Synthesis of vinyl-type functionalized polynorbornenes with cyclic pendant imide side groups by using palladium-based catalyst for low dielectric constant materials

A set of functionalized polynorbornenes with various substituted pendant imide groups (N-substituent imide group = adamantyl, cyclohexyl, tolyl, and phenyl) have been prepared via vinylic pathway by using di-μ-chloro-bis-(6-methoxybicyclo[2.2.1]-hept-2-ene-endo-5σ,2π)-palladium(II) catalyst as a means of developing materials for low dielectric constant. The effects of molar ratio of monomer to catalyst, solvent polarity, reaction time, and temperature on the polymerization of substituted norbornene-5,6-dicarboximide were investigated. Among the monomers used, exo-N-cyclohexyl-norbornene-5,6-dicarboximide recorded the highest activity, giving 90% conversion in 30 min. All the resulting functionalized polynorbornenes are characterized by good thermal properties (∼5% weight loss at 440 °C) and low dielectric constants (2.26-2.53), which are desirable for the next generation of microprocessors and memory for computers to provide insulation in the increasingly shrinking feature sizes of faster microprocessors.