Catalyzed and Non‐catalyzed Synthetic Approaches to Obtain Isocyanate‐free Polyurethanes

Abstract

By reactions of both catalyzed and non-catalyzed pathway, we attempt to show that the synthetic route of non-isocyanate polyurethanes (NIPU) is developed quite recently. The advancement of sustainable, bio-renewable, impermeable and moisture-insensitive NIPU has started to contribute its role in academia and industry. In case of NIPU formulation, polycondensation of dicarbonate with diamine precursors as well as waste-free polyaddition of multifunctional cyclic carbonates with diamines via ring-opening polymerization. Obviously, since the hydroxyl groups (both primary and secondary hydroxyl group) arisen in NIPU is employed to reveal fairly different attributes compared to trivial polyurethanes (PU). The advantage of NIPU comprises of the role of carbon dioxide and renewable feedstock, while various cyclic carbonates obtained to react with diamine substrates to incorporate desired physicochemical and mechanical properties. Indeed, NIPU are noted to be non-toxic, biodegradable and exhibit remarkable properties. In this review, we account the imperative strategies employed in developing essential sustainable NIPU have been discussed in detail.

Biorenewable vegetable oil based nonisocyanate polyurethanes and nanocomposites; formulation, characterisation, biodegradation, anticorrosion and antifouling coatings

“…11–14 Our early reports focused on the use of biodegradable and bioderived polyols to develop PU and PU nanocomposites as films, foams and foam strips. 15–20 Recently, two of us reported NIPU films based on newly developed polycaprolactone cyclic carbonate (the derivative of biodegradable polycaprolactone triol) and published a review article in the area of NIPUs. 19,20 Over the past few decades, extensive research on NIPUs has been carried out in both academia and industry.…”

“…15–20 Recently, two of us reported NIPU films based on newly developed polycaprolactone cyclic carbonate (the derivative of biodegradable polycaprolactone triol) and published a review article in the area of NIPUs. 19,20 Over the past few decades, extensive research on NIPUs has been carried out in both academia and industry. 21 NIPU synthesis was performed via three major routes: (i) aminolysis of cyclic carbonate, (ii) self-polycondensation of monomers containing hydroxyl and acyl azide functionalities and (iii) transurethanization involving carbamates and diols.…”