Foaming of a phenol formaldehyde resin was studied. Twenty-one foaming agents were tried Out in the experiments. Foaming was evaluated by viscosity, density, and surface tension measurements. The study shows that spray dried blood and beta-lactoglobulin-enriched whey were the best foaming agents to foam phenol formaldehyde resin. There are also some other materials, which might work as foaming agents for phenol formaldehyde resin after some formula optimization. They include sodium lauryl sulfate sodium-n-alkyl (C-10-C-13) benzene sulfonate, and a fatty acid amine derivate. (C) 2004 Wiley Periodicals, Inc.