Synthesis and characterization of a temperature-sensitive hydrogel based on sodium alginate and N-isopropylacrylamide

In this study, a temperature-sensitive hydrogel was synthesized using N-isopropylacrylamide (NIPAm), acrylic acid, sodium alginate (SA), and starch as the raw materials, ammonium persulfate as the initiator, and N,N-methylenebisacrylamide as the crosslinker by the free radical polymerization. The structure and properties of the hydrogel were studied. The morphology and structure were characterized by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy was used to investigate the effects of the amount of NIPAm, SA, crosslinker, and initiator on the swelling rate (SR) of the hydrogel. The SEM images show that the surface of the hydrogel was uneven and covered with pores, sockets, and laminated intervals, favoring the swelling. The pore size increased with increasing SA amount. The volume phase transition temperature of the hydrogel decreased at a higher NIPAm amount. The SR of the hydrogel stabilized with increasing amount of SA. Increasing amount of NIPAm decreased the SR, and increasing amount crosslinker and initiator increased SR initially, followed by a decrease. Copyright (c) 2015 John Wiley & Sons, Ltd.