Density and Strength of Plastic Foams

A general density/compressive strength relationship for low density cellular material was tested for open cell phenolic, closed cell polyurethane and closed cell polystyrene insulation foams. There is a good fit between theory and experimental data for phenolic foams but the simple relationship is not adequate for others. The deviation is not caused by the intricate differences in the dodecahedral geometry but can be largely reduced by the inclusion of an elliptical distortion factor in the model equation.