Entry flows of polylactides with slip

• Rheological characterization of 4 PLAs of various MWs.
• Slip was determined using the Mooney technique.
• Slip is included in the flow simulations.
• Results are given up to 650 1/s, rates relevant to industrial practice.
• Experiments and simulations found to agree using the K-BKZ model.

The entry capillary flow of four different polylactides (previously characterized by Othman et al. (2012)) has been modeled with both a viscous (Cross) and a viscoelastic (K-BKZ) model. The modeling takes into account slip-at-the-wall, which was found to increase with decrease of molecular weight. The flow through different capillary dies and apparent shear rates show the excess pressure losses (ends correction), which are smaller than those for other similar linear polymer melts. The viscous simulations capture well the ends correction, while the viscoelastic simulations improve these predictions, as they also account for the viscoelastic nature of the polymer melts. It is concluded that solely viscous modeling can capture their flow behavior satisfactorily.