Computational analysis on mechanical property reinforcement of nylon 6 polymer and nanofiller dispersion through addition of CNT/Graphene/CNT-Graphene nanofillers

Carbon nanofillers, such as carbon nanotubes (CNTs) and graphene (G) sheets, have long held interest for reinforcement of polymer matrices. However, a number of factors, including polymer interaction and nanofiller agglomeration, limited the potential of these carbon nanofillers for polymer reinforcement. Recent research highlights that CNT-G complexes potentially improve the dispersion and interaction of the nanofillers with polymer matrices, such as nylon 6, but the effects on the properties remain poorly examined. This study uses molecular dynamics (MD) simulation with the Polymer Consistent Force Field (PCFF) to examine the effects of uniformly-dispersed CNT, single layer graphene, and CNT-G on the mechanical properties of amorphous nylon 6 nanocomposites. For all nanofillers, bulk modulus remained unaffected by increasing concentrations of carbon nanofiller where values were dependent on the interaction energy/atom of the nanofiller with the polymer matrix. Young’s moduli increased linearly with addition of carbon nanofillers, indicating that agglomeration of the nanofillers causes the plateaus seen in experimental research. CNT-G nanofillers significantly improved bulk and Young’s moduli of the nylon 6 nanocomposite compared to CNT or graphene. Predicted mechanical property trends agree moderately well with experimental results until agglomeration occurs where discrepancies are attributed to crystallinity effects and nanofiller alignments.