Influence of conductive network structure on the EMI shielding and electrical percolation of carbon nanotube/polymer nanocomposites

• Published in: Synthetic metals Vol. 205; pp. 78 - 84
• Main Author: Al-Saleh, Mohammed H.
• Format: Journal Article
• Language: English
• Published: 01.07.2015
• Subjects: Carbon nanotubes; Electromagnetic interference; Microstructure; Nanocomposites; Nanostructure; Networks; Polyethylenes; Shielding
• ISSN: 0379-6779
• DOI: 10.1016/j.synthmet.2015.03.032

Conductive polymer nanocomposites (CPNC) are promising materials for electromagnetic interference shielding (EMI) applications. However, the relatively high cost of high aspect ratio nanofillers hinders the wide commercial use of these materials. Promoting the competitiveness of CPNCs requires formulation nanocomposites with the desired EMI capabilities at the lowest possible nanofiller loading. This requires better understanding for relation between the microstructure and EMI attenuation mechanisms, which is the objective of this work. Herein, CNPCs with segregated conductive network were prepared by placing carbon nanotube (CNT) particles at the external surface of ultrahigh molecular weight polyethylene (UHMWPE) powder by wet mixing. The microstructure, electrical and EMI shielding properties of the nanocomposites after compression molding were investigated. The EMI SE was found to increase with CNT content. An EMI SE of 50dB was reported for a 1.0mm thick plate made of 10wt% CNT/UHMWPE nanocomposite. This nanostructured material is suitable for many applications in the computer and electronics industries. Compared to CNT/polymer nanocomposite of fine and well-dispersed CNT microstructure, the unique structure of the CNT/UHMWPE characterized by thick and segregated CNT network was found to enhance the EMI shielding by absorption and reduce the reflection of the EMI.