Synthesis of Carbon Nanotubes

We produced carbon nanotubes (CNTs) by pyrolysis of composite films of poly (vinyl alcohol) (PVA) with fly ash and physically/chemically modified fly ash at 500 °C for 10 min under a nitrogen flow of 2 L/min. Different geometrical structures, e.g.; knotted and twisted, U- and spiral-shaped, bamboo-shaped, rod, fiber and ribbon-shaped CNT materials were observed in the images of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The widths of the CNT ribbons measured in TEM varied in the ranges 18 ~ 80 nm. X-ray photoelectron spectroscopy analysis showed five types of carbon binding peaks, C¿C/C¿H, C¿O¿H, ¿C¿O¿C, C=O and ¿O¿C=O with different percentages. The ratio of intensities of G and D bands, IG/ID show different values analysed by Raman Spectroscopy in relation with nature of fly ash particles. CNT materials grown on the surface of fly ash have potential for the fabrication of high-strength composite materials with polymer and metal.