New publication in ACIE online

 

Next Generation of Zinc Bisguanidine Polymerization Catalysts towards Highly Crystalline, Biodegradable Polyesters

The Herres-Pawlis group showed repeatedly the potential of biocompatible catalysts for the production of bioplastics by ring-opening polymerization, which are an alternative use to the toxic industrially used tin(II) 2-ethylhexanoate. The focus of the group is the investigation of robust alternatives that can be used under industrial conditions. The iron(II) hybrid guanidine complex published in this group in 2019 is the first robust catalyst that surpasses the industrial catalyst in its activity in the ring-opening polymerization of lactide.

With the zinc-bisguanidine complex shown in the new publication it is possible to obtain an even higher activity under industrial conditions in the ring-opening polymerization of cyclic esters. Not only lactide as monomer was investigated, but also the cyclic ester e-caprolactone. The high activity of the published zinc complex is mainly reflected in the lactide polymerization. Here the catalyst shows a reaction rate that is about ten times faster than the industrial tin complex. Additionally, this high catalyst activity enables polymerization in solution, which is particularly advantageous for specific applications, e.g. in the medical field. Thus, this zinc bisguanidine complex is not only the most active catalyst at present, but also the first guanidine complex which can polymerize lactide in solution. Additional material investigations of the produced polymers showed that zinc-based polylactide has a significantly higher crystallinity than the same material produced with tin. This is an important property for e.g. medical implants.

The authors thank the Bioeconomy Science Center (BioSC) for generous funding within the project R2HPBio.

The article Next Generation of Zinc Bisguanidine Polymerization Catalysts towards Highly Crystalline, Biodegradable Polyesters is available on the website of the publisher.