Ring‐opening polymerization (ROP) of lactones or cyclic (di)esters is a powerful method to produce well‐defined, high‐molecular‐weight (bio)degradable aliphatic polyesters. While the ROP of lactones of various ring sizes has been extensively studied, the ROP of the simplest eight‐membered lactone, 7‐heptanolactone (7‐HL), has not been reported using metal‐based catalysts. Accordingly, this contribution reports the ROP of 7‐HL via metal‐catalyzed coordinative‐insertion polymerization to the corresponding high‐molecular‐weight polyester, poly(7‐hydroxyheptanoate) (P7HHp). The resulting P7HHp is a semi‐crystalline material, with a
Bacterial poly(3-hydroxybutyrate) (P3HB) is a perfectly isotactic, crystalline material possessing properties suitable for substituting petroleum plastics, but high costs and low volumes of its production are impractical for commodity applications. The chemical synthesis of P3HB via ring-opening polymerization (ROP) of racemic
- Award ID(s):
- 1664915
- NSF-PAR ID:
- 10154287
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 9
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract T mof 68 °C, which is ~10 °C higher than poly(ε ‐caprolactone) derived from the seven‐membered lactone. Mechanical testing showed that P7HHp is a hard and tough plastic, with elongation at break >670%. P7HHp‐based polyesters with higherT mvalues have been achieved through stereoselective copolymerization of 7‐HL with an eight‐membered cyclic diester, racemic dimethyl diolide (rac ‐8DLMe), known to lead to highT mpoly(3‐hydroxyburtyrate) (P3HB). Notably, catalyst's strong kinetic preference for polymerizingrac ‐8DLMeover 7‐HL in the 1/1 comonomer mixture rendered the formation of di‐block copolymer P3HB‐b ‐P7HHp, showing two crystalline domains withT m1 ~ 65 °C andT m2 ~ 160 °C. Semi‐crystalline random copolymers withT mup to 164 °C have also been obtained by adjusting copolymerization conditions. Mechanical testing showed that P3HB‐b ‐P7HHp can synergistically combine the high modulus of isotactic P3HB with the high ductility of P7HHp. -
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rac ‐8DLR, R=alkyl group). In this combined experimental and computational study, polymerization kinetics, stereocontrol, copolymerization characteristics, and the properties of the resulting PHAs have been examined. Most notably, stereoselective copolymerizations ofrac ‐8DLMewithrac ‐8DLR(R=Et, Bu) have yielded high‐molecular‐weight, crystalline isotactic PHA copolymers that are hard, ductile, and tough plastics, and exhibit polyolefin‐like thermal and mechanical properties. -
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P mup to 0.95) that forms the crystalline sc‐material with aT mof up to 171 °C. This sc‐material can be fully depolymerized back to rac‐monomer in a quantitative yield and purity, thus establishing its circular life cycle.
