Impact of humidity on the durability of E-glass/polymer composites

Severe environmental exposure affects physical and mechanical properties of polymeric composite materials resulting in an undesirable degradation. This paper studies the impact of high humidity exposure (98% relative humidity), which simulates the outdoor conditions in the gulf region, on the durability of symmetric and anti-symmetric E-glass-fiber-reinforced (GFR) composite laminates. Samples were placed in the high humidity room for 2000 h. Aged samples were then examined using the three-point bending test (ASTM D 790-02) in order to assess the impact of humidity exposure on the flexure modulus and strength of the GFR laminates. Scanning electron microscope (SEM) was used in order to examine the fractured samples microstructure. Results show that the humidity environment has affected the strength and flexure modulus of the exposed samples. Symmetric laminates lost approximately 54% of the flexural stiffness and 19% of the flexural strength, whereas anti-symmetric samples lost 27% of the flexural stiffness and 7% of the flexural strength.