All-Polyhydroxyalkanoate Triblock Copolymers via a Stereoselective-Chemocatalytic Route

Andrea H Westlie; Sarah A Hesse; Xiaoyan Tang; Ethan C Quinn; Celine R Parker; Christopher J Takacs; Christopher J Tassone; Eugene Y-X Chen

doi:10.1021/acsmacrolett.3c00162

All-Polyhydroxyalkanoate Triblock Copolymers via a Stereoselective-Chemocatalytic Route

ACS Macro Lett. 2023 May 16;12(5):619-625. doi: 10.1021/acsmacrolett.3c00162. Epub 2023 Apr 24.

Authors

Andrea H Westlie¹, Sarah A Hesse², Xiaoyan Tang¹, Ethan C Quinn¹, Celine R Parker¹, Christopher J Takacs², Christopher J Tassone², Eugene Y-X Chen¹

Affiliations

¹ Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States.
² Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.

PMID: 37094112
DOI: 10.1021/acsmacrolett.3c00162

Abstract

Biodegradable polyhydroxyalkanoate (PHA) homopolymers and statistical copolymers are ubiquitous in microbially produced PHAs, but the step-growth polycondensation mechanism the biosynthesis operates on presents a challenge to access well-defined block copolymers (BCPs), especially higher-order tri-BCP PHAs. Here we report a stereoselective-chemocatalytic route to produce discrete hard-soft-hard ABA all-PHA tri-BCPs based on the living chain-growth ring-opening polymerization of racemic (rac) 8-membered diolides (rac-8DL^R; R denotes the two substituents on the ring). Depending on the composition of the soft B block, originated from rac-8DL^R (R = Et, ⁿBu), and its ratio to the semicrystalline, high-melting hard A block, derived from rac-8DL^Me, the resulting all-PHA tri-BCPs with high molar mass (M_n up to 238 kg mol^-1) and low dispersity (Đ = 1.07) exhibit tunable mechanical properties characteristic of a strong and tough thermoplastic, elastomer, or a semicrystalline thermoplastic elastomer.