Partially miscible EVOH/copolyamide-6/6.9 blends: Thermal, dynamic-mechanical and shear rheology behavior

Binary blends of two random copolymers, ethylene-vinyl-alcohol (EVOH) consi sting of different ethylene contents, and copolyamide-6/6.9 with an approxi mate 1:1 comonomer ratio, have been prepared via blown film extrusion as fi lms, 20 mu m thick. Thermal, dynamic-mechanical, and rheological properties were determined. It was found that these blends are partially miscible. Th e-EVOH-rich blends exhibit much lower miscibility than the copolyamide-rich blends. The ethylene content in the EVOH affects the miscibility of the bl ends: a higher ethylene content results in a lower miscibility. This is due to fewer intermolecular hydrogen bonds between the OH group of the EVOH an d the amide group of the copolyamide. The interactions between the blends' components affect their thermal, dynamic-mechanical and their rheological b ehavior.