Colorado State University Research Foundation

Xiaoyan Tang

Eugene Y Chen

Miao Hong

Biodegradable polymers with advantageous physical and chemical properties are described, as well as methods for making such polymers. In one embodiment, a new chemical synthesis route to technologically important biodegradable poly(3-hydroxybutyrate) (P3HB) with high isotacticity and molecular weight required for a practical use is described. The new route can utilize racemic eight-membered cyclic diolide (rac-DL), meso-DL, or a rac-DL and meso-DL mixture, derived from bio-sourced dimethyl succinate, and enantiomeric (R,R)-DL and (S,S)-DL, optically resolved by metal-based catalysts. With a stereoselective racemic molecular catalyst, the ROP of rac-DL under ambient conditions produces rapidly P3HB with essentially perfect isotacticity ([mm]&#x3e;99%), high crystallinity and melting temperature (T=171&#xb0; C.), as well as high molecular weight and low dispersity (M=1.54&#xd7;10g/mol, &#xd0;=1.01).

Synthesis of polymers from cyclic diolides

Synthesis of crystalline polymers from cyclic diolides

The invention provides polymers of Formulas I-III, such as polyesters and unsaturated polyesters, and crosslinked and copolymerized polymers thereof. The invention also provides methods to catalytically ring-open five-membered rings such lactones, lactams, and thiolactones, as via ring-opening polymerization. The polymerization products are recyclable and can be depolymerized back to their monomer form via thermolysis and acid or base catalysis.

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Fort Collins, CO, United States of America

Xiaoyan Tang