scholarly journals Temperature dependence of axial thermal expansion coefficient of multi-walled carbon nanotubes (A procedure based on measurements of coefficient of thermal expansion for aligned carbon nanotube/epoxy composites)

2016 ◽  
Vol 82 (844) ◽  
pp. 16-00228-16-00228 ◽  
Author(s):  
Keiichi SHIRASU ◽  
Akihiro NAKAMURA ◽  
Go YAMAMOTO ◽  
Toshio OGASAWARA ◽  
Yoshinobu SHIMAMURA ◽  
...  
2017 ◽  
Vol 51 (12) ◽  
pp. 1693-1701 ◽  
Author(s):  
EA Zakharychev ◽  
EN Razov ◽  
Yu D Semchikov ◽  
NS Zakharycheva ◽  
MA Kabina

This paper investigates the structure, length, and percentage of functional groups of multi-walled carbon nanotubes (CNT) depending on the time taken for functionalization in HNO3 and H2SO4 mixture. The carbon nanotube content and influence of functionalization time on mechanical properties of polymer composite materials based on epoxy matrix are studied. The extreme dependencies of mechanical properties of carbon nanotube functionalization time of polymer composites were established. The rise in tensile strength of obtained composites reaches 102% and elastic modulus reaches 227% as compared to that of unfilled polymer. The composites exhibited best mechanical properties by including carbon nanotube with 0.5 h functionalization time.


2013 ◽  
Vol 284-287 ◽  
pp. 204-210
Author(s):  
Yi Ming Jen ◽  
Chien Yang Huang

This study experimentally analyzed the hygrothermal effect on the static and fatigue strengths of acid-treated multi-walled carbon nanotubes (CNTs)/epoxy composites. The nanocomposite specimens with various CNT contents (0., 0.5, and 1.0 wt.%) were statically and fatigue-tested under three different hygrothermal conditions (25 °C/60% RH, 25° C/85% RH, and 40 °C/85% RH) to investigate the influences of hygrothermal conditions and CNT contents on the tensile static and fatigue strengths of the studied nanocomposites. The results show that the static and fatigue strengths decreased slightly at 25 °C/85% RH environments compared with those tested under the 25 °C/60% RH condition. However, the static and fatigue strengths of the studied nanocomposites decreased substantially under the 40 °C/85% RH condition. The combined temperature and humidity environments weaken the interfacial adhesion between the CNT surfaces and the epoxy matrix. Moreover, the experimental results show that the addition of 0.5 wt.% of carbon nanotubes improved the static and fatigue strengths considerably under the same hygrothermal environments. However, when an excessive amount of CNTs was used (1.0 wt.%), the nanocomposite exhibited the lowest strengths compared with the specimens with 0 and 0.5 wt.% CNTs. The stress concentration effect caused by the CNT aggregates was detrimental to the static and fatigue strengths of the studied nanocomposites.


2017 ◽  
Vol 52 (8) ◽  
pp. 1045-1060 ◽  
Author(s):  
Majid TabkhPaz ◽  
Dong-Yeob Park ◽  
Patrick C Lee ◽  
Ron Hugo ◽  
Simon S Park

In this study, new composite coatings are fabricated and investigated for their applications as the metal coating. The studied coatings consist of two-layered composites with various nanoparticulates as fillers in a polymeric matrix (styrene acrylic). The first layer bonded to the steel plate uses a combination of zinc particles, multi-walled carbon nanotubes, and graphene nanoplatelets. For the second layer, hexagonal boron nitride with high electrical insulation properties is added to the matrix. The morphology of the nanoparticulates is conducted using a scanning electron microscope. The coefficient of thermal expansion, cathodic disbondment resistance, gas penetration, and scratch resistance of the coatings are evaluated. The corroded area on the cathodic disbondment test specimens reduced down up to 90% for the composite with zinc (20 wt%), multi-walled carbon nanotubes (2 wt%), and graphene nanoplatelets (2 wt%), compared to a specimen coated with a pure polymer. It is seen that the presence of nanoparticulates decreased gas permeation and thermal expansion of the matrix by 75% and 65%, respectively. The addition of nanoparticulates also enhanced scratch resistance of the coating composites.


2013 ◽  
Vol 27 (25) ◽  
pp. 1350180 ◽  
Author(s):  
RAGHUVESH KUMAR ◽  
GEETA SHARMA ◽  
MUNISH KUMAR

A simple theoretical model is developed to study the effect of size and temperature on the coefficient of thermal expansion and lattice parameter of nanomaterials. We have studied the size dependence of thermal expansion coefficient of Pb , Ag and Zn in different shape viz. spherical, nanowire and nanofilm. A good agreement between theory and available experimental data confirmed the model predictions. We have used these results to study the temperature dependence of lattice parameter for different size and also included the results of bulk materials. The temperature dependence of lattice parameter of Zn nanowire and Ag nanowire are found to present a good agreement with the experimental data. We have also computed the temperature and size dependence of lattice parameter of Se and Pb for different shape viz. spherical, nanowire and nanofilm. The results are discussed in the light of recent research on nanomaterials.


2013 ◽  
Vol 716 ◽  
pp. 373-378
Author(s):  
Qian Zhang ◽  
Xin Bao Gao ◽  
Tian Peng Li

Carbon nanotube/expanded graphite composite material was prepared by expanding the mixture of multi-walled carbon nanotubes and expansible graphite under the condition of high temperature. The microstructure and composition was studied by using SEM and XRD. The study shows that the tubular structure of carbon nanotubes in the composite material is changed by high temperature expanding process, and the microstructure is different with different expanding temperature. When the expanding temperature was 900°C, carbon nanotubes transformed, then attached to the surface of expanded graphite flake, so carbon nanotubes and expanding graphite combined strongly; globular carbon nanotubes attached to the surface of expanded graphite flake at the temperature of 700°C, both were combined much more strongly; carbon nanotubes retained the tube structure at the temperature of 500°C, combination was looser due to the simple physical adsorption. The result shows that the choice of expanding temperature has an important effect on microstructure of carbon nanotube/expanded graphite composite material.


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