Synthesis of castor-oil based polyurethanes bearing alkene/alkyne groups and subsequent thiol-ene/yne post-modification

An efficient route to obtain allyl- and propargyl-containing diols from 10-undecen-1-ol, and their polymerization with isophorone diisocyanate to produce alkene- and alkyne-functionalized polyurethanes (PUs) is described. The bio-based PUs have been further modified by thiol-ene/yne coupling of thioglycerol into unsaturation to obtain a series of PUs with enhanced hydrophilicity. All the synthesized PUs were characterized by FTIR-ATR and NMR spectroscopy. As expected, the PUs were amorphous and DSC revealed glass transition temperatures in the range of 40 degrees C-5 degrees C for the PUs before and after modification. The PUs exhibited highly tunable thermal and mechanical properties. The mechanical properties of these bio-based polymers (E modulus from 774 MPa to 6 MPa and at break from 45% to 401%) make the suitable materials for a large range of applications. (C) 2016 Elsevier Ltd. All rights reserved.