Green Chemistry in Waterborne Polyurethanes Production: Castor Oil as a Renewable Resource

ABSTRACT Polyurethane is a versatile polymer extensively used in industries for foams, coatings, adhesives, leather finishing, and so forth. Researchers have developed waterborne polyurethanes (WPUs) using water as a solvent to improve biocompatibility. Recently, there has been increasing interest in utilizing vegetable oils, particularly castor oil, as raw materials to enhance or replace polyol content in WPU synthesis, offering a more sustainable and eco‐friendlier alternative. This study involves searching scientific databases to investigate WPU, the chemical structure and processes of castor oil, the effects of the NCO/OH molar ratio, and the impact of chain extenders on the properties of castor oil‐based WPU. It also reviews the diversity in synthesis methods and castor oil‐based WPUs (CWPUs) applications. The study concludes with a discussion of findings and prospects. CWPUs are biodegradable and have a lower carbon footprint than petroleum‐based polyurethanes, positioning them as a sustainable alternative. Incorporating castor oil into WPU formulations aligns with the industry's shift toward greener solutions. A life cycle analysis (LCA) confirms their environmental benefits over traditional materials. The review emphasizes the potential of castor oil‐based WPUs, addresses challenges, and provides valuable insights for researchers and professionals focused on sustainable polymer materials.