Influence of particle size and shape on electrical and mechanical properties of graphite reinforced conductive polymer composites for the bipolar plate of PEM fuel cells

Heo, Seungyang; Yun, Jooyeong; Oh, Keun Sang; Han, Kap Su

doi:10.1163/156855106776829356

Cited by 67 publications

(31 citation statements)

References 22 publications

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“…Bauhofer and Kovacs 1 have indicated t values obtained from experiments for three-dimensional percolating systems between 1.3 and 4. Other studies have also shown that the percolation threshold is dependent of conductive fillers morphology (size, shape and the aspect ratio) [30][31][32][33] . In this piece of work, the value of t obtained was 2.34 ± 0.19 for a regression coefficient of 0.94, which is evidence of a three-dimensional conductive network of MWCNT into the polymer matrix.…”

Section: Volumetric Electrical Conductivitymentioning

confidence: 93%

Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites

et al. 2014

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Nanocomposites of poly (methyl methacrylate) (PMMA) and carbon nanotubes have a high potential for applications where conductivity and low specific weight are required. This piece of work concerns investigations of the level of dispersion and morphology on the electrical properties of in situ polymerized nanocomposites in different concentrations of multi-walled carbon nanotubes (MWCNT) in a PMMA matrix. The electrical conductivity was measured by the four point probe. The morphology and dispersion was analyzed by Transmission Electron Microscopy (TEM) and Small Angle X-ray Scattering (SAXS). The correlation between electrical conductivity and the MWCNT amount, presented a typical percolation behavior, whose electrical percolation threshold determined by power law relationship was 0.2 vol. (%) The exponent t from the percolation power law indicated the formation of a 3D network of randomly arranged MWCNT. SAXS detected that the structures are intermediate to disks or spheres indicating fractal geometry for the MWCNT aggregates instead of isolated rods. HR-TEM images allowed us to observe the MWCNT individually dispersed into the matrix, revealing their distribution without preferential space orientation and absence of significant damage to the walls. The combined results of SAXS and HR-TEM suggest that MWCNT into the polymeric matrix might present interconnected aggregates and some dispersed single structures.

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Section: Volumetric Electrical Conductivitymentioning

confidence: 93%

Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites

et al. 2014

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“…In this case, molds had to be cooled down to room temperature before dispersion of the blend to prevent the mixed blend from curing. Figure 5 represents the curing cycle of the existing compression molding method [18]. …”

Section: Fabricationmentioning

confidence: 99%

“…These works have been carried out with respect to the size, shape and weight contents of fillers, etc. [16][17][18][19]. Many researchers have focused on the commercialization of PEM fuel cells, especially the reduction of the cost and weight of the bipolar plates [20,21].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Expanded Graphite Filled Conductive Polymer Composites for PEM Fuel Cell Bipolar Plates

Heo

Yun

et al. 2008

Advanced Composite Materials

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This study aims to optimize the mechanical and electrical properties of electrically conductive polymer composites (CPCs) for use as a material of bipolar plates for PEM fuel cells. The thin CPCs consisting of conductive fillers and polymer resin were fabricated by a preform molding technique. Expanded graphite (EG), flake-type graphite (FG) and carbon fiber (CF) were used as conductive fillers. This study tested two types of CPCs, EG/FG filled CPCs and EG/CF filled CPCs, to optimize the material properties. First, the characteristics of EG/FG filled CPCs were investigated according to the FG ratio for 7 and 100 µm sized FG. CPCs using 100 µm FG showed optimal material properties at 60 wt% FG ratio, which were an electrical conductivity of 390 S/cm and flexural strength of 51 MPa. The particle size was an important parameter to change the mechanical and electrical behaviors. The flexural strength was sensitive to the particle size due to the different levels of densification. The electrical conductivity also showed size-dependent behavior because of the different contributions to the conductive network. Meanwhile, the material properties of EG/CF filled CPCs was also optimized according to the CF ratio, and the optimized electrical conductivity and flexural strength were 290 S/cm and 58 MPa, respectively. The electrical conductivity of this case decreased similarly to the EG/FG filled case. On the other hand, the behavior of the flexural strength was more complicated than the EG/FG filled case, and the reason was attributed to the interaction between the strengthening effect of CF and the deterioration of voids.

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“…A traditional approach in fabrication of such a composite material is addition of electrically conductive fillers into insulating polymer to incorporate two complementary properties of electrical conductivity and processability. For example, carbon fillers such as graphite, carbon black and carbon fibers are commercially added to the insulating polymers [4][5][6][7][8]. They have advantages of low density and good conductivity; however, the addition of a high amount of carbon fillers for producing conductivity causes increase of viscosity resulting in degradation of processability.…”

Section: Introductionmentioning

confidence: 99%

Novel method of polymer/low-melting-point metal alloy/light metal fiber composite fabrication

Park¹,

Shin²

2016

Express Polym. Lett.

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Abstract.A novel method of polymer/low-melting-point metal alloy (LMA)/light metal fiber composite fabrication is proposed to solve problems of polymer/metal composites. The first step is mixing light metal particles with LMA at a temperature above the melting point of the LMA. The second step is cold extrusion of the LMA/light metal particles to fabricate LMA/light metal fibers. Thus, the LMA/light metal fibers with a density of ~4.5 g/cm 3 were obtained. The last step is compounding a polymer with the LMA/light metal fibers at the processing temperature of the polymer above the melting points of the LMA. The effects of the length and the cross-sectional shape of light metal fiber on the morphology of the LMA/light metal fibers in the polymer matrix were studied, as were electrical conductivities and mechanical properties of the composites. As the length and/or the cross-sectional aspect ratio of the fibers was increased, the domains of LMA/light metal fibers formed more networks so that the electrical conductivity increased, and specific surface area of the domains increased so that notched Izod impact strength was improved. Thus, the polymer/LMA/light metal fiber composites were fabricated without degrading processability even at 60 vol% loading and the electrical conductivities over 10 3 S/cm were achieved.

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Influence of particle size and shape on electrical and mechanical properties of graphite reinforced conductive polymer composites for the bipolar plate of PEM fuel cells

Cited by 67 publications

References 22 publications

Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites

Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites

Characteristics of Expanded Graphite Filled Conductive Polymer Composites for PEM Fuel Cell Bipolar Plates

Novel method of polymer/low-melting-point metal alloy/light metal fiber composite fabrication

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