Degradation behavior of glass fiber reinforced cyanate ester composites under hydrothermal ageing

This work investigates the effect of hydrothermal ageing on the mechanical and thermo-mechanical properties of glass fiber reinforced cyanate ester composites. A large test campaign was realized to this direction. Coupons from in-house autoclave manufactured plates were immersed in distilled water at four different temperatures 40, 60, 75 and 90 °C for up to 61 days. Moisture absorption measurements followed by dynamic mechanical analysis as well as a series of mechanical tests were conducted at regular intervals during the ageing process. In addition, scanning electron microscopy was utilized in order to identify the exact degradation mechanisms that are active and dominant in the different ageing scenarios. The analysis of the results outlines the degradation behavior of the material properties and the accelerating effect of temperature elevation on the activation and acceleration of certain degradation mechanisms. Based on the existing literature this is probably the first thorough experimental study regarding the hydrothermal ageing of cyanate ester glass fiber reinforced composites.