The imaging mechanism, imaging depth, and parameters influencing the visibility of carbon nanotubes in a polymer matrix using an SEM

Li, Wenjing; Buschhorn, Samuel T.; Schulte, Karl; Bauhofer, W.

doi:10.1016/j.carbon.2010.12.069

Cited by 43 publications

(37 citation statements)

References 20 publications

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“…It is noted that clear conductive network can be observed, nevertheless, no network can be observed in the representative picture from CPCs containing 0.5 wt% hybrid filler (MWNTs:CB) in the ratio of: 4:1, 1:4, 5:0, 0:5. This further con- Zhang et al -eXPRESS Polymer Letters Vol.6, No.2 (2012) firms the presence of conductive network in the CPCs containing 0.25 wt% MWNTs and 0.25 wt% CB, and the absence of that in the rest, as non-conductive specimens are charged up during voltage contrast imaging in SEM [35,36]. It is well known that MWNTs has higher conductivity than CB.…”

mentioning

confidence: 74%

“…More SEM study is carried out to further investigate their morphology. firms the presence of conductive network in the CPCs containing 0.25 wt% MWNTs and 0.25 wt% CB, and the absence of that in the rest, as non-conductive specimens are charged up during voltage contrast imaging in SEM [35,36]. It is well known that MWNTs has higher conductivity than CB.…”

Section: Morphology Of the Compositesmentioning

confidence: 98%

“…High accelerating voltage is applied to give enriched secondary electrons to perform voltage contrast imaging as demonstrated in literature [34][35][36]. Figure 3a and 3b shows the morphology of the conductive network formed by MWNTs and CB, respectively, and Figure 3c, 3d and 3e shows that of hybrid fillers, where the bright phase is conductive filler and the black background is co-PP matrix.…”

Section: Morphology Of the Compositesmentioning

confidence: 99%

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Synergistic effect in conductive networks constructed with carbon nanofillers in different dimensions

Zhang¹,

Li²,

Deng³

et al. 2012

Express Polym. Lett.

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Abstract. Herein, investigation on synergistic effect during network formation for conductive network constructed with carbon nanofillers in different dimensions is conducted. Multi-walled carbon nanotubes (MWNTs) and carbon black (CB) are employed as conductive fillers in this system. Morphological control of the conductive network is realized by adjusting the ratio between different fillers. Classical percolation threshold theory and adjusted excluded volume theory are used to analyze the electrical percolating behavior of these systems. It is observed that the percolation threshold of hybrid fillers filled conductive polymer composites (CPCs) is much lower than that of MWNTs or CB filled CPCs, and it can be reduced from 2.4 to 0.21 wt% by replacing half of the MWNTs with CB. Possible mechanism of this phenomenon is discussed together with morphological observation. A model is proposed to understand the mechanism of the percolation behavior in the composites containing various proportions of nanofillers. Our work is important for the design and preparation of low cost conductive polymer composites with novel electrical property. Vol.6, No.2 (2012) 159-168 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2012.17 * Corresponding author, e-mail: huadeng@scu.edu.cn © BME-PT PE/MWNTs composites prepared by melt blending. The value is often between 1 to 5 wt% for melt compounded systems and considered as statistical percolation threshold [22]. The mechanism behind this significant difference between kinetic and statistical percolation is the prohibition of re-aggregation between CNTs during melt compounding process [22,24]. It was reported that the re-aggregation process of CNTs within polymer melt can take hours to complete [25]. To achieve better conductivity or lower cost, more than one kind of filler, particularly fillers in different aspect ratios, are used to prepare CPCs. Regarding the formation of conductive network with fillers in different aspect ratios, theoretical study has shown that it is not necessary to build conductive network with high aspect ratio filler alone [26], and the percolation threshold is sensitive to the portion of high aspect ratio filler in a system containing fillers in different aspect ratios [27]. There are a number of investigations reported in the literature on mixed carbon fillers filled CPCs [26,[28][29][30][31]. However, the percolation thresholds of these systems filled with mixed fillers are only simple average of that for systems filled with a particular kind of carbon filler. Therefore, more study is needed to study the true synergistic effect between conductive fillers of different dimensionality in building conductive network. In current study, CPCs based on mixed filler between carbon nanofillers in different dimensions and polypropylene will be fabricated. It is well known that polyolefin is a widely used material and its processability is prominent. Moreover, due to the difference in filler dimension and intrinsic structure, the networ...

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mentioning

confidence: 74%

Section: Morphology Of the Compositesmentioning

confidence: 98%

Section: Morphology Of the Compositesmentioning

confidence: 99%

See 1 more Smart Citation

Synergistic effect in conductive networks constructed with carbon nanofillers in different dimensions

Zhang¹,

Li²,

Deng³

et al. 2012

Express Polym. Lett.

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“…Furthermore, the carbon nanotubes are nano-scale units with high specific surface area. tration and improve the strength of composites greatly [1,5]. On the other hand, when the content of MWCNTs is over certain content, the extra carbon nanotubes aggregate more seriously, and the CNTs dispersion becomes inhomogeneous in the matrix.…”

Section: Morphology Of Fracture Surfacementioning

confidence: 99%

“…Due to their high aspect ratio and huge surface area, CNTs have strong tendency to agglomerate, which leads to inhomogeneous dispersion in the polymer matrix. Various techniques for dispersing CNTs have been extensively investigated and compared [3][4][5][6]. However, when trying to assess CNT dispersion, researchers always find it is very difficult to judge the grade of dispersion with conventional microscopy techniques [7].…”

Section: Introductionmentioning

confidence: 99%

A Micro-Mechanical Model for Elastic Modulus of Multi-Walled Carbon Nanotube/Epoxy Resin Composites

Srivastava¹,

Singh²

2012

CMATERIALS

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Multi-walled carbon nanotube (MWCNT) powder was used as reinforcement in epoxy resin with weight percentages 0.5, 1, 2 and 3% respectively. Dispersion of MWCNTs in the epoxy resin was obtained by a three mill rolling process. Tensile strength, compressive strength and elastic modulus were obtained from load versus displacement results. A theoretical model was developed to calculate the elastic modulus and compare with the experimental results. There was a similar trend in the experimentally obtained elastic modulus and in a modified Halpin-Tsai theory. Results show that the tensile strength, compressive strength and elastic modulus of epoxy resin are increased with the increasing of percentage of MWCNT fillers. The significant improvements in tensile strength, compressive strength and elastic modulus were attributed to the excellent dispersion of MWCNT filler in the epoxy resin.

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Visualization of CNTs in Polymer Composites

Bauhofer

2014

Polymer Nanotube Nanocomposites

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The imaging mechanism, imaging depth, and parameters influencing the visibility of carbon nanotubes in a polymer matrix using an SEM

Cited by 43 publications

References 20 publications

Synergistic effect in conductive networks constructed with carbon nanofillers in different dimensions

Synergistic effect in conductive networks constructed with carbon nanofillers in different dimensions

A Micro-Mechanical Model for Elastic Modulus of Multi-Walled Carbon Nanotube/Epoxy Resin Composites

Visualization of CNTs in Polymer Composites

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