Alain Bourmaud

A story of plant fibers for composite reinforcement: when cell walls bite the dust.     Université de Bretagne Sud, IRDL Institute, Lorient, France

Biography

Alain Bourmaud is a Researcher at the University of South Brittany since Sept. 2001. He received a PhD in Materials Science and Engineering in the multi-scale characterization of biocomposites in 2011 (University of South Brittany) and the French habilitation to manage research (HDR) in 2017 (University of South Brittany). He published around 165 papers in international journals on biocomposite processing or plant fibre structure and properties; he supervised 18 PhD students and 4 post-docs (currently 4 PhD students and 1 post-doc). Alain is also the scientific coordinator of the FLOWER project (INTERREG Cross-Channel, 8 partners, 5.6M€, 2018-2023) and scientific leader of a French Research Project dedicated to the study of archaeological Egyptian flax fibres (ANUBIS, 2021-2025, 1.2 M€). Alain Bourmaud is involved in many academic and industrial research collaborations at the national and international scale. Finally, Alain Bourmaud is an expert in Horizon Europe projects, MSC fellowships or other French scientific calls, and Associate Editor for Industrial Crops and Products journal.

Abstract

Plant fibres are complex and hierarchical cells with a large range of biochemical compositions and morphologies, depending on their in-planta functions. This talk will be divided into two main sections: first, we will detail the main plant fibre structural parameters, i.e., biochemical composition, microfibrillar angle and architecture; their impact on the behaviour and mechanical performance of the fibres will be described, thanks in particular to characterisations carried out recently on Synchrotron beamlines. In a second step, a link will be made with the manufacturing stage by exploring the impact of the processing parameters, and in particular shear, time and temperature on the ultrastructure of the fibres. Their very specific architecture and structure can be significantly altered by the mechanical stresses involved in conventional composite tools. These structural modifications have a significant impact on the dimensions of the fibres, and therefore on their aspect ratio, and degree of crystallinity, but also on inter-polymer bonds and on the overall parietal structure of plant fibres which strongly conditions their reinforcement ability. The importance of the time-temperature relationship but also the choice of fibres will be particularly highlighted.