A fully bio-based waterborne polyurethane dispersion from vegetable oils: From synthesis of precursors by thiol-ene reaction to study of final material

A new linear saturated terminal diisocyanate was synthesized from castor oil-derived undecylenic acid by thiol-ene coupling (TEC) and Curtius rearrangement. The structure of the diisocyanate was carefully examined using Fourier transform infrared spectroscopy, H-1 nuclear magnetic resonance (NMR), and C-13 NMR. This diisocyanate was used as a starting material for the preparation of a fully bio-based waterborne polyurethane dispersion (BPUD) by reacting with castor oil and castor oil-based carboxylic acid-type hydrophilic chain extender, which was prepared from castor oil by using 3-mercaptopropionic acid via TEC. The thermal/mechanical properties of the formed BPUD film were characterized via differential scanning calorimetry, thermogravimetric analysis, tensile test, hardness test, and water resistance test. The fatty acid-derived diisocyanate and the castor oil-based hydrophilic chain extender were used to produce BPUD with favorable properties. (C) 2013 Elsevier B.V. All rights reserved.