Modelling mechanical percolation in graphene-reinforced elastomer nanocomposites

Abstract

Graphene is considered an ideal filler for the production of multifunctional nanocomposites; as a result, considerable efforts have been focused on the evaluation and modeling of its reinforcement characteristics. In this work, we modelled successfully the mechanical percolation phenomenon, observed on a thermoplastic elastomer (TPE) reinforced by graphene nanoplatelets (GNPs), by designing a new set of equations for filler contents below and above the percolation threshold volume fraction (Vp). The proposed micromechanical model is based on a combination of the well-established shear-lag theory and the rule-of-mixtures and was introduced to analyse the different stages and mechanisms of mechanical reinforcement. It was found that when the GNPs content is below Vp, reinforcement originates from the inherent ability of individual GNPs flakes to transfer stress efficiently. Furthermore, at higher filler contents and above Vp, the nanocomposite materials displayed accelerated stiffening due to the reduction of the distance between adjacent flakes. The model derived herein, was consistent with the experimental data and the reasons why the superlative properties of graphene cannot be fully utilized in this type of composites, were discussed in depth.2

MXene Enabling the Long-Term Superior Thermo-Oxidative Resistance for Elastomers

“…After samples dissolve in toluene for three days, we barely found bound rubbers in NR, while we observed lots of bound rubbers in NR/MXene. MXene absorbing polymer chains results in the increase of bound rubber content, which is similar to the effects of graphene and carbon black [ 33 , 34 , 35 , 36 , 37 ]. Such interaction between NR and MXene inhibits the migration of MXene toward the surface of the sample, improving the long-term thermo-oxidative effect.…”

Mechanisms of mechanical reinforcement by graphene and carbon nanotubes in polymer nanocomposites

“…In a bulk nanocomposite, the t/T ratio is associated strongly with the proximity of neighbouring particles and hence the volume fraction of the filler. Liu et al 199 proposed a mechanical percolation mechanism for the reinforcement of a thermoplastic elastomer by graphene. The authors designed a set of equations for V f below and above the percolation threshold volume fraction (V p ).…”

Electro-mechanical properties of thermoplastic polyurethane films and tubes modified by hybrid carbon nanostructures for pressure sensing

“…On the other hand, given the geometry, two-dimensional topology and flexibility of MLGS, they are prone to become folded or crimpled when dispersed into a polymer matrix [35,36].…”