Polyethylene terephthalate (PET) is one of the most common plastics and can be cascaded mechanically during its life cycle. However, recycling affects the mechanical properties of the material, and the virgin material is constantly in demand. If a worn material could be depolymerized to its chemical building blocks, then a virgin polymer could be generated from old fibers. In this work, we have developed a benign organo-catalytic depolymerization of PET to yield dimethyl terephthalate (DMT) and ethylene glycol (EG) without the need for purification of generated monomers. By recirculating the solvent and organo-catalyst, a solvent/substrate ratio of 3:1 was achieved. The depolymerization was successfully applied to other polyesters, polycarbonates, and polycotton. The cotton isolated from the polycotton depolymerization was successfully processed into viscose fibers with a tenacity in the range of nonwaste cotton-derived viscose filaments. The global warming potential (GWP) of PET depolymerization was evaluated by using life cycle assessment (LCA). The GWP of 1 kg PET recycling is 2.206 kg CO₂ equivalent, but the process produces DMT, EG, and heat, thereby avoiding the emissions equivalent to 4.075 kg CO₂ equivalent from the DMT, EG, and steam-energy production through conventional pathways. Thus, the net result potentially avoids the emission of 1.88 kg of CO₂ equivalent. The impact of this process is lower than that of waste PET incineration and conventional PET recycling technologies.

In the future, materials will need to be biobased and produced sustainably without compromising mechanical properties. To date, in many cases, the advantages of the bio-origin of the raw material are overridden by the environmental impact of the process. In the present study, we have developed a novel composite material based on woven hemp fabric which reinforce a thermoset polymer produced from birch bark, a low-value forestry byproduct. Results show that this fully biobased composite has specific stiffness and strength equivalent to those of flax fibre-reinforced petroleum-based epoxy composites and slightly lower than glass fibre-reinforced petroleum-based epoxy composites. The sustainability of the material was also evaluated by life-cycle assessment from cradle to gate and showed significantly superior performance with respect to the potential global warming impact than commercial benchmark materials. Furthermore, toxicology studies showed no endocrine disruptive activities. This is an important proof of concept study demonstrating that biobased structural materials can be produced sustainably.

To achieve a viable forest-based biorefinery, both the carbohydrate and lignin parts of the raw material should be valorized. While lignin-first approaches have successfully been applied to hardwoods, where up to 50% of the lignin -close to the 'theoretical maximum yield'- has been transformed to valuable monophenols; limited studies have targeted softwoods. Softwood lignin comprises lower amount of beta-ether bonds and this results in lower theoretical and observed yields of monophenols in reductive catalytic fractionation (RCF): below 5 wt% yield of initial biomass has been reported. In this study, we use beetle infected spruce, a softwood, as raw material. A fast fractionation was developed to give a pulp and a lignin fraction in the absence of transition metal catalysts. The carbohydrate matrix was valorized to dissolving grade pulp in 37 wt% from biomass (86% yield), and suc-cessfully spun to Lyocell fibers. The lignin fraction was dissolved in furfural -operating as green 'solubility-enhancing-agent'- to blend lignin in inert carrier liquids to promote controlled hydrotreatment to yield biofuels in 10 wt% (60% carbon yield) from initial biomass. Life cycle assessment (LCA) of the value-chain showed improved sustainability in several footprint categories compared to cotton production. Thus, upgrading of a considered forestry waste to high value textile fibers and biofuels has been achieved: in case of lignin beyond the 'theoretical maximum yield'. This is an important step to mitigate a future growing demand of textiles without negatively affecting irrigation or land use.

To make biorefining more environmentally sustainable, preferably residues from forestry should be used and more than one fraction should be upgraded. A third of raw materials from forestry & horbar;tops and branches (T & B)― are either left in the forests or collected and incinerated to a low value. Herein, we apply a fast fractionation to valorize two of the fractions of this forestry residue. The cellulose is converted to textile fibers and all the lignin to hydrocarbons. The environmental sustainability of the novel value chain was studied by life cycle assessment (LCA), and benefits were found in four out of five impact categories. These are important steps to increase fiber production without affecting environmental impact, making biorefining competitive.