Polyethylene (PE) nanocomposite samples were prepared with Cloisite 25 A, 30B, and 93 A and Nanofil 5 and 3000 nanofillers. The amount of modified Na+ montmorillonite (MMT Na+) was fixed to 5 wt%. For the compounding of PE matrix and nanofillers, two different compounding equipments were used, KO Kneader Buss and APV twin-screw extruder. In all samples, maleic anhydride-modified PE (PEMa) was added as a compatibilizer. The content of PEMa in mixtures was always 5 wt%. The level of MMT exfoliation in the nanocomposite systems was studied by X-ray diffraction and by transmission electron microscopy observations. The properties of samples were evaluated by dynamical mechanical analysis (E* modulus at 30 degrees C) and by the measurement of tensile properties (stress and strain at break). Because of the possibility of usage of prepared materials in packaging industry, barrier properties were measured with focus on oxygen, carbon dioxide, and water vapor permeability. The influence of two different used compounding equipments on the prepared nanocomposite samples of PE nanocomposites was discussed
