Green Synthesis of Polyurethanes Using Soybean Oil-Based Polyols for Bioactive Functional Fabrics

Polyurethanes (PUs) pose great potential in diverse applications, including the functionalization of fabrics, owing to their promising mechanical characteristics and biological compatibility. Here, a green synthesis of PUs has been carried out using the dispersion polymerization technique. The process includes the production of soybean oil-polyol through epoxidation, the preparation of PUs through the formation of polyurethane pre-polymer using an aromatic diisocyanate, i.e., toluene-2,4-diisocyanate, and different mole ratios of sodium alginate used as chain extender. Polyurethane dispersions were obtained by adding specific amount of distilled water. Further, structural attributes of soybean-sodium alginate-based waterborne polyurethanes (SO-SA-PUAro) were identified using an ATR-based Fourier Transform Infrared (FTIR) spectrophotometer, and physico-chemical properties like solid contents, physical appearance, and dispersion stability were observed and co-related with other outcomes. Moreover, synthesized polyurethane dispersions were applied to the plain weaved polyester-cotton blended textile substrate using pad-dry-cure methods. Significant gradual improvements in textile attributes like tensile strengths (from 873 N/m to 989 N/m on warp and 639 N/m to 729 N/m on warp and weft side of fabrics respectively), rubbing fastness (from 3 to 4/5 and 2 to 4 for dry and wet rubbing tests respectively), washing fastness (from 3–4 to 4–5), anti-pilling property (from 2–3 to 4–5), crease recovery angle (from 1.96 cm to 2.74 cm and 1.95 cm to 2.62 cm on warp and weft sides of the fabrics respectively), bending lengths (from 98° to 122° and 88° to 114° on warp and weft sides of the fabrics respectively), and anti-microbial tests (26 mm for E.coli and 27 mm for Cocci bacterial strains) were observed with increasing moles of sodium alginate as chain extender. However, a decreasing trend in tear strengths (from 12.89 lbf/in to 11.65 lbf/in and 10.12 lbf/in to 8.92 lbf/in on warp and weft sides of the fabrics) of the treated fabrics was noted. The outcomes of the study demonstrated that polyurethanes synthesized through bio-based polyol and chain extender have considerably enhanced the textile attributes of fabric and are good alternatives to replace petroleum-based raw materials.