Enhancement in creep resistance of pristine polystyrene with incorporation of exfoliated 2D graphene nanosheets at low filler loading

Abstract

Determination of the reliability and durability of polymers in structural applications is highly dependent on the resistance to time-dependent plastic deformation. In this study, creep behaviour and enhancement in creep resistance of polystyrene-graphene nanocomposites is investigated at low filler loading. Herein, 2D material (graphene) is synthesised by the liquid-phase exfoliation method (LPE) using the tetrahydrofuran (THF) solvent via batch sonication. Samples are characterised by Scanning Electron Microscopy (SEM) for morphology analysis and X-rays Diffraction (XRD) for identification of polystyrene-graphene (PS-G) peaks in nanocomposites. Additionally, Atomic Force Microscopy (AFM) is employed to quantify sheet’s thickness and Optical Microscopy (OM) to corroborate the dispersion of 2D sheets. The creep resistance of PS-G nanocomposites is measured at room temperature (25°C) by incorporating 2D sheets of flake length ∼359 μm with 0.1, 0.3, 0.5, 0.7 and 0.9 wt.%. A significant enhancement in the time to withstand constant creep load (1 N) is observed. The creep resistance of the samples exhibits a maximum increase of 79%, 258.24%, 647.25%, 417.58% and 760.44%, respectively, compared to pristine polystyrene. This increase in creep resistance resulted from intense interfacial contact between polymer chains and filler accompanied by adequate scattering/dispersion in the polymer matrix.