Bio-based epoxidized natural rubber/chitin nanocrystals composites: Self-healing and enhanced mechanical properties

A kind of epoxidized natural rubber (ENR)/CNCs composites without using conventional crosslinking agents was successfully fabricated in this paper, in which a supramolecular network based on hydrogen bonds is formed. FTIR confirmed that parts of hydroxyl groups of CNCs reacted with the epoxy group of ENR and hydrogen bonds were developed between CNCs and ENR. This made CNCs involve in the formation of supramolecular network, effectively improving the mechanical properties and endowing the ENR/CNCs composites with superior self healing capacity simultaneously. The tensile strength of ENR/CNCs composites with 20 wt% CNCs rises to 1.19 MPa, almost 2 times than that of the neat ENR. Importantly, the ENR/CNCs composite with a filler loading of 20 wt% exhibits impressive self-healing efficiency of 83% of the its original strength and 95% of the original extensibility without any external stimulus at room temperature. Healing behavior is strongly influenced by CNCs contents, healing temperature, healing time and its times.