The effects of processing and carbon nanotube type on the impact strength of aerospace-grade bismaleimide based nanocomposites

While the addition of well-dispersed carbon nanotubes (CNTs) in polymer nanocomposites typically improves the polymers' impact strength, herein, we report that good CNT dispersion alone is not a sufficient condition to improve the impact strength of the nanocomposites. Our results demonstrate that the impact strength of the nanocomposite also depends on the CNT type and the nanocomposite processing conditions. Depending on these factors, CNTs can either disrupt the crosslinking network of bismaleimide (BMI), or the CNTs themselves can be compressed by up to 2.9 GPa upon the curing of BMI or both. The effect of these factors on the impact strength is discussed. Overall, impact strength of up to 54 kJ/m² has been achieved, which is 80% higher than the best impact strength reported for any CNT-BMI system in the literature.