Page 53 - Polymer-based Nanocomposites for Energy and Environmental Applications

32 Polymer-based Nanocomposites for Energy and Environmental Applications

Table 2.1 Calculated elastic modulus values [19]
Specimens Elastic modulus, E indent (MPa)

Unreinforced UPE only 5393
1% w/w UPE/LK-EP-C 6192 (15% increase)
33% w/w UPE/LK-EP-C 6074 (13% increase)
5% w/w UPE/LK-EP-C 6646 (23% increase)

unsaturated polyester nanocomposites by a nanoindentation method. Their results
showed that the nanohardness of unreinforced polyester samples has been increased
from 301 to 387 MPa with the introduction of 1% w/w of nanoclay, and the elastic
modulus has been increased from 5393 MPa for unreinforced polyester to
6646 MPa with the introduction of 5% w/w nanoclay. The calculated tensile values
are presented in Table 2.1. Moreover, they have found that the homogeneous disper-
sion of nanoclay particles within the unsaturated polyester resin (UPE) matrix is cru-
cial to achieving improved mechanical properties. Also, they have found, that the
optimum nanoclay loads of 1 and 5% w/w for nanohardness and elastic modulus,
respectively.
An experimental setup to produce homogenous nanoclay/epoxy composites has
been proposed by Chan et al. [20]. During their experiment, it is found that the Young
modulus and tensile strength of the composites have increased with increasing the
nanoclay content of 5 wt% as optimal amount of nanoclay loading. Further increasing
of the nanoclay resulted in decreasing the mechanical properties of resultant
composites.
Chieruzzi et al. [21] have studied the thermal stability of polyester resin (UP) and
montmorillonite (MMT) clays. They have reported that the coefficient of thermal
expansion (CTE) of both neat resin and nanocomposites with various concentrations
of MMT are reduced with incorporation of clay particles. The reduction of CTE is
found at 5 wt% clay loading. The various nanocomposites are analyzed in their study
they are presented in Table 2.2. The CTE values obtained for various composites are

Table 2.2 UP/MMT nanocomposite samples analyzed [21]
Sample code Sample formulation

A Neat resin
A1 5 wt% D43B
A2 10 wt% D43B
A3 10 wt% D43B+1% VR
A4 5 wt% D43B+5% D72T
A5 5 wt% D43B+5% D72T+1% VR