Introducing bone-shaped carbon nanotubes to reinforce polymer nanocomposites: A molecular dynamics investigation

Typically, the edges of single-walled carbon nanotubes (SWCNTs) are capped with fullerene hemispheres having the same diameter as the nanotubes. In the present numerical study, a bone-shaped (BS) carbon nanotube (CNT) is introduced in order to test its reinforcing capabilities when used as filler within a polymer matrix. The specific complex molecular structure is composed by a SWCNT, the two open edges of which are appropriately closed with larger fullerenes. Specifically, the tubular shape of the proposed nanofiber (NFB) is achieved by the utilization of the zigzag (10,0) SWCNT while the fullerene C-500 is appropriately attached at the nanotube open edges for the formation of two spherical heads. The developed BS NFB is used as reinforcement in a polyethylene (PE) matrix at several mass fractions. Corresponding periodic unit cells are developed and simulated via molecular dynamics (MD) to predict the tensile and shear stress-strain response of the investigated nanocomposites. Additionally, appropriate numerical tests are also conducted for computing the NFB/PE interfacial binding energy and, thus, characterizing the interfacial strength of the nanocomposites. For comparison purposes, all numerical tests are repeated by using as reinforcement the conventionally capped (10,0) SWCNT of the same number of atoms instead of the BS one.