The aim of the present work is to explore and enhance two important aspects in polymer blends: mixing efficiency and compatibilisation, either separately or in a combined fashion in order to target a potential application on the wastes treatment from the food packaging sector. In a first approach, non-compatibilized model blends made of PP/LDPE and EVOH/LLDPE were prepared in a batch and extensional-type mixer, RMX®, where a fine polymer blend’s morphology was obtained. Simultaneously, same blends were obtained in a continuous extensional-type mixer, Meteor®, which shares the principle of contracted-flow geometry with the RMX®, and also in a twin-screw extruder for reference. The assessment of the mixing performance was then followed in by morphology characterization using AFM and SEM techniques as well as mechanical behavior. Morphology comparison between mixing devices was validated by the estimation of the specific energy (SME). It was found that, at relatively similar morphologies, the batch mixer required lesser SME values, followed by Meteor® and the Twin-screw extruder. With this procedure it was possible to estimate the gap of SME values between mixing devices so as to adjust mixing conditions of the continuous extensional mixer towards higher efficiencies. On the other hand, compatibilisation issues in blends have been addressed on proposing a reactive blending procedure based on the generation of reactive sites in the polymer chain and selective grafting of copolymer macromolecules.