Comparison of aliphatic polyesters prepared by acyclic diene metathesis and thiol-ene polymerization of alpha,omega-polyenes arising from oleic acid-based 9-decen-1-ol

Authors: Moser, Bryan; Doll, Kenneth - Ken; Price, Neil

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2022
Publication Date: 11/29/2022
Citation: Moser, B.R., Doll, K.M., Price, N.P. 2022. Comparison of aliphatic polyesters prepared by acyclic diene metathesis and thiol-ene polymerization of alpha,omega-polyenes arising from oleic acid-based 9-decen-1-ol. Journal of the American Oil Chemists' Society. 100:149-162. https://doi.org/10.1002/aocs.12668
DOI: https://doi.org/10.1002/aocs.12668

Interpretive Summary: This research compares two sustainable alternative routes that lead to renewable polymers from vegetable oils. Renewable polymers are important because they are bio-based alternatives to existing petrochemically-based materials, which often cause negative environmental, ecological, and human health effects. This research discovered that fatty acids, derived from vegetable oils, can be readily converted into thermoplastic polymers (pliable or moldable at certain temperatures) in high yield using simple, rapid, and mild polymerization methods. These polymers have applications as coatings, thickening agents, and gels. This research will 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: Development of more sustainable and environmentally friendly polymers as alternatives to petroleum-based polymers is a priority. We report the synthesis of six linear, aliphatic, renewable polymers by acyclic diene metathesis (ADMET) and thiol-ene polymerization of alpha,omega-polyenes resulting from thermal esterification of adipic, azelaic, and itaconic acids with 9-decen-1-ol. ADMET homopolymerization was performed with 1.0 mol% Hoveyda–Grubbs second generation metathesis catalyst. Thiol-ene copolymerization was conducted photochemically with 1 wt% 2,2-dimethoxy-2-phenyl-acetophenone and stoichiometric 1,2-ethanedithiol (EDT). Although the thiol-ene copolymers exhibited carbon and atom economies of 100%, the ADMET-derived polyesters possessed superior renewable carbon content (100%) and environmental factors (<4). These results were attributed to incorporation of non-renewable EDT into poly(thioether-ester)s and loss of ethene during production of ADMET polyesters. The M-n (>26kDa), M-w (>92kDa), and dispersities (>3.4) of the poly(thioether-ester)s were higher than the corresponding polyesters, which in part explained why the poly(thioether-ester)s gave higher melting (>61°C), crystallization (>49°C) and glass transition (>-31°C) temperatures. The cross-linked itaconate polymers did not melt or crystallize, thereby suggesting amorphous morphology. Lastly, the ADMET polyesters were more thermally stable (T50>408°C) than the poly(thioether-ester)s (T50<377°C). In summary, the aliphatic biopolymers displayed a wide range of properties that were impacted by polymerization method as well as the nature of the monomer.