The Characterization of Superabsorbent Polyacrylates

FTIR, DSC, heat stability and hygroscopility of superabsorbent polyacrylates were investigated. It was illustrated in FTIR spectra that superabsorbent polyacrylate had stretching vibration band of carboxyl group of —COONa in 1629 cm -1 , 1562 cm -1 , 1457 cm -1 and bend vibration band of carboxyl group of —COOH in 1407 cm -1 . It was rather difficult to determine the T g of crosslinked polyacrylate directly by DSC because even a small amount of water had significant plasticization to the polymer. Superabsorbent polyacrylate had good heat stability and high hygroscopility. In the range of 0.5 ℃ and 99 ℃, the effect of water temperature on water absorbency was rather small. There were crystallizable water and non_crystallizable water in polyacrylate hydrogel; the content of the non_crystallizable water was 2.13 g/g dry resin, much higher than that in non_ionic hydrogels.