Although EcoReFibre is an Innovation Action project, it also supported the three-year research work of a PhD candidate. While the project focuses on developing and validating recycling solutions, this PhD addressed scientific questions that help improve understanding of fibreboard recycling at its core. 

Flore Lebreton successfully completed her thesis intitled “A study of end-of-life fibreboard: their characteristics and availability in Europe”, which she defended the 27^th November 2025 at the Ecole Supérieure du Bois, France. Her research provides new insight into how recycled fibres behave, at a time when fibreboard waste in Europe could, by 2035, reach the same order of magnitude as fibreboard production. This work is particularly relevant in the environmental transition and the development of circular economy strategies for wood-based materials. 

Experimental work at the core of the thesis 
The thesis is built on an ambitious experimental programme carried out at the laboratory scale. It addressed two scientific questions: the impact of recycling processes on fibre properties and the number of times fibres could be recycled. The study focused on individual fibres within a closed-loop recycling process. Industrial virgin fibres were recycled up to six times using a gentle hydrothermal disintegration process to preserve fibre integrity. 

Key Experimental Results 
After six recycling cycles, several fibre characteristics remained stable. No change was observed in fibre length and width, no variation was measured of surface roughness, and no major changes were detected in the chemical proportion of wood constituents. At the same time, some physical changes were identified. 

A linear change in colour was identified and linked to chemical rearrangements. Twists appeared more frequently, with twenty times more fibres showing with at least one twist after six recycling cycles. Despite these changes, fibres retained nearly 80% per cent of their original tensile strength. Even with a material loss of around ten per cent at each recycling stage, the results show that recycled fibres remain a valuable resource after multiple recycling cycles, providing a solid basis for further work and analysis. 

Collaboration and knowledge exchange within EcoReFibre 
Flore’s work strongly benefited from the collaborative environment created by EcoReFibre. Close contact with industrial partners provided real insight into practical constraints and opportunities. Participation in project general assemblies allowed her to draw on live demonstrations and technical discussions. In return, industrial partners, gained valuable insight into fibre behaviour, during recycling through experimental results. During the most recent General Assembly, one consortium partner reported observing similar early colour changes in industrial fibres, confirming the relevance of the chemical mechanisms identified in the thesis. 

Looking Beyond EcoReFibre 
The results of this PhD work extend beyond the project. The dataset and analyses produced will support future research activities, industrial validations, and modelling efforts. The doctoral manuscript will soon be available online as an open-access publication, enabling wide dissemination. These findings can contribute to other circular-economy initiatives, support material flow analysis, and help guide the design of future recycling processes for wood-based composites.