GENEPI project ANR JCJC - Piezoelectric biobased polymers - Data set n°1 - Role the oriented amorphous phase on piezoelectric properties of PLA

GENEPI Project – Micro Energy Generators Based on Bio-Based and Piezoelectric Materials – Financed by ANR (French National Agency) under the JCJC program - Grant number ANR-21-CE06-003

The objective of the GENEPI project is to convert poly(L-lactide) (PLA), a bio-based thermoplastic material, into an efficient piezoelectric and ferroelectric material that can compete with traditional piezoelectric ceramics and fluorinated polymers, which have negative environmental impacts. GENEPI aims to advance scientific understanding of shear-mode piezoelectricity in PLA, particularly the relationships between processing, structure, and properties. Several challenges need to be addressed in terms of formulation, processing, and characterization of piezoelectric PLA. The CERI MP at IMT Nord Europe is specifically working on an extrusion-orientation process to manufacture piezoelectric PLA films, a process that is easily scalable for industrial use. To assess the potential of these PLA-based piezoelectric technologies, GENEPI also focuses on developing functional devices (mechanical sensors, vibration energy harvesters, and actuators). Additional innovative proof-of-concept devices are currently under development, such as piezoelectric effect-based chemical reactors.

Project Website: https://anr.fr/Projet-ANR-21-CE06-0003

Funding: French National Research Agency (ANR) – AAPG 2021 – CE06 “Polymers, composites, soft matter physics and chemistry, processes” – “Young Researchers” (JCJC) program

Principal Investigator: Cédric Samuel

Duration: 2022 – 2025

Data set n°1 - Role the oriented amorphous phase on piezoelectric properties of PLA - This dataset includes physico-chemical properties for oriented films made from PLA LX975 (amorphous grade of PLA). It includes extrusion conditions, MDO conditions, stretching / dimensional analysis, DSC, DMA, FTIR (non polarized and polarized) and shear piezoelectric properties. The related article "Unveiling the Amorphous Phase Contribution to Shear Piezoelectric of Polylactide" will be published soon.

 The study highlights :

• Amorphous and piezoelectric PLA films were produced by extrusion followed by machine-direction orientation (MDO) using a specific PLA grade with D-content 12%.
• The orientation factor of PLA films is controlled by the draw ratio imposed during MDO in agreement with classical deformation theories of rubber networks.
• Shear piezoelectric properties up to 2 pC/N are detected with a linearly coupling to the orientation factor of PLA films.
• Based on recent structural models, the intrinsic piezoelectricity of the amorphous phase of PLA is estimated to 7 pC/N, a pioneer value in the scientific literature that help future optimization strategies.
• High draw rates imposed by MDO favor high orientation factors of PLA films and enhanced piezoelectric properties due to inactive chain relaxation phenomena in these conditions.
• The impact of the optical purity on the piezoelectric characteristics of the amorphous phase is low within commercial D-content ranges below 10 %.