Polycondensation-type poly(amic acid) (PAA) was synthesized with 3,3',4,4'-benzophenonetetracarboxylic dianhydride as a dianhydride monomer and 4,4'-diaminodiphenylmethane and 4,4'-oxydianiline as diamine monomers under microwave irradiation in dimethylformamide. Then, PAA was used to make polyimide (PI) by imidization at a low temperature. The structure and performance of the polymers, were characterized with Fourier transform infrared (FTIR), proton nuclear magnetic resonance (H-1-NMR), viscosity, X-ray diffraction (XRD), and thermogravimetry (TG) curve analyses. The FTIR spectra of the polymers showed characteristic peaks of PI around 1779 and 1717 cm(-1). The H-1-NMR spectrum of PAA indicated a singlet at 6.55 pprn assigned to -NHCO- and a singlet at 10.27 pprn assigned to carboxylic acid protons. The XRD spectrum demonstrated that the obtained PI had a low-order aggregation structure with a d-spacing of 0.5453 nm. The TG results revealed that the PI was thermally stable with 10% weight loss at 565 degrees C in an N-2 atmosphere. (C) 2007 Wiley Periodicals, Inc.