Enhancing dispersion and mechanical properties of carbon nanotube-reinforced cement-based material using polymer emulsions

Abstract

This study explores the effect of polymer concentration on the dispersion of carbon nanotubes (CNTs) and the mechanical properties of cement-based materials via tests and molecular dynamics (MD) simulations. The results showed that all three polymers (ethylene-vinyl acetate (EVA), styrene-acrylate (SAE), and styrene-butadiene (SB) copolymers) significantly enhanced CNTs’ dispersion. The key factors driving this improvement are the coordination bond, H-bonds, π-π stacking, and van der Waals forces between the polymer and CNTs, which promote strong adsorption. This reduces the interaction energy generated among the CNTs. Additionally, the combined use of polymers and CNTs improves the mechanical properties of cement-based materials. First, the polymer films and CNTs formed a mesh structure inside the mortar, linking the hydration products, unhydrated cement particles, and aggregates. Secondly, the polymer films wrapped around the surface of the CNTs, which promoted the bond strength between the CNTs and calcium silicate hydrate. The synergistic effect between the polymers and CNTs is a promising approach for the development of advanced cementitious composites. The polymer promoted the dispersion of CNTs, whereas the CNTs compensated for the reduced compressive strength of the polymer-modified mortar and promoted hydration.