Alkylammonium AlPO-kanemite as support for tuning catalytic activity of metallocene: In situ preparation of polyethylene nanocomposites

Abstract

Several alkylammonium-AlPO-kanemites were prepared to display a range of interlayer distances due to the presence of variable n-butyl/n-dodecylammonium concentrations. Zirconocene and titanocene dichlorides reacted with these layered materials to produce new supported metallocene catalysts. The characterization of these materials confirmed their formation and the presence of the anchored metallocene on the solid support. This study aimed to test these samples for the first time as catalysts for ethylene polymerization for verification of the influence of the metallocene supports with tunable interlayer distances on the catalytic behavior and for in situ production of nanocomposites. The data showed that the highly active new supported systems reaches values of activity comparable to that obtained by analogous homogeneous system. The increase in the interlayer space acted to increase the activity, showing that the possibility of change the interlayer space is a tool to control the activity. Polymers obtained by the supported catalysts presented higher molecular weight and lower polydispersities index than that synthetized with homogeneous catalyst. The ethylene polymerization promoted the exfoliation of the alkylammonium-AlPO-kanemite layers in the polymer matrix, characterizing the formation of a nanocomposite. Compared to the pristine polymer, the presence of inorganic fillers in the polymer matrix increased the melting temperature of the nanocomposite.