4,4'-Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites were prepared by the sol-gel process of tetrabutyl titanate in the presence of 4,4'-bismaleimidodiphenyl methane modified novolak resin prepolymers with acetyl acetone as a stabilizer. These nanocomposite materials were characterized by Fourier transform infrared analysis, dynamical mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and field emission scanning electron microscopy. Nanometer titania particles were formed in the novolak resin matrix, and the average original particle size of the dispersed phase in the nanocomposites was less than 150 nm, but particle aggregates of larger size existed. The introduction of the titania inorganic phase with a nanoscale domain size did not improve the glass-transition temperature of the nanocomposites but lowered the thermal resistance of the material because of the incomplete removal of acetyl acetone coordinated with tetrabutyl titanate, and it improved the modulus of the material at lower temperatures (< 200 degrees C) but lowered the modulus at higher temperatures (> 250 degrees C). (c) 2006 Wiley Periodicals, Inc.