Organic Nanoparticles with Polypropyleneoxide Chains as Support for Metallocene Catalysts: Influence of the Concentration of PPO Chains on the Surface of Nanoparticles on the Catalyst Activity in Ethylene Polymerization

Summary

In this paper the influence of the surface of organic nanoparticles used as supports in metallocene catalysed olefin polymerization is investigated. Several latex particles with different amounts of polypropylene oxide (PPO) chains on the surface were synthesized by miniemulsion polymerization and used as supports for the Me₂Si(2MeBenzInd)₂ZrCl₂ / MAO complex. These catalysts were applied in heterogeneous ethylene polymerization. It was observed that longer PPO chains on the supports coordinated more metal sites than shorter ones to give catalysts with higher activities. An increased amount of PPO chains on the supports, however, led to catalysts with lower activities. It is suggested that a higher amount of PPO chains on the support could result in a stronger network between the different nanoparticles due to the enhanced interaction of the PPO with the methylaluminoxanes so that the diffusion of the ethylene monomer to the active metal sites is hindered.