Abstract
Bacterial polyhydroxyalkanoates (PHAs) are a unique class of biodegradable polymers due to their biodegradability in ambient environments and structural diversity enabled by side-chain groups. However, the biosynthesis of PHAs is slow and expensive, limiting their broader applications as commodity plastics. To overcome such limitation, the catalyzed chemical synthesis of bacterial PHAs has been developed via the metal-catalyzed stereoselective ring-opening (co)polymerization of racemic cyclic diolides ( rac-8DL R , R = alkyl group). In this combined experimental and computational study, polymerization kinetics, stereocontrol mechanism, copolymerization characteristics, and the resulting PHAs' properties have been examined. Most notably, stereoselective copolymerizations of rac-8DL Me with rac-8DL R (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.
This work was supported by the US National Science Foundation (NSF-1664915) for the study carried out at Colorado State University. The computational study used the resources of the King Abdullah University of Science and Technology (KAUST) Super-computing Laboratory (KSL).