REACTIVE BLENDING IN A TWIN-SCREW EXTRUDER - EXPERIMENTAL AND THEORETICAL APPROACHES

We studied the morphology of a reactive blend, constituted by an EVA/E MA phase dispersed in a polypropylene matrix. The dispersed phase was crosslinked in-situ during the extrusion through a transesterification reaction, catalysed by dibutyltin oxide. Rheological studies allowed the define the changes in rheological behaviour during the crosslinkin g reaction. Using a flow model developed for two in screw extruders, w e computed the reaction extent along the screws and the corresponding blend morphology using a very simple approach. Theoretical results und erestimate the extent of the reaction, but explain qualitatively the g eneral tendencies when varying operating parameters.