Coaxial electrospinning of epoxy and amine monomers in a pullulan shell for self-healing nanovascular systems

Coaxial electrospinning was used to produce submicron core-shell fibers with a polymer shell that encapsulates the liquid monomers needed for the use in a vascular self-healing epoxy. A two component epoxy-amine healing chemistry was used for the cores and a polysaccharide spun from an aqueous solution forms the shell. Core continuity was proven by fluorescence microscopy for both the fibers containing amine and the fibers containing epoxy. Thermal analysis and carbon, nitrogen element analysis showed 36-48 wt% and 31-34 wt% availability of epoxy and amine, respectively. Introduction of these core-shell fibers in the epoxy matrix resulted in no decrease of the flexural properties and an increase in Mode II interlaminar fracture toughness of 69% of core-shell containing fiber reinforced epoxy composites. Mode I testing showed no decrease in fracture toughness but instead blunting of the crack tip, showing potential for healing micro-cracks.