Synthesis and characterization of temperature sensitive hemicellulose-based hydrogels

Temperature sensitive hemicellulose-based hydrogels were synthesized using hemicellulose obtained from acetic acid pulping of eucalyptus and N-isopropylacrylamide (NIPAAm) through UV photo-crosslinking. Firstly, a derivative of hemicellulose (Hce-MA) containing vinyl bonds within the side chains was prepared by grafting maleic anhydride (MA) to hemicellulose. The Hce-MA was then photo-crosslinked with NIPAAm in LiCl/DMF solvent using UV light to form the hydrogels. The lower critical solution temperature (LCST) and the morphology of the hydrogels were investigated by DSC and SEM, respectively. The LCST of the well-defined honeycomb-like hydrogels was found to increase with the content of Hce-MA. The swelling and de-swelling behaviors of the hydrogels under different temperatures were studied as well. The equilibrium swelling ratio and morphology of the hydrogels were dependent on environment temperature, implying their potential as smart materials for medical application.