Melt strength and drawability of HDPE, LDPE and HDPE/LDPE blends

The melt strength and drawability of a low-density polyethylene (LDPE), a high-density polyethylene (HDPE) and HDPE/LDPE blends during extension flow were studied using a Rheotens test method under die extrusion temperature ranging from 160 to 200 °C and die extrusion rates varying from 9 to 36 mm/s. The results showed that the melt strength of the HDPE, the LDPE and the blends decreased with increasing die extrusion temperature while it increased with increasing die extrusion rate. The drawability of the HDPE, the LDPE and the blend melts could be improved through increasing die extrusion temperature and reducing die extrusion ratio. The dependence of the melt strength of the HDPE, the LDPE and the blend melts on the die extrusion temperature approximately obeyed the Arrhenius equation.