Synthesis of Crystalline Polymers from Cyclic Diolides

Technologically important biodegradable polymers with physical and chemical properties required for practical use.

Background

Poly(hydroxyalkanoate)s (PHAs), naturally produced by bacteria and other living microorganisms from biorenewable resources such as carbohydrates and fats, are an important class of commercially implemented aliphatic polyesters as biodegradable and/or biocompatible materials for biomedical, pharmaceutical, and packaging applications. The most prominent, most extensively studied, PHA is poly(3-hydroxybutyrate) (P3HB), which is a perfect stereoregular, pure isotactic crystalline thermoplastic material. Thanks to its comparable thermal and mechanical properties to those of high-performance isotactic polypropylene (it-PP), highly isotactic P3HB is being considered as an attractive biodegradable alternative to petroleum-based plastics. However, high current production costs and limited production volumes of bacterial/microbial PHAs, including P3HB, render them impractical in many applications in areas such as biorenewable and biodegradable “green” commodity thermoplastics.

Technology Overview

The invention is a new chemical synthesis route to technologically important biodegradable poly(3-hydroxybutyrate) (P3HB) with high isotacticity and molecular weight required for a practical use. The new route utilizes racemic eight-membered cyclic diolide (rac-DL) derived from bio-sourced dimethyl succinate and enantomeric (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 perfect isotacticity, high crystallinity and metal temperature, as well as high molecular weight and low dispersity.

Benefits

• High isotacticity and molecular weight
• Low dispersity

Publication

Tang, Xiaoyan, and Eugene Y.-X. Chen. “Chemical Synthesis of Perfectly Isotactic and High Melting Bacterial Poly(3-Hydroxybutyrate) from Bio-Sourced Racemic Cyclic Diolide.” Nature News, Nature Publishing Group, 11 June 2018, www.nature.com/articles/s41467-018-04734-3.

Last updated: November 2019