Promising environmental degradation of PISOX polyesters

A paper by researchers of the Industrial Sustainable Chemistry group at the University of Amsterdam’s Van ‘t Hoff Institute for Molecular Sciences shows the degradation potential of novel fully renewable (bio- and CO2-based) PISOX copolyesters that have a broad range of applications. The research, carried out in cooperation with researchers at the UvA’s Institute for Biodiversity and Ecosystem Dynamics, has recently been published in the ACS journal Environmental Science & Technology.

The paper describes a family of novel bio- and CO₂-based poly(isosorbide-co-diol) oxalate (PISOX-diol) copolyesters that are not only fully renewable but also show very promising environmental degradation characteristics. It describes how tuning the composition of the copolyesters can target a broad range of applications – from the polymer coating of controlled-release fertilizers to film applications as well as rigids for packaging, 3D printing and many other purposes. The paper provides a strategy for optimizing the resulting properties (thermal, mechanical, barrier, hydrolysis, and biodegradation) with respect to the intended applications.

Abstract of the paper

To reduce the global CO₂ footprint of plastics, bio- and CO₂-based feedstock are considered the most important design features for plastics. Oxalic acid from CO₂ and isosorbide from biomass are interesting rigid building blocks for high T_g polyesters. The biodegradability of a family of novel fully renewable (bio- and CO₂-based) poly(isosorbide-co-diol) oxalate (PISOX-diol) copolyesters was studied. We systematically investigated the effects of the composition on biodegradation at ambient temperature in soil for PISOX (co)polyesters. Results show that the lag phase of PISOX (co)polyester biodegradation varies from 0 to 7 weeks. All (co)polyesters undergo over 80% mineralization within 180 days (faster than the cellulose reference) except one composition with the cyclic co-diol 1,4-cyclohexanedimethanol (CHDM). Their relatively fast degradability is independent of the type of noncyclic co-diol and results from facile nonenzymatic hydrolysis of oxalate ester bonds (especially oxalate isosorbide bonds), which mostly hydrolyzed completely within 180 days. On the other hand, partially replacing oxalate with terephthalate units enhances the polymer’s resistance to hydrolysis and its biodegradability in soil. Our study demonstrates the potential for tuning PISOX copolyester structures to design biodegradable plastics with improved thermal, mechanical, and barrier properties.

Paper details

Yue Wang, Kevin van der Maas, Daniel H. Weinland, Dio Trijnes, Robert-Jan van Putten, Albert Tietema, John R. Parsons, Eva de Rijke, and Gert-Jan M. Gruter: Relationship between Composition and Environmental Degradation of Poly(isosorbide-co-diol oxalate) (PISOX) Copolyesters. Environ. Sci. Technol. 2024, 58, 5, 2293–2302. Publication Date: January 26, 2024. DOI: 10.1021/acs.est.2c09699

Source

UvA, press release, 2024-03-05.

Supplier

ACS journal Environmental Science & Technology
University of Amsterdam (UvA)
Van't Hoff Institute for Molecular Sciences

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