Polyolefin nanocomposites formed by melt compounding and transition metal catalyzed ethene homo- and copolymerization in the presence of layered silicates

Nanocomposites of high density polyethylene (HDPE), linear low density poly ethylene (LLDPE) and highly branched polyethylene rubbers were prepared bot h by means of melt compounding and ethene homo- and copolymerization in the presence of layered silicates which were rendered organophilic via ion exc hange with various quaternary alkyl ammonium cations. In comparison to melt compounding, in-situ ethene homo- and copolymerization, catalyzed with MAO -activated zirconocene (MBI), nickel (DMN) and palladium (DMPN) catalysts, proved more effective in nanocomposite formation, as evidenced by larger in terlayer spacings and formation of exfoliated anisotropic nanosilicates wit h high aspect ratio.