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Supramolecular evolution over an initial period of biodegradation of lactide and caprolactone based medical (co)polyesters.
Supramolecular evolution over an initial period of biodegradation of lactide and caprolactone based medical (co)polyesters.
- Source :
-
Polymer Degradation & Stability . Oct2014, Vol. 108, p87-96. 10p. - Publication Year :
- 2014
-
Abstract
- Phase-structural changes and enthalpic relaxation behavior of poly( d , l -lactide) (PDLLA), poly( l -lactide) (PLLA) and poly( l -lactide-co-ε-caprolactone) (PLCL) copolymers with a lactide molar content ∼70% and having different randomness character (PLCL r 1 : R = 0.69; PLCL r 2 : R = 0.92) were evaluated over 7 days in phosphate buffered saline (PBS) at 37 °C. Results obtained by Temperature Modulated Differential Scanning Calorimetry (TMDSC) and Dynamic Mechanical Analysis (DMA) showed an increase in the value of enthalpic relaxation ( δ ) and the narrowing of the tan δ peak, respectively, indicating the reduction in molecular mobility and a more uniform distribution of the entropic states as the aging time increased. The results obtained for PLCLs were clearly affected by chain microstructural magnitudes, l LA (PLCL r 1 = 4.35 and PLCL r 2 = 3.45). Both showed a crystallization process accompanied by amorphous phase separation during the early stage in PBS. DSC and DMA results also revealed faster structural changes as a result of new supramolecular arrangements as well as a higher tendency to crystallize for PLCL r 1 regarding PLCL r 2 . [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01413910
- Volume :
- 108
- Database :
- Academic Search Index
- Journal :
- Polymer Degradation & Stability
- Publication Type :
- Academic Journal
- Accession number :
- 98359208
- Full Text :
- https://doi.org/10.1016/j.polymdegradstab.2014.06.004