Simultaneous effect of temperature and sulfuric acid concentration on degradation of fibre reinforced plastics by investigating weight loss and mechanical strength

The simultaneous effect of temperature and sulfuric acid concentration on the degradation of FRP composites has been studied using the weight loss technique. The immersion tests were designed using RSM methodology based on Design Expert software. ICP-Mass tests were performed to analyze the ion concentration in sulfuric acid solution after immersion. Additionally, the morphology of FRP samples was studied through SEM-EDS analysis. Furthermore, the mechanical properties of the immersed samples were assessed through mechanical bending and micro-hardness tests. The study proposed a three-dimensional view of the variation in FRP weight loss as a response to changes in temperature and sulfuric acid concentration. The results showed that the maximum weight loss occurred at 60°C and 6% sulfuric acid concentration. A linear model for the variation of FRP weight loss was proposed based on independent parameters and ANOVA variance analysis. The effect of sulfuric acid concentration on FRP weight loss was found to be more significant than temperature in the range of investigated parameters. It was concluded that immersion of FRP in sulfuric acid resulted in corrosion and degradation, followed by weight loss and a decrease in flexural bending strength and Vickers micro-hardness.