Photo-Induced Carbonate-Amine Polyaddition for the On-Demand Synthesis of Non-Isocyanate Polyurethanes

Photopolymerization is one of the most promising technologies for the advanced manufacturing of polymers. It is a flexible method meeting the latest demands of Industry 4.0, notably with the breakthrough of 3D-printing by stereolithography (SLA). If the field has long been dominated by radical chemistry, it is currently experiencing a regain of interest for step-wise photo-polymerizations based on radical-free reactions. When it comes to polyurethanes, one of the most prominent polymer families used in SLA 3D-printing, it is now possible to photo-initiate the isocyanate-alcohol polyaddition reaction itself. However, isocyanates are toxic precursors posing well-known problem of domestic and occupational hazards. In this context, the idea of the PICADDILY project is to develop a photo-polyaddition reaction enabling the synthesis of Non-Isocyanate Polyurethanes (NIPUs). The polyaddition of 5-membered cyclic carbonates (5CCs) and amines is arguably the most promising reaction for the synthesis of NIPUs. But the study of the 5CC-amine reaction has always been restricted to thermo-activated approaches. The idea here is to introduce the 5CC-amine chemistry to the field of photo-chemistry. A toolbox of tailor-made monomers and photocatalysts will be conceived to address two challenges: 1- the design of latent 5CC-amine formulations that are unreactive at room temperature and before exposure to light, 2- the photo-catalytic initiation of the 5CC aminolysis after irradiation under UV or visible light. From a broader perspective, the ambition of PICADDILY is to expend the knowledge of 5CC reactivity to bridge the gap with well-established chemistries (e.g. epoxy, isocyanate)