Effects of mixed acid solution on bromide epoxy vinyl ester and its glass fiber reinforced composites

Abstract

Abstract As fiber reinforced plastics (FRP) have been increasingly widely used, they may sometimes come into contact with several corrosive media simultaneously, for example, the condensate in the smokestack liners of coal-fired power FGD systems. To study the long-term performance and degradation mechanism of FRP in these complicated environments, an accelerated aging test of bromide epoxy vinyl ester (Br-VE) and its glass fiber reinforced composites (GF/VE) in a mixed acid solution(H2SO4, HNO3, HF and HCl) at three different temperatures(25, 55 and 80 °C) for 180 days was carried out. Weight changes, flexural properties, Fourier transforming infrared spectra (FTIR), dynamic thermal mechanical (DMA), macroscopic and microscopic morphology were investigated. Results showed that immersion temperature has important effects on the corrosion behavior of specimens. The long-term weight change behavior of GF/VE at normal temperature was in accordance with Fick’s second law, but deviated at higher temperature. Flexural properties of GF/VE declined more drastically than those of Br-VE at elevated temperatures. The Tg of GF/VE decreased with rising temperatures. Results also indicted that Br-VE and GF/VE manifested varied degradation mechanisms when subject to the same mixed acid medium immersion. The degradation of GF/VE mainly involved plasticization, embrittlement, the hydrolysis of resin, an ion exchange between HF, H+ and Si-O-Si or alkali metal of the fiber as well as the debonding of the resin/fiber interface.