Study On Morphology And Properties Of High-Strength PP/HDPE Alloy Extruded In Stretch Flow Fields

This paper successfully prepared PP/HDPE (90/10), PP/HDPE (80/20), PP/HDPE (70/30), and pure PP sheets, extruded through the die with stretch flow fields in the plunger extruder, whose strength increased not only in longitudinal properties but also in transverse properties. The paper had studied the properties and the morphology of the PP/HDPE alloy in different proportion and at different extrusion temperature, extruded in stretch fields, and tested by intensile, DSC, WAXD and SEM.The main research work and the conclusions are listed as follows: 1) The strength of PP/HDPE (90/10), PP/HDPE (80/20), PP/HDPE (70/30), and pure PP sheets, extruded through the die with stretch flow fields, showed the distinct enhancement than melt extruded sheets, both in longitudinal properties and in transverse properties.The longitudinal strength of PP/HDPE (90/10) alloy extruded at 145℃ achieved 267MPa, enhanced 551% than that of melt extruded ones, and enhanced 63.8% than that of pure PP by solid extrusion. The transverse strength of PP/HDPE (90/10) alloy reached peak 46MPa, enhanced 21% than that by melt extrusion, and enhanced 12.2% than that of pure PP by solid extrusion.The processing windows of the material became broader in the semi-solid state when HDPE added into PP.2) The PP/HDPE(90/10) alloy sheets, extruded at 145 ℃ --160 ℃ different temperature, were measured by DSC. The results showed that the crystallinity of HDPE and PP decreased as extrusion temperature increased.