New crosslinkers for electrospun chitosan fibre mats. Part II: mechanical properties

Few studies exist on the mechanical performance of crosslinked electrospun chitosan (CS) fibre mats. In this study, we show that the mat structure and mechanical performance depend on the different crosslinking agents genipin, epichlorohydrin (ECH), and hexamethylene-1,6-diaminocarboxysulphonate (HDACS), as well as the post-electrospinning heat and base activation treatments. The mat structure was imaged by field emission scanning electron microscopy and the mechanical performance was tested in tension. The elastic modulus, tensile strength, strain at failure and work to failure were found to range from 52 to 592 MPa, 2 to 30 MPa, 2 to 31 per cent and 0.041 to 3.26 MJ m(-3), respectively. In general, neat CS mats were found to be the stiffest and the strongest, though least ductile, while CS-ECH mats were the least stiff, weakest, but the most ductile, and CS-HDACS fibre mats exhibited intermediary mechanical properties. The mechanical performance of the mats is shown to reflect differences in the fibre diameter, number of fibre-fibre contacts formed within the mat, as well as varying intermolecular bonding and moisture content. The findings reported here complement the chemical properties of the mats, described in part I of this study.