ProcurementPolyimide monomers:2-(4-Aminophenyl)-1H-benzimidazol-5-amine(CAS:7621-86-5)99.9%min; 3,3",4,4"-Biphenyltetracarboxylic dianhydride(CAS:2420-87-3)99.5%min; ,4,4"-(Hexafluoroisopropylidene) diphth