Nanotube Superfiber Materials: Chapter 23. Aligned Carbon Nanotube Composite Prepregs (Micro and Nano Technologies)

Carbon nanotubes (CNTs) possess the unique combination of extreme mechanical and physical properties at the level of the individual tube. They are often considered one of the best candidates for the reinforcement of the next generation of multifunctional composite materials. It is essential to assemble the CNTs into macroscopic assemblies resembling traditional fiber-reinforced composites to begin to realize their potential and make them a serious candidate for commercial composite structures. This chapter presents a general introduction to aligned and high-volume fraction CNT composites and then explores two recent promising approaches for fabricating strong, stiff and multifunctional aligned CNT/polymer composite prepregs at satisfactory processing rates. One approach involves incorporating drawable superaligned CNT sheets into high-volume fraction composites through spraying or spray-stretching and winding. The other approach is based on directly shear pressing vertically aligned CNT arrays into horizontally aligned sheets with subsequent polymer infiltration. Both approaches produced CNT composite prepregs with desirable structural features and excellent properties. Aligned CNT/bismaleimide composites produced by stretch winding exhibited a combined tensile strength and elastic modulus exceeding carbon fiber composites. The exceptional mechanical performance coupled with unique electrical and thermal properties makes these materials promising for a wide range of applications, such as multifunctional composite structures, lightweight and flexible conductors, thermal interface materials, and sensors.