Development of biobased poly(urethanes--oxazolidones) organogels.

Polyurethanes are largely employed in various fields such as building, insulation and adhesive industries, but there is the constant need to develop sustainable formulations using "green" components and feasible processes. Here, a new series of sustainable castor oil and epoxidized castor oil-based (CO/EpCO) polyurethane networks was synthetized and characterized. The added epoxy functions react with isocyanates forming oxazolidinone linkages in the gels' network, reducing the gelation time from over 3 hours up to 0.5 hours, increasing thermal resistance from 385 °C to 400 °C, tuning the gels' chemical affinity to organic solvents, and modulating some of their structural features at the nanoscale (, polymer mesh size and characteristic persistence lengths), which altogether affect the mechanical behavior and the functionality of the gels. The key features of the new gels are fast gelation, good mechanical properties in the solvent-less and swollen states, and interactions with organic solvents, together with the high sustainability of the whole syntethic process. These features make the novel poly(urethanes--oxazolidones) castor oil organogels promising sustainable materials for potential use in several scientific and technological fields, ranging from cleaning/detergency to the adhesives and sealant industry.