scholarly journals Strength and modulus of carbon nanotubes under a tensile load

2014 ◽  
Vol 23 (1-2) ◽  
pp. 15-19 ◽  
Author(s):  
Khaled A. Alnefaie

AbstractCarbon nanotubes (CNTs) were fabricated using low-pressure chemical vapor deposition and then embedded in epoxy polymer at several weight ratios, 0, 0.75, 1.5, and 3 wt%, for tensile testing and Young’s modulus determination using an Instron machine. The tensile strength and Young’s modulus of the epoxy resin were increased with the addition of CNTs to a certain extent, and then decreased with the increase in the weight fraction of CNTs. The best properties occurred at 1.5 wt% of CNTs. Scanning electron microscopy was used to reveal the dispersion status of CNTs in the nanocomposites.

1999 ◽  
Vol 594 ◽  
Author(s):  
T. Y. Zhang ◽  
Y. J. Su ◽  
C. F. Qian ◽  
M. H. Zhao ◽  
L. Q. Chen

AbstractThe present work proposes a novel microbridge testing method to simultaneously evaluate the Young's modulus, residual stress of thin films under small deformation. Theoretic analysis and finite element calculation are conducted on microbridge deformation to provide a closed formula of deflection versus load, considering both substrate deformation and residual stress in the film. Silicon nitride films fabricated by low pressure chemical vapor deposition on silicon substrates are tested to demonstrate the proposed method. The results show that the Young's modulus and residual stress for the annealed silicon nitride film are respectively 202 GPa and 334.9 MPa.


2018 ◽  
Vol 52 (22) ◽  
pp. 3039-3044 ◽  
Author(s):  
Daniel Choi ◽  
Eui-Hyeok Yang ◽  
Waqas Gill ◽  
Aaron Berndt ◽  
Jung-Rae Park ◽  
...  

We have demonstrated a three-dimensional composite structure of graphene and carbon nanotubes as electrodes for super-capacitors. The goal of this study is to fabricate and test the vertically grown carbon nanotubes on the graphene layer acting as a spacer to avoid self-aggregation of the graphene layers while realizing high active surface area for high energy density, specific capacitance, and power density. A vertical array of carbon nanotubes on silicon substrates was grown by a low-pressure chemical vapor deposition process using anodized aluminum oxide nanoporous template fabricated on silicon substrates. Subsequently, a graphene layer was grown by another low-pressure chemical vapor deposition process on top of a vertical array of carbon nanotubes. The Raman spectra confirmed the successful growth of carbon nanotubes followed by the growth of high-quality graphene. The average measured capacitance of the three-dimensional composite structure of graphene-carbon nanotube was 780 µFcm−2 at 100 mVs−1.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Numan Salah ◽  
Abdulrahman Muhammad Alfawzan ◽  
Abdu Saeed ◽  
Ahmed Alshahrie ◽  
Waleed Allafi

AbstractCarbon nanotubes (CNTs) are widely investigated for preparing polymer nanocomposites, owing to their unique mechanical properties. However, dispersing CNTs uniformly in a polymer matrix and controlling their entanglement/agglomeration are still big technical challenges to be overcome. The costs of their raw materials and production are also still high. In this work, we propose the use of CNTs grown on oil fly ash to solve these issues. The CNTs of oil fly ash were evaluated as reinforcing materials for some common thermoplastics. High-density polyethylene (HDPE) was mainly reinforced with various weight fractions of CNTs. Xylene was used as a solvent to dissolve HDPE and to uniformly disperse the CNTs. Significantly enhanced mechanical properties of HDPE reinforced at a low weight fraction of these CNTs (1–2 wt.%), mainly the tensile strength, Young’s modulus, stiffness, and hardness, were observed. The tensile strength and Young’s modulus were enhanced by ~20 and 38%, respectively. Moreover, the nanoindentation results were found to be in support to these findings. Polycarbonate, polypropylene, and polystyrene were also preliminarily evaluated after reinforcement with 1 wt.% CNTs. The tensile strength and Young’s Modulus were increased after reinforcement with CNTs. These results demonstrate that the CNTs of the solid waste, oil fly ash, might serve as an appropriate reinforcing material for different thermoplastics polymers.


Author(s):  
Kristopher Jones ◽  
Brian D. Jensen ◽  
Anton Bowden

This paper explores and demonstrates the potential of using pyrolytic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolytic carbon, a ceramic, is currently used in medical implant devices due to its preferable biocompatibility properties. Micropatterned pyrolytic carbon implants can be created by growing carbon nanotubes (CNTs), and then filling the space between with amorphous carbon via chemical vapor deposition (CVD). We prepared multiple samples of two different stent-like flexible mesh designs and smaller cubic structures out of carbon-infiltrated carbon nanotubes (CI-CNT). Tension loads were applied to expand the mesh samples and we recorded the forces at brittle failure. The cubic structures were used for separate compression tests. These data were then used in conjunction with a nonlinear finite element analysis (FEA) model of the stent geometry to determine Young's modulus and maximum fracture strain in tension and compression for each sample. Additionally, images were recorded of the mesh samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Young's modulus values confirmed that the material was similar to that used in previous carbon-infiltrated carbon nanotube work. The average percent elongation was 86% with a maximum of 145%. This exceeds a typical target of 66%. The material properties found from compression testing show less stiffness than the mesh samples; however, specimen evaluation reveals poorly infiltrated samples.


2008 ◽  
Vol 23 (6) ◽  
pp. 1785-1796 ◽  
Author(s):  
E. López-Honorato ◽  
P.J. Meadows ◽  
J. Tan ◽  
P. Xiao

Stoichiometric silicon carbide coatings the same as those used in the formation of TRISO (TRistructural ISOtropic) fuel particles were produced by the decomposition of methyltrichlorosilane in hydrogen. Fluidized bed chemical vapor deposition at around 1500 °C, produced SiC with a Young’s modulus of 362 to 399 GPa. In this paper we demonstrate the deposition of stoichiometric silicon carbide coatings with refined microstructure (grain size between 0.4 and 0.8 μm) and enhanced mechanical properties (Young’s modulus of 448 GPa and hardness of 42 GPa) at 1300 °C by the addition of propene. The addition of ethyne, however, had little effect on the deposition of silicon carbide. The effect of deposition temperature and precursor concentration were correlated to changes in the type of molecules participating in the deposition mechanism.


2007 ◽  
Vol 1052 ◽  
Author(s):  
Yung-Dong Lau ◽  
Tso-Chi Chang ◽  
Hong Hocheng ◽  
Rongshun Chen ◽  
Weileun Fang

AbstractThis study has successfully demonstrated a novel tensile testing approach to mount the thin film test specimen onto the MEMS instrument using microfabrication process. The MEMS instrument consists of thermal actuator, differential capacitance sensor, supporting spring. The thermal actuator applies tensile load on the test specimen to characterize the Young's modulus and the residual stress of thin films. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of thin film test specimens with the testing instrument can be prevented. Furthermore, the parylene passivation technique of MEMS fabrication process allows the changing of testing film materials easily. In application, the present approach has been employed to determine the Young's modulus and the residual stress of Al films.


Author(s):  
Yung-Dong Lau ◽  
Hong Hocheng ◽  
Rongshun Chen ◽  
Weileun Fang

This study has successfully demonstrated a novel tensile testing approach to mount a thin film test specimen onto a MEMS instrument using microfabrication processes. The MEMS instrument consists of a thermal actuator, differential capacitance sensor, and supporting spring. The thermal actuator applies a tensile load on the test specimen to characterize the Young’s modulus and the residual stress of the thin film. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of a thin film test specimen with the testing instrument can be prevented. Furthermore, the parylene passivation technique with the MEMS fabrication process allows the user to change the test materials easily. In application, the present approach has been employed to determine the Young’s modulus and the residual stress of Au and Al films.


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