Synthesis and Characterization of a Phosphonated Graft Copolyimide
Keywords:Copolyimide, phosphonic acid, PEM fuel cell.
A new synthesis route of phosphonated multiblock, branched copolyimide is proposed in this research. The synthesis and characterization of the series of new phosphonated graft copolyimides were prepared by combination of one-step high temperature polymerization and phosphonation method by lithiation and reaction with excess diethylchlorophosphate. The phosphonate ester product was converted to the phosphonic acid by hydrolysis. A branched polyimide structure was achieved by coupling the two polyimides with 3, 3'-diaminobenzidine. A phosphonated branched copolyimide with 32% mol phosphonation exhibited high thermal stability, with a decomposition temperature in nitrogen of ∼475°C. Proton exchange membranes prepared from these copolyimides had proton conductivity of 0.02 - 0.03 S/cm at 100% humidity over a temperature range of 40 - 100°C.
Authors who publish with Engineering Journal agree to transfer all copyright rights in and to the above work to the Engineering Journal (EJ)'s Editorial Board so that EJ's Editorial Board shall have the right to publish the work for nonprofit use in any media or form. In return, authors retain: (1) all proprietary rights other than copyright; (2) re-use of all or part of the above paper in their other work; (3) right to reproduce or authorize others to reproduce the above paper for authors' personal use or for company use if the source and EJ's copyright notice is indicated, and if the reproduction is not made for the purpose of sale.