Vegetable oil based polyurethane coatings – A sustainable approach: A review

The scientific community has been pooling all its resources, for the past decade, towards the development of “sustainable development” to usher into an eternally green and sustainable tomorrow. As part of this endeavor, the conventional petroleum-based polyurethane (PU) coatings have been replaced by their green counterparts, i.e., bio-based polyurethane coatings. These green alternatives provide a suitable replacement for the coating industry due to their easy availability, biodegradability, low cost, and lesser environmental impact. The production of such green PU coatings is further facilitated by the utilization of bio-based materials, including vegetable oils and their derivatives such as methyl ester, fatty acid, and other bio-renewable sources. This review discusses the different chemical modifications used to convert these bio-based precursors into desired polyols and isocyanates. Furthermore, the formulation of different PU coatings and their subsequent potential applications are also elaborated on in this review. The coatings sector has already been introduced to the notion of eco-friendly technologies such as UV-curable, less or zero solvent, waterborne, hyperbranched, and high solids coatings, complemented by the incorporation of renewable feedstock in monomer synthesis. The review examines the future hurdles that hinder the utilization of these materials in a wide range of applications and presents technologies that facilitate potential solutions and mention key players in the coating sectors that are at the forefront of bringing these revolutionary changes.