Environmental degradation of epoxy-organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Ricky S.C. Woo, Yanghai Chen, Honggang Zhu, Jing Li, Jang Kyo Kim, Christopher K.Y. Leung

Research output: Contribution to journalArticlepeer-review

170 Scopus citations

Abstract

The environmental degradation mechanisms of epoxy-organoclay nanocomposites due to accelerated UV and moisture exposure are studied. Various characterisation tools, including FTIR, SEM, XRD and XRF analyses, were used to evaluate the effects of clay content on the progressive changes in chemical element, topography and colour of the nanocomposite. It is found that microcracks started to appear on both the neat epoxy and nanocomposite surface after about 300 h of UV exposure. The nanocomposite exhibited thicker and shallower cracks with a less degree of discoloration than the neat epoxy due to the diffusion barrier characteristics of organoclay with high aspect ratio. The presence of transition metal ions along with low-molecular-weight organic modifiers in organoclay, however, accelerated the degradation of polymer, counterbalancing the above ameliorating barrier properties of clay. FTIR analysis indicated that photo-degradation generated carbonyl groups by chain scission and the rate was slightly higher for the nanocomposites than for the neat epoxy. While moisture further accelerated the photo-degradation process through the enhanced mobility of free radicals and ions, the organoclay could limit the deteriorating effect of moisture, resulting in much better overall resistance to photo-degradation in the presence of moisture for the nanocomposite than the neat epoxy.

Original languageBritish English
Pages (from-to)3448-3456
Number of pages9
JournalComposites Science and Technology
Volume67
Issue number15-16
DOIs
StatePublished - Dec 2007

Keywords

  • A. Epoxy/Clay Nanocomposite
  • A. Nano-structures
  • A. Polymer-matrix composites (PMCs)
  • B. Environmental degradation
  • D. Chemical analysis

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