Effect of drying method on mesoporosity of resorcinol-formaldehyde drygel and carbon gel

Resorcinol-formaldehyde hydrogels were synthesized by sol-gel polycondensat ion of resorcinol with formaldehyde in a slightly basic aqueous solution. R F cryogels, RF xerogels, and RF xerogels (MW gets) were respectively prepar ed from RF hydrogels by freeze drying, hot air drying, and microwave drying . Carbon cryogels, carbon xerogels and carbon MW gels were subsequently obt ained by pyrolyzing RF drygels in an inert atmosphere. Freeze drying and mi crowave drying were effective to prepare mesoporous RF drygels and carbon g els. RF cryogels and carbon cryogels showed high mesoporosity over wide ran ges of the molar ratio of resorcinol to catalyst (R/C) and the ratio of res orcinol to water (R/W) used in sol-gel polycondensation, Although RF xeroge ls had a few mesopores, carbon xerogels had no mesopores. RF MW gels and ca rbon MW gels showed mesoporosity if appropriate values of R/C and R/W were selected.