Study on the behavior of accelerated ageing fabric-reinforced epoxy composites

This paper presents an experimental investigation result of the effects of accelerated ageing upon the hygrothermal flexural and interlaminal shear properties of a graphite fabric- reinforced epoxy matrix that cured at moderate temperature. Two common used accelerated ageing methods that are either immersing specimens in water at temperature up to boiling point for 48 hours or exposing specimens in a hot-wet chamber in which the temperature and relative humidity were kept constantly at 70 degrees C and 100% for 1000 hours. Test results show that water pick-up has detrimental effects on flexural strength, especially on ILSS than modulus at ambient environment and elevated temperature. DMA results demonstrate that the Tg is reduced up to 30 degrees C and modulus critical temperature Tm determines the maximum service temperature at hygrothermal environment for the composites in this study. SEM observations indicate boiling ageing and hot-wet ageing have the different accelerated ageing mechanism.