scholarly journals A Comparative Study of the Electrical and Electromechanical Responses of Carbon Nanotube/Polypropylene Composites in Alternating and Direct Current

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 484
Author(s):  
Abraham Balam ◽  
Raúl Pech-Pisté ◽  
Zarel Valdez-Nava ◽  
Fidel Gamboa ◽  
Alejandro Castillo-Atoche ◽  
...  
Keyword(s):  
Direct Current ◽  
Significant Contribution ◽  
Electrical Response ◽  
Multiwall Carbon Nanotubes ◽  
Nanocomposite Films ◽  
Sensitivity Factor ◽  
Polypropylene Composites ◽  
Electromechanical Responses ◽  
Multiwall Carbon ◽  
Higher Sensitivity

The electrical and electromechanical responses of ~200 µm thick extruded nanocomposite films comprising of 4 wt.% and 5 wt.% multiwall carbon nanotubes mixed with polypropylene are investigated under an alternating current (AC) and compared to their direct current (DC) response. The AC electrical response to frequency (f) and strain (piezoimpedance) is characterized using two configurations, namely one that promotes resistive dominance (resistive configuration) and the other that promotes the permittivity/capacitive contribution (dielectric configuration). For the resistive configuration, the frequency response indicated a resistive–capacitive (RC) behavior (negative phase angle, θ), with a significant contribution of capacitance for frequencies of 104 Hz and above, depending on the nanotube content. The piezoimpedance characterization in the resistive configuration yielded an increasing impedance modulus (|Z|) and an increasing (negative) value of θ as the strain increased. The piezoimpedance sensitivity at f = 10 kHz was ~30% higher than the corresponding DC piezoresistive sensitivity, yielding a sensitivity factor of 9.9 for |Z| and a higher sensitivity factor (~12.7) for θ. The dielectric configuration enhanced the permittivity contribution to impedance, but it was the least sensitive to strain.

Anisotropic thermal conductivity of polypropylene composites filled with carbon fibers and multiwall carbon nanotubes

2014 ◽  
Vol 36 (11) ◽  
pp. 1951-1957 ◽  
Author(s):  
Ilya Mazov ◽  
Igor Burmistrov ◽  
Igor Il'inykh ◽  
Andrey Stepashkin ◽  
Denis Kuznetsov ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Fibers ◽  
Multiwall Carbon Nanotubes ◽  
Polypropylene Composites ◽  
Anisotropic Thermal Conductivity ◽  
Multiwall Carbon

Nucleation ability of multiwall carbon nanotubes in polypropylene composites

2003 ◽  
Vol 41 (5) ◽  
pp. 520-527 ◽  
Author(s):  
E. Assouline ◽  
A. Lustiger ◽  
A. H. Barber ◽  
C. A. Cooper ◽  
E. Klein ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Polypropylene Composites ◽  
Multiwall Carbon

Optical Transport Properties of Oriented Isotactic Polypropylene and Carbon Nanotube Nanocomposite Thin Films

2012 ◽  
Vol 1410 ◽  
Author(s):  
Sabyasachi Sarkar ◽  
Parvathalu Kalakonda ◽  
Georgi Y. Georgiev ◽  
Germano S. Iannacchione ◽  
Peggy Cebe
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Isotactic Polypropylene ◽  
Optical Transmission ◽  
Multiwall Carbon Nanotubes ◽  
Index Of Refraction ◽  
Nanocomposite Films ◽  
Nanocomposite Thin Films ◽  
Optical Transport ◽  
Multiwall Carbon

ABSTRACTOptical transport through Isotactic Polypropylene (iPP) and multiwall carbon nanotubes (MWCNTs) nanocomposite thin films is important to many applications where optical transmission or polarization are used. Especially interesting is the case where the optical properties are anisotropic as in oriented thin films and the optical transport is different in the direction of orientation and perpendicular to it. Changing the orientation of the film or the polarization of the light can change the way in which the nanocomposite film interacts with light. Our polymer of choice, Isotactic Polypropylene, is one of the most widely used polymers which will increase the applicability of our results. We blended iPP with different concentration of carbon nanotubes (CNTs): 1%, 2% and 5% and oriented the thin film samples using melt-shear at 200°C and 1Hz in a Linkam microscope sharing hot stage. We measured that the index of refraction of the nanocomposites slightly decreased when CNTs are added and that when nanocomposites were shear-oriented at low loading of CNTs the index of refraction showed small difference in directions parallel and perpendicular to the direction of orientation. The extinction coefficient increased therefore it’s tuning in the nanocomposite films by the content of the carbon nanotubes can help devise new materials with the desired values of this property.

Electrical self-sensing of strain and damage of thermoplastic hierarchical composites subjected to monotonic and cyclic tensile loading

2019 ◽  
Vol 30 (10) ◽  
pp. 1527-1537 ◽  
Author(s):  
O Rodríguez-Uicab ◽  
C Martin-Barrera ◽  
A May-Pat ◽  
A Can-Ortiz ◽  
PI Gonzalez-Chi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrical Response ◽  
Multiwall Carbon Nanotubes ◽  
Tensile Loading ◽  
Multiwall Carbon Nanotube ◽  
Aramid Fibers ◽  
Hierarchical Composites ◽  
Polypropylene Matrix ◽  
Multiwall Carbon

Electrical monitoring of strain and damage in multiscale hierarchical composites comprising unidirectional aramid fibers modified by multiwall carbon nanotubes and polypropylene as matrix is investigated. The key factor for electrical self-sensing in these thermoplastic composites is the formation of a multiwall carbon nanotube network, which is achieved by using two material architectures. In the first architecture, the multiwall carbon nanotubes are dispersed within the polypropylene matrix, while aramid fibers remain unmodified. The second architecture uses also multiwall carbon nanotube-modified polypropylene matrix, but the aramid fibers are also modified by depositing multiwall carbon nanotubes. Under tensile loading, the electrical response is nonlinear with strain ( ε), and the piezoresistive sensitivity was quantified by gage factors corresponding to low ( ε < 0.25%) and high ( ε > 0.3%) strain regimes. Such gage factors were 4.83 (for ε < 0.25%) and 13.2 (for ε > 0.3%) for composites containing multiwall carbon nanotubes only in the polypropylene matrix. The composites containing multiwall carbon nanotubes in the matrix and fibers presented higher piezoresistive sensitivity, with average gage factors of 9.24 ( ε < 0.25%) and 14.0 ( ε > 0.3%). The higher sensitivity to strain and damage for a specific material architecture was also evident during cyclic and constant strain loading programs and is attributed to the preferential localization of multiwall carbon nanotubes in the hierarchical composite.

Research on the Gas Sensing Enhancement by Using CNT/ZnO Composites

2013 ◽  
Vol 562-565 ◽  
pp. 1522-1526
Author(s):  
Ling Min Yu ◽  
Xin Hui Fan ◽  
Jing Yi Shui ◽  
Li Jun Qi ◽  
Wen Yan
Keyword(s):  
Gas Sensing ◽  
Multiwall Carbon Nanotubes ◽  
Weight Ratio ◽  
Fast Response ◽  
Zno Nanowires ◽  
Zno Films ◽  
Response Recovery ◽  
Hybrid Sensors ◽  
Multiwall Carbon ◽  
Higher Sensitivity

Multiwall carbon nanotubes (CNT) were added into ZnO matrix to develop a CNTs/ZnO composite gas sensor. The hybrid sensor is used to detect CO in air by measuring resistance changes of thin CNTs/ZnO films at different working temperature. For comparison, pure ZnO and CNT/ZnO sensors are also examined. The gas sensing results reveal that CNTs/ZnO with the weight ratio (9:100) hybrid sensors exhibit much higher sensitivity and fast response-recovery properties towards CO, at 240°C than the blank ZnO nanowires. Hybrid material of ZnO nanowires and CNT composites could potentially display not only the unique properties of nanowires and those of CNTs, but also an additional novel property.

Boehmite Nanofibers as a Dispersant for Nanotubes in an Aqueous Sol

2018 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Aqueous Solutions ◽  
High Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
Multiwall Carbon ◽  
Nanotube Films

By exploiting the dispersibility and rigidity of boehmite nanofibers (BNFs) with a high aspect ratio of 4 nm in diameter and several micrometers in length, multiwall-carbon nanotubes (MWCNTs) were successfully dispersed in aqueous solutions. In these sols, the MWCNTs were dispersed at a ratio of about 5–8% relative to BNFs. Self-standing BNF–nanotube films were also obtained by filtering these dispersions and showing their functionality. These films can be expected to be applied to sensing materials.

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