Search Results (32)

Coconut husk lignin was fractionated using ethanol to obtain nanolignin fractions with distinct physicochemical properties. Among the fractions, CNF1 exhibited the most favorable combination of particle size, thermal stability, and antibacterial activity and was selected for further modification. Microwave-assisted esterification of CNF1 with maleic anhydride was performed under various reaction temperatures and lignin-to-maleic anhydride ratios. Structural modification was confirmed by ATR-FTIR spectroscopy through the appearance of ester carbonyl groups and an increase in the degree of esterification, which reached its highest value at 180 °C and a lignin-to-maleic anhydride ratio of 1:10. TEM analysis revealed that maleation increased nanoparticle size, whereas WAXD demonstrated that both native and modified lignins retained predominantly amorphous structures. Antioxidant activity decreased with increasing esterification due to the reduction of phenolic hydroxyl groups. Thermal analysis showed that esterification altered the degradation behavior of lignin, while thermo-oxidative stability measurements indicated improved oxidation resistance for highly esterified samples. The 10MA180 sample exhibited the highest thermo-oxidative stability, with a T₂,O₂ value of 12.55 min, a residual mass of 84.90%, and the lowest weight loss after 60 min oxidation. These findings demonstrate that microwave-assisted maleation effectively tailors the structure and functional properties of nanolignin for sustainable bio-based material applications. Full article

In the present work, oil-in-water (O/W) cosmetic emulsions containing nanolignin (NL) at 0.35, 1, and 2% w/w were developed using a single multifunctional nanoadditive concept, whereby NL simultaneously acts as an antioxidant, rheology modifier, and color/sunscreen booster. Nanolignin was characterized by FTIR, DLS, and SEM, confirming its chemical structure and nanoscale particle size. The emulsions were evaluated in terms of pH and viscosity stability, rheological behavior, colorimetric CIELAB parameters, DPPH radical scavenging activity, and in vitro sun protection factor (SPF). Incorporation of NL led to a slight pH decrease relative to the blank formulation, while maintaining values within the acceptable cosmetic range (pH 4–6), and yielded emulsions with excellent pH and viscosity stability over 28 days of storage. Increasing the NL concentration modified the rheological profile and viscosity, as well as the L*, a*, and b* color coordinates, enabling tunable visual appearance and texture. All formulations exhibited high antioxidant capacity; notably, the NL_1% emulsion displayed higher radical scavenging activity than the NL_2% system, underscoring a non-linear structure–property relationship. SPF values ranged between 14.09 ± 0.875 and 22.29 ± 1.719, demonstrating that nanolignin can enhance photoprotective performance. Overall, this study highlights the potential of nanolignin as a single multifunctional nanoadditive for designing stable, antioxidant, and photoprotective cosmetic O/W emulsions with adjustable rheology and color. Full article

The development of sustainable packaging materials with advanced functional properties is a key priority for the food industry. In this study, chitosan (CS)-based nanocomposite films incorporating titanium dioxide (TiO₂), zinc oxide (ZnO), hybrid ZnO_TiO₂ nanoparticles, lignin (LG), and nanolignin (nLG) were synthesized and comprehensively characterized. Structural analyses (FTIR, XRD, SEM) confirmed strong intermolecular interactions and homogeneous nanoparticle dispersion, particularly for TiO₂ and low ZnO concentrations. Mechanical testing showed that TiO₂ and ZnO significantly enhanced tensile strength (up to fourfold) and elongation at break. Among the prepared nanocomposite films, CS-TiO₂ films at 2 wt% exhibited the best balance of mechanical performance and antioxidant activity. Subsequent incorporation of LG and especially nLG into the CS-TiO₂ matrix further enhanced flexibility and toughness, antioxidant efficiency, and radical-scavenging activity above 90%, and improved UV-shielding capacity by reducing light transmittance. Moreover, antibacterial testing against Escherichia coli demonstrated that CS/TiO₂/nLG films achieved the highest reduction (~46%), attributed to synergistic electrostatic, oxidative, and phenolic mechanisms. Overall, CS/TiO₂/nLG nanocomposites emerge as multifunctional, biodegradable films with significant potential for next-generation active food packaging applications. Full article

This paper presents the synthesis of sustainable lignin nanoparticles (LNPs) and their application in methylcellulose (MC) as LNP/MC coatings for handmade papers. LNPs were produced from bulk kraft lignin via an acetone/water and sonication method, then incorporated into a 1 wt% methylcellulose (MC) matrix at concentrations of 0.4, 1, and 2 wt%. Groundwood and cotton linter papers were coated and exposed to 90 °C and 45% relative humidity (RH) for 16 days and the samples’ response to ageing at different concentrations of nanolignin was tested using a multi-analytical approach. The morphology of the LNPs was revealed with scanning electron microscopy, and most LNPs measured below a diameter of 30.8 nm. Colourimetry showed coated samples were inherently darker than uncoated samples but mostly stable in colour. pH remained near neutral for coated groundwood papers during ageing, but cotton papers were consistently acidic. Fourier transform infrared (FTIR) spectroscopy identified spectral similarities between uncoated and coated groundwood samples at approximately 1635 cm^–1 and 1725 cm^–1, attributed to carbonyl and carboxyl groups, suggesting that LNPs did not contribute to the formation of these groups during ageing. Controlled environment dynamic mechanical analysis (DMA-RH) found improved consolidation and lower elongation in most LNP/MC-treated samples. These results indicate that there may be potential for LNPs within paper conservation. Full article

Cardanol is a derivative of cashew nut shell liquid (CNSL) and has the potential to be used when developing adhesives for wood boards. Adding nanostructures to adhesive can increase its bonding and reduce formaldehyde emission. Therefore, this study aimed to evaluate the different concentrations of nanolignin (1, 2, and 3%) added to the cardanol-formaldehyde adhesive for gluing plywood, in comparison to the cardanol-formaldehyde adhesive without nanolignin (0%). The plywood’s physical, mechanical, and formaldehyde emission properties were assessed. Plywoods with nanolignin showed shear strength increases of around 160% in the wet condition. With the addition of nanolignin, the modulus of rupture and of elasticity increased by approximately 150% and up to 400% in the parallel direction, respectively. The resistance to combustion also significantly improved. Physical properties did not show statistically significant differences with the percentages of nanolignin. Despite the increase in formaldehyde emission with nanolignin, all treatments met the marketing requirements (≤80 mg of formaldehyde/kg), demonstrating the adhesive potential for indoor use in plywood industries. Natural adhesives using cardanol and nanolignin are an innovative and ecological alternative, combining sustainability and high potential to reduce environmental impacts, which is aligned with at least four sustainable development goals (SDGs). Full article

Wood, a vital material for both modern and heritage objects, is particularly susceptible to degradation caused by water due to its hydrophilic nature and porous structure. Therefore, developing sustainable strategies to protect wood is of significant importance. This study aims to produce a highly hydrophobic coating for the protection of wood following a straightforward procedure and using materials that are compatible with wood. First, nano/sub-microlignin (NL) is isolated and produced from beech wood through a one-step tailored organosolv process. Next, NL is incorporated into Sivo 121, a water-borne and solvent-free silane system recommended by the manufacturer for protecting wood surfaces. Composite coatings containing various concentrations of NL and Sivo 121 are applied to chestnut (Castanea spp.) and oak (Quercus spp.). The impact of NL concentration on the contact angles of water drops (CAs) and colour changes (ΔE) of the treated wood specimens is investigated. The coating with 4% w/w NL demonstrates enhanced hydrophobicity (CA = 145°) and has a negligible effect on the colour of pristine oak (ΔE < 3). The wetting properties of coated oak are not affected after 100 tape peeling cycles. However, the coating exhibits poorer performance on chestnut, i.e., CA = 135°, which declines after 80 peeling cycles, and ΔE > 5. The drop pH does not have any noticeable effect on CA. The latter remains stable even after prolonged exposure of coated oak and chestnut samples to artificial UV radiation and outdoor environmental conditions. Finally, the composite coating offers good and comparable protection for both wood species in the biological durability soil burial test Full article

Materials with antimicrobial properties and high adsorption capabilities are crucial for managing exudate in post-surgical cases. However, achieving both properties simultaneously remains a challenge. In this study, we first synthesized curcumin-loaded organosolv lignin nanoparticles (Lig-Cur Nps) using a solvent-shifting approach in a continuous flow reactor. These Lig-Cur NPs were then dispersed in a polyvinyl alcohol (PVA) solution. The PVA-Lig-Cur NP colloidal suspension was further crosslinked with tannic acid (TA) through hydrogen bonding interactions. A simple freeze–thaw cycle of the PVA-Lig-Cur NP suspension with TA resulted in the formation of a stable gel, which was then lyophilized to fabricate the PVA-Lig-Cur-TA hydrogel scaffold. This scaffold features an interconnected microporous network with a swelling percentage of 800%, enabling the rapid adsorption of exudates. Its excellent properties and antimicrobial efficacy against Staphylococcus aureus, a bacterium commonly found on the skin, and Pseudomonas aeruginosa highlight its potential to effectively remove exudates while preventing bacterial colonization. Full article

This work aimed to extract nanolignin from green coconut husk and fiber using the acetosolv method, with the aim of transforming waste into high-value-added products and promoting sustainability and bioeconomy. The acetosolv pulping was carried out in two stages, varying temperature conditions and the presence or absence of extractives. Lignin was obtained by precipitation and subsequently characterized through chemical and morphological analyses. The analyses of the primary components of the coconut husk and fiber demonstrated lignin, cellulose, and hemicellulose contents of 40%, 15.90%, and 15.86%, respectively. Then, nanolignin was produced through ultrasonication (850 W for 10 and 20 min). The characteristics of the obtained products were analyzed, considering the influence of two temperatures (100 °C and 120 °C) and the need for a pretreatment step (removal of extractives). The temperature variation between 100 °C and 120 °C, as well as the presence of extractives, did not significantly influence the lignin quality or extraction efficiency. The nanolignin produced under this condition was subjected to the DLS technique to determine the hydrodynamic diameter and polydispersity of the nanoparticles obtained, with an average diameter of 533.75 ± 15.12 nm after 20 min of ultrasonication. The purity of the lignin was confirmed by analyses such as the Klason lignin and ash content, which presented values of 78.82 ± 0.81% and 0.55 ± 0.26%, respectively. FTIR analyses revealed typical lignin characteristics, such as the presence of ketone groups, aromatic structures, and methoxylation, while thermograms confirmed the thermal stability of the lignin. Acetosolv pulping proved to be particularly interesting, preserving good quality lignin and allowing for partial recovery of the solvents used, promoting the sustainability and energy efficiency of the process. Full article

Plywood production relies on phenol–formaldehyde (PF), which is why bio-based wood adhesives (BBWAs) were developed as potential replacements, showing promising results in several tests performed. A control sample (PLY-C) with PF and two samples (PLY-1 and PLY-2) with BBWA were manufactured, on which physical and mechanical properties, adhesive bonding morphology, formaldehyde emissions, and accelerated UV aging were evaluated. The adhesive penetration results, into the wood cells, were according to the viscosity of each adhesive. About the mechanical properties, the sample PLY-2 presented the same MOE and tensile strength as the sample PLY-C and reached 87% of the sample PLY-C MOR in the parallel direction. On the other hand, the sample PLY-1 presented the same behavior in the Janka hardness test as the sample PLY-C. All the samples subjected to shear strength tests met the requirement, and the samples PLY-1 and PLY-2 reached 68% and 80% of the PLY-C sample, respectively. The samples manufactured with BBWA presented a decrease in formaldehyde emissions by 88% and they were less susceptible to color change than the control sample under UV aging. According to the results obtained, it is concluded that plywood manufactured with BBWA might be a considerable replacement for plywood manufactured with PF adhesives at a laboratory scale. Full article

The demand for high-performance bio-based materials towards achieving more sustainable manufacturing and circular economy models is growing significantly. Kraft lignin (KL) is an abundant and highly functional aromatic/phenolic biopolymer, being the main side product of the pulp and paper industry, as well as of the more recent 2nd generation biorefineries. In this study, KL was incorporated into a glassy epoxy system based on the diglycidyl ether of bisphenol A (DGEBA) and an amine curing agent (Jeffamine D-230), being utilized as partial replacement of the curing agent and the DGEBA prepolymer or as a reactive additive. A D-230 replacement by pristine (unmodified) KL of up to 14 wt.% was achieved while KL–epoxy composites with up to 30 wt.% KL exhibited similar thermo-mechanical properties and substantially enhanced antioxidant properties compared to the neat epoxy polymer. Additionally, the effect of the KL particle size was investigated. Ball-milled kraft lignin (BMKL, 10 μm) and nano-lignin (NLH, 220 nm) were, respectively, obtained after ball milling and ultrasonication and were studied as additives in the same epoxy system. Significantly improved dispersion and thermo-mechanical properties were obtained, mainly with nano-lignin, which exhibited fully transparent lignin–epoxy composites with higher tensile strength, storage modulus and glass transition temperature, even at 30 wt.% loadings. Lastly, KL lignin was glycidylized (GKL) and utilized as a bio-based epoxy prepolymer, achieving up to 38 wt.% replacement of fossil-based DGEBA. The GKL composites exhibited improved thermo-mechanical properties and transparency. All lignins were extensively characterized using NMR, TGA, GPC, and DLS techniques to correlate and justify the epoxy polymer characterization results. Full article

The present review was conducted to investigate the possibilities in realizing novel nanostructured tissues containing functional molecules that can be commercialized as solid products (without using emulsifiers and preservatives) for cosmeceutical and nutraceutical applications. After considering the principal concepts regarding skin and mucous features and physiologies, the possibilities in using bio-based, biodegradable and biocompatible materials was explored by investigating the correlations between their structures and morphologies with respect to the characteristics of the skin extracellular matrix (ECM). Regarding the new smart type of biodegradable tissues, their possible composition was reviewed in relation to the skin aging process and to the current contest for novel, innovative cosmeceuticals and nutraceuticals that consider the “beauty from within” concept. The barriers to the development of these new tissues were mainly identified due the necessity in defining the claim regarding green products. Moreover, the market growth data regarding these novel products were highlighted to support the idea that the diffusion of smart tissue-based cosmeceuticals and nutraceuticals is an opportunity for new sustainable industrial chains in the development of bioeconomies. Full article

Lignocellulose consists of cellulose, hemicellulose, and lignin and is a sustainable feedstock for a biorefinery to generate marketable biomaterials like biofuels and platform chemicals. Enormous tons of lignocellulose are obtained from agricultural waste, but a few tons are utilized due to a lack of awareness of the biotechnological importance of lignocellulose. Underutilizing lignocellulose could also be linked to the incomplete use of cellulose and hemicellulose in biotransformation into new products. Utilizing lignocellulose in producing value-added products alleviates agricultural waste disposal management challenges. It also reduces the emission of toxic substances into the environment, which promotes a sustainable development goal and contributes to circular economy development and economic growth. This review broadly focused on lignocellulose in the production of high-value products. The aspects that were discussed included: (i) sources of lignocellulosic biomass; (ii) conversion of lignocellulosic biomass into value-added products; and (iii) various bio-based products obtained from lignocellulose. Additionally, several challenges in upcycling lignocellulose and alleviation strategies were discussed. This review also suggested prospects using lignocellulose to replace polystyrene packaging with lignin-based packaging products, the production of crafts and interior decorations using lignin, nanolignin in producing environmental biosensors and biomimetic sensors, and processing cellulose and hemicellulose with the addition of nutritional supplements to meet dietary requirements in animal feeding. Full article

Sulfite liquor is the by-product of wood chips treatment. An alternative method for recovering the carbonaceous components from sulfite liquor was investigated. A 3% CS suspension surprisingly incorporated almost all the carbon–sulfite phase in an aerogel system rising up at the surface of a beige liquid phase. The resulting solid and liquid phases were analytically characterized usingTEM-EDX, XRD, FTIR, ICP-OES, and UV-Vis methods, respectively. The TEM-EDX analysis revealed nanoparticles and microneedles with high C, O, Na, and S contents ionotropically adsorbed by CS, with this new hybrid material appearing as a biopolymer–carbon–metal nanocomposite aerogel with potential adsorbent, catalytic, and/or semiconductive properties. Full article

Lignin, a lignocellulosic polymer material, is an important active ingredient for the high-value use of renewable resources. Thus, policies for the recovery and high value-added use of renewable lignocellulosic biomass are a realistic engineering approach to address concerns such as the climate and energy crisis. In this work, the mechanical properties, thermal stability and morphology of cellulose/lignin nanocomposites were studied. Nanocomposite films containing different proportions of lignin (2.5%, 5%, 10% and 20%) were prepared. Thermal properties were assessed via thermogravimetric analysis and differential scanning calorimetry, mechanical properties via tensile test and morphological properties via scanning electron microscopy techniques. It was observed that nanolignin and nanocellulose structures are compatible with each other and depending on the main degradation temperature, the thermal stability of 2.5% lignin-containing nanocomposites is higher than that of other composites. From the results obtained, it was determined that the nanocomposite film containing 2.5% nanolignin had high thermal stability, mechanical strength and suitable morphological structure compared to other samples. Full article

The rapid population growth, increasing global energy demand, climate change, and excessive use of fossil fuels have adversely affected environmental management and sustainability. Furthermore, the requirements for a safer ecology and environment have necessitated the use of renewable materials, thereby solving the problem of sustainability of resources. In this perspective, lignocellulosic biomass is an attractive natural resource because of its abundance, renewability, recyclability, and low cost. The ever-increasing developments in nanotechnology have opened up new vistas in sensor fabrication such as biosensor design for electronics, communication, automobile, optical products, packaging, textile, biomedical, and tissue engineering. Due to their outstanding properties such as biodegradability, biocompatibility, non-toxicity, improved electrical and thermal conductivity, high physical and mechanical properties, high surface area and catalytic activity, lignocellulosic bionanomaterials including nanocellulose and nanolignin emerge as very promising raw materials to be used in the development of high-impact biosensors. In this article, the use of lignocellulosic bionanomaterials in biosensor applications is reviewed and major challenges and opportunities are identified. Full article