Ultrasonic assisted microwave synthesis of poly (Chitosan-co-gelatin)/polyvinyl pyrrolidone IPN hydrogel

The hydrogels based on gelatin cross-linked with chitosan (CS) and polyvinyl pyrrolidone (PVP) were synthesized using microwave and ultrasonic coupling technique in this study. This interpenetrating polymer network (IPN) hydrogels were cross-linked by glutaraldehyde and 1,2-Epoxy-4-vinylcyclohexane. The presence of function groups in the structure of hydrogel films were confirmed using Fourier transform infrared spectroscopy (FT-IR), thermal stability was measured by DSC, and the swelling behaviors were measured gravimetrically in distilled water at the temperature of 27°C. At last, the mechanical properties were tested. The results showed that the hydrogel prepared with microwave and ultrasonic exhibited the highest tensile strength (86.68MPa), comparing with the hydrogel prepared with traditional method and only microwave reactive field. The FT-IR and XRD results showed that the chemical reactions occurred between the NH₂ of chitosan and the COOH of gelatin, and the introduction of ultrasound can improve the reaction rate. The hydrogel film gained in microwave and ultrasonic coupling field has the best combination properties. Therefore, the new microwave-ultrasonic coupling technique is the potential technology to prepare the new hydrogel due to less synthesis time.