THE MECHANISMS OF REINFORCEMENT OF NANOCOMPOSITES POLYURETHANE/CARBON NANOTUBE

Spravochnik Inzhenernyi zhurnal ◽

10.14489/hb.2020.09.pp.003-007 ◽

2020 ◽

pp. 3-7

Keyword(s):

Carbon Nanotube ◽

Polymer Nanocomposites ◽

Modulus Of Elasticity ◽

Maximum Degree ◽

Micromechanical Model ◽

Strong Interactions ◽

High Modulus ◽

Nanocomposite Structure ◽

Practical Conclusion ◽

Degree Of Reinforcement

The aim of present work is theoretical analysis of high values of reinforcement degree of nanocomposites polyurethane/carbon nanotube. For this two micromechanical models were used, showing identical results. The indicated models demonstrated, that densely-packed high-modulus interfacial regions, which serve the same reinforcing element of nanocomposite structure, as and nanofiller (carbon nanotubes) actually. The formation of interfacial regions defines by strong interactions polymer matrix – nanofiller. This means that nanofiller efficiency is controlled by its ability to generate densely-packed interfacial regions. It is important also to point out, that any micromechanical model, including mixtures rule, describes correctly modulus of elasticity of polymer nanocomposites, if in it real, but not nominal, characteristics of nanofiller were used. The content of interfacial regions in nanocomposite is controlled by structure of nanofiller. This allows to obtain important practical conclusion – for realization maximum degree of reinforcement it is necessary to cause structure of nanofiller, allowing to generate greatest content of interfacial regions. Absence of interfacial regions results to reduction of modulus of elasticity of nanocomposite in comparison with matrix polymer.

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A closed-form model for estimating the effective thermal conductivities of carbon nanotube–polymer nanocomposites

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406218797967 ◽

2018 ◽

Vol 233 (8) ◽

pp. 2909-2919 ◽

Cited By ~ 11

Author(s):

Reza Moheimani ◽

M Hasansade

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Carbon Nanotube ◽

Closed Form ◽

Polymer Nanocomposites ◽

Micromechanical Model ◽

Polymer Nanocomposite ◽

Interfacial Thermal Resistance ◽

Full Potential ◽

Thermal Conductivities

This paper describes a closed-form unit cell micromechanical model for estimating the effective thermal conductivities of unidirectional carbon nanotube reinforced polymer nanocomposites. The model incorporates the typically observed misalignment and curvature of carbon nanotubes into the polymer nanocomposites. Also, the interfacial thermal resistance between the carbon nanotube and the polymer matrix is considered in the nanocomposite simulation. The micromechanics model is seen to produce reasonable agreement with available experimental data for the effective thermal conductivities of polymer nanocomposites reinforced with different carbon nanotube volume fractions. The results indicate that the thermal conductivities are strongly dependent on the waviness wherein, even a slight change in the carbon nanotube curvature can induce a prominent change in the polymer nanocomposite thermal conducting behavior. In general, the carbon nanotube curvature improves the nanocomposite thermal conductivity in the transverse direction. However, using the straight carbon nanotubes leads to maximum levels of axial thermal conductivities. With the increase in carbon nanotube diameter, an enhancement in nanocomposite transverse thermal conductivity is observed. Also, the results of micromechanical simulation show that it is necessary to form a perfectly bonded interface if the full potential of carbon nanotube reinforcement is to be realized.

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Interphase influences on the mechanical behavior of carbon nanotube–shape memory polymer nanocomposites: A micromechanical approach

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x18812704 ◽

2018 ◽

Vol 30 (3) ◽

pp. 463-478 ◽

Cited By ~ 7

Author(s):

MK Hassanzadeh-Aghdam ◽

MJ Mahmoodi ◽

R Ansari ◽

A Darvizeh

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Shape Memory ◽

Polymer Nanocomposites ◽

Elastic Moduli ◽

Volume Fraction ◽

Shape Memory Polymer ◽

Micromechanical Model ◽

Elastic Behavior ◽

Interphase Region

The effects of interphase characteristics on the elastic behavior of randomly dispersed carbon nanotube–reinforced shape memory polymer nanocomposites are investigated using a three-dimensional unit cell–based micromechanical method. The interphase region is formed due to non-bonded van der Waals interaction between a carbon nanotube and a shape memory polymer. The influences of temperature, diameter, volume fraction, and arrangement type of carbon nanotubes within the matrix as well as two interphase factors, including adhesion exponent and thickness on the carbon nanotube/shape memory polymer nanocomposite’s longitudinal and transverse elastic moduli, are explored extensively. Moreover, the results are presented for the shape memory polymer nanocomposites containing randomly oriented carbon nanotubes. The obtained results clearly demonstrate that the interphase region plays a crucial role in the modeling of the carbon nanotube/shape memory polymer nanocomposite’s elastic moduli. It is observed that the nanocomposite’s elastic moduli remarkably increase with increasing interphase thickness or decreasing adhesion exponent. It is found that when the interphase is considered in the micromechanical simulation, the shape memory polymer nanocomposite’s elastic moduli non-linearly increase as the carbon nanotube diameter decreases. The predictions of the present micromechanical model are compared with those of other analytical methods and available experiments.

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A new form of a Halpin–Tsai micromechanical model for characterizing the mechanical properties of carbon nanotube-reinforced polymer nanocomposites

Bulletin of Materials Science ◽

10.1007/s12034-019-1784-6 ◽

2019 ◽

Vol 42 (3) ◽

Cited By ~ 5

Author(s):

Mohammad Kazem Hassanzadeh-Aghdam ◽

Jamaloddin Jamali

Keyword(s):

Mechanical Properties ◽

Carbon Nanotube ◽

Polymer Nanocomposites ◽

Micromechanical Model ◽

Reinforced Polymer ◽

New Form

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IMPROVING THE STRENGTH CHARACTERISTICS OF PACKERS' SEALING ELEMENTS MADE OF POLYMER NANOCOMPOSITES.

ETM Equipment, Technologies, Materials ◽

10.36962/etm0703202134 ◽

2021 ◽

Vol 07 (03) ◽

pp. 34-39

Author(s):

Arzu Süleymanova Arzu Süleymanova

Keyword(s):

Tensile Strength ◽

Polymer Nanocomposites ◽

Interfacial Adhesion ◽

Micromechanical Model ◽

Interfacial Interaction ◽

Nano Composites ◽

Interfacial Region ◽

Strength Model ◽

High Modulus ◽

Sealing Elements

On the basis of a micromechanical model of the tensile strength of a polymer composite, it is shown that, in contrast to the case of adhesion between two polymers, when there is a linear correlation between the thickness of the interfacial region and the level of interfacial adhesion, the strength of the interface in nanocomposites of the "polymer-high modulus filler" type decreases with growth. its thickness. The dependence of the tensile strength of polymer nano-composites on the properties of the material and the level of interfacial interaction has been established. Keywords: strength model, interfacial adhesion, nanocomposite, seal material, packer.

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WIELAND DURO TUNGSTEN

Alloy Digest ◽

10.31399/asm.ad.w34 ◽

2020 ◽

Vol 69 (10) ◽

Keyword(s):

Melting Point ◽

Physical Properties ◽

Tensile Properties ◽

Modulus Of Elasticity ◽

Radiation Shielding ◽

High Melting ◽

High Modulus ◽

High Melting Point ◽

Structural Applications ◽

Very High

Abstract Wieland Duro Tungsten is unalloyed tungsten produced from pressed-and-sintered billets. The high melting point of tungsten makes it an obvious choice for structural applications exposed to very high temperatures. Tungsten is used at lower temperatures for applications that can benefit from its high density, high modulus of elasticity, or radiation shielding capability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on machining. Filing Code: W-34. Producer or source: Wieland Duro GmbH.

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Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

Mathematics and Mechanics of Solids ◽

10.1177/10812865211021460 ◽

2021 ◽

pp. 108128652110214

Author(s):

Xiaodong Xia ◽

George J. Weng

Keyword(s):

Experimental Data ◽

Electrical Conductivity ◽

Carbon Nanotube ◽

Percolation Threshold ◽

Polymer Nanocomposites ◽

Electromagnetic Interference ◽

Effective Medium Theory ◽

Scale Model ◽

Shielding Effectiveness ◽

Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

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Interaction Stresses in Carbon Nanotube–Polymer Nanocomposites

ACS Applied Materials & Interfaces ◽

10.1021/am200652f ◽

2011 ◽

Vol 3 (9) ◽

pp. 3425-3431 ◽

Cited By ~ 20

Author(s):

Meysam Rahmat ◽

Kaushik Das ◽

Pascal Hubert

Keyword(s):

Carbon Nanotube ◽

Polymer Nanocomposites

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A Carbon Nanotubes Aggregation in Polymer Nanocomposites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.935.55 ◽

2018 ◽

Vol 935 ◽

pp. 55-60 ◽

Cited By ~ 1

Author(s):

Louise B. Atlukhanova ◽

George V. Kozlov

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Polymer Nanocomposites ◽

Packing Density ◽

Elasticity Modulus ◽

Aggregation Process ◽

Walk Dimension

Carbon nanotubes aggregation process in aggregates (bundles) has been studied. This process results in essential reduction of nanocomposites attainable elasticity modulus. The bundles packing density is defined by aggregation expectation time and corresponding carbon nanotube walk dimension up to sticking with a similar nanotube.

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