Effect of chain orientation on the brittle to ductile transition in Polylactide

XU, Shanshan; Stoclet, Gregory; De Waele, Isabelle; Gaucher, Valerie

Document type :

Autre communication scientifique (congrès sans actes - poster - séminaire...): Conférence plénière

Permalink :

http://hdl.handle.net/20.500.12210/106565

Title :

Effect of chain orientation on the brittle to ductile transition in Polylactide

Author(s) :

XU, Shanshan [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Stoclet, Gregory [Auteur]

Unité Matériaux et Transformations (UMET) - UMR 8207
De Waele, Isabelle [Auteur]

Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Gaucher, Valerie [Auteur]

Unité Matériaux et Transformations (UMET) - UMR 8207

Conference title :

EPF 2022

City :

Prague (République Tchèque)

Country :

République tchèque

Start date of the conference :

2022-06

English abstract : [en]

Polylactide (PLA) is one of the most promising biopolymers that actually takes part in commercialized biopolymer market. However, its intrinsic brittleness has found to be a major limit to a wider range of applications. ...
Show more >Polylactide (PLA) is one of the most promising biopolymers that actually takes part in commercialized biopolymer market. However, its intrinsic brittleness has found to be a major limit to a wider range of applications. Among the various chemical and physical approaches reported in literature aiming at improving the mechanical properties, biaxial stretching is known as an elaboration process that can improve the ductility of some brittle polymers. In this context, the goal of this work is to study the influence of chain orientation on the mechanical behavior of Polylactide (PLA). While isotropic PLA exhibits as expected a brittle behavior upon uniaxial tension at room temperature, pre-oriented PLA samples display a ductile behaviour with a strain at break exceeding 100%. In order to better understand the origin of this Brittle to Ductile (B-D) transition, both a crystallizable grade of PLA (C-PLA) and a non-crystallizable grade (NC-PLA) were studied to be able to separate the effects induced by macromolecular orientation from the ones due to crystalline phase. Through an in-depth structural characterization of the pre-oriented films, we have demonstrated that it is the macromolecular orientation in the amorphous phase which is the key parameter governing this B-D transition. Additional structural analyses by Small-Angle X-ray Scattering (SAXS) carried out in situ during the stretching of preoriented or non-oriented samples, combined with morphological observations, have shown that the B-D transition corresponds to a change in the elementary plasticity mechanisms: crazing, predominant in the case of brittle samples, gradually evolves toward the development of shear bands. Supplementary postmortem analyses by SAXS have also shown that the macromolecular orientation has no influence on the geometry of the cracks but induces a reduction in the density of cracks formed during stretching. From these analyses, the critical crack nucleation stress (σcr) as a function of the degree of orientation has been determined. It has thus been shown that the change in deformation mechanisms results from the increase in the crack initiation stress σcr with the macromolecular orientation while the shear band initiation stress is unchanged.Show less >

Language :

Anglais

Peer reviewed article :

Non

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Ingénierie des Systèmes Polymères

Submission date :

2024-02-07T15:52:15Z

Version	Link	Modification date
2	20.500.12210/106565	2024-02-08T08:48:13Z
1	20.500.12210/106565.1*	2024-02-07T15:52:15Z

Effect of chain orientation on the brittle ...

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Effect of chain orientation on the brittle ...

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