Study On Synthesis And Properties Of Novel Polyaspartamide Derivative Hydrogels

Polyaspartate and its derivative hydrogels were prepared by two cross-linking methods in order to get the high biocompatible medical control-release carrier materials.Polyaspartate hydrogels were synthesized by using a two-step cross-linking reaction. L-lysine was first introduced into PSI as the side chain by ring-opening reaction; the hydrogel was then prepared by cross-linking reaction with glutaraldehyde as the agent. The structure and morphology of the hydrogel was characterized by Fourier Transform Infrared Spectroscopy(FTIR) and scanning electron microscopy (SEM). The existing status of the water molecules in the hydrogel was analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG). Results showed that the hydrogel contains a large amount of free water and a small amount of freezing bond water. Furthermore, effects of polymerization conditions, such as, molecular weight of the polysuccinimide, reaction time and temperature, and the amount of the cross-linking agents, on the swelling behavior of hydrogels were studied. The hydrogels swelling mechanism was also discussed. The swelling process was proved to be non-Fickian diffusion. pH sensitivity measurements indicated hydrogels shrink at pH=3.4 but swell when pH not equal to 3.4, and the swelling ratio (SR) increases as the pH increases. The releasing behavior of the Chloramphenicol entrapped in the hydrogel was distinctly different in different pH media. The drug release ratio of the Chloramphenicol at pH = 7.4 and 9.2 is higher than at pH = 1.5. The hydrogel has a rapid release process in above three pH value media.A novel sulfonicα,β-polyaspartamide hydrogel was synthesized by the ring-opening reaction of PSI with taurine and lysine. The existing status of the water molecules in the hydrogel, and the effect of the sulfonic acid group introduction on the water adsorption of the hydrogel were analyzed by DSC and TG. Results showed that the water adsorption ability of the hydrogel has been greatly improved by the introduction of the sulfonic acid group. The water absorption capacity increased from 47 times to 174 times. The status of the water molecules in theα,β-polyaspartamide hydrogels were the same as those in the polyaspartate hydrogels. Effects of reaction conditions and environmental factors on the...