Esterified Lignin Nanoparticles for Targeted Chemical Delivery in Plant Protection.

There is a growing demand for biobased functional materials that can ensure targeted pesticide delivery and minimize active ingredient loss in the agricultural sector. In this work, we demonstrated the use of esterified lignin nanoparticles (ELNPs) as carriers and controlled-release agents of hydrophobic compounds. Curcumin was selected as a hydrophobic model compound and was incorporated during ELNP fabrication with entrapment efficiencies exceeding 95%.

Fully bio-based water-resistant wood coatings derived from tree bark.

Surface protection is essential when using wood as a construction material. However, the industry lacks sustainable alternatives to replace the presently dominant fossil-based synthetic water-resistant coatings. Here, we show a fully bio-based wood surface protection system using components sourced from birch bark and spruce bark, inspired by the natural barrier function of bark in trees.

Overcoming Challenges of Lignin Nanoparticles: Expanding Opportunities for Scalable and Multifunctional Nanomaterials.

ConspectusThe increasing demand for polymeric materials derived from petroleum resources, along with rising concerns about climate change and global plastic pollution, has driven the development of biobased polymeric materials. Lignin, which is the second most abundant biomacromolecule after cellulose, represents a promising renewable raw material source for the preparation of advanced materials. The lucrative properties of lignin include its high carbon content (>60 atom %), high thermal stability, biodegradability, antioxidant activity, absorbance of ultraviolet radiation, and slower biodegradability compared to other wood components.

Designed to Degrade: Tailoring Polyesters for Circularity.

A powerful toolbox is needed to turn the linear plastic economy into circular. Development of materials designed for mechanical recycling, chemical recycling, and/or biodegradation in targeted end-of-life environment are all necessary puzzle pieces in this process. Polyesters, with reversible ester bonds, are already forerunners in plastic circularity: poly(ethylene terephthalate) (PET) is the most recycled plastic material suitable for mechanical and chemical recycling, while common aliphatic polyesters are biodegradable under favorable conditions, such as industrial compost.

Elucidating intermolecular forces to improve compatibility of kraft lignin in poly(lactic acid).

Owing to its abundant supply from renewable resources, lignin has emerged as a promising functional filler for the development of sustainable composite materials. However, achieving good interfacial compatibility between lignin and synthetic polymers, particularly poly (lactic acid) (PLA), remains a fundamental challenge. To advance the development of high-performance bio-based composites incorporating lignin and PLA, our study has scrutinized to unravel the nuances of interfacial binding interactions with the lignin and PLA composite system.

Mechanically recyclable melt-spun fibers from lignin esters and iron oxide nanoparticles: towards circular lignin materials.

The inferior thermoplastic properties have limited production of melt-spun fibers from lignin. Here we report on the controlled esterification of softwood kraft lignin (SKL) to enable scalable, solvent-free melt spinning of microfibers using a cotton candy machine. We found that it is crucial to control the esterification process as melt-spun fibers could be produced from lignin oleate and lignin stearate precursors with degrees of esterification (DE) ranging from 20-50%, but not outside this range.

Ag-lignin hybrid nanoparticles for high-performance solar absorption in photothermal antibacterial chitosan films.

There is an urgent need for antimicrobial films based on sustainable resources and production methods. In this study, we present a bio-based nanocomposite film composed of chitosan (∼60 wt %), lignin nanoparticles (LNPs, ∼40 wt %), a small amount of glutaraldehyde (1.5 wt %), and a trace level of silver nanoparticles (AgNPs, 0.

Photonic crystals with rainbow colors by centrifugation-assisted assembly of colloidal lignin nanoparticles.

Photonic crystals are optical materials that are often fabricated by assembly of particles into periodically arranged structures. However, assembly of lignin nanoparticles has been limited due to lacking methods and incomplete understanding of the interparticle forces and packing mechanisms. Here we show a centrifugation-assisted fabrication of photonic crystals with rainbow structural colors emitted from the structure covering the entire visible spectrum.

Urushi as a Green Component for Thermally Curable Colloidal Lignin Particles and Hydrophobic Coatings.

Colloidal lignin nanoparticles are promising building blocks for sustainable functional materials. However, their instability in organic solvents and aqueous alkali limits their applicability. Current stabilization methods require nonrenewable and toxic reagents or tedious workup procedures.

Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers.

Lightweight iron oxide nanoparticle (IONP)/TEMPO-oxidized cellulose nanofibril (TOCNF) hybrid foams with an anisotropic structure and a high IONP content were produced using magnetic field-enhanced unidirectional ice-templating. Coating the IONP with tannic acid (TA) improved the processability, the mechanical performance, and the thermal stability of the hybrid foams. Increasing the IONP content (and density) increased the Young's modulus and toughness probed in compression, and hybrid foams with the highest IONP content were relatively flexible and could recover 14% axial compression.

MoS nanoflower-decorated lignin nanoparticles for superior lubricant properties.

Lignin has been, for a long time, treated as a low-value waste product. To change this scenario, high-value applications have been recently pursued, , the preparation of hybrid materials with inorganic components. Although hybrid inorganic-based materials can benefit from the reactive lignin phenolic groups at the interface, often responsible for optimizing specific properties, this is still an underexplored field.

Breathable Lignin Nanoparticles as Reversible Gas Swellable Nanoreactors.

The design of stimuli-responsive lignin nanoparticles (LNPs) for advanced applications has hitherto been limited to the preparation of lignin-grafted polymers in which usually the lignin content is low (<25 wt.%) and its role is debatable. Here, the preparation of O -responsive LNPs exceeding 75 wt.

Multifunctional lignin-poly (lactic acid) biocomposites for packaging applications.

Lignin is the most abundant aromatic biopolymer with many promising features but also shortcomings as a filler in polymer blends. The main objective of this work was to improve the processability and compatibility of lignin with poly (lactic acid) (PLA) through etherification of lignin. Commercial kraft lignin (KL) and oxypropylated kraft lignin (OPKL) were blended with PLA at different weight percentages (1, 5, 10, 20, and 40%) followed by injection molding.

Stabilized Lignin Nanoparticles for Versatile Hybrid and Functional Nanomaterials.

Spherical lignin nanoparticles are emerging biobased nanomaterials, but instability and dissolution in organic solvents and aqueous alkali restrict their applicability. Here, we report the synthesis of hydroxymethylated lignin nanoparticles and their hydrothermal curing to stabilize the particles by internal cross-linking reactions. These colloidally stable particles contain a high biobased content of 97% with a tunable particle size distribution and structural stability in aqueous media (pH 3 to 12) and organic solvents such as acetone, ethanol, dimethylformamide, and tetrahydrofuran.

Electrochemical Depolymerization of Lignin in a Biomass-based Solvent.

Invited for this month's cover is the group of Adam Slabon at the University of Wuppertal. The image illustrates the reductive depolymerization of lignin into monomers using copper as electrocatalyst. The Research Article itself is available at 10.

Electrochemical Depolymerization of Lignin in a Biomass-based Solvent.

Breaking down lignin into smaller units is the key to generate high value-added products. Nevertheless, dissolving this complex plant polyphenol in an environment-friendly way is often a challenge. Levulinic acid, which is formed during the hydrothermal processing of lignocellulosic biomass, has been shown to efficiently dissolve lignin.

Fully Biobased Photothermal Films and Coatings for Indoor Ultraviolet Radiation and Heat Management.

Sustainable materials are needed to mitigate against the increase in energy consumption resulting from population growth and urbanization. Here, we report fully biobased nanocomposite films and coatings that display efficient photothermal activity and selective absorption of ultraviolet (UV) radiation. The nanocomposites with 20 wt % of lignin nanoparticles (LNPs) embedded in a chitosan matrix displayed an efficient UV blocking of 97% at 400 nm along with solar energy-harvesting properties.

Catalyst-Free Synthesis of Lignin Vitrimers with Tunable Mechanical Properties: Circular Polymers and Recoverable Adhesives.

Biobased circular materials are alternatives to fossil-based engineering plastics, but simple and material-efficient synthetic routes are needed for industrial scalability. Here, a series of lignin-based vitrimers built on dynamic acetal covalent networks with a gel content exceeding 95% were successfully prepared in a one-pot, thermally activated, and catalyst-free "click" addition of softwood kraft lignin (SKL) to poly(ethylene glycol) divinyl ether (PDV). The variation of the content of lignin from 28 to 50 wt % was used to demonstrate that the mechanical properties of the vitrimers can be widely tuned in a facile way.

Multifunctional lignin-based nanocomposites and nanohybrids.

Significant progress in lignins valorization and development of high-performance sustainable materials have been achieved in recent years. Reports related to lignin utilization indicate excellent prospects considering green chemistry, chemical engineering, energy, materials and polymer science, physical chemistry, biochemistry, among others. To fully realize such potential, one of the most promising routes involves lignin uses in nanocomposites and nanohybrid assemblies, where synergistic interactions are highly beneficial.

Unravelling the Hydration Barrier of Lignin Oleate Nanoparticles for Acid- and Base-Catalyzed Functionalization in Dispersion State.

Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions.

Lignin-Based Porous Supraparticles for Carbon Capture.

Multiscale carbon supraparticles (SPs) are synthesized by soft-templating lignin nano- and microbeads bound with cellulose nanofibrils (CNFs). The interparticle connectivity and nanoscale network in the SPs are studied after oxidative thermostabilization of the lignin/CNF constructs. The carbon SPs are formed by controlled sintering during carbonization and develop high mechanical strength (58 N·mm) and surface area (1152 m·g).

Solvent-Resistant Lignin-Epoxy Hybrid Nanoparticles for Covalent Surface Modification and High-Strength Particulate Adhesives.

Fabrication of spherical lignin nanoparticles (LNPs) is opening more application opportunities for lignin. However, dissolution of LNPs at a strongly alkaline pH or in common organic solvent systems has prevented their surface functionalization in a dispersion state as well as processing and applications that require maintaining the particle morphology under harsh conditions. Here, we report a simple method to stabilize LNPs through intraparticle cross-linking.