A Solvent-Free and Scalable Method To Prepare Soybean-Oil-Based Polyols by Thiol-Ene Photo-Click Reaction and Biobased Polyurethanes Therefrom

A solvent-free and scalable method was developed for the preparation of soybean-oil-based polyols by a thiol-ene photo-click reaction with a homemade photochemical reactor. The effect of reaction parameters, including photoinitiators, reaction time, molar ratios of thiols to carbon-carbon double bonds, and power of the mercury lamp, on the structures of the resulting polyols was investigated. The mechanism of the thiol-ne photo-click reaction was also discussed. On the basis of these novel polyols, several polyurethanes were prepared using different diisocyanates (aliphatic, cycloaliphatic, and aromatic isocyanate) and characterized. The resulting polyurethane films possess good performance, including the highest glass transition temperature of 41.3 degrees C, tensile strength of 15.7 MPa, and elongation at break of 471.0%.