The energy supply of the chemical industry in Germany relies to a large extent on natural gas as an energy carrier. In order to achieve the climate targets, natural gas must be replaced by other CO2-neutral energy carriers in the future. There is a wide range of technologies that can be used for this purpose. In this study, a variety of energy supply concepts are analysed and compared on the basis of an existing industrial application. This work focuses on a techno-economic analysis of integrating a Carnot battery, that is, a power-to-heat-to-power system. The results show that hybrid concepts using both biogas and renewable electricity as an energy carrier and a thermal energy storage are the most economical and offer the greatest flexibility in terms of energy procurement.
Three synthetic routes, thermally initiated thiol-ene polyaddition, isocyanate-based polyaddition, and transurethanization, were compared for the synthesis of non-isocyanate poly(urethane)s (NIPUs). Relatively high molecular weight polymers (Mn up to 19 kgxmol-1) were successfully achieved via thiol-ene coupling using alpha,omega-diene-functionalized carbamates and aliphatic dithiols as monomers under solvent-free conditions and dicumyl peroxide as a thermal initiator at a [SH]/[Ene] ratio of 1.05. Compared to conventional isocyanate and transurethanization methods, the thiol-ene approach demonstrated slightly higher molar mass and reduced formation of urea and carbonate byproducts, independent of the formulation prepared. Thermal and mechanical characterization revealed that NIPUs, especially the ones prepared via thiol-ene, exhibited thermal transitions, tensile strength, and elongation at break comparable to or superior to those of their isocyanate-based counterparts. Adhesive performance was further enhanced through a thermally activated thiol-ene reactive bonding strategy, where in situ polymerization at the substrate interface led to a fourfold increase in lap shear strength (8 MPa) compared to a thermoplastic hot-melt application (2 MPa). These findings highlight that thermally initiated thiol-ene polyaddition is promising for the synthesis of high-performance, isocyanate-free polyurethane materials with potential applications in coatings, adhesives, and thermoplastics.
