Preparation, Characterization And Application Of γ - Polyglutamic Acid Hydrogels

Poly (y-glutamic acid) (y-PGA) is an all natural bacterium bio synthesized polymer. y-PGA hydrogels are three-dimensional hydrophilic polymeric networks, which can be prepared from y-PGA by cross-linking. y-PGA hydrogels provide the material with interesting properties of moisture sorption. high water absorbency, water retention, biodegradability and biocompatibility, which ideally substitute for chemical hydrogels. Fabric was functionalized by y-PGA hydrogels with properties of moisture sorption and high water absorbency.In this paper, biocompatible, pH sensitive, degradable PGA/PL hydrogels were prepared. The structure and structure-related behaviors of PGA/PL hydrogels were studied. In addition, the swelling kinetics of PGA hydrogels swelled in different salt solution of three variours valence state metal ions were studied, its structural changes before and after the swelling were observed as well. Finally, a novel highly water-absorbed finishing agent was prepared by using the PGA hydrogels, and the Moisture Absorbent & Quick Drying Finishing was exert on polyester knitted fabrics, the polyurethane adhesives was added to improve the finishing effect, and the performances of finished fabrics were tested. The conclusion of this paper was summed up as follows:Firstly, when the ratios of PGA/PL were 1-0.1-0.4, PGA/PL hydrogels could be prepared through the EDC/NHS crosslinking reaction. FTIR and XPS proved that PGA and PL were crosslinked by amide bond, the conversion rate reached 96.1%. SEM found that the surfaces of PGA/PL gels were wrinkled and no holes, cross section was full of holes with approximately 20 mm diameter. The swelling kinetics of PGA/PL hydrogels in deionized water followed the Voigt model, the increasing of the PL and crosslinking agent could reduce the swelling performance.But in normal saline and PBS solution with ion-sensitivity, swelling behaviour conforms to the pseudo-second kinetics model, and swelling are greatly influenced by PL content but almost not affected by the dosage of crosslinking agent.And PGA/PL gel with a pH sensitive, intelligent adjusting the solution pH of 5. The increasing dosage of PL and crosslinking agent could improving mechanical properties, when PGA:PL= 1:0.2. the concentration of crosslinking agent was 0.15 mol/L, the mechanical properties of the hydrogel was the best. And PGA/PL gel good biocompatibility, biodegradable in PBS solution, is an extremely promising biological materials.In addition, PGA hydrogel was studied in three different valence metal ions (Na+, Ca2+, Fe3+) adsorption rule and the influence of factors such as solution concentration.Found that with the increase of the concentration of the metal ion valence and the stronger the ion charge shielding effect of the gel, the lower the gel swelling degree. SEM results showed that the NaCl adsorbed gels had crystallization, CaCh adsorbed gels were full of organized hole, the diameter of holes were about 6 mm, FeCl3 adsorbed gels were collapsed.Finally, highly water-absorbed finishing agent was prepared by PGA hydrogels and polyurethane, the rheology study showed that it is applicable in finishing. According to the national standard method of testing, we found that the Moisture Absorbent & Quick Drying finished polyester knitted fabrics reached moisture quick-drying fabric. Moreover, bending strength and bending hysteresis of treated fabrics as twice of the treated fabric is not increased, the fabric more stiff. By added PU adhesives. hydrophilic finished fabrics could reached a semi-durable fastness.