The Polymer Society of Korea

Abstract

Model polynorbornenes with high heat resistance were synthesized via vinyl-addition polymerization of alkyl-substituted norbornenes using a palladium(II)-catalyzed system specifically designed to maintain homogeneous catalytic activation. A weakly solvating catalytic environment was established through the rational combination of a monodentate phosphine ligand and a weakly coordinating solvent, which effectively preserved the homogeneous nature of the catalyst throughout polymerization. This design enabled stable initiation and propagation of methyl-, ethyl-, and butyl-norbornene monomers, yielding polymers with narrow molecular weight distributions (Đ < 1.10) and high molecular weights (M_n up to 500 kDa).  The resulting polymers exhibited high optical transmittance exceeding 90% at 400 nm and glass transition temperatures reaching 300 °C. Importantly, these findings suggest that living polymerization behavior can emerge through tuning of the catalytic environment.