Bio-based Polymers from Lignin Oligomers – BIOPOLIOL

The BIOPOLIOL project proposes a new way to manufacture bio-based polyhydroxyurethane (PHU) foams, derived from technical lignins for the insulation industry. Lignin is a natural resource with a renewable aromatic structure that is co-produced in the pulp industry in large quantities (up to 100 million tons/year) and that has been under-used until now. An innovative valorization of lignin consists in using it as a macromonomer for the preparation of new biosourced polymers. Continuously growing, due to the high demand in many applications of everyday life, the polymer industry is now facing global warming and the depletion of fossil fuels by using sustainable resources. According to recent reports, of the 360 Mt of polymers produced worldwide, the share of bio-based polymers is only 1%. The incorporation of lignin or modified lignin into industrial polymers can lead to foams with new properties such as mechanical strength and fire resistance. Polyurethane foams (PUR) are widely used in the construction industry as insulating materials. However, the synthesis of PUR relies on the use of toxic isocyanates. The most promising alternative to isocyanate-free polyurethanes is the polyaddition of cyclic carbonate and amine groups to produce UHP, which are good candidates to replace conventional PUR.
The main objective of the BIOPOLIOL project is to provide access to new biobased polyhydroxyurethane (PHU) polymers for the industry through the incorporation of functionalized lignin derivatives.
Oligomers enriched in OH functions will be targeted by a controlled depolymerization of lignin in the presence of catalysts promoting the breaking of ether bonds and the demethylation of aromatic methoxy functions (P1, IRCELYON). The characterization of lignins and converted fractions will be performed by classical methods well known by the partners such as GPC, NMR and GCXGC. However, these methods do not allow to characterize precisely the produced oligomers and dedicated analytical methods must be implemented. In particular, we propose the development of a complete LC x SFC-QToF method to perform the characterization of OH oligomers and its subsequent use to monitor lignin depolymerization (P3, ISA). The separation of OH-enriched oligomers is also a challenge. Purification will be implemented using membranes either as an innovative approach in combination with liquid/liquid extraction, with a hollow fiber membrane contactor, or as a more conventional approach in the form of a membrane cascade by P2 (ABI). Then, the functionalization of the oligomeric fragments will be carried out in particular by using OH groups. Two types of modifications will be developed, to obtain lignins or oligomers with cyclic carbonate or primary amine groups by P4 (ICPEES). The modified lignins or oligomers will then be reacted with bifunctional molecules presenting complementary chemical functions (amines or cyclic carbonates). Their incorporation in formulations containing surfactants and blowing agents will finally allow the production of NIPU foams (Soprema, P5). The comparison between the reactivity and the final properties of the material obtained with the various lignin oligomers will allow to identify the structure-properties relationships according to the main characteristics of the oligomers. Finally, Soprema will carry out a technico-economic study to evaluate the interest of this approach for an industrial valorization on the basis of the partners' data.