The rheological and morphological properties of linear low-density polyethylene/cyclo olefin copolymer (LLDPE/COC blends were investigated, as were their peel seal characteristics when heat sealed to films of either polyethylene (PE) or polyethylene terephtalate (PET). Three blend systems, with COC volume percentages of 5, 10, and 15%, were melt blended in a twin-screw extruder. A partial phase miscibility/compatibility was initially suggested by Cole-Cole and equivalent plots of the dynamic rheological properties and subsequently confirmed by scanning electron microscopy. The investigation of the systems' heat sealing properties pointed out all interesting industrial potential for PET sheets covered with a fine layer of a LLDPE/COC blend before beat sealing to a PE film for packaging applications. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 2015-2022, 2010