Melting of a polyethylene/polyamide blend in a co-rotating twin-screw extruder: experiments and preliminary modelling

Abstract During the compounding of immiscible polymer blends in a twin-screw extruder, the melting is a crucial point, as the morphology of the blend is initiated during this phase. If the melting process of a single polymer is now correctly understood, it is not yet the case for a blend. In this paper, an experimental study of the melting of a polyethylene/polyamide blend is presented, allowing an accurate quantification of the melting process. Results for the blend are compared to those of the single components and the influence of the processing parameters (screw speed, feed rate, barrel temperature) is investigated. Based on these experiments, a preliminary theoretical model is derived, allowing one to calculate the changes in dimensions and volume fraction of the solid pellets during the melting process. Exploratory results on a simplified geometry are in qualitative agreement with the experiments.