​Anthony Monmagnon
Systèmes Moléculaires et nanoMatériaux pour l'Énergie et la Santé (SyMMES)/ Equipe STEP
​ UMR 5819
 CEA-CNRS-UGA-Grenoble-INP​

Cross-linked polyurethanes (PU) are synthetic polymers that occupy a prominent place in industry, serving as assembly elements in transport and construction, thermal or acoustic insulators and essential components in comfort articles such as pillows and mattresses. However, PU are subject to severe regulatory restrictions, notably under the REACH regulation, due to their negative impact on health and the environment. In this context, the replacement of conventional PUs with more durable isocyanate-free polyurethanes (NIPUs, non-isocyanate polyurethanes) is of great interest in reducing the environmental and health impact of PUs. However, because of their reduced reactivity compared with conventional PUs, the times required to cure NIPUs are currently incompatible with the production rates expected by industry, and therefore need to be optimised. The aim of this thesis project is therefore to develop flexible biobased NIPU foams with optimised reactivity, to replace flexible PUs with the same thermal and mechanical properties. In this context, new two-component resins with a high content of renewable raw materials (70-90%m) were synthesised from biobased diamines and hemp oil functionalised with cyclic carbonates, for the production of a range of polyhydroxyurethane (PHU) foams. To quickly identify the experimental conditions that would accelerate the reaction kinetics of model formulations, an in situ characterisation method was developed using NMR spectroscopy. The influence of the concentration and nature of the catalyst, as well as the temperature, was highlighted. The second stage involved optimising cross-linking times by studying cross-linkable formulations using rheometry. Very interesting cure times (>10 min at 80°C) were obtained by adjusting the residual epoxy content in the carbonated oil, the nature of the diamine and the catalyst concentration. After optimising the expansion method for these new materials, PHU foams with a glass transition temperature (Tg) of around -20°C, a density of less than 150 kg/m3 and a compression set of less than 5% were obtained, in line with industrial specifications, for the design of seats in the automotive sector. 

Supervision:  Renaud DEMADRILLE & Sébastien ROLERE.​​​