New strategy for preparation of LLDPE nanocomposites through tandem catalytic system

Tandem catalytic system composed of the ethylene trimerization catalyst CrCl₃/bis(2-butylsulfanyl-ethyl)amine) (SNS) ( I ) and the ethylene copolymerization catalyst zirconocene dichloride ( II ) has been introduced for preparation of linear low-density polyethylene (LLDPE). The catalytic behavior of the novel catalyst ( I ) activated by modified methyl aluminoxane was tested that afforded 1-hexene (1-C₆) with the activity of 141,370 g 1-C₆/mol-Cr h. The butyl branches in the polymers prepared by tandem catalysis method were determined utilizing Fourier transform infrared (FTIR) spectroscopy for the first time. The higher Cr/Zr molar ratio led to increasing the butyl content within the prepared copolymer up to 10.38 butyl branches per 1000 C in the polymer chain. LLDPE nanocomposites having different types of nanofillers (TiO₂, Santa Barbara Amorphous-15, and Fe₃O₄ magnetic nanoparticles) were prepared and analyzed by FTIR, scanning electron microscopy (SEM), differential scanning calorimetry, and thermogravimetric analysis. Increasing the sonication time up to 60 min enhanced the nanoparticles dispersion in the polymeric matrix. SEM images of the nanocomposites with various amounts of nanofillers, showed the best dispersion of the nanofillers in the presence of 50 mg nanofiller in toluene solvent. The presence of the nanofillers also increased the hydrophilicity of the polymer surface. Antibacterial activity against Gram-negative bacteria was also observed for the prepared nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47497.