Efecto del pH y la concentración del fosfato dibásico de sodio en las propiedades de hinchamiento de hidrogeles de quitosana
Effect of pH and sodium phosphate dibasic concentration on the swelling properties of chitosan hydrogels
F. Becerra–Bracamontes1, J. C. Sánchez–Díaz2, J. Arellano–Ceja2, A. González–Álvarez2 y A. Martínez–Ruvalcaba2*
1 Departamento de Química, Universidad de Guadalajara, 44430 Guadalajara, México.
2 Departamento de Ingeniería Química, Universidad de Guadalajara, 44430 Guadalajara, México. * Autor para la correspondencia. E–mail: agustin21@gmail.com Tel/Fax: (33) 1378– 5900, ext. 7595.
]]>Recibido 14 de Octubre 2008
Aceptado 13 de Enero 2009
Resumen
En este trabajo fueron sintetizados hidrogeles de quitosana por entrecruzamiento ionotrópico con fosfato dibásico de sodio (FDS) en solución acuosa de ácido acético al 2% en volumen. Los resultados indican que la interacción iónica de los grupos aminos de la cadena de quitosana con los grupos aniónicos del FDS es dependiente del pH del medio de hinchamiento. Se investigaron las propiedades de hinchamiento de los hidrogeles quitosana/FDS en función del pH del medio de hinchamiento (3, 5, 7 y 11) y de la proporción de sólidos totales (2, 3 y 4% en peso). Cuando se colocaron en un medio ácido se observó mayor capacidad de hinchamiento que en medio básico y neutro, además como era de esperarse, con una proporción de sólidos totales del 2% en peso se obtuvieron los mayores porcentajes de hinchamiento. Se observo en estos sistemas un sobrehinchamiento seguido de un deshinchamiento hasta llegar a un equilibrio.
Palabras clave: fosfato dibásico de sodio, quitosana, hidrogeles, hinchamiento, pH.
Abstract
In this work were prepared chitosan hydrogels by ionotropic gelation technique with sodium phosphate dibasic (SPD) in an aqueous acetic acid solution 2% v/v. The results obtained shows that the ionic interaction of the NH+3 groups liked to the chitosan chain with the SPD anionic groups is depending of the pH of the swelling solvent. Were studied the swelling properties of the chitosan/SPD in function the the swelling media pH (3, 5, 7, and 11) and the percentage of solids in the hydrogel (2, 3, and 4% w/w). In the acid swelling medium the swelling capacity of the hydrogels was higher respect to the capacities obtained in basic and neutral media; moreover with a percentage of solids of 2% w/w the swelling capacities were higher. An overshooting effect in the hydrogels was observed, followed by a lost in the volume of the hydrogels until the swelling equilibrium is attained.
]]> Keywords: sodium phosphate dibasic, chitosan, hydrogels, swelling properties, pH.
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