Reversible TAD chemistry as a convenient tool for the design of (re)processable PCL-based shape-memory materials

A chemically cross-linked but remarkably (re)processable shape-memory polymer (SMP) is designed by cross-linking poly(ε -caprolactone) (PCL) stars via the efficient triazolinedione click chemistry, based on the very fast and reversible Alder– ene reaction of 1,2,4-triazoline-3,5-dione (TAD) with indole compounds. Typically, a six-arm star-shaped PCL function- alized by indole moieties at the chain ends is melt-blended with a bisfunctional TAD, directly resulting in a cross-linked PCL-based SMP without the need of post-curing treatment. As demonstrated by the stress relaxation measurement, the labile character of the TAD–indole adducts under stress allows for the solid-state plasticity reprocessing of the permanent shape at will by compression molding of the raw cross-linked material, while keeping excellent shape-memory properties.