Hyperbranched polyaspartimides were successfully prepared from bismaleimides (A(2)) and triamines (B-3) through the Michael addition reaction. Two bismaleimides of 4,4'-bismaleimidodiphenylmethane (BMDM) and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (BEMM) and two triamines of tris(3-aminophenyl)phosphine oxide (TAPPO) and tris(4-aminophenyl)amine (TAPA) were employed in the preparation of these hyperbranched polyaspartimides. The chemical structures of the polymers were characterized with Fourier transform infrared (FTIR), H-1 and P-31 NMR, and elemental analysis. Degrees of branching ranging from 0.51 to 0.69 were found with the polyaspartimides, ensuring their hyperbranched structure. The polymers also showed good solubility in common solvents, high glass-transition temperatures of 256 degreesC, and excellent thermal stability above 370 degreesC. (C) 2004 Wiley Periodicals, Inc.