Inverse TMR Effect in a Granular Fe3O4/CrO2 System near the Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

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Electrically Conductive Ti3C2Tx MXene/Polypropylene Nanocomposites with an Ultralow Percolation Threshold for Efficient Electromagnetic Interference Shielding

Industrial & Engineering Chemistry Research ◽

10.1021/acs.iecr.1c00320 ◽

2021 ◽

Vol 60 (11) ◽

pp. 4342-4350 ◽

Cited By ~ 2

Author(s):

Ming-Ke Xu ◽

Ji Liu ◽

Hao-Bin Zhang ◽

Yu Zhang ◽

Xinyu Wu ◽

...

Keyword(s):

Percolation Threshold ◽

Electromagnetic Interference ◽

Electromagnetic Interference Shielding ◽

Electrically Conductive ◽

Polypropylene Nanocomposites

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D.C. conductivity calculation and the percolation threshold in dilute Bethe lattices

Solid State Communications ◽

10.1016/0038-1098(90)90392-o ◽

1990 ◽

Vol 76 (12) ◽

pp. 1387-1390 ◽

Cited By ~ 5

Author(s):

A. Latgé ◽

E.V. Anda

Keyword(s):

Percolation Threshold ◽

Bethe Lattices

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

Mathematics and Mechanics of Solids ◽

10.1177/10812865211021460 ◽

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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