Bismaleimide (2,2-bis[4-(4-maleimidophenoxy phenyl)]propane) is prepared, blended with cloisite 15a (1, 2, 3, 4, 5, 7 and 9 wt%) by ultrasonically and thermally polymerized. The FTIR studies reveal that the clay particles affect the maleimide ring and ether linkage of the polybismaleimide. Thermogravimetric studies of cured materials show that the incorporation of clay particles does not affect the degradation temperature values at low levels of clay loading. At higher loadings, the degradation temperature decreases compared to pure polybismaleimide. Degradation kinetics is performed using Vyazovkin and Friedman methods. At lower loadings of clays the apparent activation energy for thermal degradation is nearly constant (alpha = 0.1-0.8) and at higher loadings the trend is similar to pure polybismaleimide, but the values are lower. This is due to the aggregation of nanoclays leading to microcomposites. The clay particles are well dispersed in the polybismaleimide matrix as evidenced by SEM and TEM studies of the nanocomposites. (C) 2013 Elsevier B.V. All rights reserved.