Characterization of elongation viscosity for polyethylene melts

Elongation viscosity is an important characterization of flow properties for polymer melts. In the present article, a new extensional viscosity equation for polymer melts was established by introducing a relaxation time equation based on the Cross model. The elongation viscosities of a low-density polyethylene (LDPE) melt at 200 °C and a metallocene linear low-density polyethylene (mLLDPE) melt at 130 °C were estimated using this equation; then, the calculations of the melt elongation viscosity were compared with the measured data from the extension experiments of the LDPE melt and the mLLDPE melt reported in the reference. Good agreement was found between the predictions and the measured data from the LDPE and mLLDPE melts. In addition, this equation is easy to use for characterization of elongation viscosity during single shaft elongation flow for polymer melts.