Self-densified microstructure and enhanced properties of carbon nanotube fiber by infiltrating polymer

Polymer infiltration is an efficient way to strengthen carbon nanotube fibers in the process of spinning. Given the carbon nanotube/polymer composite fibers obtained from this approach possess higher mechanical properties than the ones of their components, the general rule of mixtures for a composite material is not applicable. Accordingly, a novel coarse-grained molecular dynamics model is proposed to investigate the mechanical behavior and microstructural evolution of the composite fibers, in which the carbon nanotubes and polymer chains are represented by mesoscale coarse-grained beads. Then the reinforcing mechanism of the composite fibers is illustrated. Dependence of the mechanical behavior on the microstructure of the composite fiber under different strain rates is revealed as well. Furthermore, the variations of mechanical properties of the composite fibers with cycle numbers under relatively low load are predicted.