Development of Sustainable Citric Acid-Based Polyol To Synthesize Waterborne Polyurethane for Antibacterial and Breathable Waterproof Coating of Cotton Fabric

Polyurethane (PU) is widely used in the coating of technical textiles. PUs are generally solvent-based and derived from synthetic polyols. In this work, a bio-sourced acid (citric acid (CTA)) and polyglycol (polyethylene glycol (PEG200)) were coupled together to synthesize sustainable functional polyol (SFP). SFP was confirmed chemically by ATR-FTIR, NMR, and MALDI-MS and then explored for its application for preparing waterborne polyurethane (WPU). SFP concentration was optimized to impart appreciable functional properties to cotton fabric. Without a reduction in mechanical properties of the cotton fabric, WPU-coated samples showed inherent antibacterial properties ranging from 84% to 99% against Escherichia coli bacteria, water barrier property of 100+ cm of water pressure, and water vapor transmission rate up to 1506 g per day, indicating nonporous breathable coating. SFP can be claimed as the sustainable waterborne antibacterial ingredient for PU synthesis, which can find applications in the coating of textiles for outdoor applications.