Synthesis and Characterization of Conducting Gas Barrier Polyacrylonitrile/Graphite Nanocomposites

Graphite platelets were expanded by functionalization with inorganic acids followed by strong thermal treatment. The expanded graphite (EG) was exfoliated on the polyacrylonitrile (PAN) matrix through in situ emulsion sonication technique with different proportions of EG. The Ultraviolet-visible (UV) spectroscopy revealed the interaction between EG and PAN matrix. In Fourier Transform Infrared spectroscopy (FTIR), the chemical interaction between EG and the cyanide group of PAN was evidenced to the formation of PAN/EG composites. The X-ray diffraction pattern of raw graphite (RG), expanded graphite (EG), polyacrylonitrile (PAN), and PAN/EG nanocomposites were evidenced the dispersion of EG with the PAN matrix. The morphology of EG, PAN, and PAN/EG composites were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The tensile strength of PAN/EG nanocomposite was measured and found to be increased with increase in EG concentrations. The conductivity and impedance of composites were measured as function of EG concentration. It was found that, conductivity of composites gradually increased with the increase in EG loading. Oxygen permeability of PAN/EG was reduced substantially with rise of EG proportion. To investigate the flame retardancy behavior of PAN/EG nanocomposites, the limiting oxygen indexes were calculated. POLYM. COMPOS., 32: 1336-1342, 2011. (C) 2011 Society of Plastics Engineers