Preparation and swelling behavior of moisture-absorbing polyurethane films impregnated with superabsorbent sodium polyacrylate particles

Moisture-absorbing composite films were prepared with superabsorbent sodium polyacrylate particles and solvent-type polyurethane for applications in fabrics. To study the effect of the particle size of sodium polyacrylates on the swelling capacity and deswelling behavior of the composite films, we prepared sodium polyacrylates with different particle sizes ranging from 277 mu m to 485 nm. The rate of absorption and the swelling capacity of the composite films were generally observed to increase with decreasing sodium polyacrylate particle size-except that the water absorbency of the composite film containing the very smallest, 485-nm-size, sodium polyacrylate particles was lower than that yielded by the larger particles, perhaps because these very small sodium polyacrylate particles were impregnated inside the polyurethane matrix rather than on the surface. Meanwhile, the deswelling behavior was not significantly affected by the particle size. Differences in the ionic solutions also significantly affected the swelling capacity of the composite film and altered its swelling kinetics. (C) 2016 Wiley Periodicals, Inc.