Smart properties of carbon nanotube-epoxy composites

2020 ◽  
Vol 234 (11) ◽  
pp. 1409-1416
Author(s):  
Changjin Tian ◽  
Youzhi Wang ◽  
Qilin Yang ◽  
Zhi Ge ◽  
Yefeng Du
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Smart Materials ◽  
Rate Of Change ◽  
Epoxy Composites ◽  
Effect Of Temperature ◽  
Architectural Structures ◽  
Sensitive Property

Intelligent smart materials can not only monitor the damage and degradation of architectural structures in real time but also the health structure. In recent years, carbon nanotubes materials have emerged to possess both excellent mechanical and electrical properties. Moreover, when carbon nanotubes are added to epoxy resin, intelligent composite materials with significant sensitivity are created. In this study, the stress–strain curves and anelasticity of carbon nanotube/epoxy resin composites with different carbon nanotube concentrations is analyzed. Through changing the level of carbon nanotubes using the two-pole method, the percolation threshold of carbon nanotube/epoxy composites was determined. Thereafter, the effect of temperature on the composites’ conductive properties was investigated. Moreover, using the stepwise cyclic loading method, the piezoresistivity of the carbon nanotube/epoxy composites was investigated. The test results show that the elastic limit, the yield point, and the elastic modulus range of the carbon nanotube/epoxy composites is approximately 45 MPa, 50 MPa, and 1–2 GPa, respectively. The anelasticity of the carbon nanotube/epoxy composites increases with the gradual increase of the stress level. The percolation threshold interval of carbon nanotube/epoxy composites ranges from 0.5 to 1.0 wt%. The rate of change of resistance for the different concentrations on carbon nanotube/epoxy specimens corresponds to the temperature. Notably, the carbon nanotube/epoxy composites have better discrimination and pressure sensitivity for different grades of load. When the carbon nanotube content is 0.5 wt%, the sensitivity of the carbon nanotube/epoxy composites pressure-sensitive property is the largest, which is in agreement with the threshold curve. The results of this investigation have implications for the application of carbon nanotube/epoxy composites in structural health monitoring.

Effects of Carboxyl Functionalized Carbon Nanotube on the Tensile Strength and Wear Resistance of Epoxy Composites

2014 ◽  
Vol 809-810 ◽  
pp. 175-179
Author(s):  
Li He Mao ◽  
Hong Zhang Geng ◽  
Wen Yi Wang ◽  
Li Jun Cui ◽  
Chang Rui Cui ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Epoxy Composites ◽  
Functionalized Carbon Nanotubes ◽  
Structure Characteristics ◽  
Functionalization Of Carbon Nanotubes ◽  
Carboxyl Functionalization

Epoxy resin presents 3D cross-linking network structure characteristics after curing, resulting in a lower wear resistance of epoxy resin, which limits its extensive applications. In this paper, the effects of adding carboxyl functionalized carbon nanotubes on the tensile strength and wear resistance of carbon nanotube/epoxy composites were studied. The results showed that the tensile strength and wear resistance of the composites were effectively improved through carboxyl functionalization of carbon nanotubes.

The influence of functionalization time of carbon nanotube on the mechanical properties of the epoxy composites

2017 ◽  
Vol 51 (12) ◽  
pp. 1693-1701 ◽  
Author(s):  
EA Zakharychev ◽  
EN Razov ◽  
Yu D Semchikov ◽  
NS Zakharycheva ◽  
MA Kabina
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Polymer Composites ◽  
Epoxy Composites ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

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.

scholarly journals Dielectric Spectroscopy and Tunability of Multi-Walled Carbon Nanotube / Epoxy Resin Composites

2010 ◽  
Vol 19 (6) ◽  
pp. 096369351001900 ◽  
Author(s):  
Z Špitalský ◽  
S N Georga ◽  
C A Krontiras ◽  
C Galiotis
Keyword(s):  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Temperature Region ◽  
Dielectric Response ◽  
Effective Dielectric Constant ◽  
Free Energy Barrier ◽  
Resin Composites ◽  
Multi Walled Carbon Nanotube ◽  
Epoxy Resin Composites

The dielectric response of oxidized multi-walled carbon nanotube / epoxy resin composites, is investigated with respect to filler content concentration, over a wide temperature and frequency range. Specimens, below the percolation threshold, exhibit similar behaviour to that of the neat epoxy. Two relaxation modes are observed in the low temperature region, attributed to the re-arrangement of small parts of the polymer chain (γ-mode) and the reorientation of polar side groups (β-mode) respectively, where in the high temperature region the evolution of the α-mode is present. Direct current (DC) conduction follows the Vogel – Tamann - Fulcher equation as expected. The dielectric response of specimens, above the percolation threshold, follows the “Random Free Energy Barrier Model”. DC conductivity exhibits Arrhenius temperature dependence with two distinct regions. The activation energies of both regions were evaluated. The contact resistance between two adjacent carbon nanotubes was also calculated. The effective dielectric constant as well as the capacitance of the specimens, above the percolation threshold, can be modulated by means of an applied DC bias voltage.

scholarly journals Effect of structure regulation of hyper-branched polyester modified carbon nanotubes on toughening performance of epoxy/carbon nanotube nanocomposites

RSC Advances ◽  
2019 ◽  
Vol 9 (23) ◽  
pp. 12864-12876 ◽  
Author(s):  
Lu Li ◽  
Xia Liao ◽  
Xingyue Sheng ◽  
Zengheng Hao ◽  
Leilei He ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Hyperbranched Polyesters ◽  
Structure Regulation ◽  
Modified Carbon Nanotubes ◽  
Effect Of Structure ◽  
Properties Of Composites

Carboxylic carbon nanotubes were modified by a series of hyperbranched polyesters (HBP), and epoxy resin/carbon nanotubes composites were prepared. The effect of structure regulation of HBP on toughening properties of composites was discussed.

scholarly journals Simulation of Percolation Threshold, Tunneling Distance, and Conductivity for Carbon Nanotube (CNT)-Reinforced Nanocomposites Assuming Effective CNT Concentration

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 114 ◽  
Author(s):  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Experimental Results ◽  
Filler Concentration ◽  
Experimental Measurements ◽  
Tunneling Conductivity ◽  
Tunneling Distance

This article suggests simple and new equations for the percolation threshold of nanoparticles, the tunneling distance between nanoparticles, and the tunneling conductivity of polymer carbon nanotubes (CNTs) nanocomposites (PCNT), assuming an effective filler concentration. The developed equations correlate the conductivity, tunneling distance, and percolation threshold to CNT waviness, interphase thickness, CNT dimensions, and CNT concentration. The developed model for conductivity is applied for some samples and the predictions are evaluated by experimental measurements. In addition, the impacts of various parameters on the mentioned terms are discussed to confirm the developed equations. Comparisons between the calculations and the experimental results demonstrate the validity of the developed model for tunneling conductivity. High levels of CNT concentration, CNT length, and interphase thickness, as well as the straightness and thinness of CNTs increase the nanocomposite conductivity. The developed formulations can substitute for the conventional equations for determining the conductivity and percolation threshold in CNT-reinforced nanocomposites.

Static and Fatigue Strengths of Carbon Nanotube/Epoxy Composites under Hygrothermal Environments

2013 ◽  
Vol 284-287 ◽  
pp. 204-210
Author(s):  
Yi Ming Jen ◽  
Chien Yang Huang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Stress Concentration ◽  
Interfacial Adhesion ◽  
Epoxy Composites ◽  
Hygrothermal Effect ◽  
Multi Walled Carbon Nanotubes ◽  
Hygrothermal Environments ◽  
Stress Concentration Effect ◽  
Walled Carbon Nanotubes

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.

Microstructure and Mechanical Property of Carbon Nanotube and Continuous Carbon Fiber Reinforced Epoxy Resin Matrix Composites

2006 ◽  
Vol 11-12 ◽  
pp. 517-520 ◽  
Author(s):  
Dong Lin Zhao ◽  
Ren Hai Qiao ◽  
Cheng Zhong Wang ◽  
Zeng Min Shen
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Resin Matrix ◽  
Internal Diameter ◽  
Matrix Composites ◽  
Epoxy Resin Matrix ◽  
Continuous Carbon Fiber

The carbon nanotubes (CNTs) were prepared by catalytic decompose of benzene using floating transition method at 1100-1200°C. Benzene was used as carbon source and ferrocene as catalyst with thiophene. The carbon nanotubes are straight with diameter 20-50 nm, internal diameter 10-30 nm and length 50-1000 μm. The carbon nanotube and continuous carbon fiber (T300) reinforced unidirectional epoxy resin matrix composites was fabricated. The volune fraction of continuous carbon fiber (first filler) in the composites without second filler (carbon nanotube) was 60%. The mechanical properties of the composites were investigated under bending, shear, and impact loading. The flexural strength and modulus of the composites increased firstly and then decreased with the increasing of carbon nanotube contents in epoxy resin matrix. The flexural strength of the composites reached the maximum value of 1780 MPa when the weight percent of carbon nanotube in epoxy resin matrix was 3%.

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