A new self-healing epoxy with tungsten (VI) chloride catalyst

Abstract

Using self-healing materials in commercial applications requires healing chemistry that is cost-effective, widely available and tolerant of moderate temperature excursions. We investigate the use of tungsten (VI) chloride as a catalyst precursor for the ring-opening metathesis polymerization of exo- dicyclopentadiene ( exo -DCPD) in self-healing applications as a means to achieve these goals. The environmental stability of WCl 6 using three different delivery methods was evaluated and the associated healing performance was assessed following fracture toughness recovery protocols. Both as-received and recrystallized forms of the WCl 6 resulted in nearly complete fracture recovery in self-activated tests, where healing agent is manually injected into the crack plane, at 12 wt% WCl 6 loading. In situ healing using 15 wt% microcapsules of the exo -DCPD produced healing efficiencies of approximately 20%.