Synergistic effects in stress corrosion cracking of glass reinforced polymer composites

Abstract

Synergistic effects of nitric acid exposure, elevated temperature, applied flexural stress and time were examined in the Stress Corrosion Cracking (SCC) of widely used unidirectional Glass Reinforced Polymer (GRP) composites. The composites were composed of two different E-CR glass fibers with a vinylester-epoxy resin as the matrix with E-glass fibers in the same matrix used for a baseline comparison. SCC damage, as measured by the number of fiber cracks, amount of metallic ion leaching from the fibers, and the reduction of residual flexural strength and stiffness properties of the composites, affected the composites differently depending on their composition. As expected, the E-CR composites greatly outperformed the E-glass composites under all conditions. Long term exposure of the E-CR composites did not greatly increase the amount of stress corrosion fiber damage; instead, interface issues and matrix decomposition led to reduced mechanical properties over extended periods of time. The synergistic effect of the combined testing conditions was found to be much stronger in the E-glass than the E-CR glass composites.

Synergistic environmental degradation of glass reinforced polymer composites

“…Despite significant differences in their original surface properties such as the amounts of exposed glass fibers, fiber distributions, fiber alignment, fiber diameters, etc. [19], all composites, including A, responded in quite similar fashions to all three test environments with the exception of composite D. Therefore, A was picked as an example to illustrate the aging effects on the composites ( Figure 1A). The polyester composite (D) had apparently UV blockers applied to its resin which resulted in less surface damage by UV ( Figure 1B).…”

Durability sensor using low concentration carbon nano additives

“…Although these composite structures are designed to last for decades, it is important to monitor their health in real-time [4][5][6]. The swelling and hydrolysis of the matrix are two general results of this kind of exposure [7][8][9]. Swelling leads to deformation of structure and hydrolysis leads to direct failure.…”

“…Swelling leads to deformation of structure and hydrolysis leads to direct failure. However, corrosive chemicals lead to bleaching of fiberglass reinforcement [8,10]. In order to avoid these degradations, an in situ embedded sensor is critical to monitor the diffusion of aggressive chemicals into the composite [4].…”

“…Chemical attacks of composites by aggressive chemicals result in severe damage to polymer matrix and fibers, especially under hydrothermal and stressed conditions [10,22]. For decades, stress corrosion cracking (SCC) has been one main focus in order to understand the interaction between chemicals and composites [8,23]. Using acid as an example, the penetration of acid occurs initially during the diffusion process.…”

Effects of electrical-hydrothermal aging degradation on dielectric and trap properties of high temperature vulcanized silicone rubber materials

“…Composite insulators are widely used in power systems because of their light weight and strong resistance to pollution ashover. [1][2][3][4][5][6][7][8] As an important material for the sheaths and sheds of composite insulators, high temperature vulcanized silicone rubber (HTV SR) plays an important role. However, as the operating life increases, the aging problem becomes more and more serious.…”