Bio-based Thermoplastic Polyurethane Research Articles

Functional Thermoplastics from Linear Diols and Diisocyanates Produced Entirely from Renewable Lipid Sources

An unsaturated terminal diol, 1,18-octadec-9-endiol (ODEDO), and a saturated terminal diol, 1,9-nonanediol (NDO), were synthesized from oleic acid. The feasibility of utilizing these new diols for the production of thermoplastic polyurethanes (TPUs) was demonstrated by reacting them with a fatty acid-derived diisocyanate, 1,7-heptamethylene diisocyanate (HPMDI), and a commercially available petroleum-derived diisocyanate, 1,6-hexamethylene diisocyanate (HDI). One type of phase structure was obtained for both TPUs in this study, owing to the similarity between the ODEDO and NDO molecular structure. In addition, double yielding behavior (observed for the first time in polyurethanes) was observed in the stress-strain curves for both TPU systems. Compared to the TPUs prepared from HDI, the totally biobased TPUs (ODEDO-NDO-HPDMI) demonstrated comparable properties within acceptable tolerances, considering the impacts on physical properties due to the odd-even effect introduced by the HPDMI. This work is the first that establishes the production of linear thermoplastic polyurethanes entirely from lipid feedstock.