Hydrogels from n,n'-dimethylacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid with salt-, temperature- and ph-responsiveness properties

• S. AMALIA POOLEY ^[1] ; BERNABÉ L RIVAS ^[2] ; AMITZA L CÁRCAMO ^[2] ; GUADALUPE DEL C PIZARRO ^[2]
  1. [1] Universidad de Concepción

     Universidad de Concepción

     Comuna de Concepción, Chile

     
  2. [2] Technological Metropolitan University Department of Chemistry
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 53, Nº. 2, 2008, págs. 1483-1489
• Idioma: inglés
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• Resumen

  • The synthesis of copolymer hydrogels of JV, W-dimethylacrylamide (NNDMAAm) with 2-acrylamido-2-methyl- 1-propanesulfonic acid (AMPS) were prepared by solution free radical polymerization at different feed mole ratios (mole ratios of nNNDMAAm/nAMps = 0.5/0.5; 0.33/0.66; 0.66/0.33; 0.25/0.75; 0.75/0.25). In this reaction ammonium persulfate (APS) and N,N'-methylene-bis-acrylamide (MBA) were used as initiator and cross-linking reagents respectively. These copolymers were insoluble in water and it were characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Aqueous solutions of the copolymers showed lower critical solution temperature behavior (LCST). The phase transition temperatures of aqueous solutions of these copolymers increased with increasing of hydrophilic AMPS comonomer content in the copolymers. The effects of reaction parameters, including the concentration of cross-linking reagent, the monomer concentration, pH, temperature, salt solutions, and solvent polarity on the water absorption have been also studied. Under the experimental conditions, the copolymer poly(NNDMAAm-co-AMPS) with a feed mol ratio 1:2 presents the best swelling properties. The monomer reactivity ratios for poly(NNDMAAm-co-AMPS) are the following: r1 = 0.217 and r2 = 2.20, (r1 x r2 = 0.48).