| Authors |
Stankevich, Stanislav ; Zeleniakiene, Daiva ; Sevcenko, Jevgenijs ; Bulderberga, Olga ; Zetkova, Katerina ; Tedim, Joao ; Aniskevich, Andrey |
| Abstract [eng] |
The integration of layered double hydroxides (LDHs) into polymer systems offers significant potential for enhancing material properties, particularly for multilayer coatings used in aeronautical and offshore sectors. These materials serve as eco-friendly nanofillers with ion-exchange capabilities, which enable them to interact with and stabilise various chemical species, improving properties such as flame retardancy, thermal stability, and barrier performance [1, 2]. In the context of corrosion protection, this mechanism allows the capture and immobilisation of corrosive anions, thereby enhancing moisture resistance and structural integrity [3]. This study investigates the moisture absorption behaviour of epoxy-based polymer systems modified with Mg-Al/NO3 LDH nanoparticles (up to 5 wt%). The aim is to characterise moisture sorption parameters, validate the computational model based on Fick's law of diffusion using obtained parameters, and simulate more complex absorption cases for multilayer systems. Experimental investigations were conducted under diverse environmental conditions, including distilled water, seawater, concentrated salt solutions (up to 26 wt%), and elevated temperatures (up to 50 °C). The results indicated that the diffusion coefficient of water in the epoxy matrix increased significantly with temperature, showing a 3–5-fold rise in hot water compared to room temperature. The presence of salts in water also influenced the diffusion behaviour, increasing the diffusion coefficient by up to 25 % in concentrated salt solutions. Equilibrium moisture content varied with environmental conditions; for example, a higher salinity of 26 wt% reduced water absorption capacity by up to two times. Conversely, elevated temperatures of 50 °C increased equilibrium moisture content by 20–30 %. These findings were further used to inform the development of a numerical model based on Fick's law of diffusion, employing the finite-difference method for accurate moisture concentration field predictions in single and multilayer systems. The validated models demonstrated excellent agreement with experimental data, capturing the temporal and spatial distribution of absorbed moisture across multilayered structures. |
