Moisture Absorption, Desorption and Reabsorption Effects on Mechanical Properties of Glass-Epoxy Composites

Abstract

The glass-epoxy composite laminates were fabricated using BID glass fabric and RT cure epoxy matrix by Room Temperature Vacuum Bag Moulding (RTVBM) Technique. The Inter laminar shear strength (ILSS), compression and flexural strength values were determined at room temperature for their dry mechanical property evaluation. The test specimens were exposed to a temperature/humidity condition at 45° C/95% RH for moisture absorption studies. The moisture desorption studies were carried out in a temperature oven at 45° C and 85° C. The mechanical properties of the exposed specimens were evaluated during absorption and desorption conditions. Scanning Electron Microscopy (SEM) studies were carried out on the dry and exposed specimens to determine the effect of moisture on the fracture behaviour of glass-epoxy composites. Results show that, moisture reabsorption and full desorption are faster than the absorption and partial desorption. This may be due to, change of material properties after a cycle of moisture absorption and desorption phenomenon. The mechanical strength (ILSS, compression and flexural) has been found to reduce continuously with increased duration of environmental exposure, but a slight shift back of the strength has been observed for desorbed samples.