Previously, it wasreported that hig

Previously, it was
reported that high clay strengthening effect is mainly caused by a
large interfacial surface between polymer and clay [1,17,28,29,46].
Yasmin et al. [1] reported that epoxy NCs based on Cloisite 30B had
better mechanical properties compared to systems based on nanoclay I28E (modified with octadecyl trimethyl ammonium salt) at
a same clay content, due to a higher extent of the Cloisite 30B dispersion in epoxy resin. Also, Xidas et al. [29] have reported similar
findings for both glassy and rubbery epoxy NCs, which exhibited
more significant improvements of the storage modulus in the rubbery state than that in the glassy state. This phenomenon could
be related to the presence of the exfoliated clay layers with a high
surface area and a high aspect ratio, which act as physical crosslinkers in polymer matrix. It was reported [13] that the mechanical
properties of the epoxy coating modified with SiO2 nanoparticles
showed a significantly enhanced Young’s modulus of 2.5 GPa, while
for those others modified with Zn, Fe2O3 and halloysite nanoclay it
was in the range from 60 to 350 MPa. These results were obtained
by using the AFM-based nanoindentation technique. In this paper,
we present the mechanical properties of the epoxy nanocomposites evaluated by using the dynamic mechanical spectroscopy. The
storage shear modulus of epoxy resin in the glassy state which was
0.76 GPa (25 ◦C) and increased when organoclay was added upto
1 GPa. In addition, the improvement in stiffness of the NC composites was more pronounced in the rubbery state and ranged from 9.7
to 17 MPa (160 ◦C)