Effect of Acid and Thermal Aging on the Mechanical Properties of E-glass Fibers

Fiber glasses are widely used fibers in the composites industry and have different types. The most common and well-known group of these fibers are E-glass fibers. In this research, some E-glass fibers were investigated at the acid-thermal aging condition. To this end, some fibers with sizing and some without sizing fibers were tested after different periods of conditioning at the same environmental condition. The used fibers were cut at the same size, and some of their sizings were removed using the ASTM standard. The used condition was a 20% w/w acid-soluble contained 98% extra pure sulfuric acid at 70℃, and the samples were tested after different periods of 0, 1, 2, 5, 20 days. The results of tensile tests showed glass fibers did not resist to abovesaid acid condition and the primary degradation occurred in with-sizing fibers when sizing removed in the mentioned condition. After the first day, the modulus increased a little and decreased again and the tensile strength had a gradual reduction. The samples without any sizing were only testable for 0 and 5 days and both had less value than all the with-sizing samples. As the immersion time passed, the strength and modulus of these samples decreased too.