Fast Healing of Polyurethane Thermosets Using Reversible Triazolinedione Chemistry and Shape-Memory

Healable and remoldable polyurethane networks having poly(ε-caprolactone) soft segments were prepared in a one-pot procedure using a thermoreversible cross-linker based on triazolinedione (TAD) chemistry. A single heating step triggers both shape-recovery and reversible TAD chemistry, which allows fast shape-memory assisted healing from large scale damage up to 1 mm. The network compositions were optimized to maximize healing efficiency. The thermomechanical properties of the materials were studied in-depth by thermal analysis, tensile measurements, and rheology. This work validates reversible TAD chemistry as a novel, highly effective chemistry for fast intrinsic healing of high-modulus thermosets without loss of structural integrity.