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Mun S.C.,Korea Advanced Institute of Science and Technology | Kim M.,Korea Advanced Institute of Science and Technology | Lee C.S.,Corporative Research and Development Division | Lee M.H.,Corporative Research and Development Division | And 3 more authors.
Macromolecular Research | Year: 2013

Morphological characteristics and electrical conductivity of polyamide 6,6/poly(p-phenylene ether)/multi-walled carbon nanotube (PA66/PPE/MWCNT) ternary nanocomposites were investigated. The MWCNTs were modified by 60Co gamma ray (γ-ray) irradiation under a dry condition and O2 atmosphere, which introduces oxygen-containing functional groups on the surfaces of the MWCNTs and thereby provides better compatibility with the hydrophilic PA66 phase. It was observed that the MWCNTs are preferentially positioned in the continuous PA66 matrix, whereas PPE domains are almost free of MWCNTs. Since PA66 consists of a continuous phase and the MWCNTs are preferentially positioned in the PA66 phase, electrical conductivity of PA66/PPE/MWCNT ternary composites is higher than that of PA66/MWCNT binary composites at the same MWCNT content. It was observed that raising the processing temperature and increasing the mixing time were effective means of improving the electrical conductivity of the composites, via enhancement of MWCNT dispersion. [Figure not available: see fulltext.] © 2013 The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht.


Kim M.,Korea Advanced Institute of Science and Technology | Mun S.C.,Korea Advanced Institute of Science and Technology | Lee C.S.,Corporative Research and Development Division | Lee M.H.,Corporative Research and Development Division | And 2 more authors.
Carbon | Year: 2011

Multi-walled carbon nanotubes (MWCNTs) were treated with γ-ray irradiation to show enhanced interaction with polyamide 6,6. X-ray photoelectron spectroscopy and Raman spectroscopy revealed that oxygen atoms were found on the surface of the MWCNTs, which can enhance the interaction with hydrophilic polymers such as polyamide 6,6. Both morphological investigation and electrical conductivity measurements have demonstrated better dispersion and electrical percolation with a smaller amount of MWCNTs when they were subjected γ-ray irradiation. The electrical percolation thresholds were reduced from 0.934 wt% to 0.401 wt% and 0.332 wt% when MWCNTs were irradiated with 10 and 30 kGy, respectively. Rheological data showed consistent behavior, exhibiting a positive effect of γ-ray treatment on MWCNTs. Allowing large volume treatment in a simple, solvent free process, the proposed γ-ray irradiation based method is potentially suitable for further commercialization. © 2011 Elsevier Ltd. All rights reserved.

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