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 þ montmorillonite (MMT Na þ ) 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 308C) 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.

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Polyethylene and polypropylene nanocomposites were investigated with focus on mechanical and barrier properties. Structure was observed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Four types of nano‐filler were used: Nanofil 5, 8, 9 and 3000. In case of polyethylene nanocomposites the dispersion and intercalation was to low extent. Mechanical and barrier properties were worse compared to pure PE. In case of polypropylene with Nanofil 5, 9 and 3000 tensile strength was better compared to pure PP. Also PP with Nanofil 9 and 3000 had better barrier properties than pure PP for both O2 and CO2. This was explained by better intercalation and dispersion of the filler documented by XRD measurement and TEM observation.

The comparison of calculated data from proposed mathematic model and experimentally obtained data of PP/clay nanocomposites was done with the focus on the layered shape of MMT platelets. Based on the well-known Kerner's model and the Halpin-Tsai' equation with the use of some described presumption, the mathematic model for PP/clay nanocomposite was proposed. Data from the measurement of prepared PP/clay samples were taken and compared with the calculated ones from the proposed model. The good agreement was found.

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