Effects of modified single-wall carbon nanotubes on the mechanical properties of polyvinyl alcohol composites by molecular dynamics simulation

Abstract

Polyvinyl alcohol (PVA) matrix composites reinforced by single-wall carbon nanotubes (SWCNTs) modified by three different functional groups were established and computed employing molecular dynamics (MD) simulation to identify the mechanical properties, energy characteristics and morphological characteristics of PVA/SWCNT composites and analyzed the reinforcement mechanism. It is found that adding SWCNTs can effectively enhance the mechanical properties of PVA matrix composites, and the SWCNTs with modified functional groups can improve the mechanical properties more significantly. Besides, the interfacial interaction between SWCNTs modified with different functional groups and PVA was measured by the pullout method. It is found that modified SWNT can produce a stronger effect on PVA than unmodified SWNT. By analyzing the radius of gyration, mean square displacement, and radial distribution function of the model, the relationship between the mechanical properties of the composite and the interface properties were explored and supported. It is found that Young’s modulis of composites increase with the growth of interfacial interaction between PVA and SWCNTs. Furthermore, the results for mean square displacement, the radius of gyration, and interfacial energy show that modified SWCNTs limit the motion of PVA chains compared with unmodified SWCNTs, and the displacement limit is the primary factor of improving properties compared with the radius of gyration.