Polyimides from Cyclic Aliphatic Diamine Monomer

Abstract

Polyimides are of interest because of their characteristic thermal properties such as high glass transition and decomposition temperatures and chemical resistance to many conventional solvents. The synthesis of polyimides from cyclic aliphatic diamine monomers would ideally incorporate enhanced rigidity and toughness to the typically brittle films while maintaining excellent clarity. Similar work has been shown by Kelsey and co-workers where terephthalate-based copolyesters have been found to “exhibit high impact resistance combined with good thermal properties, ultraviolet stability, optical clarity, and low color.”1 The low color property is a result of the aliphatic monomer disrupting the aromaticity of the polymer backbone which could reduce some of the yellow tint common to most polyimides. The improvement in mechanical properties such as impact resistance, toughness, and modulus, while observed, are inexplicable at this point in the research of polymers incorporating cyclic aliphatic monomers.2,3 A series of polyimides was synthesized with l,4-bis(aminomethyl)cyclohexane, a cyclic, aliphatic diamine monomer, and four commercially available dianhydrides. The polymers showed good thermal properties, excellent chemical resistance, and fair mechanical properties consistent with similar polyimides.