Novel phthalocyanine crystals as a conductive filler in crosslinked epoxy materials: Fractal particle networks and low percolation thresholds

Chen, Z Zhe; Brokken-Zijp, Jcm José; Michels, Maj Thijs

doi:10.1002/polb.20670

Cited by 20 publications

(38 citation statements)

References 26 publications

(44 reference statements)

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“…Up to now, there have been many investigations on reducing the percolation threshold by manipulating the distribution of CB particles, such as multipercolation, [19][20][21][22] segregated distribution, 14,17,23 and electrical field-induced method, 24 etc. Multipercolation is an effective technology through melt mixing method.…”

Section: Introductionmentioning

confidence: 99%

Preparation of carbon black/polypropylene nanocomposite with low percolation threshold using mild blending method

Liu

Yang

2009

J of Applied Polymer Sci

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A new approach, mild blending method, to prepare carbon black (CB) filled polypropylene (PP) nanocomposite using CB aqueous suspension was reported in this study. In this compounding process, the CB particles were first dispersed in aqueous suspension by using an ultrasonic irradiation. Subsequently, the CB suspension was blended with melting PP using an extruder with low shear strength screw configuration, followed by removing the vapor from the vent by vacuum. The morphological observation showed that the CB particles were dispersed at a nanometer level in the nanocomposites as they were in aqueous suspension and distributed homogeneously in PP matrix. The CB/PP nanocomposite prepared by this method exhibited a very low percolation threshold, i.e., 2.49 vol %, and a high-critical resistance exponent t (t ¼ 5.82). These phenomena, which deviated from the classical percolation theory, were likely to come down to the homogeneous distribution of CB particles and the tunneling conduction.

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Section: Introductionmentioning

confidence: 99%

Preparation of carbon black/polypropylene nanocomposite with low percolation threshold using mild blending method

Liu

Yang

2009

J of Applied Polymer Sci

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“…11, 14,15,21 Another problem is that the networks may be distributed in an inhomogeneous way through the matrix. 22 Fractal network geometry is closely related to percolation theory and, at present, is sometimes used to quantify the particle network morphological features of conducting polymer composites. 14,15,23 Fractal geometry was initially developed by Mandelbrot, 24 and at present, the theory of fractal structures is extensively employed in many branches of physics, chemistry, and mechanics.…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown earlier that a semiconductive homogeneous thin Phthalcon 11/epoxy layer can be made with a low percolation threshold. 22 This low percolation threshold was explained by the formation of a fractal particle network because of the large surface tension difference between particle and matrix. 22 We here describe that also other factors may have a large influence on the φ c and σ v of cross-linked Phthalcon 11/epoxy materials.…”

Section: Introductionmentioning

confidence: 99%

Cross-Linked Epoxy Composites Filled with Intrinsically Conductive Phthalocyanine Nanocrystals. Influence of Filler Amount, Layer Thickness, and Cross-Linkers Used on the Percolation Threshold and Conductivity Level of the Composites

Chen¹,

Brokken-Zijp²,

Huinink³

et al. 2006

Macromolecules

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Novel aquocyanophthalocyaninatocobalt(III) (Phthalcon 11) nanocrystals were used as intrinsically conducting fillers in cross-linked epoxy composites. The prepared conductive composites had a percolation threshold φ c between 0.9 and 9 vol %. The φ c appeared to be strongly dependent on layer thickness. Modeling showed that when the layer thickness was sufficiently large the φ c could be as low as 0.55 vol %. The occurrence of such a low and variable φ c was explained by the presence of a percolating Phthalcon 11 fractal particle network. Quantitative fractal analysis of these networks indicates that these networks were formed by diffusion-limited cluster−cluster aggregation of the small primary Phthalcon 11 fractal aggregates, which were already present in the Phthalcon 11 powder itself. Moreover, it was found that φ c and σv also strongly depended on the choice of the cross-linker used and on the chosen processing conditions for making the epoxy molecular network, such as cross-linking temperature and gel time. Rheological experiments were done, and models were proposed to explain these unexpected phenomena. The results presented here suggest that also in other thermoset matrices containing other (non)conductive nanoparticles the above-mentioned factors may have a major impact on the final particle distribution in the matrix and therefore on the final material properties of these composites.

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“…Conductive polymer composites (CPCs) are designed by mixing an insulating polymeric matrix with conductive fillers. Typically, conductive fillers are metallic powders or carbonaceous fillers containing graphite, carbon black, and carbon fibers [1]. Substantial effort has been devoted in the past decade to understanding the features of CPCs with respect to conductivity changes under external stimuli, such as thermal, electrical, mechanical, or chemical stresses [2].…”

Section: Introductionmentioning

confidence: 99%

Thermoplastic Starch–Based Composite Reinforced by Conductive Filler Networks: Physical Properties and Electrical Conductivity Changes during Cyclic Deformation

et al. 2021

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Conductive polymer composites (CPC) from renewable resources exhibit many interesting characteristics due to their biodegradability and conductivity changes under mechanical, thermal, chemical, or electrical stress. This study is focused on investigating the physical properties of electroconductive thermoplastic starch (TPS)–based composites and changes in electroconductive paths during cyclic deformation. TPS–based composites filled with various carbon black (CB) contents were prepared through melt processing. The electrical conductivity and physicochemical properties of TPS–CB composites, including mechanical properties and rheological behavior, were evaluated. With increasing CB content, the tensile strength and Young’s modulus were found to increase substantially. We found a percolation threshold for the CB loading of approximately 5.5 wt% based on the rheology and electrical conductivity. To observe the changing structure of the conductive CB paths during cyclic deformation, both the electrical conductivity and mechanical properties were recorded in parallel using online measurements. Moreover, the instant electrical conductivity measured online during mechanical deformation of the materials was taken as the parameter indirectly describing the structure of the conductive CB network. The electrical conductivity was found to increase during five runs of repeated cyclic mechanical deformations to constant deformation below strain at break, indicating good recovery of conductive paths and their new formation.

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Novel phthalocyanine crystals as a conductive filler in crosslinked epoxy materials: Fractal particle networks and low percolation thresholds

Cited by 20 publications

References 26 publications

Preparation of carbon black/polypropylene nanocomposite with low percolation threshold using mild blending method

Preparation of carbon black/polypropylene nanocomposite with low percolation threshold using mild blending method

Cross-Linked Epoxy Composites Filled with Intrinsically Conductive Phthalocyanine Nanocrystals. Influence of Filler Amount, Layer Thickness, and Cross-Linkers Used on the Percolation Threshold and Conductivity Level of the Composites

Thermoplastic Starch–Based Composite Reinforced by Conductive Filler Networks: Physical Properties and Electrical Conductivity Changes during Cyclic Deformation

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