|
Abstract:
|
Graphene has captured the attention of scientific community due to recently emerging high performance
applications. Hence, studying its reinforcing effects on epoxy resin is a significant step. In this study,
microwave exfoliated reduced graphene oxide (MERGO) was prepared from natural graphite for subsequent
fabrication of epoxy nanocomposites using triethylenetetramine (TETA) as a curing agent via insitu
polymerization. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Raman spectroscopy,
Fourier transform infrared spectroscopy (FTIR), C13 NMR spectroscopy, X-ray photoelectron spectroscopy
(XPS) and ultravioletevisible (UVevis) spectroscopy were employed to confirm the simultaneous
reduction and exfoliation of graphene oxide. The reinforcing effect of MERGO on epoxy resin was
explored by investigating its static mechanical properties and dynamic mechanical analysis (DMA) at
MERGO loadings of 0 to 0.5 phr. The micro-structure of epoxy/MERGO nanocomposites was investigated
using scanning electron microscope (SEM), transmission electron microscope (TEM) and XRD techniques.
The present work reports an enhancement of 32%, 103% and 85% in tensile, impact and flexural strength
respectively of epoxy by the addition of even 0.25 phr MERGO. At this loading elastic and flexural moduli
also increased by 10% and 65%, respectively. Single-edge-notch three-point-Bending (SEN-TPB) fracture
toughness (KIC) measurements were carried out where a 63% increase was observed by the introduction
of 0.25 phr MERGO. The interfacial interactions brought about by graphene also benefited the dynamic
mechanical properties to a large extent in the form of a significant enhancement in storage modulus and
slightly improved glass transition temperature. Considerable improvements were also detected in
dielectric properties. The epoxy nanocomposite also attained an ac conductivity of 10 5 S/m and a
remarkable increase in dielectric constant. The simple and cost effective way of graphene synthesis for
the fabrication of epoxy/MERGO nanocomposites may be extended to the preparation of other MERGO
based polymer nanocomposites. This remarkable class of materials has thrown open enormous opportunities
for developing conductive adhesives and in microelectronics |