Effect of hydrophilic groups in the polymer matrix on the porosity of organic and carbon aerogels produced from melamine, phenolic resole and formaldehyde

Organic and carbon aerogels were synthesized by the solution-sol-gel polymerization of melamine (M), phenolic resole (PR), m-cresol and formaldehyde in a basic aqueous solution followed by supercritical petroleum drying and pyrolysis. The effect of hydrophilic groups in the polymer matrix on the porosity of organic and carbon aerogels was investigated by varying the M/PR ratio under otherwise identical conditions. It was found that increasing hydrophilic melamine content increases intermolecular interactions of polymers that form gels, which favors an improvement in the stability of gels in supercritical drying and pyrolysis. The increase of melamine content also increases the mass loss of organic aerogels during pyrolysis, which is unfavorable for their stability. The pore size distributions, surface areas, meso-porosity and macroporosity of carbon aerogels were a compromise between the two opposing factors.