Page 76 - Polymer-based Nanocomposites for Energy and Environmental Applications

Preparation and properties of nanopolymer advanced composites: A review 53

properties have been experimentally studied by Anbusagar et al. [47]. Microstruc-
tural characterization is carried out through X-ray diffraction and scanning electron
microscopy analysis. Incorporation of nanoclay in FRP and polystyrene foam core
sandwich laminates enhances the properties of resulting nanocomposites. The
nanophased FRP polystyrene foam core sandwich laminates composite has suffi-
ciently high flexural strength and stiffness ratio of about 60% and 21 improvement
at 4 wt% increment of nanoclay, respectively, over the control sample (GF0).
Table 2.10 shows the flexural properties of FRP and sandwich laminate samples.
From impact test results, it is seen that Charpy impact strength increased by signif-
icant amount of 43% at 6 wt% nanoclay loading. Fig. 2.24 shows the variation of
impact strength of the different samples with respect to various clay combinations.
4 wt% nanoclay seems to be an optimum loading for FRP sandwich polyester lam-
inates in terms of flexural properties, 6 wt% nanoclay seems to be an optimum load-
ing for impact and water absorption (see Fig. 2.25), respectively, properties of same
combination. X-ray diffraction studies of the composite samples revealed that 52%
increase in the gallery spacing of the nanoclay, thus indicates effective intercalation
of nanoclay platelets by the polyester matrix. The results of the X-ray diffraction
study are shown in Fig. 2.26.

2.5 Nanopolymer natural fiber reinforced hybrid
composites

Many researchers have used MMT and CNT nanoparticle as filler in hybrid polymeric
composites and their laminates. These minerals are well-known for exfoliation/inter-
calation dispersion, high surface area, surface reactivity, cost-effectiveness, and easy
availability [48,49]. Some of the important research work on nanoclay-based polymer
composites with variety of natural fibers is summarized below.
Huang and Netravali [50] have prepared composite made of soy protein concen-
trate (SPC) resins and flax yarns and fabrics. The modified SPC resin was prepared
by blending SPC with nanoclay particles and then cross-linked using glutaraldehyde.
The modified SPC resin showed significantly improved mechanical properties. Two
forms of flax fiber fabrics are used as the reinforcement, namely, yarn and fabric
forms, individually, to fabricate “green” composites. Among these composites, the
unidirectional flax yarn-reinforced SPC resin composites showed longitudinal tensile
failure stress of 298 MPa and Young’s Modulus of 4.3 GPa. Also, it exhibited excel-
lent flexural properties in the longitudinal direction. The flexural stress is 117 MPa,
and the flexural modulus is 7.6 GPa. Further, it is observed that both yarn and fabric-
reinforced composites have the potential to replace nonbiodegradable materials in
many fields due to their good mechanical properties.
High-density polyethylene (HDPE)/bamboo composites with different nanoclay
content and melted polyethylene (MAPE) composites are prepared by Han et al.
[51] using melt compounding and compression molding. The compounding charac-
teristics, clay dispersion, HDPE crystallization, and mechanical properties of the com-
posites were studied. The increase Young’s modulus values found at 5% clay loading.