Thermodynamic assessment of the effect of strongly swelling polymer hydrogels on the water retention capacity of model porous media

• Published in: Eurasian soil science 2014-04, Vol.47 (4), p.287-296
• Main Authors: Sadovnikova, N. B., Smagin, A. V., Sidorova, M. A.
• Format: Article
• Language: English
• Subjects: Analysis; Capillary water; Comparative studies; Earth and Environmental Science; Earth Sciences; Geotechnical Engineering & Applied Earth Sciences; Hydrogels; Polyacrylamide; Polymer industry; Polymers; Pore size; Porosity; Porous media; Retention; Retention capacity; Soil Physics; Soil sciences; Thermodynamics
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229314040061

The effect of different rates and fractions of strongly swelling polymer hydrogel (SSPH) based on radiation-grafted polyacrylamide on the water retention capacity and structural state of model porous media in the form of quartz sand fractions with different degrees of dispersion has been studied. The water retention curve (WRC) of sandy porous media obtained by the capillarimetric method has been used as a basic thermodynamic parameter. An original method has been proposed for the comparative study of the effect of SSPHs on the WRC based on the approximation of data by the nonlinear van Genuchten function followed by differential analysis. Equations are given for the calculation of capillary water capacity and structural curves of pore size distribution. SSPH concentrations in the range 0.05–0.2% of enclosing material weight reliably increase the water retention capacity of sandy fractions and the total, capillary, and field capacities (determined by the Voronin secant method) by 2–3 times; as well as the range of available water and the contents of fine macropores and mesopores. Factors limiting the swelling of SSPHs in model porous media have been revealed.