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Journal of Nanomaterials
Volume 2011, Article ID 307589, 8 pages
http://dx.doi.org/10.1155/2011/307589
Research Article

Preparation, Characterization, and Modeling of Carbon Nanofiber/Epoxy Nanocomposites

1Department of Materials Science, Fudan University, Shanghai 200433, China
2Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA
3Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA

Received 6 July 2010; Accepted 19 October 2010

Academic Editor: Sulin Zhang

Copyright © 2011 Lan-Hui Sun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

There is a lack of systematic investigations on both mechanical and electrical properties of carbon nanofiber (CNF)-reinforced epoxy matrix nanocomposites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nanocomposites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nanocomposites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nanocomposite with a 1.0 wt% CNFs. The alternate-current (AC) electrical properties of the CNF/epoxy nanocomposites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt% (0.058 vol%) CNFs and by ten orders of magnitude for nanocomposites with CNF volume fractions higher than 1.0 wt% (0.578 vol%). The percolation threshold (i.e., the critical CNF volume fraction) is found to be at 0.057 vol%.