We present (R)-1,3-butylene carbonate (R-BC) as a biorenewable monomer for the preparation of semicrystalline aliphatic polycarbonates. This conversion is achieved by using enantiomerically pure, biobased (R)-(-)-1,3-butanediol (bio-BG) as a renewable feedstock. Ring-opening polymerization from select catalysts at low temperatures can yield regioregular poly((R)-1,3-butylene carbonate) (R-PBC) with semicrystalline properties (Xreg = > 0.99; Tm = 72 °C). Along with the R-enantiomeric polymer, the alternate stereochemical polymers (using S- and racemic BC) were investigated. Our analysis shows that the highest level of crystallinity is achieved with regioregular, biobased R-PBC compared to the petrol-based S- and racemic congeners. This work shows the potential of stereochemically pure bio-BG as a starting material for semicrystalline, aliphatic carbonates when high regioregularity is achieved in the polymer microstructure. The synthesis and thermal characterization of regioregular butylene carbonate polymers are described in detail.
Bibliographical noteFunding Information:
We thank Genomatica for supplying the enantiomerically pure ( R)-(−)-1,3-butanediol and for the financial support for this work. We thank Fasil Tadesse, Juila Khandurina, Jeff Lievense, and others at Genomatica for their helpful inputs. Powder XRD was carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC and NNCI programs. We also acknowledge the NSF Center for Sustainable Polymers, CHE-1901635 at the University of Minnesota for providing support for this work.
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