Fumaric acid cross-linked carboxymethylcellulose/poly(vinyl alcohol) hydrogels

Carboxymethylcellulose (CMC)/poly(vinyl alcohol) (PVA) hydrogels were synthesized by crosslinking in presence of fumaric acid (FA) and characterized with different methods (FTIR, TGA/DTG, XRD and SEM) of analysis. The water absorbencies of these hydrogels in different pH solutions were investigated. The equilibrium swelling capacity of the gels reduced due to increasing crosslinking between CMC and PVA. pH sensitivity and reversibility of hydrogels were also investigated. The results indicated that the hydrogels had pH reversibility behavior which swelled at pH = 8 and shrinked at pH = 2.6. The FTIR results pointed toward the cross-linking reaction between carboxyl group of FA with hydroxyl groups of PVA and NaCMC through ester formation. The crosslinking improved the thermal stability of the hydrogels. SEM analysis showed highly porous structure for 10FA and 15FA hydrogels.