scholarly journals Study on the Effects of the Interphase Region on the Network Properties in Polymer Carbon Nanotube Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 182 ◽  
Author(s):  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Excluded Volume ◽  
Positive Role ◽  
Interphase Region ◽  
Network Properties ◽  
High Fraction ◽  
Filler Network

The interphase region around nanoparticles changes the percolation threshold of long and thin nanoparticles, such as carbon nanotubes (CNT) in polymer nanocomposites. In this paper, the effects of the interphase region on the percolation threshold of nanoparticles and the network fraction are studied. New percolation threshold (φP) is defined by the role of the interphase in the excluded volume of nanoparticles (Vex). Moreover, the influences of filler and interphase size on the percolation volume fraction, the fraction of nanoparticles in the network as well as the volume fraction and relative density of the filler network are investigated. The least ranges of “φP” are obtained by thin and long CNT. Similarly, a thick interphase increases the “Vex” parameter, which causes a positive role in the percolation occurrence. Also, thin CNT and a thick interphase cause the high fraction of the filler network in the nanocomposites.

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

2018 ◽  
Vol 30 (3) ◽  
pp. 463-478 ◽  
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.

scholarly journals Effects of added SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposites

2018 ◽  
Vol 30 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Mohammad Javad Mahmoodi ◽  
Mohammad Kazem Hassanzadeh-Aghdam ◽  
Reza Ansari
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Shape Memory Polymer ◽  
Polymer Nanocomposite ◽  
Thermal Expansion Behavior ◽  
Interphase Region ◽  
Expansion Behavior

In this study, a unit cell–based micromechanical approach is proposed to analyze the coefficient of thermal expansion of shape memory polymer nanocomposites containing SiO2 nanoparticles. The interphase region created due to the interaction between the SiO2 nanoparticles and shape memory polymer is modeled as the third phase in the nanocomposite representative volume element. The influences of the temperature, volume fraction, and diameter of the SiO2 nanoparticles on the thermal expansion behavior of shape memory polymer nanocomposite are explored. It is observed that the coefficient of thermal expansion of shape memory polymer nanocomposite decreases with the increase in the volume fraction up to 12%. Also, the results reveal that with the increase in temperature, the shape memory polymer nanocomposite coefficient of thermal expansion linearly increases. The role of interphase region on the thermal expansion response of the shape memory polymer nanocomposite is found to be very important. In the presence of interphase, the reduction in nanoparticle diameter leads to lower coefficient of thermal expansion for shape memory polymer nanocomposite, while the variation of nanoparticles diameter does not affect the coefficient of thermal expansion in the absence of interphase. Based on the simulation results, the shape memory polymer nanocomposite coefficient of thermal expansion decreases as the interphase thickness increases. In addition, the contribution of interphase coefficient of thermal expansion to the shape memory polymer nanocomposite coefficient of thermal expansion is more significant than that of interphase elastic modulus.

scholarly journals Calculation of the Electrical Conductivity of Polymer Nanocomposites Assuming the Interphase Layer Surrounding Carbon Nanotubes

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 404 ◽  
Author(s):  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Electrical Conductivity ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Tunneling Effect ◽  
Interphase Layer ◽  
Conductive Network ◽  
Effective Volume ◽  
Effective Volume Fraction ◽  
Filler Fraction ◽  
High Fraction

The interphase layer surrounding nanoparticles can reflect the tunneling effect as the main mechanism of charge transferring in polymer/carbon nanotube (CNT) nanocomposites (PCNT). In this paper, the percolation threshold, effective volume fraction of CNT, and the portion of percolated filler after percolation are expressed by interphase and CNT waviness. Moreover, the developed terms are used to suggest the influences of CNT dimensions, interphase thickness, and waviness on the electrical conductivity of PCNT by conventional and developed models. Thin and long CNT, thick interphase, and low waviness obtain a high fraction of percolated CNT. However, the highest level of effective filler fraction is only calculated by the thinnest CNT and the thickest interphase. Furthermore, both models show that the thinnest and the longest CNT as well as the thickest interphase and the least CNT waviness cause the highest conductivity in PCNT, because they positively contribute to the formation and properties of the conductive network.

scholarly journals Structural Arrest and Thermodynamic Scaling in Filler-Reinforced Polymers

2009 ◽  
Vol 82 (2) ◽  
pp. 202-213 ◽  
Author(s):  
C. G. Robertson ◽  
R. Bogoslovov ◽  
C. M. Roland
Keyword(s):  
Glass Transition ◽  
Volume Fraction ◽  
Filler Concentration ◽  
Scaling Exponent ◽  
Segmental Dynamics ◽  
Reinforced Polymers ◽  
Filler Volume Fraction ◽  
Segmental Relaxation ◽  
Filler Network

Abstract The role of small silica particles on the stiffness and glass transition dynamics of polyvinylacetate (PVAc) was examined for filler volume fraction (ϕ) from 0 to 0.28. Whereas the influences of bound polymer and a strain-dependent filler network were clearly noted in the shear properties, the only effect of filler on the bulk modulus was the reduction in deformable polymer. The calorimetric glass transition of PVAc and its dependence on cooling rate were unaltered by the presence of the silica, in agreement with previous dielectric relaxation results. In contrast to the temperature dependence of the segmental dynamics, which was independent of ϕ, the effect of volume on segmental relaxation was amplified by the addition of silica. This resulted in larger values for the thermodynamic scaling exponent (γ), which also increased sharply at the filler concentration corresponding to the development of a percolated filler network.

Role of the interstitial matrix during intestinal volume absorption

1980 ◽  
Vol 238 (3) ◽  
pp. G183-G189 ◽  
Author(s):  
D. N. Granger ◽  
N. A. Mortillaro ◽  
P. R. Kvietys ◽  
G. Rutili ◽  
J. C. Parker ◽  
...  
Keyword(s):  
Blood Cells ◽  
Interstitial Fluid ◽  
Volume Fraction ◽  
Lymph Flow ◽  
Excluded Volume ◽  
Interstitial Volume ◽  
Volume Absorption ◽  
Interstitial Fluid Volume ◽  
Rate Of Absorption

The effects of net volume absorption rate (Jv,m) on intestinal interstitial fluid volume (VI), lymph flow (JL), and the excluded volume fraction for interstitial albumin (FE) were analyzed in an autoperfused cat ileum preparation. Tissue blood volume, extracellular space, and extracellular albumin (VA) were estimated using 51Cr-labeled red blood cells, 99mTc-labeled diethylenetriamine pentaacetic acid (DTPA), and 125I-labeled human serum albumin, respectively. Nonabsorptive values of 27.8 ml/100 g, 18.2 ml/100 g, and 0.37 were acquired for VI, VA, and FE, respectively. Net volume absorption results in an increase in intestinal interstitial volume and lymph flow and decreases the degree of albumin exclusion in the interstitial matrix. The magnitude of the changes in interstitial volume, lymph flow, and excluded volume of albumin during net volume absorption are related to the rate of absorption. The increased matrix hydration during absorption serves to enchance vascular and lymphatic removal of absorbed volume.

scholarly journals Analysis of the Connecting Effectiveness of the Interphase Zone on the Tensile Properties of Carbon Nanotubes (CNT) Reinforced Nanocomposite

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 896 ◽  
Author(s):  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Properties ◽  
Polymer Nanocomposites ◽  
Simulation Study ◽  
Tensile Modulus ◽  
Excluded Volume ◽  
Interphase Region ◽  
Important Character

The establishment of interphase region around nanoparticles accelerates the percolating of carbon nanotubes (CNT) in polymer nanocomposites reinforced with CNT (PCNT), due to the linking productivity of interphase district before the physical connecting of nanoparticles. Therefore, the interphase is an important character in the networks of CNT in PCNT. Here, a simulation study is presented to investigate the interphase connection in the mechanical possessions of PCNT including tensile modulus and strength. A number of models comprising Takayanagi, Ouali, Pukanszky and Callister are developed by the assumption of an interphase district in the CNT excluded volume. The advanced models depict the optimistic influences of reedy and lengthy CNT besides dense interphase on the stiffness and tensile power of nanocomposites. The Pukanszky calculations depict that the interphase strength plays a more noteworthy role in the nanocomposites strength compared to the CNT length.

Are Three Items Sufficient to Measure Sense of Coherence?

2018 ◽  
Vol 34 (4) ◽  
pp. 229-237 ◽  
Author(s):  
Francesca Chiesi ◽  
Andrea Bonacchi ◽  
Caterina Primi ◽  
Alessandro Toccafondi ◽  
Guido Miccinesi
Keyword(s):  
Sense Of Coherence ◽  
Convergent Validity ◽  
Clinical Sample ◽  
Clinical Samples ◽  
Depression Symptoms ◽  
Time Saving ◽  
Positive Role ◽  
Patients With Cancer ◽  
Measure Sense

Abstract. The present study aimed at evaluating if the three-item sense of coherence (SOC) scale developed by Lundberg and Nystrom Peck (1995) can be effectively used for research purpose in both nonclinical and clinical samples. To provide evidence that it represents adequately the measured construct we tested its validity in a nonclinical (N = 658) and clinical sample (N = 764 patients with cancer). Results obtained in the nonclinical sample attested a positive relation of SOC – as measured by the three-item SOC scale – with Antonovsky’s 13-item and 29-item SOC scales (convergent validity), and with dispositional optimism, sense of mastery, anxiety, and depression symptoms (concurrent validity). Results obtained in the clinical sample confirmed the criterion validity of the scale attesting the positive role of SOC – as measured by the three-item SOC scale – on the person’s capacity to respond to illness and treatment. The current study provides evidence that the three-item SOC scale is a valid, low-loading, and time-saving instrument for research purposes on large sample.

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