Effect of Physical State of Carbon Nanocomposite on Hydrogen Adsorption and Desorption

Abstract

AbstractThe inclusion of multiwalled carbon nanotubes in a conjugated polymer matrix results in extensive alterations in the polymer morphology. When the physical state of a substance is changed, heat is either absorbed or liberated but the temperature remains constant. The flexibility of chain molecules arises from rotation round the saturated chain bond moreover the potential energy barriers hindering this rotation. It is not surprising therefore that the flexibility of polymer chains is an important factor in determining their melting points and stability. If the substitution of carbon nanotube is random the primary effect is a decrease in the degree of crystallinity. These microstructures are governed by the balance of interactions between hydrodynamic forces (both viscous and elastic) and the forces working to retain the integrity of the disperse particles, such as interfacial tension or, in the case of solid filler and their mechanical strength. Carbon materials have long been shown to absorb as much as 60 wt% hydrogen due to their large surface areas as well as their high surface to volume ratios. In the present approach conducting polyaniline was doped with metal oxide, such as SnO2, as well as carbon nanotubes. The resulting carbon nanocomposite was made in both gel- and solid-state to study the effect of physical state on hydrogen adsorption and desorption by weight percentage. The morphology formation process and its impact on the rheological properties of complex polymer systems, i.e. polymer blends and composites are being studied. The materials are also compared with regard to their thermal stability using DSC, and further characterized using various techniques such as FTIR. Further experiments are in progress to better understand the nature of the hydrogen storage mechanism.