Non‐Isocyanate Polyurethanes for Sustainable Materials:Synthesis Routes, Applications, and Circular Economy Aspects

ABSTRACT Conventional Polyurethanes (PUs) are inseparable in modern industry but rely heavily on isocyanates and phosgene‐based synthesis routes, posing significant environmental and safety risks. Non‐isocyanate polyurethanes (NIPUs) have emerged as a promising substitute by offering a pathway to greener materials without compromising performance. This review critically examines the recent advancements in NIPU technology, with specific focus on the polyaddition of cyclic carbonates and amines as the dominant synthetic route. The transition from petrochemical to biobased feedstocks, including vegetable oils, lignin, and terpenes, and evaluation of novel solvent‐free and catalyst‐free synthesis methods has been critically discussed. Beyond synthesis, the review highlights the structure–property relationships that enable diverse applications, from self‐blowing foams and hydrogels to high‐performance coatings. Uniquely, this article integrates a circular economy perspective, assessing the potential for closed‐loop recycling and the life cycle implications of NIPU materials. Finally, the critical barriers to commercialization, such as reaction kinetics and viscosity have been discussed, along with suggestions for strategic research directions to bridge the performance gap between NIPUs and conventional PUs.