Bailly, ChristianWagner, CamilleCamilleWagner2025-05-142025-05-142025-05-142020https://hdl.handle.net/2078.2/31909Composites have many noteworthy properties and epoxy resins are widely used as matrices enabling them to be essential in many fields of activity such as aerospace, automobile, electronic and painting industry. However due to high cross-linking density, epoxy resin are intrinsically brittle and notch sensitive limiting their use. In addition, most of petrochemical epoxy resins use derivatives of bisphenol A (BPA) which has highly negative health effects. This is why engineers try to replace those petroleum-based composites by bio-sourced ones. The aim of the work is to study the influence of the addition of thermoplastic nanocomposite in bio-sourced epoxy resin. Semicrystalline and amorphous polylactic acid (PLA) based composites with different loading rate of lignin particles are studied. Morphological, thermal and mechanical properties are highlighted thanks to a number of analysis and tests including scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamical mechanical analysis (DMA) and tensile test. PLA/Lignin nanocomposite can be a good candidate to toughen bio-sourced epoxy resin. Indeed, DMA analysis reveals a significant increase of the storage modulus with the addition of lignin for both semi-crystalline and amorphous PLA. In addition, tensile test shows an increase in stiffness when the content of lignin in the blend increases however at the same time the maximum strength σmax and the strain at break decrease significantly. Above 20wt% of lignin, the decrease of those mechanical properties becomes detrimental compare to the profit of the stiffness’ increase. Though glass transition temperature decreases slightly with lignin addition and melting temperature of semi-crystalline PLA is also slightly lowered with lignin addition which is indicative of the existence of a intermolecular interaction between PLA and lignin. Potential lignin agglomerates of different sizes in amorphous PLA/Lignin blends are observed suggesting that the manual mixing and the extrusion do not allow to blend at molecular level the two components.PLALigninPolymer lignin nanocompositetext::thesis::master thesisthesis:24463