A tough polyurethane elastomer with self-healing ability

Abstract

Due to sufficient polymer chain mobility and molecular diffusion, most of the present intrinsic self-healing polymers that heal damage by utilizing reversible bonds are soft or gel. However, a tough self-healing polymer is needed as they can be used as strong and light weight material for engineering applications. Based on the high versitility of polyurethanes, herein we report the development of a disulfide-containing poly(urea-urethane) (PUU) network, where aromatic disulfide diamine is used to establish linkages for tri-functional homopolymer of hexamethylene diisocyanates (tri-HDI) as well as aliphatic prepolymer chains, resulting in the readily conversion between a well cross-linked network and an un-crosslinked structure. With this linkage, the network is able to balance the two seemly contradictory forces, exhibiting simultaneously superior mechanical performances and high self-healing efficiencies in the absence of any catalyst or external intervention. In addition, these materials are capable of repairing themselves repeatedly thus possessing a high potential for industrial applications with further investigation.