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Journal of Nanotechnology
Volume 2011, Article ID 637395, 9 pages
Research Article

Investigation of MWCNT Reinforcement on the Strain Hardening Behavior of Ultrahigh Molecular Weight Polyethylene

1Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA
2Mechanical Engineering Department, The University of Texas at El Paso, El Paso, TX 79968, USA
3Physics Department, Florida Atlantic University, Boca Raton, FL 33431, USA
4Department of Physics, National Technical University of Athens, Zografou Campus, 157 80 Athens, Greece

Received 14 September 2010; Revised 19 February 2011; Accepted 20 February 2011

Academic Editor: Valery Khabashesku

Copyright © 2011 Hassan Mahfuz 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.


We have investigated strain hardening behavior of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with 2.0 wt% loading of multiwalled carbon nanotubes (MWCNTs). A solution spinning process was used to produce neat and MWCNT-reinforced filaments of UHMWPE. Tensile tests of filaments showed 62% and 114% improvement in strength and modulus, respectively. Strain hardening tests on filaments revealed spectacular contribution by MWCNTs in enhancing strength and modulus by more than one order of magnitude. SEM micrographs showed sufficient coating of nanotube surface with the polymer that promoted interface adhesion. This intimate interfacial interaction enforced alignment of nanotubes during repeated loading-unloading sequences and allowed effective load transfer to nanotubes. Close interaction between UHMWPE and nanotubes was further evidenced by Raman spectral distribution as a positive shift in the D-band suggesting compressive stress on nanotubes by lateral compression of polymer. Nanotubes thus deformed induced the desired strain hardening ability in the UHMWPE filament. Differential scanning calorimetry (DSC) tests indicated around 15% increase in crystallinity after strain hardening—which together with nanotube alignment resulted in such dramatic improvement in properties.