Catalytic Emulsion Polymerization of Olefins: Ab-Initio Polymerization of a Family of Norbornene-Derived Monomers

The use of late transition metal catalysts for the polymerization of olefins in aqueous media has created new opportunities to produce latex particles based on ethylene and its olefinic derivatives. In this work we report on the production of water-based latices from a variety of monomers based on the strained cyclic olefin, norbornene. These have been carried out as ab-initio batch emulsion polymerizations using allylpalladium catalysts and a lithium borate activator as well as sodium dodecyl sulfate surfactant. We find that the n-alkylnorbornenes can be polymerized in aqueous emulsion and that the mechanisms for latex particle formation are likely the same as that for norbornene monomer alone. The latex particles created are small, averaging about 45 nm in diameter. As in the case of norbornene, large amounts of coagulum can be formed if the catalyst and activator are allowed to reach the emulsified monomer droplets and effect polymerization in that location. As the substituents on the norbornene become larger and nonpolar, it is necessary to consider their effect on the water solubility of the monomers in order to analyze the experimental results in an effective manner. Our studies included butyl- and decylnorbornene, vinyl- and butenylnorbornene, and methanol−norbornene.