Chitosan-based hydrogels (CSAD1, CSAD2 and CSAD3) have been successfully prepared by dynamic imine reaction between chitosan and varying ratios of 2-[(2,3-dihydroxy)-1propoxy]benzaldehyde (SAD) as a linker group respectively. SAD was synthesized from salicylaldehyde and glycidol by atom economy method. FT-IR and NMR data were used to determine the SAD and hydrogels' structures. The fabricated hydrogels exhibit a porous structure that the pore size decreased with increasing ratio of SAD group. Hydrogels were swelled in aqueous media but not soluble in both acidic and alkaline medium. The highest swelling capacity was obtained at pH 7 with the order of CSAD1, CSAD2, and CSAD3, respectively. The high thermal behavior of the hydrogels was tested by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Ibuprofen was selected as a model drug for the drug release behaviors of the hydrogels. Release of ibuprofen is influenced by the pore sizes of the hydrogels in order of CSAD1, CSAD2, and CSAD3, respectively.

The concentrations of linker group effect different physicochemical features of the biopolymer, including thermal stability, shape, swelling, and water solubility. Herein, three novel chitosan (CH) based films (CHSD1-3) have been prepared by a facile method for their film characteristics. Thus, amphiphilic salicylaldehydediol (SD) was synthesized from hydrophilic glycidol and salicylaldehyde in high yield and regioselectivity. CHSD1-3 films were prepared by the imine condensation reaction of polymeric chitosan backbone and various ratios of SD linker. The reaction takes place with high conversation and amazingly mechanically resistant thickness films without using any plasticizer that exhibits low water solubility and low swelling ratios at pH > 3, which can be suggested as thin layer protecting systems for medical devices. Chitosan-salicylaldehydediol biopolymer films were characterized by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) methods. The FT-IR, DSC, and XRD results show a clear linkage of the SD group to the chitosan backbone, high thermal stability of the films, and a change in the original nature of chitosan, respectively. Scanning Electron Microscopy (SEM) observations have also supported the successful grafting of the SD group onto the chitosan.