Effect of Cross-linking Agents Chain Length on the Network Characteristics of Dextran Hydrogel, A Rheometric and Swelling studies

The rheological characteristics during chemical gelation of semidilute solutions of dextran with the addition of various cross-linking agents are reported. Two different cross-linking agents, which provide a range of cross-linking chain lengths and flexibilities were added to the Dextran solution in various concentrations, and their effects on the incipient gel point and the mechanical properties of the resulting networks were investigated. The rheological results disclosed that for all systems the gelation process proceeds over a long time, and both the complex viscosity and the power law exponent reveal that solid-like gel structures are formed in the post-gel region. These results clearly show that the rheological characteristics of incipient dextran hydrogels can be tuned by changing the chain length of Crosslinking agents. Furthermore, the swelling studies were carried out as a simple and reliable tool for the determination of structural prepared hydrogels network parameters.