The epoxy resin nanocomposites stud

The epoxy resin nanocomposites studied here displayed intercalated
and exfoliated organo-montmorillonite particles. The most significant
improvement in flexural strength and fracture toughness were obtained
for montmorillonite modified with the longest alkylammonium ions.
Optimum clay mineral levels were determined regarding both mechanical and flammability properties due to the competition between
reinforcing filler content and dispersability of the filler at the nanoscale.
Fig. 9. Flexural strain at break of nanocomposites with ODTMA, HDTMA and DDTMA
montmorillonites as a function of clay mineral level.
Table 2
Limiting oxygen index values of tested specimens.
LOI
(vol% O2 ± 2σ)
Neat epoxy resin 20.9 ± 0.3
E + 0.5%DDTMA 21.4 ± 0.3
E + 1%DDTMA 21.5 ± 0.5
E + 2%DDTMA 23.2 ± 0.3
E + 3%DDTMA 22.7 ± 0.4
E + 3%HDTMA 22.4 ± 0.3
E + 3%ODTMA 22.4 ± 0.5
Fig. 10. TGA thermograms of neat epoxy resin and the nanocomposite with 2 mass%
DDTMA montmorillonite.
Fig. 8. Flexural moduli of nanocomposites with ODTMA, HDTMA and DDTMA montmorillonites as a function of clay mineral level.
C. Kaynak et al. / Applied Clay Science 46 (2009) 319–324 323
Based on flexural strength and fracture toughness, the reported optimum clay mineral levels were independent of the modifier chain length.
Flammability was reduced with the incorporation of organo-montmorillonite at low levels due to the formation of a physical barrier of
collapsed montmorillonite particles. Nanocomposites degraded in the
oxygen index tests exhibited basal reflections very close to that of
unmodified Na-montmorillonite, independent of the type of modifier,
clay mineral level and oxygen index performa