The deformation of the dispersed phase in polystyrene/high density polyethylene (PS/HDPE) blends produced by ribbon extrusion was studied numerically and experimentally. A mathematical model for the deformation of the dispersed phase in ribbon extrusion processing of polymer blends was developed assuming uniaxial deformation of the ribbon and the equilibrium shapes of the dispersed particles with a pressure balance over a drop. Simulated morphologies as function of the post‐extrusion parameters were obtained and compared with experiments. The analysis of the ribbon extrusion process showed that parameters such as draw ratio (DR) and ribbon‐water contact length (X) significantly influence the ribbon dimensions, the extensional stress, and the stretching force. The results also showed that deformation and coalescence of the dispersed phase in the ribbon extrusion processing of polymer blends increase at higher DR and/or lower X values. The comparison between the model and the experimental morphologies of PS/HDPE produced a good agreement.

Blends of high density polyethylene and polystyrene were produced via ribbon extrusion to study the effect of post-extrusion conditions on the ribbon final dimensions and morphology. An experimental setup was designed to measure the stretching force as a function of draw ratio and water contact distance for blends of 3, 6 and 9 % PS in HDPE. Numerical simulations of the non-isothermal process using Matlab were in good agreement with the experimental data only when both viscous and elastic effects are included. The results show that both draw ratio and water contact distance have a definite influence on the final dimensions of the ribbon and the stretching force. It was found that deformation of the dispersed phase increases with draw ratio, but decreases with water contact distance.