Influence of Evaporation Drying on the Porous Properties of Carbon/Carbon Composite Xerogels

Carbon/carbon (C/C) composite xerogels dried by evaporation were prepared in this study to observe the change of their porous properties and their morphology by nitrogen sorption apparatus and a scanning electron microscope. Resorcinol and formaldehyde (RF) sols as a matrix phase and cotton fibers (CF) as a dispersed phase were mixed and gelated to be CF/RF composite hydrogels. The composite hydrogels were exchanged by t-butanol (TBA), dried by evaporation at 50 degrees C, and carbonized at 1000 degrees C to become the C/C composite xerogels. The results show that the CF addition does not decrease the mesoporous properties of the C/C composite xerogels. Moreover, the CF addition can alleviate the pore shrinkage, and it can maintain the mesopore structure. The mesopore size and the micropore size of C/C composites are insignificantly changed because the CF addition and the solvent exchange using TBA may suppress the pore shrinkage despite the gas-liquid interface existing during the evaporation drying.

Automated summary

In this study, C/C composite xerogels were prepared and it was found that the addition of CF does not impact the mesoporous properties of the material and can alleviate pore shrinkage. The use of TBA during evaporation drying helps to maintain the pore structure.