Durability evaluation of moderate temperature cured E-glass/vinylester systems

FRP composites using vinylester resins are increasingly being fabricated for use in civil and marine structures using processes that incorporate ambient and moderate temperature cure regimes. This often results in the final use of the material when cure progression has not reached one hundred percent. This paper presents results of an investigation into deterioration in pultruded E-glass/vinylester composites due to immersion in deionized water and alkaline solution. Degradation is accelerated through the use of elevated temperatures and results are characterized through moisture uptake measurements, mechanical tests (tension and short-beam-shear), dynamic mechanical thermal analysis (DMTA), and microscopy. It is shown that degradation due to alkali exposure is more severe than due to the deionized water. Data from accelerated tests is used to provide long-term predictions, which are shown to correlate well with experiments in the short-term. The use of DMTA characteristics as a basis for the development of an understanding of degradation phenomena and for further modeling is shown to be a promising avenue for further research.