Recent developments in sustainable high Tg (co)polyesters from 2,5-furandicarboxylic acid, isosorbide, and oxalic acid. Performance and social perspectives

Renewable polyesters with good balance between impact strength and elastic modulus are rare, especially when combined with a high glass transition temperature (T g ). Meeting such performance would enable the substitution of polymers like ABS and polycarbonate with chemically recyclable polyesters from bio-based, CO 2 -based or recycled sources. Recently, we showed that the low reactivity of isosorbide can be overcome. The synthesized copolyesters are very competitive regarding the goals of T g , modulus and impact strength. CO 2 -based oxalate esters and isosorbide are an intriguing monomer combination. These polyesters offer a combination of outstanding mechanical-, thermal- and barrier properties in combination with unique home compostability and marine degradability. In this minireview we will highlight some recent polymer technology developments on high T g (co)polyesters and we look at recent behaviour of consumers on their willingness to pay for sustainability which can create a strong market pull that can help to accelerate the plastic materials transition. • Renewable polyesters are reported with a good balance between impact strength and elastic modulus (stiffness). These are rare, especially when combined with a high glass transition temperature (Tg). • The low reactivity of isosorbide can be overcome by using aryl alcohols as reactive solvents to convert all acid groups into aryl esters (removing water) which are very reactive in transesterification and (unlike water) hardly play a role in the backward reaction. • Poly(isosorbide-co-cyclohexanedimethanol terephthalate) (PICT) and poly(isosorbide-co-1,4-butanediol terephthalate) (PIBT) have very competitive Tg, modulus and impact strength versus ABS. • From CO 2 -based oxalate (diguaiacyl ester) and isosorbide, PISOX polymers with high molecular weights can be produced, in the absence of a catalyst due to the good leaving ability of phenyl groups. These polyesters show a combination of outstanding mechanical-, thermal- and barrier properties in unique combination with home compostability. • Recent history’s main lesson about the plastic transition is that large brands are not prepared to pay a premium for a bio-based drop-in which has the same performance. As an example, Coca-Cola’s Bio-glycol PlantBottle PET volumes went down from more than 1.0 M ton in 2016 to 0.1 Mt in 2024, even though most of the consumers are willing to pay for this premium.