Method of making a low-friability, thermosetting foam

A method of preparing a thermosetting foam product, which method comprises reacting a furfuryl-alcohol polymer with a phenol-formaldehyde resin, having a mole ratio of phenol to formaldehyde of from about 1:1.2 to 1:2.0, in the presence of from about 1 to 15 parts per 100 parts of polymer and resin of a blowing agent and of from about 0.05 to 10 parts per 100 parts of polymer and resin of a catalytic amount of a sulfonic-acid catalyst and a small cell-control amount of a silicone surfactant, to effect the generally simultaneous condensation of the phenol-formaldehyde resin and the condensation of the furfuryl-alcohol polymer, the amount of the polymer and the resin ranging from about 10% to 90% by weight of the reaction mixture, and the polymer comprising an acid-catalyzed furfuryl-alcohol polymer which generally comprises a head-to-tail polymerization of the furfuryl alcohol in the polymer chain, and having reactive hydroxyl groups in the polymer, to provide an integral thermosetting foam product characterized by low-friability, high-compressive-strength and good flame-resistant properties.