LGP2 internship's opportunity - 5-6 months - Starting in February 2025 - Paper and cardboard recycling has made great strides in recent decades. However, conventional processes cannot recycle more than 90% of the material. The PACkaging, Recycling, Recyclability, Re-use of papers and cardboards (PAC3R) project focuses on cellulose-based packaging. The aim is to develop new and sustainable processes to improve the properties of fibres obtained from the recycling of corrugated paper. To compensate for the loss of quality of recycled fibres, paper mills currently add starch and/or virgin fibres. Objective 1: avoid these additions by increasing the binding potential of the fibres by introducing COOH groups (oxidation) into the fibres or by cross-linking the fibres (esterification). Objective 2: to improve the hydrophobic nature of recycled fibres, a major problem in the textile industry.