(465d) Discovery and Development of New Sustainable Polyesters from Biomass

One of the greatest challenges facing the world today is the accumulation of plastic waste in the environment. Researchers have long pursued the development of biodegradable plastics, and some are already widely used, for example the popular poly(lactic acid) PLA or poly(hydroxybutyrate) PHB. However, the poor thermo-mechanical properties of such polymers limit their use for many applications. Therefore, it has become essential to discover and develop a new biodegradable polymer platform with robust mechanical properties, which can be derived from biosources to meet societal needs. In this work, we have explored the development of such new polyesters based on hydroxyacid monomers that can be produced from biomass. After searching the literature for a chemically diverse set of target molecules, this class of monomers was carefully evaluated for its polymerizability to narrow down to the most promising candidates. Initial efforts to synthesize high molecular weight homopolymer was challenging due to high crystallinity of short alkyl chain hydroxyacid compounds. However, copolymer made out of 3-hydroxypivalic acid and 6-hydroxyhexanoic acid exhibited high molecular weight as well as good thermo-mechanical properties that allowed the thermal processing window to be systematically widened by tuning copolymer composition. Lastly, a high throughput degradation was introduced and performed to assess the biodegradation of such polymers. The results from biological discovery, chemical synthesis and environmental metabolic engineering indicate that polyesters made from biosourced hydroxyacids have potentials to simultaneously meet the need for polymers with improved performance and improved sustainability.