Ring-opening metathesis polymerization of cyclic olefin monomers containing imide rings

Abstract

Tricyclic norborneneimides with a cyclohexyl or n-hexyl side chain were synthesized and polymerized to new thermally stable and transparent polymers. The monomers, exo,exo-1,1a,4,4a,5,6,7,8-octahydro-1,4-methanonaphthalene-6,7-dicarboxylic cyclohexylimides and n-hexylimides were synthesized by Diels-Alder reactions of cyclopentadiene, with the corresponding 1,2,3,6-tetrahyhdrophthalic imide compound. Ring-opening metathesis polymerization (ROMP) of the monomers was carried out with ruthenium carbene catalyst. Polymerization proceeded very fast, and the polymers with molecular weight ranging from 46,000 to 220,000 were obtained by controlling the amount of catalyst employed. The polymers were soluble in chlorinated solvents such as dichloromethane and chloroform. UV/visible spectrum of the polymer solution did not show any absorption in visible range. 5% weight loss temperature of the polymers was over 400$^\circ C$ in nitrogen and 350$^\circ C$ in air. Hydrogenated polymers had no noticeable changes in solubilities and transparencies, but they showed improved thermo-oxidative stability.