Synthesis of NIPUs for Application as Water-Based and Solvent-Free Adhesives and Coatings

The development of sustainable alternatives to conventional polyurethanes (PUs) has become a key research priority in polymer science due to environmental, health, and safety concerns associated with the use of isocyanates. In this context, non-isocyanate polyurethanes (NIPUs) are emerging as a promising, viable approach; however, their broader implementation in adhesives and coatings remains hindered by intrinsic limitations, including slow reaction kinetics, limited precursor availability, and challenges in achieving high-performance formulations under application-relevant conditions. This thesis addresses these limitations through the design of solvent-free and waterborne NIPU systems for adhesive and coating applications at mild temperatures, guided by sustainability as a core research principle. A strategy for the functionalization of water-soluble polyamines was devised, enabling the preparation of one-component waterborne NIPU thermosets using water as the sole reaction medium. Post-polymerization modification of poly(vinylamine) with a functional cyclic carbonate allowed the introduction of reactive groups for subsequent crosslinking, yielding thermoset coatings upon mild thermal treatment. ... mehrThe resulting transparent materials exhibited rapid gelation, high hydrophilicity, and rigid polymer networks, demonstrating the feasibility of fully aqueous NIPU coating systems. Solvent-free NIPU formulations capable of curing at room temperature were developed via bulk polyaddition between a highly reactive liquid bis(𝛼-alkylidene cyclic carbonate) and various liquid polyamines. Complete conversion was achieved under ambient conditions, and the resulting materials exhibited tunable thermomechanical and coating properties. Adhesive testing revealed lap-shear strengths exceeding 10 MPa on aluminum, with further enhancement upon incorporation of dopamine, surpassing commercial PU adhesives and indicating suitability for structural applications. To bridge the gap between academic research and industrial practice, conventional solvent-free, room-temperature-curable PU systems were formulated and optimized at the French company COP Chimie™ to enable direct comparison with solvent-free NIPUs. This benchmarking provided additional insight into the structure–property relationships governing adhesive and coating phenomena and further demonstrated that NIPU systems can match or exceed the performance of conventional PU counterparts. Finally, a fully bio-based, fatty acid-derived triamine was synthesized via a three-step route, providing a versatile renewable crosslinker for sustainable polymer design. The triamine was reacted with the liquid bis(𝛼-alkylidene cyclic carbonate) to prepare solvent- and catalyst-free NIPU formulations under mild conditions, yielding fast-curing materials with enhanced chemical resistance. Overall, this work provides evidence that NIPU adhesives and coatings can be obtained under mild conditions through rational formulation design and systematic structure–property– performance analysis, contributing to the understanding of key technological challenges and supporting the development of more sustainable isocyanate-free PU materials.