This study focuses on the synthesis and properties of novel polymers from biomass-based chemicals, hydroxymethylfurfural (HMF) and isohexides. The chiral nature of the cis-fused tetrahydrofuran rings on the isohexide core makes them an interesting monomeric precursor allowing for the study of strereochemical influences on material properties. Isosorbide (IS) and its stereoisomer isomannide (IM), were converted to diisocyanate tethered monomers; isosorbide and isomannide bis(3-isocyanatopropanoate) (ISBIP and IMBIP, respectively). These were polymerized at varying feed ratios with 2,5-bishydroxymethylfuran (BHMF), a diol synthesized from reduction of HMF, to formulate novel polyurethanes with varying stereochemistry incorporated into the backbone. Mechanical testing, differential scanning calorimetry, pycnometry, and rheology were explored to determine the stereochemical influence of the chosen isohexide feed on properties. Number average molar mass of ~10 kg mol-1 were obtained with dispersity values typical for a step-growth mechanism (&gt;1.5). Polyurethanes synthesized solely from isosorbide (PU-IS) were found to be slightly entangled at this molar mass while those from isomannide (PU-IM) and a 1:1 mixture of the two isohexides (PU-IS0.5PU-IM0.5) were unentangled. As a result, PU-IS was found to be tougher than PU-IM (239.4 ± 54.6 versus 167.0 ± 48.1 kJ m−3) and less ductile ε (1.33 ± 0.25 %), where PU-IS0.5PU-IM0.5 had a toughness nearly an order of magnitude less. The totality of these results suggest that the choice and purity of isohexide stereochemistry within the polymer microstructure can have significant influence on material properties.

Biomass based polyurethanes and the effects of stereochemistry on physical properties

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.