| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Vert, Michel
French National Centre for Scientific Research
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (4/4 displayed)
- 2014Head-to-Head Comparison of a Drug-Free Early Programmed Dismantling Polylactic Acid Bioresorbable Scaffold and a Metallic Stent in the Porcine Coronary Arterycitations
- 2011Thermal and strain-induced chain ordering in lactic acid stereocopolymers: Influence of the composition in stereomerscitations
- 2009Lipase-catalysed degradation of copolymers prepared from e-caprolactone and DL-lactidecitations
- 2003Mechanical properties and lipase-catalyzed biodegradation of alpha-methyl, epsilon-caprolactone/epsilon-caprolactone copolymers obtained by chemical modification of poly(epsilon-caprolactone)
Places of action
| Organizations | Location | People |
|---|
article
Thermal and strain-induced chain ordering in lactic acid stereocopolymers: Influence of the composition in stereomers
Abstract
cited By 32 ; International audience ; The present work reports on the study of the influence of the composition in stereomer on the mechanical behavior of d- and l-lactic acid stereocopolymers in relation with strain-induced structural evolution. The stress-strain behavior and structural changes upon stretching above the glass transition temperature have been investigated by means of in situ wide-angle X-ray scattering for a series of nearly random stereocopolymers covering a large range of compositions. All members of the family behaved like elastomers in the initial stage of stretching. However, stereocopolymers of low contents in d-units, [d], exhibited a strain-hardening phenomenon starting at strain 150% < ε < 200%, depending on the draw temperature. This strain-hardening decreased with increasing [d] up to the critical concentration [d]* ≈ 8 mol % above which all copolymers displayed an un-cross-linked rubber behavior over the whole strain range. The decrease of the strain-hardening also depended on the draw temperature, yet this sensitivity did not affect the critical concentration [d]* of the position of the transition. The occurrence of the strain-hardening has been correlated with the buildup of a strain-induced ordered phase, the nature of which being directly related to the draw temperature. Drawing at Td = 90 °C, i.e., about 20-30 °C above Tg depending on the [d] value of the copolymer, resulted in the strain-induced α′-crystalline phase. In contrast, for drawing at Td = Tg + 5 °C, the mesomorphic phase was formed. Moreover, it has been shown that the higher [d], the lower the content of ordered phase, irrespective whether it was crystal or mesophase. A parallel is made between the crystallization capabilities of the copolymers from the quiescent melt and under straining. Only stereocopolymers with [d] < [d]* were able to crystallize from the melt, as in the case of strain-induced crystallization. The occurrence of the strain-induced mesophase only in the case of crystallizable copolymers ...