Leila Akbarian-Feizi - Iran Polymer and Petrochemical Institute, P.O.Box ۱۴۹۶۵/۱۱۵, Tehran, Iran.
Shahram Mehdipour-Ataei - Iran Polymer and Petrochemical Institute, P.O.Box ۱۴۹۶۵/۱۱۵, Tehran, Iran.
Hamid Yeganeh - Iran Polymer and Petrochemical Institute, P.O.Box ۱۴۹۶۵/۱۱۵, Tehran, Iran.

New sulfonated copolyimides with ether and oligo ethylene glycol sequence in back bone were synthesized by reaction of synthesized diamine 4,4'-bis(5-amino-1-naphtoxy)-benzhophenon-3,3΄-disulfonic acid(BANBPDS) in companion with two nonsulfonated diamines 4,4΄-oxydianiline (ODA) and 1,8-diamino-3,6-dioxaoctane (DADO) and reaction with 1,4,5,8-naphtalene tetracarboxylic dianhydride (NTDA). After characterization of the monomers and polymers with common methods the sulfonated polyimides were characterized for their viscosity, molecular weight, processability, solubility, and thermal stability. All the sulfonated polyimides had good thermal stability and exhibited a three-step degradation pattern while have good processability and solubility.

sulfonated copolyimide, ether group, oligo ethylene glycol sequence, thermal stability