Gamma Irradiation Mediated Synthesis of a New Superabsorbent Hydrogel Network Based on Poly(acrylic acid) Grafted onto Salep

A novel and smart biopolymer-based hydrogel was synthesized by graft copolymerization of acrylic acid onto the salep backbones. The new superabsorbent hydrogel was synthesized via simultaneous crosslinking and graft copolymerization of acrylic acid (AA) monomer onto salep backbones using radiochemical methods. In radiochemical methods, γ-rays as initiator, energy source and crosslinker are applied. In our experiments, the effects of reaction variables such as relative contents of salep and AA, as well as γ-rays total dose were examined. According to water absorbency of the entitled network, the best synthesis condition is reported. FTIR spectroscopy, SEM photograph and TGA analysis were used for confirming the structure of the final product and a mechanism for superabsorbent hydrogel formation is also suggested. Furthermore, in this research, several factors affecting the swelling behavior of hydrogel including pH of medium, sensitivity to the salt solution and mixture of solvents were studied.