Sustainable polyesters via direct functionalization of lignocellulosic sugars

Abstract

The development of sustainable plastics from abundant renewable feedstocks has been limited by the complexity and efficiency of their production as well as their lack of competitive material properties. Here, we demonstrate the direct transformation of the hemicellulosic fraction of non-edible biomass into a diester plastic precursor at 83% yield (95% from commercial xylose) during integrated plant fractionation with glyoxylic acid. Melt polycondensation of the resulting xylose-based diester with a range of aliphatic diols led to high-molecular weight amorphous polyesters with combined high glass transition temperatures, tough mechanical properties, and strong gas barriers, which could be processed by injection-molding, thermoforming, and 3D-printing. These polyesters could then be chemically recycled from mixed plastic waste streams or digested under biologically relevant conditions. The transformation’s simplicity led to projected costs that were competitive with fossil alternatives and significantly reduced associated greenhouse gas emissions, especially if glyoxylic acid was sourced from CO2.

Extraction and Surfactant Properties of Glyoxylic Acid‐Functionalized Lignin

“…Finally, in comparison to fossil-based surfactants, GA-lignin could be entirely biosourced, as glyoxylic acid can be produced by reduction of CO 2derived oxalic acid [43] or from the oxidation of bio-based ethylene glycol. [44] Even though biocompatibility and overall economics of GA-lignin are still under evaluation, [45] the data shown here confirm how this type of material could facilitate the transition from fossil to bio-based materials.…”

“…These lignins have the added benefit that they can be produced in concert with highly digestible cellulose and GAstabilized xylose, which has been directly used for the production of sustainable bioplastics. [45] Overall, the chemistry shown in this work could allow both the tailoring of lignin properties and the straightforward valorization of all major biomass fractions, which could ultimately make biorefineries more profitable and sustainable.…”

Back to the Future with Biorefineries: Bottom‐Up and Top‐Down Approaches toward Polymers and Monomers

“…Most investigations have looked at the enzymatic or fermentative valorization of the hemicellulosic feedstock mainly on xylose, as it is by far the most abundant sugar obtained from hemicellulose at around 30 wt% within certain biomasses. [101,102] A variety of studies have looked at synthesizing monomers from these feedstocks and include monomers with ring structures, such as oxetanes [103] or carbonates, [104] monomer diesters, [105] or monomers bearing an unsaturation, e.g., acrylates. [33,106,107] The most promising ones use few, high-yielding steps to get from the sugars to the monomer and only add bio-based functionalities (if any) and thus preserve the inherent renewability of the sugars.…”

“…[33,106,107] The most promising ones use few, high-yielding steps to get from the sugars to the monomer and only add bio-based functionalities (if any) and thus preserve the inherent renewability of the sugars. From these monomers, a multitude of polymers have been obtained, such as polyesters, [105,108] polycarbonates, [104] and polyethers. [108] One challenge of all these approaches is that they use pure xylose, which is an expensive raw material.…”