Abstract

POOLEY, S.AMALIA; RIVAS, BERNABÉ L  and  PIZARRO, GUADALUPE DEL C. HYDROGELS BASED ON (DIMETHYLAMINO)ETHYLACRYLATE (DMAEA) AND N,N'-DIMETHYLACRYLAMIDE (NNDMAAM): SYNTHESIS, CHARACTERIZATION, AND SWELLING BEHAVIOR. J. Chil. Chem. Soc. [online]. 2013, vol.58, n.1, pp.1597-1602. ISSN 0717-9707.  http://dx.doi.org/10.4067/S0717-97072013000100021.

Hydrogels of 2-(dimethylamino)ethylacrylate (DMAEA) with N,N'-dimethyl acrylamide (NNDMAAm) were synthesized by solution free-radical polymerization at different feed mol ratios. These copolymers were completely water-insoluble. Polymers were characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The monomer reactivity ratios were determined by Kelen-Tüdos method. According to that, the monomer reactivity ratios for poly(DMAEA-co-NNDMAAm) were r₁ = 0.288 (M₁=DMAEA) and r₂ = 1.460 (M₂=NNDMAAm), (r₁x r ₂ = 0.419). Low critical solution temperatures (LCST) values of hydrogels are around 60°C, which was significantly higher than that poly(NIPAAm) and increased with increasing of hydrophilic DMAEA unit content in the copolymers. The hydrogels achieved a water-absorption value of 188 g of water/g of dry polymer (xerogel) in distilled water. Effects of time, temperature, pH, salt concentration, cross-linking concentration, and solvent polarity on the water absorption were studied. Experimental results indicated that the copolymer poly(DMAEA-co-NNDMAAm) with a feed mol ratio 2:1 presents the best swelling properties.

Keywords : Hydrogels; radical polymerization; swelling; stimuli-sensitive polymers.

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