Water Sorption-Desorption-Resorption Effects on Mechanical Properties of Epoxy-Nanoclay Nanocomposites

The present work aims to study the effect of water sorption–desorption–resorption conditions on the mechanical properties of epoxy-nanoclay nanocomposites (ENNCs). To prepare ENNCs specimens, nanoclay and epoxy are mixed together by a stirrer and a sonicator. The nanoclay-epoxy and hardener mixture are moulded into specimens that meet the dimensions prescribed by the ASTM standards. The specimens fabricated are subjected to three conditions viz., water sorption, desorption and resorption for a total of 140 days. Water sorption–desorption–resorption effects on the mechanical properties of pure epoxy and ENNCs are studied by tensile and flexural tests. Results showed that the nanoclay presence improved the mechanical properties and lowered the percentage of water uptake. Tensile and flexural strengths of epoxy and ENNCs are reduced under sorption conditions and recovered to more than 90% of their original strengths under desorption conditions. The lowest tensile and flexural strengths were displayed by specimens subjected to resorption in comparison to specimens subjected to the other two conditions. The flexural and tensile strengths of epoxy are more severely affected compared to ENNCs under water sorption–desorption–resorption conditions. Scanning electron microscopy images are employed to learn the causes of specimen failure under a tensile load