Long term performance study of glass reinforced composites with different resins under marine environment

For marine structural applications which poses significant challenges to the choice of materials due to presence of corrosive seawater, polymer matrix based fiber reinforced composites are increasingly becoming the material of choice. However the performance properties of composites are greatly influenced by the moisture absorbed by the composite. In the current study, the long term performance is assessed by determining the amount of moisture absorbed and the reduction of mechanical properties over 12 months in a simulated sea-water environment at different temperatures. Three commonly used thermoset resins with different chemistry such as unsaturated polyester (USP), epoxy resin (EP) and vinylester (VE) are chosen. The effect of fiber reinforcement on the long term performance is investigated. A suitable method for manufacturing glass reinforced composite with good interfacial bonding and high volume fraction is also developed in current study. It is observed that vinylester plaques and composites absorb lesser moisture compared to USP and Epoxy systems resulting in lesser reduction in flexural strength and making the best performing among polymers studied. It is also found that sea-water diffusion into the composite follows non-Fickian behaviour and diffusion relaxation model fits well with the experimental data and corresponding model parameters are evaluated.