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Authors: Naz, Asima
Keywords: Natural Sciences
Physical chemistry
Issue Date: 2018
Publisher: Quaid-i-Azam University, Islamabad, Pakistan
Abstract: Conducting polymer blends and nanocomposites constituting conducting polymers (CPs) have fascinated noteworthy considerations for both academic and industrial research due to their important and captivating applications. In the current endeavor eight different series of nanocomposites of conjugated polymers have been efficiently fabricated via layer by layer in situ oxidative polymerization i.e. NF-G & F-G/PANi/PSMA/ODA, FG & FG-NH2/PANi/PMMA/PPG-b-PEG-b-PPG, NF-G & FG/PPy/PEG/PSMA/MDA, FG & FG-NH2/PPy/PVC/PDA. The fabrication of nanocomposites of polyaniline (PANi) and poly(styrene-co-maleic anhydride)cumene terminated (PSMA), polypyrole (PPy), polyethylene glycol (PEG) and poly(styrene-co-maleic anhydride)cumene terminated (PSMA), polyvinyl chloride (PVC), poly(methyl methacrylate) (PMMA) and poly(propylene glycol)-b-poly(ethylene - - - - - - - 1 -phenylene diamine (PDA) as crosslinking agent with non-functional and functional graphite as filler was performed. For each series we studied the influence of various feeding ratios by varying weight % of CP (2%, 5% and 10%). Physical characteristics of resultant nanocomposites were evaluated by Fourier transform infrared (FT-IR), X-ray photon spectroscopy (XPS), energy dispersive x-ray spectroscopy (EDX) and scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) respectively. The thermal, electrical and surface area properties of the conducting polymer blends and nanocomposites were also investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Brunauer Emmett Teller (BET) analysis. Relative to non-functional composites, functional composites displayed more improved characteristics such as exhibited higher thermal stability and improved electrical conductivity by the incorporation of modified graphite. According to the differential scanning calorimetry the glass transition temperature, melting temperature and crystallization temperature of the composites increases with the incorporation of modified graphite. FG-NH2 in resultant nanocomposites play an important role in forming conducting network in matrix indicating synergistic effect between polymer matrices and filler. The DSC studies are also complimented by X-ray diffraction results. The PMMA copolymer chains can stabilize the growth of PANi chains by the formation of hydrogen bonding between imine groups in PANi and carbonyl groups in MMA units and by providing sites for electrostatic interactions. Moreover, the electrical conductivity of nanocomposites was also found to be a function of CPs loadings. However, nanocomposites possessed higher conductivities values ascribed to the presence of thermally more stable and electrically conductive modified graphite in composites. According to four probe test, the conductivity of ultimate nanocomposites increased dramatically. The composites constituting higher mass ratio shows increased electrical conductivity performance. Newly fabricated series of conducting nanocomposites may act as useful contenders in industrial appliances such as polymer Li-ion batteries.
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