Chain‑End Functional di‑Sorbitan Oleate Monomer Obtained from Renewable Resources as Precursors for Bio‑Based Polyurethanes

Abstract

A three-step synthetic route was proposed and tested to obtain a chain-end functional di-sorbitan oleate monomer: First, 1,18-octadec-9-enedioic acid compound was produced by self-metathesis reaction of an oleic acid; then, the 1,18-octadec 9-enoyl dichloride compound was yielded by chlorination of the di-acid with thionyl chloride, and fnally, the 1,18-di-sorbitan oleate monomer was yielded by esterifcation of the dichloride with 1,4-sorbitan. The di-sorbitan oleate monomer was purifed and then characterized by FTIR, 1 H-NMR, DSC and TGA to establish its structure and properties. A bio-based polyurethane (PU) was synthesized by reacting the obtained 1,18-di-sorbitan oleate monomer and MDI. Rheological analysis showed that a curing reaction occurs as a signifcant increase of the storage modulus (G’) and the complex viscosity (η*) at 100 °C. The obtained bio-based PU was characterized by FTIR, TGA and DMA, confrming that 1,18-di-sorbitan oleate is a feasible monomer for synthesizing polyurethanes.