Effect of water absorption on the flexural strength of a green sandwich composite

Abstract

Abstract The main objective of this paper is to study the effect of water absorption on the flexural strength of new green sandwich composite material made of flax as skin reinforcement and agglomerated cork as core. In this work, three different types of skin reinforcements and three different densities of agglomerated cork core have been used for the manufacturing of sandwich composites. The manufactured sandwich composites were subjected to three-point bending tests under both dry and wet conditions. The three-point bending results confirmed a decrease in the specific flexural strength by 14-42 % in wet samples due to water absorption. Also, the increase in core density leads to an increase in flexural strength both in dry and wet conditions. During testing under dry conditions, the specific flexural strength of flax reinforced sandwich composite was found to be superior because of the higher strength to weight ratio factor of flax fiber when compared to a glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite. Due to the hydrophilic nature of flax fibers, flax reinforced sandwich composite has a reduced specific flexural strength in wet conditions when compared to glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite.