| Abstract |
The report presents the results of tests to evaluate the effects of various types and durations of wet exposure on the tensile, compressive, and flexural properties of epoxy, polyester, phenolic, and silicone laminates reinforced with 181 glass fabric that had various types of fabric finish. The tests were made after normal conditioning and after various periods of wet exposure. Wet conditions used were (1) immersion in water at 73 F., (2) exposure to an atmosphere at 100 F. and approximately 100 percent humidity, or (3) boiling in water. Tensile strengths were reduced about equally by 30 days in water at 73 F. or by 2 hours in boiling water. Compressive strengths were reduced about the same amount by either 2 hours in boiling water, 30 days in water at room temperature, or 30 days at high humidity. Modulus of rupture was reduced about equally by equal periods of immersion in water at room temperature or exposure to high humidity at 100 F. At either of these conditions, the reduction after 30 days was generally similar to that observed after exposure in boiling water for 1/2 or 1 hour, but was generally less than that observed after exposure for 2 hours in boiling water. The various laminates differed considerably in their response to the various wet exposure conditions. However, the results indicate that a 2-hour wet exposure in boiling water is a reasonable substitute for the standard 30-day immersion in water at room temperature. (Author) |
