Jing Xiabin

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

A series of segmented poly(L-lactide)-polyurethanes (PLA-PUs) were synthesized by a two-step 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°C from the lowest recovery temperature (22°C–37°C). 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.

Effect of polymer chain structure and chain distance on luminescent efficiency

Three kinds of PPV-based copolymers were synthesized and characterized. Their luminescent properties were investigated and discussed by PL spectrum, and time-dependence luminescent spectrum in film and solution state. The results show that in the range of our study, the PL intensity and lifetime of luminescent decay increase with the increasing length of flexible segments and the solution diluting, indicating the tendency of the increase of luminescent efficiency.