) removal.

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