scholarly journals Сравнительный анализ эффективности углеродных нанотрубок и графена в армированнии полимерных нанокомпозитов

2020 ◽  
Vol 62 (8) ◽  
pp. 1240
Author(s):  
Г.В. Козлов ◽  
И.В. Долбин
Keyword(s):  
Carbon Nanotubes ◽  
Comparative Analysis ◽  
Polymer Matrix ◽  
Fractal Analysis ◽  
Percolation Theory ◽  
Outer Diameter ◽  
Main Role ◽  
Technological Aspect ◽  
High Modulus ◽  
Reinforcement Efficiency

The comparative analysis of reinforcement efficiency (modulus of elasticity enhancement) of polymers with carbon nanotubes and grapheme was performed using the methods of fractal analysis and percolation theory. It has been shown that such comparison is correct only at the same structure of the indicated anisotropic nanofillers in polymer matrix. For carbon nanotubes reinforcement efficiency depends strongly on their geometry, i.e. length and outer diameter. In addition the main role in polymers reinforcement play not initial characteristics of nanofiller, but its structures, obtained in production process of nanocomposites. In technological aspect carbon nanotubes are more suitable for manufacture of high-modulus nanocomposites, that is due to possibility of simple enough realization of their orientation.

scholarly journals HEAT CONDUCTIVITY OF POLYMERIC MICRO- AND NANOCOMPOSITES BASED ON POLYETHYLENE AT VARIOUS METHODS OF THEIR PREPARATION

2017 ◽  
Vol 39 (4) ◽  
pp. 21-26
Author(s):  
N. M. Fialko ◽  
R. V. Dinzhos ◽  
Yu. V. Sherenkovskiy ◽  
N. O. Meranova ◽  
R. A. Navrodskaya
Keyword(s):  
Carbon Nanotubes ◽  
Comparative Analysis ◽  
Concentration Dependence ◽  
Polymer Matrix ◽  
Heat Conductivity ◽  
Aluminum Particles ◽  
Methods Of Synthesis ◽  
Percolation Thresholds

The results of a comparative analysis of the heat conductivity properties of polymer micro- and nanocomposites based on polyethylene obtained using methods based on the mixing of components in a dry form or a melt of a polymer matrix are submitted. For polyethylene, filled with carbon nanotubes and aluminum particles, data on the effect of methods of synthesis of composites on the values of percolation thresholds, the concentration dependence of the coefficients of heat conductivity, etc. are presented.  

Evaluation of the structural state of carbon nanotubes in the polymer matrix of nanocomposites

2019 ◽  
Vol 85 (9) ◽  
pp. 42-45 ◽  
Author(s):  
L. B. Atlukhanova ◽  
G. V. Kozlov ◽  
I. V. Dolbin
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Matrix ◽  
Fractal Analysis ◽  
Fractal Dimensions ◽  
Order Of Magnitude ◽  
Degree Of Anisotropy ◽  
Irreversible Aggregation ◽  
Cluster Mechanism ◽  
Form Ring ◽  
High Degree

By virtue of high degree of anisotropy and small transverse stiffness, carbon nanotubes are known to form ring-shaped annular structures (fractal objects) in the polymer matrix of nanocomposites. We used the fractal dimension for quantitative and physically strict characterization of the nanofiller structure (carbon nanotubes) in the polymer matrix of nanocomposites. Two methods of calculation based on the models of irreversible aggregation and fractal analysis are proposed. The results obtained using both approaches match each other within 6%. It has been shown that formation of the annular structures occurs according to the cluster-cluster mechanism (i.e., by combining small formations into larger ones, rather than individual nanotubes). Moreover, the method of fractal analysis takes into account the effect of the polymer matrix on the structure of ring-shaped formations and, hence, on the properties of polymer nanocomposites. The correctness of the methods thus used was proved using the percolation model, which showed good agreement between the theory and experiment when using fractal dimensions determined by both methods. This means that for a fixed nanofiller content, the properties of nanocomposites are determined only by the nanofiller structure. In other words, a significant change in the properties (for the degree of reinforcement more than by an order of magnitude) is possible even at a low content of a nanofiller, which is realized only through change in the nanofiller structure using various methods of nanofiller treatment (ultrasound, functionalization, construction of special types of nanofiller frame, etc.).

scholarly journals Modeling Annular Structures of Carbon Nanotubes as Macromolecular Coils – a Possibility of Gel Formation

2020 ◽  
pp. 37-43
Author(s):  
Luiza Atlukhanova ◽  
Georgiy Kozlov
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Matrix ◽  
Percolation Theory ◽  
Solid Phase ◽  
Polymer Nanocomposite ◽  
Effective Elastic Modulus ◽  
Liquid System ◽  
Gel Formation ◽  
Gelation Process ◽  
High Degree

Carbon nanotubes (nanofibers) form folded ring-like structures in the polymer nanocomposite that look like macromolecular tangles. This behavior of these nanofillers is due to their high degree of anisotropy and low transverse stiffness. In this case, the ring-like structures of the nanotubes are considered as a macromolecular tangle, and the polymer matrix is considered as a solvent. This interpretation of nanocomposites polymer/carbon nanotubes makes it necessary to study the possibility of implementing the gelation process in them, which is understood as the transition of liquid (easily mobile and viscous) microheterogenic or homogeneous systems to the solid-phase state of gel or jelly. Gel formation is caused by the appearance of a spatial phase or molecular grid (frame) in the volume of the liquid system, which deprives the system of fluidity and gives it some properties of a solid body (elasticity, plasticity, brittleness, strength), which is of particular interest in studying the properties of polymer nanocomposites. The purpose of this work is to study the properties of polymer/carbon nanotubes (nanofibers) nanocomposites in the framework of the percolation theory and the possibility of implementing the gelation process in them. The possibility of gel formation by carbon nanotubes (nanofilaments), which are simulated as macromolecular coils, in nanocomposites based on polypropylene, is studied within the framework of the fractal analysis and the percolation theory. The paper shows that for achieving the point of gel formation the specific (straight-line) configuration of the indicated nanofillers is necessary and realization of this effect can lead to a sharp discrete change of nanocomposites in consideration. The authors find out that the effective elastic modulus of nanofillers in the polymer matrix is defined not by their stiffness, but by the efficiency of transfer of the applied mechanical stress from the polymer matrix to the nanofiller.

scholarly journals The structure of graphene oxide in polymer matrix and its effect on reinforcement degree of nanocomposite

2019 ◽  
Vol 486 (4) ◽  
pp. 426-429
Author(s):  
G. V. Kozlov ◽  
I. V. Dolbin ◽  
L. N. Nikitin
Keyword(s):  
Graphene Oxide ◽  
Polymer Matrix ◽  
Percolation Theory ◽  
Structural State ◽  
Single Factor ◽  
Interfacial Interactions ◽  
Reinforcement Efficiency

The methodics of characterization of 2D-nanofiller tactoids structure in polymer matrix of nanocomposite was proposed, which shown that the indicated tactoids are fractal objects with dimension of 1.75-2.16. This variation of tactoids structural state is due to interfacial interactions. It has been shown within the framework of reinforcement percolation theory, that structure of tactoids is single factor, defining reinforcement efficiency is characterized by its ability to create interfacial regions.

scholarly journals Условия получения высокомодульных нанокомпозитов полимер/углеродные нанотрубки

2021 ◽  
Vol 91 (3) ◽  
pp. 440
Author(s):  
Г.В. Козлов ◽  
И.В. Долбин
Keyword(s):  
Carbon Nanotubes ◽  
Fractal Dimension ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Polymer Matrix ◽  
Mechanical Characteristics ◽  
High Strength ◽  
High Modulus ◽  
Positive Effects ◽  
Main Factors

The physical basis of realization of high-modulus and high-strength nanocomposites polymer/carbon nanotube, having mechanical characteristics comparable with the same ones for steel, were considered. Two main factors, allowing to create such nanocomposites, were defined – the structure of nanofiller in polymer matrix and large enough content of nanofiller. The indicated structure fractal dimension should be close to dimension of surrounding Euclidean space, i.e. three one. Besides, elastic modulus of nanofiller depends on stiffness of polymer matrix. Therefore additional drawing of nanocomposite gives two positive effects: reduction of waviness of carbon nanotubes and enhancement of elastic modulus of polymer matrix owing to orientation of its macromolecules.

Comprehensive review on carbon nanotubes embedded in different metal and polymer matrix: fabrications and applications

2021 ◽  
pp. 1-28
Author(s):  
Fahad Saleem Ahmed Khan ◽  
N. M. Mubarak ◽  
Mohammad Khalid ◽  
Mohammad Mansoob Khan ◽  
Yie Hua Tan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Matrix ◽  
Comprehensive Review

Control of the outer diameter of thin carbon nanotubes synthesized by catalytic decomposition of hydrocarbons

2000 ◽  
Vol 317 (1-2) ◽  
pp. 71-76 ◽  
Author(s):  
I Willems ◽  
Z Kónya ◽  
J.-F Colomer ◽  
G Van Tendeloo ◽  
N Nagaraju ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Decomposition ◽  
Outer Diameter ◽  
Thin Carbon ◽  
Decomposition Of Hydrocarbons

Effect of carbon nanotubes modified with different concentrations of rare earth lanthanum on the mechanical and tribological properties of epoxy composites

2021 ◽  
pp. 002199832098764
Author(s):  
Mingren Jiang ◽  
Xianhua Cheng
Keyword(s):  
Carbon Nanotubes ◽  
Rare Earth ◽  
Polymer Matrix ◽  
Photoelectron Spectroscopy ◽  
Polymer Matrix Composites ◽  
Testing Machine ◽  
Matrix Composites ◽  
Mechanical And Tribological Properties ◽  
The Coefficient Of Friction ◽  
The Rare Earth

Rare earth modified acidified carbon nanotubes were prepared by functionalization of acidified carbon nanotubes with different concentrations of LaCl3. The modification results were characterized by Fourier-transform infrared and X-ray photoelectron spectroscopy. The rare earth successfully increases the surface activity of the acidified carbon nanotubes. Polymer matrix composites were prepared by using the rare earth modified acidified carbon nanotubes as the reinforcement in epoxy matrix. Mechanical properties were analyzed by Zwick Z100 testing machine and the tribological behaviors were test by multifunctional tribological tester. Compared with pure epoxy (epoxy resin), the mechanical strength of the best composite sample was increased by 50–120%, the coefficient of friction was reduced by 19.4% and the wear rate was reduced by approximately 40 times. The experimental results show that the RE concentration of 0.2–0.3 wt% has the most obvious influence on the properties of polymer composites. The mechanism of rare earth reinforcement in polymer matrix is analyzed and suggested.

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