Influence of Macro-Topography on Damage Tolerance and Fracture Toughness of 0.1 wt % Multi-Layer Graphene/Clay-Epoxy Nanocomposites

Abstract

Abstract:Influence of topographical features on mechanical properties of 0.1 wt % Multi-Layer Graphene (MLG)/clay-epoxy nanocomposites has been studied. Three different compositions were made: (1) 0.1 wt % MLG-EP; (2) 0.1 wt % clay-EP and (3) 0.05 wt % MLG-0.05 wt % clay-EP. The objective of making hybrid nanocomposites was to determine whether synergistic effects are prominent at low weight fraction of 0.1 wt % causing an improvement in mechanical properties. The topographical features studied include waviness (W a ), roughness average (R a ), root mean square value (R q ) and maximum roughness height (R max or R z ). The R z of as-cast 0.1 wt % MLG-EP, clay-EP and 0.05 wt % MLG-0.05 wt % clay-EP nanocomposites were 43.52, 48.43 and 41.8 µm respectively. A decrease in R z values was observed by treating the samples with velvet cloth and abrasive paper 1200P while increased by treating with abrasive papers 320P and 60P. A weight loss of up to 16% was observed in samples after the treatment with the abrasive papers. It was observed that MLG is more effective in improving the mechanical properties of epoxy than nanoclay. In addition, no significant improvement in mechanical properties was observed in hybrid nanocomposites indicating that 0.1 wt % is not sufficient to generate conspicuous synergistic effects.

Environmental Stress Cracking Resistance of Halloysite Nanoclay-Polyester Nanocomposites

“…The variation in surface of roughness (R a ) measurement is shown in Figure 8(e). This measurement frequently used roughness amplitude parameter as it measures the roughness of samples surfaces [36]. The minimum increase of coarseness is an evident of crack deflection mechanism, which increase absorbed energy of fracture by increasing the crack length during deformation [10].…”

Effect of Short Term Water Exposure on the Mechanical Properties of Halloysite Nanotubes-Multi Layer Graphene Reinforced Polyester Nanocomposites

“…Other authors also proposed that HNT and other clay particles restrict the mobility of polymer chains [31,32]. In case of MLG, when it is uniformly dispersed, the wrinkled texture and high surface area influence the maximum exothermic heat flow temperature by restricting polymer chain mobility thereby causing an increase in Tg [27].…”

“…Another reason for this could be the quick curing of polyester resin as the volatiles could not escape during curing [38,39]. The casting technique used on the other hand is not usually considered 100% reproducible like latex technology [40]. The water absorption test is shown in Figure 7(b).…”

“…Atif et al in their study reported that MLG improved Young's modulus and microhardness by 25.7% and 18.3%, respectively [24]. The MLG also increased Tg and storage modulus compared to unfilled epoxy [25][26][27].…”

“…0.1 wt% HNT and 0.1 wt% MLG are shown in Figure 8. The Ra is defined as the mean of the roughness profile and is superimposed on the surface waviness [40]. The Ra (Figure 8(a)) value for monolithic polyester was 0.32 μm.…”