Thanks to chemical stabilization, aldehyde-assisted fractionation (AAF) of lignocellulosic biomass has recently emerged as a powerful tool for the production of largely uncondensed lignin. Depolymerization of AAF lignin via ether cleavage provides aromatic monomers at near theoretical yields based on ether cleavage and an oligomeric fraction that remains largely unexploited despite its unique material properties. Here, we present an in-depth analytical characterization of AAF oligomers derived from hardwood and softwood in order to elucidate their molecular structures. These bioaromatic oligomers surpass technical Kraft lignin in terms of purity, solubility, and functionality and thus cannot even be compared to this common feedstock directly for material production. Instead, we performed comparative experiments with Kraft oligomers of similar molecular weight (Mn ∼ 1000) obtained through solvent extraction. These oligomers were then formulated into polyurethane materials. Substantial differences in material properties were observed depending on the amount of lignin, the botanical origin, and the biorefining process (AAF vs Kraft), suggesting new design principles for lignin-derived biopolymers with tailored properties. These results highlight the surprising versatility of AAF oligomers towards the design of new biomaterials and further demonstrate that AAF can enable the conversion of all biomass fractions into value-added products.

It is generally accepted in membrane technology that crystalline zones in polymeric membranes do not contribute to transport of liquids nor gases. In current study, poly(3alkylthiophene)s (P3ATs), i.e. homopolymers and random copolymers, were synthesized to study the influence of the supramolecular organization on membrane gas separations. The monomers were polymerized via KCTCP and GPC analysis shows that the polymers have a narrow dispersity. DSC analysis of the polymers reveals that the homopolymers, in contrast to the copolymers, crystallized, confirming their higher degree of supramolecular organization. This was supported by UV-vis absorption spectra of the polymer films, where a red-shift and a characteristic shoulder absorption peak around 600 nm were observed for the homopolymers, while absent for the copolymers. More surprisingly, the homopolymers were found to be two orders of magnitude more permeable to CO2 than the copolymers and also more selective.

A chain growth polymerization of a branched polythiophene (BT) using a Pd(Ruphos) catalyst, as a promising route to synthesize microporous conjugated polymers with well‐defined structures is reported. From N2 adsorptions/desorption isotherm measurements, a Brunauer–Emmett–Teller surface area of 40.7 m2 g−1 is calculated for the BT, significantly higher than that of the linear poly(3‐hexylthiophene) (P3HT) (25.7 m2 g−1). The same trend is confirmed by simulations of the two polymer structures, from which a geometric surface area (SAgeo) of 140 ± 15.8 m2 g−1 is calculated for the BT, much more higher than for the P3HT with a SAgeo of 6.7 ± 7.1 m2 g−1. Moreover, the BT is soluble in common organic solvent and is readily processed in membrane with a CO2/N2 selectivity up to 24.

No abstract