Effect of methanol content in commercial formaldehyde solutions on the porosity of RF carbon xerogels

Methanol is used commercially as a stabilizer in solutions of formaldehyde to prevent its precipitation. However, the methanol content of commercially available formaldehyde solutions differs from one supplier to another. The pH, dilution and R/F ratio have been demonstrated to be interdependent variables that can be manipulated to tailor the porous properties of RF carbon xerogels. This work considers the methanol contained in formaldehyde solutions as a new variable to be studied in conjunction with those just mentioned. For the purpose of this study, the influence of methanol on the final porous properties of RF carbon xerogels has been evaluated. It was found that carbon xerogels synthesized using formaldehyde solutions with lower concentrations of methanol showed a higher total pore volume and pore size, and in turn, a lower density and a greater porosity. The porosity of RF carbon xerogels could therefore be radically modified depending on the commercial formaldehyde solution used for their synthesis. (C) 2015 Elsevier B.V. All rights reserved.