Recently I tried to make a Polyimide PI membrane using Pyromellitic dianhydride (PMDA) and m-phenylene diamine (mPD). Using DMAc as solvent, After reaching Polyamic acid PAA stage i casted the pulp on glass plate and put it in the air circulating oven for imidization at temps of 100,150,200,250,300 for 60 minutes each. The resulting product looked like broken paint that comes off of walls.

Until now i haven't found any literature where they tried this combination for forming PI. I guess the polymer chains were too rigid.

Are there any modifications that i can make in the synthesis procedure to make it better or should i give up on it ? Which combination will work the best for me . My application is gas separation.

Kindly help