Role of Enhanced Hydrogen Bonding of Selectively Reduced Graphite Oxide in Fabrication of Poly(vinyl alcohol) Nanocomposites in Water as EMI Shielding Material

According to the available literature,,hydrophobic nature of graphene restricts the fabrication of its polymer nanocomposites in aqueous medium without its modification or through in situ synthesis from graphite oxide. In view of this, present work reports on fabrication of nanocomposites of poly(vinyl alcohol) filled with selectively reduced graphite oxide (SRGO) in aqueous medium. FTIR Study establishes the formation of nanocomposites through enhanced intermolecular hydrogen bonded network between -OH (PVA) and surplus -OH functionalities of graphene sheet in SRGO in comparison to that derived from PVA/graphite oxide (GO). PVA/SRGO-0.2 nanocomposite showed maximum improvements in tensile strength (127%), elongation at break (25%) and thermal stability (45 degrees C) Compared to neat PVA. This is ascribed to better dispersion and presence of extensive intermolecular hydrogen bonding between PVA and, SRGO. All PVA/SRGO nanocompopsites exhibited relatively higher glass transition temperature (T-g), melting temperature (T-m), and crystallization temperature (T-c). The formation of conducting network also accounts for good electromagnetic shielding efficiency (EMI SE) of PVA/SRGO nanocomposites in 2-8 GHz frequency range with respect to PVA. It is anticipated, this novel approach could be further extended in synthesizing many other SRGO-filled polar polymer nanocomposites in aqueous medium for their diverse applications.