Polymer, Vol.39, No.14, 3253-3260, 1998
Swelling of DGEBA/DDA epoxy resin during hygrothermal ageing
Understanding the swelling behaviour of polymers during hygrothermal ageing is potentially important for both composite materials and structural adhesives, since swelling may significantly influence the mechanical behaviour due to the increase of residual stresses at interfaces. In this article, the swelling of a DGEBA/DDA epoxy resin has been investigated. It has been found that the swelling of the polymer lags behind the behaviour predicted from the ideal mixing law. More importantly, our results show that swelling induced by hygrothermal ageing is not fully reversible, particularly at higher temperatures. Based on the assumption that water diffusion is governed by a classic diffusion controlled process and a swelling controlled process, a model is proposed to describe water uptake and swelling kinetics during hygrothermal ageing. The results show that the model is in good agreement with the experimental values.