Polyimides synthesized from 4,4′-(1,2-ethynediyl) bis (phthalic anhydride)

A novel substituted acetylene monomer, 4,4′-(1,2-ethynediyl) bis (phthalic anhydride) (EBPA) was made in six steps from 4-nitro-N-methylphthalimide (4-NPI) including two palladium-catalyzed acetylene coupling steps. Several new polyimides were prepared from this monomer and six aromatic diamines. In addition, copolymers were made with EBPA and BPADA with meta-phenylene diamine. All of the polymers had high glass transition temperatures, high thermal stability and good solvent resistance. The copolymer containing twenty % EBPA had a glass transition temperature 33°C higher than Ultem® (a registered trademark of GE) and improved solvent resistance.