Toughness reinforcement of bismaleimide resin using functionalized carbon nanotubes

Carbon nanotubes (CNTs) with various functionalization states were used to toughen bismaleimide resin. Differential scanning calorimeter and rheometric measurements were conducted to monitor the processability of the hybrid systems. The toughness of the corresponding composites was investigated by Charpy impact and flexural tests, while the thermal properties were obtained from dynamic mechanical and thermogravimetric analyses. The results showed that the loading and functionalization state of the CNTs in the resin matrix had a great influence on the mechanical performance and glass transition temperature, but less influence on thermal decomposition temperature of the composites. These phenomena could be attributed to the differences in dispersion state, interfacial adhesion, and interfacial compatibility of CNTs in the resin matrix. Compared with the pure resin, composites containing 0.50 wt% diaminodiphenylmethane-treated CNTs showed 60% improvement in impact strength and 100% improvement in flexural toughness while preserving their thermal properties.