Structure and Crystallinity of Expanded Graphite-Reinforced Carbon Nanocomposite Aerogels and Their Influence on Paraffin Fuel Gases Filtration Efficiency

 Aerogels are new nanostructured materials that have attracted much attention in recent decades. In the meantime, polymeric aerogels have found special applications due to their lightness and cost-effectiveness. In this study, the carbon aerogels were used to filter the gases from fossil fuels. The challenge of this research is to try to increase the efficiency of gas separation, which is proportional to the surface area and structure of the separator.

Carbon nanocomposite aerogel was made using pre-polymeric material with a high specific surface area and with nanostructure morphology during carbonization process at temperatures 600 and 1200°C. Novolac resin was selected for its low cost and solubility in alcohols as a polymer matrix in sol-gel polymerization. Expanded graphite due to its unique properties and relatively good distribution and for reaction with novolac was used as reinforcement. In this study, a sample with a distribution of fine colloids was selected by examining the distribution of carbon aerogel colloids by combining different percentages of novallac solid in primary sol. Again, by examining the size of the cavities, the production of the aerogel was made by combining the selected precursor composition with four percentages of expanded graphite. Then, the samples were pyrolized at two different temperatures. In the following, the effect of expanded graphite nanoparticles and degree of crystallinity of carbon nanocomposite aerogel on the filtration efficiency of gases from fossil fuels was investigated. To evaluate the effect of different crystallinity of aerogel, carbon aerogels were prepared at temperatures of 600 and 1200°C with different degree of crystallinity.

The results of this study showed that samples of carbon aerogel with 0.75% wt expanded graphite and pyrolized at 1200°C showed 40% higher carbon dioxide absorption efficiency than pure samples.