However, bio-based secondary diols such as isosorbide are known for their inherently low reactivity, which hinder conversion to new molecular structures. The researchers from Amsterdam present a simple but innovative synthesis strategy that provides a solution to this. They added a small amount of certain types of substituted phenols (aromatic alcohols) in the polymerisation process. As a result, reactive components (phenol esters) are formed that keep the polymerisation going and prevent isosorbide from having an inhibitory effect. In this way, a high-molecular polymer was made for the first time from isosorbide and succinic acid.
Strong and rigid
The new technology results in polyesters with very good mechanical and thermal properties and at the same time high molecular weights. This makes it possible to produce very strong and rigid bio-based plastics from building blocks that are already commercially available.
The plastics produced in the research outperform existing plastics (such as PET) in terms of heat resistance, which is relevant for reuse, for example – think of washing bottles at 85°C. In terms of mechanical and other relevant properties, the isosorbide-based polymers may also represent an improvement over existing fossil-based materials.
The research was conducted under the NWO-funded RIBIPOL project (‘Novel Rigid Bio-based Polyesters for potential large scale applications’) with contributions from industry. Toy manufacturer LEGO supported the project as part of its search for non-fossil alternatives to its iconic plastic bricks. Dutch green chemistry company Avantium is interested in bottle and film applications. The results were published in the scientific journal Nature Communications:
Daniel H. Weinland, Kevin van der Maas, YueWang, Bruno Bottega Pergher, Robert-Jan van Putten, BingWang, Gert-Jan M. Gruter: Overcoming the low reactivity of biobased, secondary diols in polyester synthesis. Nat Commun 13, 7370 (2022). DOI: 10.1038/s41467-022-34840-2