EXTRUDED OPEN-CELL FOAMS USING TWO SEMI-CRYSTALLINE POLYMERS WITH DIFFERENT CRYSTALLIZATION TEMPERATURES

摘要

This paper presents an extrusion-based open-cell foaming process with polypropylene (PP)/metallocene polyethylene (mPE) and PP/low-density polyethylene (LDPE) blends. The basic strategy for achieving a high open-cell content is to induce a hard/soft melt structure using two semi-crystalline polymers with distinctively different crystallization temperatures (T_c), and to foam this non-homogeneous melt structure with supercritical CO_2. The effects of polymer blending, die geometry, and temperature on cell opening were investigated in this study.