Water Ageing of Epoxies: Effect of Thermal Oxidation

Epoxy samples obtained by curing bisphenol A diglycidyl ether with triethylenetetramine are thermally oxidized at 160°C under air. The impact on water sorption is investigated by water uptake recorded by Dynamic Vapor Sorption and the gravimetric method. Experimental data mainly showed that water solubility in epoxies increases due to oxidative degradation, meanwhile, the formation of clustering remains limited. In the investigated ageing conditions, water diffusion obeys Fick's law. Despite a significant chain scission process, water diffusivity in polymer remains constant, possibly in line with the fact that hydroxypropylethers are the driving force of water diffusion and are not degraded during thermal ageing.