A macropolyol was successfully prepared by combining two different biomolecules from biomass, i.e. lignin and oleic acid, using a solvent-free and catalyst-free method. The chemical structures of this original lignin-fatty acid based polyol and its intermediates were determined by 1 H NMR and FT-IR analyses. A series of polyurethanes (PUs) were then prepared by a two-step procedure. Three linear isocyanate prepolymers were first synthesized from 4,4'-methylenebis( phenyl isocyanate) and poly(propylene)glycol of different molecular weights (PPG -425, 1000 and 2000 g mol −1 ). These intermediates were used to obtain different PU macromolecular architectures by varying reaction parameters in the presence of the lignin-fatty acid based macropolyol. The final lignin-based polyurethanes were thoroughly chemically characterized by FT-IR studies, whereas the properties of these polymers were assessed by DSC, TGA, DMTA, and tensile test experiments. All these were performed in order to evaluate the influence of the NCO : OH molar ratio (from 0.2 to 1.0) as well as the influence of the PPG chain length. These new polymers with controlled architectures presented advanced properties. Their high biobased content (until 89%) depicts an important output for the valorisation of lignin and they may be an optimal alternative to conventional PUs.

Thermoelectric (TE) materials have drawn enormous research interest for decades as the TE effect facilitates direct conversion of heat into electrical energy or vice versa, thereby providing an alternative for power generation/refrigeration. However, the lack of TE materials that are simultaneously inexpensive, nontoxic, and efficient limits their industrial utilization. A new approach to address this challenge could be the electrical functionalization of commercially usednontoxic, sustainable, lightweight, and low-costthermal superinsulating materials, e.g., Aerosil200, by doping. In the present work, as a first step toward this approach, we employ density functional theory calculations through the Vienna ab initio simulation package to create and validate a numerical model of pure Aerosil200. This was followed by the calculation of its electronic structure as well as TE properties using the BoltzTrap code. The calculated Seebeck coefficient and electrical conductivity, and thereby the power factor, showed excellent agreement with the experimentally determined values. Our numerical model, therefore, paves the way for further improvement of the power factor, hence ZT, through doping of Aerosil200 while retaining its low thermal conductivity.