The effects of degassing, neutralization, and dewatering on the CMC-g-poly (acrylic acid-co-methacrylic acid) hydrogel

Abstract

CMC-g-poly (acrylic acid-co-methacrylic acid) hydrogel was prepared by free radical polymerization of acrylic acid (AA) and methacrylic acid (MAA) onto carboxymethyl cellulose (CMC) backbone using ammonium persulfate (APS) as an initiator and N, N′-methylene bisacrylamide (MBA) as a crosslinker. For investigating the effects of before and after treatments of the hydrogel on the swelling equilibrium, gel fraction, and weight loss, 3 sets of experiments with 5 samples were designed and the effect of degassing (using N2), neutralization with NaOH 1 M, and two stages of dewatering with acetone and ethanol was studied. The results confirmed the positive effects of all the after-treatment stages. The final data indicate that sample (v) with N2 as reaction atmosphere, one neutralization stage, and two dewatering stages exhibit a maximum swelling of 167 g/g, maximum gel fraction of 61.4%, and also maximum weight loss of 38.6%. These outcomes show that these treatments exhibit hydrogel with a good swelling ratio which is desirable in smart delivery systems, healthcare, and biomedical applications. The optimized sample was characterized by FT-IR, SEM, and TGA too.