Ethylene/polar Monomer Copolymerization Behavior Of Bis(phenoxy-imine)ti Complexes: Formation Of Polar Monomer Copolymers

摘要

For some years now, academic and industrial scientists have been hard at work trying to discover molecular catalysts that allow for the copolymerization of olefinic hydrocarbon and polar monomers. This is because polyolefins having polar functional groups are believed to possess not only modified surface properties such as dyeability, adhesion, and wettability, but also unique bulk properties.rnFor the copolymerization of olefinic hydrocarbon and polar monomers, late transition metal catalysts have been at the forefront of catalyst development. Conversely, although early transition metal catalysts represented by metallocene catalysts have offered remarkable opportunities for the synthesis of novel olefin-based materials, they are normally regarded as unpromising for such a copolymerization. This is because early transition metal catalysts are typically oxophilic and thus are deactivated by the presence of polar monomers in a polymerization medium. Therefore, these early transition metal catalysts have limited applications and require reaction modifications such as masking the functionality as an innocuous species and/or precomplexation of functional groups by stoichiometric amounts of Lewis acidic species.