Environmentally Friendly Polyurethane Dispersion Derived from Dimer Acid and Citric Acid

Abstract

Sustainable polyurethane dispersion with smart properties has enormous potential in the polymer industries because of its unique and environmentally friendly characteristics. Biodegradable water dispersion thermoplastic polyurethanes (WBPUs) with self-healing capability were synthesized, and they were water-dispersible after neutralization with triethylamine (TEA). The biobased macroglycol and chain extender were synthesized via the catalyst-based esterification reactions of dimer acid (DA), poly(ethylene glycol) (PEG-200), citric acid (CA), and glycerol. Three different compositions of WBPUs were synthesized by reacting poly(ε-caprolactone) diol (PCL, M.W ∼ 2000 g/mol) and biobased macroglycol with aliphatic and aromatic diisocyanates in the presence of various amounts of branch generating unit. FT-IR, 1HNMR, 13CNMR, GPC, and XRD analyses of WBPUs were conducted to study the physicochemical structure, crystallinity, and molecular weight. The WBPUs exhibited high elongation at break (678.9–485.3%), toughness (51.49–32.6MJ m–3), tensile strength (9.26–7.82 MPa), scratch hardness (3.5–2 kg), gloss at 60° (25.4–15.6°), impact resistance (8.95–8.33 kJ/m), and chemical resistance. Furthermore, these WBPUs possessed microwave assisted self-healing and UV-aging characteristics, and they were found to be biodegradable.