Self-healing biodegradable poly(urea-urethane) elastomers based on hydrogen bonding interactions

Self-healing poly(urea-urethane)s (PUUs) showing a tolerance to mechanical damage are particularly desirable for high-performance elastomeric biomaterials. In this study a kind of biodegradable PUUs was synthesized from poly(É-caprolactone) diol with L-lysine ethyl ester diisocyanate (LDI) extended with L-lysine ethyl ester dihydrochloride (LEED) in DMF and characterized by using ¹H-NMR, FTIR, DSC, XRD, SEM and tensile tests. Interestingly, they exhibited a self-healing characteristic upon exposure to 37 C for as short as 30 min with the tensile strength keeping at 4.23 MPa and the elongation at break reaching to 627%. It is revealed that increasing the hard segment content in PUUs benefits the self-healing performance, and on the opposite increasing the soft segment content contributes to the biodegradability.