Design, synthesis and characterization of a pH-sensitive DS/GM hydrogel

摘要

Dextran sulfate/glycidyl methacrylate (DS/GM) hydrogels were synthesized by intermolecular side-chain reaction of DS hydroxyl groups with monomeric crosslinking agent, GM in aqueous solutions at 75 A degrees C in the basic medium in this study. The optimum conditions of effective crosslinking for DS/GM system were determined with changing amounts of crosslinker and initiator (benzoyl peroxide, BPO). The swelling abilities of the hydrogels were explained with determining of certain structural parameters for the hydrogel such as equilibrium water content, percentages of gellation, and swelling ratio. pH dependent swelling behaviors of hydrogels were investigated and swelling ability at basic medium was higher than that at acidic medium. Surface morphologies of DS and its hydrogels were examined by scanning electron microscope (SEM) and they compared. Structures and thermal stabilities of DS/GM hydrogels were characterized by infrared (FTIR), thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and Differential Scanning Calorimeter (DSC); effect of GM on crosslinking was investigated. The viscosities of DS/GM reaction products were recorded continuously as a function of time with rotary viscometer and gellation points of binary system reaction between DS and GM were determined via observed viscosity numbers, changes during reaction.