Corrosion Resistance Of GF/VE Composites In Distilled Water And Sulfuric Acid Solution

Glass fiber reinforced vinylester composites (GF/VE) have been used as shell materials for chemical containers due to superior mechanical properties and good corrosion resistance. However, in practical applications, these composites may take degradation in mechanical properties owing to the corrosion of the matrix, glass fiber and interface of the composites by the synergy of complicated environmental factors (humidity, temperature, medium, et al), resulting in the deterioration in service performance and long-term durability. Therefore, it is necessary to study the corrosion behavior of the GF/VE composites by simulating actual service environment for the purpose to select suitable shell materials for chemical containers.In this study, the moisture absorption, static and dynamic mechanical properties of two kinds of glass fiber reinforced vinylester resin composites (GF/VEA and GF/VEB) and their resin casts (VEA and VEB) in 55℃,40wt% sulfuric acid solution were comparatively studied. The microstructure and componential change were also studied using SEM and FTIR analysis. The results show that the GF/VEB composite presents a better interfacial adhesion and thus shows higher corrosion resistance than the GF/VEB composite. So the GF/VEB composite is chosen as a more suitable shell material for anticorrosive containers, and has been taken further studies in this study.In order to further investigate the corrosion mechanisms of the GF/VEB composite in sulfuric acid solution, we further comparatively investigated the corrosion behavior of the GF/VEB composite and VEB casts in distilled water and sulfuric acid solution. The results show that the flexural strength of GF/VEB composite in distilled water decline slightly and the flexural modulus is almost unchanged due to the plasticization resulting from moisture absorption and the slight interfacial de-bonding. While in sulfuric acid solution, both the flexural strength and the modulus of the GF/VE composite decrease clearly because of the more severe damages on the interface adhesion, which result from the brittleness and cracking of matrix, the cracking and/or breakage of glass fibers as well as the plasticization of the matrix.The materials strength prediction model for polymer composite laminates was applied in this paper. The good consistency between the predicted and experimental values indicates that the model can be applied to predicate the residual strength and service lifetime of the GF/VE composite. The results show that the GF/VE composite in sulfuric acid solution presents almost 16 times shorter life time than in distilled water when the 50%of flexural strength retention is considered as the failure point.