Effect of Water Exposure Cycles on Physical Properties of a Partical-Filled, Epoxy-Based Adhesive
Martin Chiang, M Fernandez-Garcia, E M. Yorkgitis
The effect of cyclic hygrothermal aging on a particle-filled, epoxy-based adhesive was studied using a sequence of water absorption, desorption and reabsorption at different temperatures. Moisture sorption characteristics were explored by measuring the mass uptake of water and the associated behaviors of swelling and the depression of the glass transition temperature (Tg). We observed that the diffusion of water in this adhesive has a non-Fickian behavior, and the depression of Tg proceeds to a definite value which is independent of the final equilibrium water content of the system. Our observations suggest that water diffuses into the polymer in a dual-sorption mode, in which water resides in two populations. In one population, water is considered to occupy apparent free volume of the adhesive, and the second population water infiltrates polymer structure and forms hydrogen-bonded clusters. Our results show that hygrothermal aging temperature and history do not alter the apparent free volume of this adhesive. We conclude that the constant value of Tg depression at saturation implies that only water in the apparent free volume is responsible for the Tg depression, whereas the swelling proceeds through the formation of hydrogen bonds in the adhesive.
Society for the Advancement of Material and Process Engineering, International Symposium | 45th | Bridging the Centuries with SAMPE's Materials and Processes Technology
, Fernandez-Garcia, M.
and Yorkgitis, E.
Effect of Water Exposure Cycles on Physical Properties of a Partical-Filled, Epoxy-Based Adhesive, Society for the Advancement of Material and Process Engineering, International Symposium | 45th | Bridging the Centuries with SAMPE's Materials and Processes Technology, Undefined, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851724
(Accessed June 10, 2023)