Structure and Nanomechanics of PPTA-CNT Composite Fiber: A Molecular Dynamics Study.

Poly phenylene terephthalamide (PPTA) fiber has both high mechanical properties and low thermal conductivities, making it ideal for the design of thermal protection material in hypersonic vehicles. In this paper, the impact of CNT additions on the nanostructure and mechanical performances of PPTA fibers is investigated by coarse-grained molecular dynamics (CGMD) simulation. It can be found that CNT addition performs as the skeleton of PPTA polymer and induces a higher degree of alignment of polymers under shear deformation during the fabrication process. Both strength and Young's modulus of the PPTA fiber can be improved by the addition of CNTs. The interaction between CNTs and PPTA polymer in PPTA fiber is important to further improve the efficiency of force transfer and mechanical performance of PPTA-CNT composite fibers.