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

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 (>26 kDa), M-w (>92 kDa), 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 degrees C), crystallization (>49 degrees C) and glass transition (>-31 degrees C) temperatures. The cross-linked itaconate polymers did not melt or crystallize, thereby suggesting amorphous morphology. Lastly, the ADMET polyesters were more thermally stable (T-50 > 408 degrees C) than the poly(thioether-ester)s (T-50 < 377 degrees 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.

Automated summary

Development of sustainable and environmentally friendly polymers as substitutes for petroleum-based polymers is a priority. In this study, six linear, aliphatic, renewable polymers were synthesized by acyclic diene metathesis (ADMET) and thiol-ene polymerization. The ADMET-derived polyesters exhibited superior renewable carbon content and environmental factors compared to the thiol-ene copolymers.