科研之友
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摘要
Thermoplastic biodegradable polymers displaying an elastomeric behavior are greatly valued for the regeneration of soft tissues and for various medical devices. In this work, terpolymers composed of epsilon-caprolactone (CL), D-lactide (D-LA), and L-lactide (L-LA) were synthesized. These poly(lactid-epsilon-caprolactone) (PLCLs) presented an elevated randomness character (R similar to 1), glass transition temperatures (T-g) higher than 20 degrees C and adjusted L-LA content. In this way, the L-LA average sequence length (lL-LA) was reduced to below 3.62 and showed little or no crystallization capability during in vitro degradation. As a result, the obtained materials underwent homogenous degradation exhibiting K-Mw ranging from 0.030 to 0.066 d(-1) and without generation of crystalline remnants in advanced stages of degradation. Mechanical performance was maintained over a period of 21 days for a rac-lactide-epsilon-caprolactone copolymer composed of similar to 85% D, L-LA and similar to 15% CL and also for a terpolymer composed of similar to 72% L-LA, similar to 12% D-LA and similar to 16% CL. Terpolymers having L-LA content from similar to 60 to 70% and CL content from similar to 10 to 27% were also studied. In view of the results, those materials having CL and D-LA units disrupting the microstructural arrangement of the L-LA crystallizable chains, an L-LA content %26lt;72% and a random distribution of sequences, may display proper and tunable mechanical behavior and degradation performance for a large number of medical applications. Those with a CL content from 15 to 30% will fulfill the demand of elastomeric materials of T-g higher than 20 degrees C whereas those with a CL content from 5 to 15% might be applied as ductile stiff materials.
- 出版日期2014-10
