Indane‐based bismaleimide and cloisite 15a nanoclay blends: Kinetics of thermal curing and degradation of particulate nanocomposites

Bismaleimide, 5(6)‐maleimide‐1(4′‐maleimidophenyl)‐1,3,3′‐trimethyl indane (BMII) was prepared, different weight ratios (1, 3, 5, 7, and 9%) of cloisite 15a were blended with BMII ultrasonically and thermally polymerized at 230°C for 6 h. The Fourier transform infrared spectrophotometry (FTIR) studies of the polymerized materials reveal that the clay particles affect only the indane nucleus present in the bismaleimide. Differential scanning calorimetry results reveal that the nanoclay particles affect the enthalpy of curing and the extent of this effect depends on the degree of clay loading. In the case of particulate nanocomposites, irrespective of the amount of clay loading, the endset degradation temperatures of the nanocomposites were found to increase (35–60°C). The change noted in the apparent activation energies (E_a) for curing and degradation with respect to the extent of the reaction (α) is much dependent on the amount of cloisite 15a present in BMII. The TG‐FTIR studies showed the compounds such as CO, CO₂, aromatic amine, and aromatic isocyanates are the major degradation products from polyBMII. Possible degradation mechanism of polyBMII is presented and discussed. The scanning electron microscopy results show that the aggregation of clay particles are noted for higher level loadings (5 and 7%) of cloisite 15a nanoclay particles in BMII. POLYM. COMPOS. 34:1279–1297, 2013. © 2013 Society of Plastics Engineers