Enhancing physical properties of chitosan/pullulan electrospinning nanofibers via green crosslinking strategies

In this study, electrospun chitosan/pullulan composite nanofiber films were crosslinked by two green methods (heating and cinnamaldehyde). With the increase of chitosan content, the morphology results indicated that the nanostructures of thermal crosslinking chitosan/pullulan (TCP) and cinnamaldehyde crosslinking chitosan/pullulan (CCP) nanofiber films became more stable. The decreases in weight loss (83.65 % to 43.85 % for TCP and 23.42 % to 15.58 % for CCP) and the increases in water contact angle (31.8° to 54.1° for TCP and 83.65 % to 43.85 % for CCP) confirmed the improved water stability. The decreases in water vapor permeability indicated that the crosslinking processes significantly improved the barrier properties of the films. Mechanical and thermal properties of TCP and CCP films were enhanced respectively. Furthermore, the corresponding properties of CCP films were more excellent than TCP films. FTIR results indicated the occurrence of Maillard reaction during the thermal crosslinking process and Schiff base reaction during the cinnamaldehyde crosslinking process.