Thick polypropylene/poly(ethylene-co-octene) (PP/POE) blend samples with three different phase morphologies were prepared by melt blending using an extruder.The blend samples were foamed at a foaming temperature of 110 ℃ in a batch process.The shape
distribution
and size of the cells in the thick foamed samples were effectively tuned by exploiting the differences in the phase morphologies of the blends
and in the viscoelasticities and supercritical carbon dioxide solubilities in the two phases.Three kinds of typical cellular structures were obtained.Ellipsoidal cells appeared in the foamed sample prepared using the 80/20 PP/POE blend sample with ellipsoidal droplets
and both cells and droplets had the same order of magnitudes of average diameter and density.Long hole cells appeared in the foamed sample prepared using the 80/20 blend sample with long fibrils
and both cells and fibrils had a close average diameter.Open-celled structure with higher connectivity was obtained from foaming the 60/40 blend sample with partly continuous phase structure.Further
closely spherical cells with more close to the average diameter and density of the dispersed droplets
and open-celled structure with further higher connectivity were obtained by changing the foaming temperature.