Radiation synthesis and properties of gelatin/polyacrylic acid/poly (N-isopropyl acrylamide) shape-memory hydrogels with high strength

A novel gelatin/polyacrylic acid/poly (N-isopropyl acrylamide) shape-memory hydrogel (GAN) with temperature and pH response and high strength was prepared by two-step irradiation method, with gelatin as matrix, acrylic acid (AAc) and N-isopropyl acrylamide (NIPAm) as monomers, and N, N'-methlene bisacrylamide (MBA) as crosslinking agent. The structure, morphology, mechanical properties, and shape-memory behavior of GAN were investigated in detail. The results showed that GAN has a dense network structure, and excellent mechanical properties with the maximum tensile strength up to (5.4 ± 0.3) MPa, and the maximum elongation at break of 745%. GAN's shape recovery time at 60℃ and pH = 12.8 can be controlled within 10 s and 15 min, with a shape fixation rate and shape recovery rate above 90%, respectively. This work provides a new method for the preparation of environmentally responsive high-strength shape-memory hydrogels. (authors)