CNF-reinforced polymer aerogels: Influence of the synthesis variables and economic evaluation

Abstract

The synthesis of organic polymer aerogels reinforced with carbon nanofibers (CNF-reinforced polymer aerogels) using polyvinyl alcohol (PVA) as the polymeric matrix, by means of the freeze-drying method has been carried out. The influence of the CNF content in the polymer aerogel and the use of different solvents on the physical, morphological and mechanical properties of the final aerogel composites have been evaluated. The thermal conductivity and the porosity of CNF-reinforced polymer aerogels increased with the content of CNF. However, the density of the synthesized aerogels decreased when the CNF content was increased up to a value of 87.5g/L. According to a dynamic mechanical analysis, the incorporation of CNF into the PVA matrix enhanced the mechanical characteristics and the glass transition temperature of the resulting CNF-reinforced polymer aerogels. On the other hand, aerogels synthesized using water as the solvent presented higher densities than those synthesized using acetone, butanol, ethanol or tert-butanol. However, their thermal conductivity values were very similar. Finally, an economic evaluation of the production of these materials using the freeze-drying technique was carried out. It was demonstrated the economic feasibility of the manufacturing process of aerogels proposed. Furthermore, no toxic pollutants were released at temperatures below 180°C.