Cell Morphology and Mechanical Properties of Rigid Polyurethane Foam

Abstract

Polyurethane foam, used as a supporting or insulating material, is sometimes formed in complex molds with significant variations in geometry and size. This work investigates the relationships between cell morphology, density, and mechanical properties in a molded polyurethane material using relatively small cylindrical molds. Understanding these relationships will help mechanical designers to analyze and predict the responses of foam components accurately. Three mold sizes are used to study changes in cell morphology (cell area, cell diameter, aspect ratio, cell angle, cell edge length, cell face thickness, and cell edge thickness), density, and mechanical properties (Young’s modulus and collapse stress) with respect to position within the mold. The density is shown to increase from the top to the bottom of the reference mold but does not change significantly in the small and tall molds. However, the mechanical and cell morphology properties show more changes in the small and tall molds when compared to the reference mold even though there are only small changes in density.