Strength behavior and crack-formation mechanisms of E-glass fiber exposed to sulfuric acid environment

Abstract

In this study, strength behavior and crack-formation mechanism of E-glass fiber exposed to sulfuric acid environment for different immersion times were investigated. In order to study the strength degradation, E-glass fibers were immersed in sulfuric acid. Strength reduction, stiffness, and fracture strain of fibers vs. immersion times were studied. The corrosion mechanism of E-glass fiber exposed to acid, were examined by quantitative X-ray fluorescence method. The results showed that corrosion of E-glass fiber was accompanied by removal of Al, Ca, and Fe ions from the fibers. Moreover, intact and degraded fibers were examined by scanning electron microscope and energy dispersive X-ray (EDX) microanalysis methods to show the relation between the reaction of E-glass fiber elements and acid environment. The ion-depletion-depth model was used to study the fracture process. The results showed that by increasing the immersion time in acid, spiral stress induced due to the shrinkage of E-glass fiber surface caused axial cracks in fibers. Different points of fibers, in which cracks were generated, were examined by EDX method. The results were used to explain the role of Al, Ca, and Fe ions in creation of surface cracks on E-glass fibers subjected to sulfuric acid for different immersion times.