Water Absorption Behavior and Its Effect on Static Mechanical and Dynamic Mechanical Properties of Flax Fabric Reinforced Epoxy Composites

In this work, four different grades of the Alkali cum Silane-treated plain-derived (irregular type) basket woven Flax fabric reinforced Epoxy (ASFE) composites were fabricated by varying their fiber weight fractions (0, 25, 35, and 45 wt.%) using compression molding technique. ASFE samples were subjected to salt water immersion test for 18 days and studied its effect on the their static and dynamic mechanical properties in accordance with ASTM standards. Also, interfacial shear strength between single flax fiber and epoxy material was determined using micro-droplet bonding test. Experimental Investigations revealed that salt water absorbed (SWA) flax/epoxy composites showed maximum drop of 23.23%, 29%, 35.43%, and 18.53% in tensile, flexural, impact and interlaminar shear strength, respectively. DMA study revealed that glass transition temperatures (T-g) of the ASFE composites were sensitive to the moisture absorption, and hence, SWA composites exhibited lower T-g value than dry composites. Furthermore, scanning electron microscopy clearly exposed fiber splitting, micro-cracks, and poor interfacial bonding of the ASFE composites.