The degradation of mechanical properties in polymer nano-composites exposed to liquid media – a review

Abstract

The advancement of polymer nano-composites has been motivated by the need for materials with a specific combination of mechanical properties beyond those achieved from only one material.Integration of reinforcement into polymers at the nanoscale can provide a significant increase in numerous physical and mechanical properties of polymer nano-composites. However, in applications where contact with liquid media is unavoidable, the mechanical properties of polymer nano-composites suffer degradation which is a commonly observed phenomenon. Non aggressive liquid such as water is capable of lowering the mechanical properties of polymer nano-composites by acting as plasticizers while moderate and severe aggressive liquid when combined with residual stresses can cause unexpected brittle failure known as ESC. To date, only a few studies are reported discussing the ability of nano-fillers to resist degradation of mechanical properties in polymer nano-composites when exposed to liquid media. In this review, various factors responsible for mechanical property degradation caused by liquid media in polymer nano-composites and their remedies are studied.

Experimental investigation on micromachining of epoxy/graphene nano platelet nanocomposites

“…1 a Scanning electron microscopy (SEM) image of GNP, reproduced from [32]. b GNP clusters, reproduced from [33] c Transmission electron microscopy (TEM) image of layered GNP in the matrix material, reproduced from [34] Fig. 2 SEM images of fracture surfaces.…”

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

“…An increase in Tg with HNT and MLG shows that the fillers were uniformly dispersed [7,26]. As for HNT, the change in Tg associated with inorganic fillers was reported and proposed by others [29].…”

“…During service, polymeric materials are exposed to a variety of environmental conditions such as moisture, solvents, oil, temperature, mechanical loads and radiation [6,7]. In particular, all polymer composites absorb moisture and the water molecules can act as a plasticizer by influencing simultaneously the fibres, the matrix and the interface, thus creating regions of poor transfer efficiency, which results in a reduction of mechanical properties [8][9][10].…”

Environmental Stress Cracking Resistance of Halloysite Nanoclay-Polyester Nanocomposites

“…However, the disadvantage of using polymer based materials is the deterioration mechanical properties triggered by aggressive liquid contact such as methanol, isopropanol and acetone [4] [5]. Environmental stress cracking failure can occur on polyester based products far below the fracture strength since most composites subjected to external stress are vulnerable to aggressive liquid exposure [6] [7].…”