ABSTRACT: In the presence of modified methylaluminoxane as cocatalyst, the behavior of a binary catalytic system based on pyridineimine nickel -N- and iron -F- catalysts was evaluated in order to reach a proper mixture of polyethylene -PE-. A computational study along with kinetic profile suggested that the catalyst F with higher electron affinity -A- and electrophilicity -ω- in the methyl cationic active center and stronger interaction with the monomer led to high integrated monomer consumption and higher activity. In addition, the samples produced by the mixture of catalysts showed a higher value of Mv [19.4 × 104 g -PE- mol -Fe+Ni-−1 h−1-], melting point -127.8 _C-, and crystallinity extent -41.29%- than the samples produced by the single catalysts. The addition of multiwalled carbon nanotubes -MWCNT- into the polymerization media reduced the activity of catalysts [from 7.50 × 104 to 0.66 × 104 g -PE- mol -Fe+Ni-−1 h−1] and the thermal properties of the low-density polyethylene nanocomposite samples. However, the sample containing 2.33% MWCNT20-30 improved the total thermal stability of the neat polyethylene blend up to 400 _C. Scanning electron microscope images of the samples demonstrated irregular to virtually uniform morphologies were obtained through the in situ and solution-mixing techniques.

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