Graphene-Induced Nano- and Microscale Modification of Polymer Structures in Cement Composite Systems

Abstract

AbstractRedispersible polymers such as ethylene–vinyl acetate copolymer (EVA) have attracted attention in construction due to their enhanced flexural strength, adhesion, flexibility and resistance against water penetration. However, EVA particles cluster in a highly alkaline cementitious matrix and exhibit poor interaction with the cement matrix. The underlying mechanism of poor dispersibility of EVA is attributed to hydrophobic groups of polymers, a variation in the adsorption rate and molecular diffusion to the interface where they cluster together. This phenomenon can negatively affect the fresh properties of cement and produce a weak microstructure, adversely affecting the resulting composites’ performance. This study highlights how graphene oxide (GO) nanomaterial alters the nano- and microscale structural characteristics of EVA to minimize the negative effects. Transmission electron microscopy (TEM) revealed that the GO sheets modify EVA’s clustered nanostructure and disperse it through electrostatic and steric interactions. Furthermore, scanning electron microscopy (SEM) confirmed altered microscale structural characteristics (viz. surface features) by GO. The altered and enhanced material scale engineering performance, such as the compressive strength of the resulting cement composite, was notable.