Thermally assisted self-healing polyurethane containing carboxyl groups

Self-healing polymer is a kind of intelligent material with the capability to repair damage automatically. In this paper, a type of polyurethane containing carboxyl groups is reported that demonstrates thermally assisted healing effects. This polymer can be healed even 72 h after cutting and also has a repeatable healing property. The self-healing efficiency can reach 90% when comparing the tensile strength of the healed sample to the original sample. Carboxyl content plays an important role in the self-healing property; polyurethane with no carboxyl groups cannot be healed. The mechanism of self-healing showed that hydrogen bonding interactions between carboxyl groups and diffusion of poly(ethylene glycol) chains contribute to the self-healing behavior. (C) 2017 Wiley Periodicals, Inc.