Humid aging of polyetherimide. II. Consequences of water absorption on thermomechanical properties

Abstract

The water sorption characteristics of aromatic polyetherimide (ULTEM 1000) were determined at various temperatures ranging from 20 to 100 °C, and reported in the first part of this article. In the second part of this article the consequences of water absorption on the physical and thermomechanical properties by differential scanning calorimetry (DSC), dynamical mechanical thermal analysis (DMTA), and Tensile testing are studied. It was found that water plasticizes the polymer but the Tg depletion (for an almost constant water content) increases with the exposure temperature. The β dissipation band is decreased and shifted to low temperature. Despite a slight decrease of the yield stress linked to plasticization, the ductility decreases indicating that water absorption favors a new, presumably localized, yielding process.