Copolyimides with trifluoromethyl or methoxy substituents. NMR characterization

In the first stage, a series of aromatic diamine compounds such as 2-methoxy-5,4′-diaminodiphenyl ether (ODAOMe) and 2-trifluomethyl-4,4′-diaminodiphenyl ether (ODACF 3) were synthesized. These aromatic diamines and 4,4′-diaminodiphenyl ether (ODA) were then used to prepare copolyimides with 4,4′-oxydiphthalic anhydride (ODPA) and bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA). Both chemical composition and the arrangements of repetitive units were characterized by 1H and 19F NMR. It was shown that solubility and thermal stability are related to the BCDA fraction in the copolymers and to the chemical structure of the diamine.