The microstructure, flexural properties, electrical conductivity, thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of epoxy composites filled with multi-walled carbon nanotubes (CNTs), exfoliated graphite nanoplatelets (xGnPs) and CNT-xGnP hybrid filler were investigated. The EMI SE of the CNT-xGnP hybrid composite was higher than 25 dB at 100 MHz while that of the xGnP based composite was almost zero. The flexural modulus of the CNT-xGnP based epoxy composite continuously increased to 3.32 GPa with combined filler content up to 10 wt% while that of the CNT based epoxy composites slightly decreased to 1.96 GPa at 4 wt% CNT, and dropped to 1.57 GPa at 5 wt% loading, which is lower than that of epoxy. The CNT and CNT-xGnP samples had the same EMI SE at the same surface resistivity, because samples with the same surface conductivity have the same amount of the charge carriers.

Abstract
 1. Introduction
 2. Experimental
  2.1. Materials
  2.2. Preparation of epoxy composites
  2.3. Characterization
 3. Results and Discussion
  3.1. Microstructures of carbon nanofiller/epoxycomposites
  3.2. Flexural properties
  3.3. Electrical, thermal, and EMI shieldingproperties
 4. Conclusions
 Conflict of Interest
 Acknowledgements
 References

• Young Sil Lee(Industry-Academic Cooperation Foundation, Kumoh National Institute of Technology)
• Yeon Ho Park(Department of Chemical Engineering, Kumoh National Institute of Technology)
• Kwan Han Yoon(Department of Chemical Engineering, Kumoh National Institute of Technology) Corresponding Author