Effect of water absorption on impact strength for epoxy-glass fibers composite.

Hand lay-up method was used to prepare sheets of epoxy (EP) reinforced with 12 layers of (0° -90° ) glass fiber mat with volume fraction equal to 30%. The sheets of Ep- glass fiber composite were cut to samples with standard dimensions for charpy impact test. The main objective of this research was to study the effect of water absorption on impact strength for epoxy-12 glass fiber composite. Diffusivity behavior and diffusion coefficient were investigated. The samples were dividing to three groups immersed in distilled water for different time, the first group 15 days ,the second group 27 days and the last 39 days at constant temperature(±20)C° the mass gain recorded every 3 days till saturation (M∞ ) after that the mass gain decreased .the results showed that the maximum diffusion coefficient (minimum absorption resistance ) was for sample (A),while the minimum diffusion coefficient (maximum absorption resistance) was for sample (C). The impact strength has been investigated for samples before and after the immersion in distilled water for different time. The results show that the impact strength decreased with increasing the time of immersion for samples.