Synthesis of high-Tg polymers by ring-opening metathesis polymerization of N-cycloalkylnorbornene dicarboximide

Ring-opening metathesis polymerization (ROMP) of N-(1-adamantyl)-exo-norbornene-5,6-dicarboximide (AdNDI) (3a) and N-cyclohexyl-exo-norbornene-5,6-dicarboximide (ChNDI) (3b) was performed using well-defined vinylidene ruthenium (II) catalysts Cl2(PR3)2RuCCH(t-Bu) (R = Ph and Cy). The homopolymer of 3a showed a Tg of 271 °C while poly-ChNDI of 3b had a Tg of 129 °C. Copolymers of these monomers with norbornene (NB) demonstrated significant Tg increases compared to unsubstituted poly-NB. Analysis of copolymers of 3a and NB isolated at the initial stages of copolymerization showed that both monomers were incorporated randomly and displayed very similar reactivity. ROMP of 3a and 3b.