Abstract: Modified open-cell aminoplastic foams with a density in the range from 5 to 1,000 kg/m3 and with an average pore diameter in the range from 1 ?m to 1 mm, comprising an amount in the range from 1 to 2,500% by weight, based on the weight of the un-modified open-cell foam, of at least one water-insoluble polymer (b), selected from polystyrene, styrene copolymers, polybutadiene, butadiene copolymers, polyvinylesters, polyvinylethers, copolymers from (meth)acrylic acid with at least one (meth)acrylate, and polyurethanes with the proviso that styrene-acrylonitrile-C1-C10-alkyl (meth)acrylate terpolymers, styrene-butadiene-n-butyl acrylate terpolymers, and styrene-maleic anhydride copolymers are excluded