Strain-sensitive electrical conductivity of carbon nanotube-graphene-filled rubber composites under cyclic loading

Nanoscale ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 578-586 ◽  
Author(s):  
Heng Yang ◽  
XueFeng Yao ◽  
Li Yuan ◽  
LinHui Gong ◽  
YingHua Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Rubber Composites ◽  
Resistance Response ◽  
Conductive Nanocomposites ◽  
Filled Rubber

We investigated the resistance response mechanisms and provided a resistance regulation strategy for conductive nanocomposites.

scholarly journals Electrical Properties Enhancement of Carbon Nanotube Yarns by Cyclic Loading

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4824
Author(s):  
Orli Weizman ◽  
Joey Mead ◽  
Hanna Dodiuk ◽  
Samuel Kenig
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Electrical Resistance ◽  
High Performance ◽  
High Strength ◽  
Intrinsic Properties ◽  
Ambient Conditions ◽  
Resistance Value ◽  
Carbon Nanotube Yarns

Carbon nanotube yarns (CNTYs) possess low density, high conductivity, high strength, and moderate flexibility. These intrinsic properties allow them to be a preferred choice for use as conductive elements in high-performance composites. To fully exploit their potential as conductive reinforcing elements, further improvement in their electrical conductivity is needed. This study demonstrates that tensile cyclic loading under ambient conditions improves the electrical conductivity of two types of CNTYs. The results showed that the electrical resistance of untreated CNTYs was reduced by 80% using cyclic loading, reaching the resistance value of the drawn acid-treated CNTYs. Scanning electron microscopy showed that cyclic loading caused orientation and compaction of the CNT bundles that make up the CNTYs, resulting in significantly improved electrical conductivity of the CNTYs. Furthermore, the elastic modulus was increased by 20% while preserving the tensile strength. This approach has the potential to replace the environmentally unfriendly acid treatment currently used to enhance the conductivity of CNTYs.

Effect of Nano-Particle Filler Type on the Piezoresistance of Polyethylene Composites

2011 ◽  
Author(s):  
Reza Rizvi ◽  
Brendan Cochrane ◽  
Elaine Biddiss ◽  
Hani Naguib
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Time Dependence ◽  
Percolation Threshold ◽  
Nano Particle ◽  
Melt Blending ◽  
Single Wall Carbon ◽  
Different Types

This study examines the piezoresistive behavior of polyethylene (PE) composites containing different types of nano-particle fillers. The fillers investigated are single-wall carbon nanotube (SWNT), multi-wall carbon nanotube (MWNT) and graphene nanoplatelets (GNP), which were dispersed in PE through melt blending in concentrations ranging between 0.5–10 wt%. The lowest percolation threshold and highest electrical conductivity was found for SWNT composites, followed by MWNT and GNP. The piezoresistance of the nano-particle-PE composites was investigated and a negative piezoresistance behavior was observed signifying a reducing mean inter-particulate distance in the composites. The highest sensitivity was exhibited by MWNT and SWNT composites at compositions closer to the percolation threshold. The time dependence of piezoresistivity was also investigated through stress relaxation and cyclic loading experiments.

scholarly journals Influence of Carbon Nanotube-Pretreatment on the Properties of Polydimethylsiloxane/Carbon Nanotube-Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1355
Author(s):  
Astrid Diekmann ◽  
Marvin C. V. Omelan ◽  
Ulrich Giese
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Mechanical Performance ◽  
Softening Effect ◽  
Electrical Percolation ◽  
Optimum Parameters ◽  
Lauryl Ether ◽  
Solvent Residues ◽  
Electrical Percolation Threshold ◽  
Filler Dispersion

Incorporating nanofillers into elastomers leads to composites with an enormous potential regarding their properties. Unfortunately, nanofillers tend to form agglomerates inhibiting adequate filler dispersion. Therefore, different carbon nanotube (CNT) pretreatment methods were analyzed in this study to enhance the filler dispersion in polydimethylsiloxane (PDMS)/CNT-composites. By pre-dispersing CNTs in solvents an increase in electrical conductivity could be observed within the sequence of tetrahydrofuran (THF) > acetone > chloroform. Optimization of the pre-dispersion step results in an AC conductivity of 3.2 × 10−4 S/cm at 1 Hz and 0.5 wt.% of CNTs and the electrical percolation threshold is decreased to 0.1 wt.% of CNTs. Optimum parameters imply the use of an ultrasonic finger for 60 min in THF. However, solvent residues cause a softening effect deteriorating the mechanical performance of these composites. Concerning the pretreatment of CNTs by physical functionalization, the use of surfactants (sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene lauryl ether (“Brij35”)) leads to no improvement, neither in electrical conductivity nor in mechanical properties. Chemical functionalization enhances the compatibility of PDMS and CNT but damages the carbon nanotubes due to the oxidation process so that the improvement in conductivity and reinforcement is superimposed by the CNT damage even for mild oxidation conditions.

Dual percolations of electrical conductivity and electromagnetic interference shielding in progressively agglomerated CNT/polymer nanocomposites

2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Polymer Nanocomposites ◽  
Electromagnetic Interference ◽  
Effective Medium Theory ◽  
Scale Model ◽  
Shielding Effectiveness ◽  
Emi Shielding

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.

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