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Journal of Nanomaterials
Volume 2010 (2010), Article ID 352746, 13 pages
http://dx.doi.org/10.1155/2010/352746
Research Article

Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

1Mechanics of Advanced Materials Laboratory, School of Mechanical and Aerospace Engineering, Oklahoma State University, 218 Helmerich Research Center, 700 N. Greenwood Avenue, Tulsa, OK 74106-0700, USA
2Laboratory for Nanotribology and Wear Mechanics, Department of Mechanical Engineering, State University of New York, 131 Light Engineering, Stony Brook, NY 11794-2300, USA

Received 17 December 2009; Accepted 2 June 2010

Academic Editor: Gaurav Mago

Copyright © 2010 Raman P. Singh 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

This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.