Prof. Dr. Laura Hartmann and Dr. Stephen Hill are delighted to report on the recent publication of research in Angewandte Chemie on the topic of the sustainable synthesis of biomass-derived polymers.
The topics of climate change and non-renewable resource usage are driving an increasing focus on sustainability in society. Significant academic and industrial efforts are now mobilising to transition towards circular economies. Although broadly defined, circular economies can constitute the production of bio-sourced products which may be then either recycled or degraded after usage, feeding those resources back into production. Plastics, in particular, are one material class where bio-based resources could be leveraged to realise circular economies.
Contemporary industrial production of biodegradable plastics like polylactide (PLA) and polycaprolactone (PCL) use toxic, heavy metal catalysts e.g. tin. To ensure circular economies can be both sustainable and biocompatible, non-toxic catalysts are required. A team of researchers from the HHU group led by Prof. Dr. Laura Hartmann, and from the RWTH Aachen led by Prof. Dr. Sonja Herres-Pawlis, have been working towards this goal. Recent published results in Angewandte Chemie report on the development of non-toxic catalysts, which exhibit record-breaking activities, to generate bio-derived, biodegradable polyesters.
Prof. Herres-Pawlis’ group developed a biocompatible, zinc catalyst with a robust and high activity profile e.g. tolerated the presence of impurities. The new catalyst can produce highly crystalline, high-molecular weight PCL and PLA. Complementary research by Prof. Hartmann’s group then analysed the polymers’ degradation profile. For example, investigations into PLA showed that the new zinc catalyst generated PLA with higher degrees of crystallinity than its tin analogue. A polymer’s level of crystallinity dictates not only properties but also potential applications. It was shown that zinc-based PLA degraded slower than tin-based PLA, meaning it is ideally placed for long-term, bio-facing applications e.g. medical implants.
Future work is looking to capitalise on these promising findings and to find further innovations to help create circular economies in plastics production. All the authors would like to acknowledge the Bioeconomy Science Center (BioSC - https://www.biosc.de/eng) for generous funding within the R2HPBio project,.
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