Renewable aliphatic polyesters from fatty dienes by acyclic diene metathesis polycondensation

Authors: Moser, Bryan; Vermillion, Karl; Banks, Benetria; Doll, Kenneth - Ken

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2020
Publication Date: 2/19/2020
Citation: Moser, B.R., Vermillion, K.E., Banks, B.N., Doll, K.M. 2020. Renewable aliphatic polyesters from fatty dienes by acyclic diene metathesis polycondensation. Journal of the American Oil Chemists' Society. 97(5):517-530. https://doi.org/10.1002/aocs.12338.
DOI: https://doi.org/10.1002/aocs.12338

Interpretive Summary: This research describes a sustainable route to a new set of renewable polymers from vegetable oils. Renewable polymers are important because they represent bio-based alternatives to existing petrochemically-based materials, which often cause water and soil pollution in addition to negative health effects. This research discovered that fatty acids derived from vegetable oils can be readily converted into thermoplastic polymers in high yield using a simple, rapid, mild, catalytic polymerization method. These polymers have potential applications as coatings, thickening agents, or organogels. This research may ultimately expand markets for bio-based polymers, thus reducing the environmental impact of and demand for petroleum-derived products while simultaneously enhancing rural economies by increasing the use of agricultural materials.

Technical Abstract: Three renewable, linear, aliphatic polyesters were prepared by Acyclie diene metathesis (ADMET) polymerization of a,w-dienes derived from fatty acids. Condensation of 9-decenoic acid with allyl 9-decenoate, ethylene glycol, and 9-decen-1-ol proceeded in high conversion (greater than or equal to 94%) and purity (>99%) to give a,w-dienes suitable for subsequent polycondensation. Polymerization was achieved using 1.0 mol% Hoveyda-Grubbs second generation metathesis catalyst in combination with 2.0 mol% 2,6-dichloro-1,4-benzoquinone as an isomerization inhibitor under vacuum to drive equilibria toward polymer formation via ethene removal. Polymerization in the presence of solvent promoted ring-closing metathesis (RCM) at the expense of polymer, with cyclization increasing as the concentration of monomer decreased. Thus, ADMET polymerizations were performed in bulk to mitigate RCM. The resulting polymers with Mn and Ð that ranged from 6.6 to 8.9 kDa and 1.75–2.14, respectively, contained 76% or more of renewable carbon content and exhibited atom and carbon economies of greater than 84%. Melt (Tm) and crystallization (Tc) temperatures were 20.8–48.4°C and 3.8–37.6°C, respectively, and increased as ester density decreased within polymer structures. Sub-ambient glass transitions ranged from -10.3 to -50.0°C. Lastly, the polymers were thermally stable below 320°C, as 10% mass loss (T10) occurred above 340°C, which indicated that they existed as liquids for at least 319°C (T10 – Tm) before decomposing.