AbstractThe effects of variations in the chemical composition and processing conditions of the series of phenolic foams described in the two previous papers were studied. Compressive stiffness and density increased with increasing concentrations of the acid catalysts, the slower reacting phenolic resin component, water, the lipophilic component of the surfactant system, and age of the phenolic resins. These properties decreased with increasing concentration of the fluorocarbon blowing agent and process temperature. The compressive stiffness and density increased to a maximum and then decreased with increasing concentrations of the hydrophilic surfactant. Permeability or “breathability” of the foam decreased with the hydrophilic surfactant at low concentrations and then became essentially independent of further increases of this component. Increasing concentrations of the lipophilic surfactant gave foam having greater breathability. In all other cases the permeability of the foam decreased as its density increased. Effects of the variations in processing and composition on the dependency of load bearing upon density, on relationships between permeability and density and permeability and compressive stiffness, and upon cell structures are also descri
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