A combined molecular dynamics-finite element multiscale modeling to analyze the mechanical properties of randomly dispersed, chemisorbed carbon nanotubes/polymer nanocomposites.

A two-stage molecular dynamics (MD)-finite element (FE) modeling method is developed based on the concepts of representative volume element (RVE) and equivalent solid fibers (ESFs) containing functionalized carbon nanotubes (ESFs-fCNTs). First, the influences of nanotubes' chirality, different percent of functionalization ( P func ), various functional atoms, and polymers on the tensile and shear properties of the fCNTs inserted into the polymer matrix (fCNTs/polymer) are discovered using MD simulations. Then, using MD information as input data, the effective Young's modulus of polymeric unit cell strengthened by ESFs-fCNTs (ESFs-fCNTs/polymer) is explored through FE modeling. The ratio of effective Young's modulus of the unit cell ( E UC ) to Young's modulus of the polymeric cube ( E P ) is reported and all findings ( E UC E P ) are compared to the ESFs-pure CNTs/polymer results as well. It is found that longitudinal Young's modulus ( E x ) of nanofillers/polymer RVEs affects remarkably the E UC E P of the ESFs-nanofillers/polymer nanocomposites. The E x decreases by increasing the P func. Generally, the reinforcing impact of zigzag nanotubes compared to armchair ones on the E x of polymer RVEs is more considerable. Additionally, FE-based results illustrate that as the volume fraction of ESFs ( v f ESF ) increases, the E UC E P is enhanced. At a specific P func , the reinforcing effect of the ESFs-armchair and zigzag fCNTs is more in favor of polyethylene nanocomposites than that of the polypropylene systems. [ABSTRACT FROM AUTHOR]