Poly(acrylic acid-sodium styrene sulfonate) Organogels: Preparation, Characterization, and Alcohol Superabsorbency

Polymeric organogels based on acrylic acid and sodium styrene sulfonate (SSS) were synthesized and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, dynamic mechanical thermal analysis (DMTA), and rheometrical analyses. The organogels exhibited medium alcohol absorbency because of counterion binding that formed in solvents with low dielectric constants. After acid treatment, the possibility of counterion binding was decreased, and the organogels achieved superabsorbency in alcohols, for example, about 80 and 50 g/g in methanol and ethanol, respectively. The superabsorbency was also measured in higher alcohols (i.e., n-propanol and isopropyl alcohol) and polyols (i.e., ethylene glycol, propylene glycol, 1,3-propanediol, and glycerol). The dielectric constant, viscosity, and structural features of the alcohols were investigated as important parameters determining the alcohol superabsorbency. DMTA of dried samples showed two glass-transition temperatures (T-g's), that is, the matrix T-g and the complex Tg, which increased with increasing SSS content. The tan delta peak intensity increased after the acid treatment. With increasing SSS, the storage modulus of the dried gel increased; whereas that of the rheometrically measured hydrated gel decreased. Tan delta decreased with increasing SSS because of enhanced counterion binding. These alcohol-specific superabsorbing organogels are suggested as excellent candidates for the manufacture of products with high alcohol contents, such as hand sanitizers and fuel gels. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2759-2769, 2011