Mechanism of reinforcement in a nanoclay/polymer composite

Using organomodified montmorillonite (MMT) (commonly called “Nanoclay”) to reinforce polymer-based composites have raised much attention to academic and industrial sectors due to the addition of small amount of nanoclay could substantially enhance the mechanical properties of pristine polymers. However, most of the works done previously have neglected to comprehensively study the basic reinforcing mechanism of the composites, particular the interaction between nanoclay and surrounding matrix even though high tensile strength and modulus were obtained. In this paper, uniformly-dispersed nanoclay/epoxy composite samples, based on our tailor-made experiment setup were fabricated. A tensile property test was conducted to examine the mechanical properties of the samples with different nanoclay content. It was found that the Young's modulus and tensile strength of a composite with 5 wt.% of nanoclay increased up to 34% and 25% respectively, as compared with a pristine sample. Images obtained from scanning electron microscopy (SEM) and results extracted from transmission electron microscope (TEM) proved that interlocking and bridging effects did exist in the composites. Nanoclay clusters with the diameter of 10 nm could enhance the mechanical interlocking inside the composites and thus, breaking up the crack propagation. The formation of boundaries between the nanoclay clusters and epoxy can refine the matrix grains and further improve the flexural strength of the composites.