posted on 2024-01-26, 19:40authored byYue Wang, Kevin van der Maas, Daniel H. Weinland, Dio Trijnes, Robert-Jan van Putten, Albert Tietema, John R. Parsons, Eva de Rijke, Gert-Jan M. Gruter
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 Tg 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 codiol 1,4-cyclohexanedimethanol (CHDM). Their relatively
fast degradability is independent of the type of noncyclic codiol
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.