Effect of Water Absorption on the Tensile Characteristics of Natural/ Synthetic Fabrics Reinforced Hybrid Composites

The effect of water absorption and swelling thickness on the tensile properties of flax/sisal/carbon/glass fabrics reinforced by unsaturated polyester-based hybrid composites was evaluated. Hybrid composites reinforced with different natural and synthetic fiber configurations have been processed using the Hand lay-up (HLU) technique. Water absorption test was carried out by immersing specimens in distilled water for different lengths of time, up to 1344 hours, and showed slight enhancement of water absorption for fibers configuration [C/C/C/C/C/C] up to 1.45%, but great enhancement of water absorption for fiber configuration [S/S/S/S/S/S] up to 14%. The tensile strength of samples before and after immersion in distilled water was evaluated. This result showed that the tensile strength of fibers configuration [C/C/F/F/C/C] is approaching fibers configuration [C/C/C/C/C/C] at dry condition. Fractured cross-section morphology of composites was investigated using scanning electron microscopy (SEM) to evaluate the fibers/matrix interface before and after hydro aging. The reduction in tensile strength due to water penetrating is slight for hybrid composite with synthetic fibers at the outer layer, but huge for hybrid composite with natural fibers at outer layer.