Diels-Alder crosslinked telechelic poly(caprolactone-thiourethane)s with self-healing of macro-damages

Healable polymers with damage healability under external stimuli are attractive materials in many industrial applications. It is also highly desirable to produce materials capable of healing at moderate conditions without sacrificing the mechanical properties when incorporating reversible interactions in a facile and practical way. A straightforward approach is proposed to manufacture networks containing dynamic Diels-Alder and thiourethane bonds and shape recovery ability. Such materials were capable of mild-temperature-triggered healing of scratches, complete cuts and deformation damages. The materials were prepared via chain-end crosslinking of maleimide-telechelic poly(caprolactone-thiourethane) precursors that contain multiple rigid bismaleimide segments. Monitoring the chain length of the precursors led to changes in the network mechanical and healing performance; the best obtained material showed high tensile strength (similar to 36 MPa) and Young's modulus (similar to 330 MPa) and good healing efficiency at mild temperature (complete healing of scratches and cuts and tensile strength recovery of 87% at 70 degrees C).