EXTRUSION OF PE/PS BLENDS WITH SUPERCRITICAL CO_2 IN A TWIN-SCREW EXTRUDER AND A TWIN/SINGLE TANDEM SYSTEM

摘要

The effects of dissolved supercritical carbon dioxide on the viscosity and morphological properties were investigated for polyethylene, polystyrene and their blends in a twin-screw extruder and a twin/single screw tandem system. The viscosities of the polymer/CO_2 and the blend/CO_2 solutions were measured using a wedge die mounted on the twin-screw extruder. The effect of CO_2 on the morphology of PE/PS blends was investigated using a twin/single screw tandem system. This system allowed for preferential dissolution of the CO_2 into the matrix and/or dispersed polymer phase. By introducing devolatilization to the tandem system, the morphological behaviors of PE/PS blends were investigated on unfoamed filaments.