Palladium(II)-catalyzed addition polymerizations of nadimides with linear alkyl and alicyclic pendant groups

Two series of polynadimides with pendant linear alkyl and alicyclic groups have been prepared by addition polymerization of N-alkyl-exo-norbornene dicarboximides (nadimides; alkyl = propyl, butyl, pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl, and cycloheptyl) in the presence of palladium(II) catalyst. The catalytic reactivity of the nadimides strongly depends on the nature and the steric bulk of the pendant groups. Nadimides with alicyclic groups (except for N-cyclopropyl nadimides) exhibit higher reactivity than the nadimides with linear alkyl groups and substituents with the same number of carbons. The polynadimides with alicyclic groups present lower dielectric constants than those with linear alkyl groups. All resulting polynadimides exhibit better thermal stability than the unsubsitituted polynorbornenes.