Cell morphology analysis of high density polymer foams

Polyolefin foams were produced by extrusion and injection molding in order to analyze their cellular morphology. This study proposes methods to calculate surface cell count as well as approaches for converting them into volumetric ones. Two methods of calculating surface cell count were examined. The first one considers an exact surface containing an undetermined number of cells, while the second considers an exact number of cells dispersed on a surface of undetermined area. Three approaches to calculate volumetric cell density were examined which are based on cell geometry: spherical, ellipsoids of revolution or true ellipsoids. It is found that both cell count methods are hampered by a 20percent uncertainty but give similar results. All three methods of estimating cell density produce similar results when analyzing injected foams (spherical cells)but diverge significantly in the case of extruded foams (ellipsoidal cells).