Extruded Open-Cell Foams Using Two Semicrystalline Polymers with Different Crystallization Temperatures

This paper presents an extrusion-based open-cell foaming process with polypropylene (PP)/polyethylene (PE) blends. The basic strategy for achieving a high open-cell content is to induce a hard/soft melt structure using two semicrystalline polymers with distinctively different crystallization temperatures ( T c ) and to foam this inhomogeneous melt structure with supercritical CO 2 . The effects of polymer blending, die geometry, and temperature on cell opening were investigated in this study. Two blends of high-melt-strength (HMS) PP/metallocene PE (mPE) and linear PP/low-density PE (LDPE) were used as case examples.