The effect of clay on the mechanical properties of epoxy resins subjected to hygrothermal ageing

TL;DR

This study investigates how moisture and heat exposure degrade the mechanical properties of epoxy resins and their nanocomposites, highlighting significant permanent damage especially in fracture toughness and modulus.

Contribution

It provides new insights into the combined effects of hygrothermal ageing on epoxy nanocomposites, quantifying permanent damage after moisture absorption and drying.

Findings

Hygrothermal ageing significantly reduces fracture toughness and modulus.

Permanent damage is less pronounced in flexural strength.

Both neat epoxy and nanocomposites are adversely affected.

Abstract

Epoxy polymers are an important class of material for use in various applications. Due to their hydrophilic nature, epoxy resins tend to absorb moisture. Absorption of moisture degrades the functional, structural and mechanical properties. For polymers, it is known that moisture absorption can lead to both reversible and irreversible changes. In this study, the combined effect of moisture and elevated temperature on the mechanical properties of Epon 862 and its nanocomposites were investigated. The extent of permanent damage on fracture toughness and flexural properties of epoxy, due to the aggressive degradation provided by hygrothermal ageing, was determined by drying the epoxy and their clay/epoxy nanocomposites after moisture absorption. From the investigation it was found that, hygrothermal ageing has detrimental effect on mechanical properties of both neat polymer and clay/polymer nanocomposite. Significant permanent damage was observed for fracture toughness and modulus, while the extent of permanent damage was less significant for flexural strength.