Low-density organic aerogels by double-catalysed synthesis

Organic aerogels are usually obtained by polycondensation of formaldehyde with a phenol derivative under basic conditions; This paper examines the lowest density that carl be achieved with a basic or acid catalyst in the case of phloroglucinol. We show that under basic conditions, shrinkage or gel time prevent densities below 0.030 g cm(-3). Under acid conditions, no homogeneous gelation occurs and the lowest density obtained is 0.023 g cm(-3). A new double base-acid catalyzed process makes organic aerogels with density of 0.013 g cm(-3). (C) 1998 Elsevier Science B.V. All rights reserved.