Shape-memory and biocompatibility properties of segmented polyurethanes based on poly(L-lactide)

Abstract

A series of segmented poly(L-lactide)-polyurethanes (PLA-PUs) were synthesized by a twostep method, with oligo-poly(L-lactide) (PLA) as the soft segments and the reaction product of 2,4-toluene diisocyanate (TDI) and ethylene glycol (EG) as the hard segments. The shape-memory properties and biocompatibility of PLA-PUs were examined. The 50% compressed PLA-PUs could recover almost 100% to their original shape within 10! from the lowest recovery temperature (22!-37!). In the recovery process the PLA-PU showed a maximum contracting stress in the range of 1.5-4 MPa. Cell incubation experiments show that PLA-PU has biocompatibility comparable to that of pure PLA. Therefore, this kind of polyurethane can be used for implanted medical devices with shape memory requirements.