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Lignin has different structural characteristics depending on the extraction conditions. In this study, three types of ethanol organosolv lignin (EOL) were produced under different extraction conditions involving the reaction temperature (140, 160, 180 °C), sulfuric acid concentration (0.5, 1, 1.5 %), and ethanol concentration (40, 60, 80 %) to compare the difference in properties when mixed with polylactic acid (PLA) matrix after atom transfer radical polymerization (ATRP). ATRP of EOL was conducted to improve its compatibility with PLA using methyl methacrylate (MMA) as a monomer. The molecular weight of each EOL increased significantly, and the glass transition temperature (T

In general, lignin exhibits unpredictable and nonuniform thermal properties due to the structural variations caused by the extraction processes. Therefore, a systematic understanding of the correlation between the extraction conditions, structural characteristics, and properties is indispensable for the commercial utilization of lignin. In this study, the effect of extraction conditions on the structural characteristics of ethanol organosolv lignin (EOL) was investigated by response surface methodology. The structural characteristics of EOL (molecular weight, hydroxyl content, and intramolecular coupling structure) were significantly affected by the extraction conditions (temperature, sulfuric acid concentration, and ethanol concentration). In addition, the correlation between the structural characteristics and thermal properties of the extracted EOLs was estimated. The relevant correlations between the structural characteristics and thermal properties were determined. In particular, EOLs that had a low molecular weight, high phenolic hydroxyl content, and low aryl–ether linkage content exhibited prominent thermal properties in terms of their initial decomposition rate and a high glass transition temperature, Tg. Correspondingly, EOL-PLA blends prepared using three EOL types exhibited improved thermal properties (starting point of thermal decomposition and maximum decomposition temperature) compared to neat PLA and had thermal decomposition behaviors coincident with the thermal properties of the constituent EOLs.

Kraft lignin (KL) was oxidized by peracetic acid, which is generated by mixing acetic acid and hydrogen peroxide, to produce polycarboxylates for use as a plasticizer for cement paste. Peracetic acid cleaves the aromatic ring structure of KL and introduces carboxylate groups with ring-opened chain structure. After oxidation, the water-soluble fraction (Cx-lig) was obtained, and the performance of the Cx-lig as a plasticizer was compared with two commercial plasticizers, lignosulfonate (LS) and polycarboxylate ether (PCE). In mortar table tests, the increase in cement fluidity with the Cx-lig was greater than with LS and PCE. Fourier-transform infrared spectroscopy, carbon-13 nuclear magnetic resonance, gel permeation chromatography, elemental analysis, and charge density analysis were used to determine the structure of the Cx-lig. Considering all the results, the Cx-lig had a polycarboxylate structure containing numerous carboxylate groups, and their high charge density was the key factor that caused the Cx-lig to increase the cement fluidity more than LS or PCE.

Activated carbon materials are moving away from traditional simple carbon-based porous materials to high-performance and functional materials. Thus, various attempts have been made to improve the performance and process efficiency of the emerging materials by doping with various heteroatoms, introducing functional nanoparticles, and modifying these materials using polymer chemistry. In this study, N and O heteroatom-doped activated carbon materials were prepared by using silk sericin, a by-product of the silk industry, as a raw material; magnetic nanoparticles were introduced into the heteroatom-doped activated carbon to prepare high-performance and easily separable adsorbent materials. N-doped activated carbon having a high surface area of 3289.1 m2g−1 was prepared by a simple and one-step chemical activated sericin carbonization process without the generally required additional N-doping process. The subsequent introduction of magnetic nanoparticles (MNPs) not only facilitated the separation of nitrogen-rich bio-activated carbon from the contaminant solution, but also enhanced the capacity for adsorption of the anionic dye, methyl orange (MO; 869.57 mg g−1), with a faster MO removal rate compared to that of N-doped activated carbon without MNPs. In addition, by simply varying the pH of the solution, effective adsorption-desorption-based recycling could be achieved. This MNP-containing N-rich activated carbon can be applied as a high-performance adsorbent for the remediation of wastewater streams as it affords excellent adsorption efficiency, a fast removal rate, and easy separation from aqueous solution.

Gelatin is a representative hydrophilic protein material with remarkable biocompatibility and biodegradability. From the aspect of materials processing, gelatin also has the advantage that its entire fabrication process can be performed in an aqueous solution. However, practical application of various gelatin materials-in particular gelatin films-has thus far been limited because of their weak mechanical properties and vulnerability under aqueous environments. To overcome these disadvantages, both physical reinforcement approaches and chemical cross-linking agents have been tested. However, little research has been done to make these two roles work at the same time. In this study, cellulose nanocrystals containing aldehyde groups were prepared via a periodate oxidation process and used for cross-linkable reinforcement of gelatin-based bio-composite films. The results revealed that the di-aldehyde cellulose nanocrystal (D-CNC) could react and covalently cross-link with the amine group of the gelatin molecules via Schiff base formation and compared with neat CNC. The gelatin bio-composite film reinforced with the prepared D-CNC exhibited excellent tensile properties and water resistance, and its mechanical and hydrophilic properties could be easily controlled by adjusting the D-CNC content and was greater than addition of same amount in CNC. Therefore, D-CNC will facilitate the widespread use of existing water-soluble polymers, especially natural hydrophilic proteins and can be used in conventional application fields such as the food, pharmaceutical, and biomedical industries.

Commonly, lignin macromolecules have limitations in application to the thermoplastics industries due to poor dispersibility and interfacial compatibility within ligno-bioplastics. In this study, the dispersibility and interfacial compatibility of ethanol organosolv lignin (EOL) in PLA-based ligno-bioplastic were improved by enhancing the thermoplasticity via oxypropylation. Further, three types of EOLs extracted from different severity conditions were applied to investigate the effect of the structural characteristics of EOLs on the changes in the thermal properties. The thermal properties of oxypropylated EOL were dependent on the structural characteristics of the initial EOL as well as the degree of polymerization of propylene oxide. The thermoplasticity of EOLs extracted under mild condition was effectively increased as a new T

The development of nanofibrous oil-water separation materials is explosively progressing, but the remarkably low productivity is the main factor hindering their practical application. In this study, biodegradable polybutylene succinate (PBS) nanofibers with excellent productivity (27.0 g/h per nozzle) were successfully fabricated using the solution blow spinning (SBS) process, breaking away from the conventional electrospinning method. The prepared PBS nanofibers exhibited extremely thin fiber diameters (130 nm) with high porosity (97.4%). Without any chemical modification or inorganic/organic hybrid materialization, the PBS nanofibrous membrane showed excellent oil adsorption capacity (minimum: 18.7 g/g and maximum: 38.5 g/g) and separation efficiency; water and oil mixtures (99.4-99.98%) and emulsions (98.1-99.5%) compared to conventional organic polymer-based nanofibers. In terms of disposal after use, this biodegradable nanofibrous membrane was able to return to nature through hydrolysis and biodegradation processes.

Because nanocellulose has a large specific surface area and abundant hydroxyl functional groups due to its unique nanomorphology, interest increases as an eco-friendly water treatment material. However, the distinctive properties of nanocellulose, which exists in a dispersion state, strongly hamper its usage in practical water treatment processes. Additionally, nanocellulose shows low performance in removing anionic pollutants because of its anionic characteristics. In an effort to address this challenge, regenerated cellulose (RC) hydrogel was fabricated through cellulose's dissolution and regeneration process using an eco-friendly aqueous solvent system. Subsequently, a crosslinking process was carried out to introduce the cationic functional groups to the RC surface PEI coating (P/RC). As a result, the PEI surface cationization process improved the mechanical rigidity of RC and showed an excellent Cr(VI) removal capacity of 578 mg/g. In addition, the prepared P/RC maintained more than 90% removal efficiency even after seven reuses.

The aim of this study is to establish prediction models for the non-destructive evaluation of the carbonization characteristics of lignin-derived hydrochars as a carbon material in real time. Hydrochars are produced via the hydrothermal carbonization of kraft lignins for 1–5 h in the temperature range of 175–250 °C, and as the reaction severity of hydrothermal carbonization increases, the hydrochar is converted to a more carbon-intensive structure. Principal component analysis using near-infrared spectra suggests that the spectral regions at 2132 and 2267 nm assigned to lignins and 1449 nm assigned to phenolic groups of lignins are informative bands that indicate the carbonization degree. Partial least squares regression models trained with near-infrared spectra accurately predicts the carbon content, oxygen/carbon, and hydrogen/carbon ratios with high coefficients of determination and low root mean square errors. The established models demonstrate better prediction than ordinary least squares regression models.

Sodium-ion batteries (SIBs) have received considerable attention as sustainable and stable energy-storage devices, but their electrochemical performance is inferior to that of current lithium-ion b...

In this study, pyroprotein-incorporated freestanding papers (PFPs) were fabricated using silk proteins and carbon nanotubes through a facile filtration and heat treatment, and hierarchically nanoporous pyroproteins (HNPs) were fabricated using silk protein fibers via thermal treatment with activation using an alkali agent. The PFPs formed a monolith without any binder and exhibited a surface area of ∼97 m2 g−1 with a microporous structure, whereas the HNPs maintained a fibrous structure with a high surface area of ∼2,880 m2 g−1. The pyroproteins presented in PFP and HNP led to the charge storage capacity originating from heteroatoms such as oxygen and nitrogen. The reversible capacities of the PFP and HNP as the anode and cathode, respectively, were ∼228 and ∼205 mA h g−1, respectively, at current density of 0.1 A g−1. In particular, the PFPs exhibit a high cycling stability over 1,000 cycles at a current density of 0.5 A g−1. Furthermore, energy storage devices based on all-fibrous pyroprotein electrodes achieved a high specific power of ∼12,100 W kg−1, a high specific energy of ∼150 Wh kg−1, and an excellent cycling performance with ∼83% capacitance retention after over 2,000 cycles.

In this study, sodium metal hybrid capacitors (SMHCs) composed of a metal anode and capacitive cathode are reported for the first time. The sodium metal anode was designed using catalytic carbon nanotemplates (C-CNTPs) and exhibited highly reversible sodium metal plating/stripping behaviors with an average Coulombic efficiency of ∼100% over 1000 galvanostatic cycles and significantly low cell-to-cell variations. Further, nanoporous pyroproteins (N-PPts) with a specific surface area of ∼4216 m2 g−1 and pore volume of 1.937 cm3 g−1 were fabricated as the capacitive cathode, exhibiting a high specific capacity of 168 mA h g−1, high rate capability of 0.5–10 A g−1, and stable cycling performance over 1000 cycles. The SMHCs based on C-CNTPs/N-PPts were operated in a voltage window of 1.0–4.0 V, delivering a high specific energy of ∼237.7 Wh kg−1 at ∼462 W kg−1 and a maximum power of ∼4800 W kg−1 at ∼66.7 Wh kg−1. In addition, stable cycling performance was maintained during 500 cycles, with a capacity retention of ∼82%.

Silver nanoparticles have been widely used in the healthcare industry, food storage, and textile coatings due to their excellent antibacterial properties. However, to introduce silver nanoparticles into a fibrous material, post-treatment methods, including surface coating, have primarily been used. The surface coating method unexpectedly changes the fiber surface morphology and induces fast silver nanoparticle release. In this work, we fabricated antibacterial silver nanoparticle-incorporated gelatin fibers via ultraviolet-visible light (UV–vis) assisted silver nanoparticle synthesis and wet-spinning methods. Various amount of silver nanoparticle-incorporated gelatin fiber was successfully prepared using water and fructose as a green solvent and crosslinker. From the TEM image and DLS data, the concentration of silver precursor greatly affected the size of synthesized silver nanoparticles, which range from approximately 50 to 100 nm using UV light and gelatin as a catalyst and stabilizer. The increasing concentration of silver nanoparticles enhances the gelatin/silver nanoparticle solution viscosity and greatly affects the morphology of the wet-spun gelatin fiber. Sugar-mediated Maillard crosslinking reaction improved the water stability and gave sustained Ag+ release behavior. The silver nanoparticle-incorporated gelatin fibers have notable antibacterial activity against both Gram-negative and Gram-positive bacteria. In general, appropriate silver nanoparticle content (50 ppm) loaded gelatin fibers are considered a potential candidate for biomedical applications due to their notable bactericidal activity.

We report a pyroprotein seed layer (PSL, ∼100 nm in thickness)-coated Cu foil electrode (PSL-Cu) demonstrating highly reversible Na metal storage behavior with a mean Coulombic efficiency (CE) of ∼99.96% over 300 cycles in a glyme-based electrolyte. Via a synergistic effect with the electrolyte, the carbonaceous thin film containing numerous nucleophilic active sites guides the homogeneous Na metal deposition/stripping process with the formation of numerous catalytic seeds, resulting in remarkably stable cycling and a low Na metal nucleation overpotential of ∼10 mV. In addition, the CE deviation values of the PSL-Cu electrode were ∼0.43% in several cell tests, demonstrating its reliable cycling behavior with low cell-to-cell variation. The practicality of PSL-Cu was further demonstrated via full-cell experiments with a polyanion cathode, in which it achieved a high specific power density and energy density of 3,800 W kg

Activated carbon has been widely used as an effective adsorbent for removing contaminants from the water stream. Preparation of activated carbon using agricultural by-products is environmentally friendly and can greatly contribute to the virtuous cycle of natural polymers. In this study, highly porous activated carbon was prepared using silk sericin, a secondary protein of the sericulture industry. For easy processability and regeneration stability, the bead-type adsorbent was prepared using alginate (Alg) as a matrix. After that, methylene blue (MB) removal behavior of sericin-derived activated carbon (S-AC)/Alg beads was investigated. S-AC obtained by NaOH chemical activation had a larger BET surface area (2150.1 m2/g), and this porous structure of S-AC was well maintained after S-AC/Alg bead preparation (1215.4 m2/g). S-AC/Alg beads had an excellent MB adsorption capacity (502.5 mg/g) with stable regeneration stability, and 90.1% of the original removal efficiency was maintained after 5 cycles of the repeated adsorption-desorption process. These findings reveal that S-AC/Alg composite beads can be used as low-cost adsorbents for the removal of contaminants in aqueous solutions.

The manufacture of eco-friendly cocoon silk-derived sericin films increases the availability of sericulture resources and the interest in expanding the range of the potential applications of sericin-based materials. However, the brittleness and weak tensile properties of sericin and its vulnerability to moist environments have limited its use. To overcome these two shortcomings of sericin, a functionalized bacterial cellulose-derived nanocrystal (average diameter: 25.4 nm) capable of physical strengthening and chemical crosslinking on existing sericin films was prepared. The improvement of the optical, physicochemical, and mechanical properties of the sericin film was observed through the dialdehyde bacterial cellulose nanocrystals (D-CNCs) incorporated into the silk sericin (SS) matrix. The physical reinforcing effect of the D-CNCs on the SS films enhances the mechanical properties of the films. Simultaneously, the chemical crosslinking reaction of D-CNCs develops the ultraviolet-blocking, water-resistant, and antioxidant properties of the films. The simultaneous fabrication, physical reinforcement, and chemical crosslinking of the SS/D-CNCs biocomposite film produced using an aqueous solution will provide information on the functionalization and performance improvement of water-soluble biopolymeric materials, especially hydrophilic protein resources.

Poly (lactic acid) (PLA) is the most widely available commercial bioplastic that is used in various medical and packaging applications and three-dimensional filaments. However, because neat PLA is brittle, it conventionally has been blended with ductile polymers and plasticizers. In this study, PLA was blended with the high-ductility biopolymer poly (butylene-sebacate&ndash, co&ndash, terephthalate) (PBSeT), and hexamethylene diisocyanate (HDI) was applied as a crosslinking compatibilizer to increase the miscibility between the two polymers. PLA (80%) and PBSeT (20%) were combined with various HDI contents in the range 0.1&ndash, 1.0 parts-per-hundred rubber (phr) to prepare blends, and the resulting physical, thermal, and hydrolysis properties were analyzed. Fourier-transform infrared analysis confirmed that &ndash, NH&ndash, C=OO&minus, bonds had formed between the HDI and the other polymers and that the chemical bonding had influenced the thermal behavior. All the HDI-treated specimens showed tensile strengths and elongations higher than those of the control. In particular, the 0.3-phr-HDI specimen showed the highest elongation (exceeding 150%) and tensile strength. In addition, all the specimens were hydrolyzed under alkaline conditions, and all the HDI-treated specimens degraded faster than the neat PLA one.

Although nanocellulose is an eco-friendly, high-performance raw material provided by nature, the agglomeration of nanocellulose that occurs during the drying process is the biggest obstacle to its advanced materialization and commercialization. In this study, a facile and simple nanocellulose drying system was designed using lignin, which is self-assembled together with cellulose in natural wood, as an eco-friendly additive. The addition of lignin not only minimized aggregation during the drying and dehydration process of nanocellulose but also ensured excellent redispersion kinetics and stability. In addition, the added lignin could be removed through a simple washing process. Through FTIR, XRD, TGA, tensile and swelling tests, it was confirmed that the addition of lignin enabled the reversible restitution of the nanocellulose physicochemical properties to the level of pristine never-dried nanocellulose in drying, redispersion, and polymer processing processes.

Applications of nanocellulose as a water treatment material are being actively pursued based on its interesting properties, such as renewability, large specific surface area, hydrophilic surface chemistry, and biodegradability. This study used carboxymethyl cellulose nanofibrils (CMCNFs) to prepare a typical bead-type adsorbent with improved structural stability as an actual water treatment restoration material. In addition, a cationized nanocellulose adsorbent was prepared by introducing polyethyleneimine (PEI) on the surface of the CMCNF (P/CMCNF), the removal efficiency of Cr(VI) was evaluated, and its mechanism was elucidated. As a result, the P/CMCNF beads showed an excellent Cr(VI) removal capacity of 1302.3 mg/g, the best result among cellulose-based adsorption materials. Cr(VI) was effectively removed by electrostatic attractions combined with chemical reduction and chelation mechanisms. Furthermore, the macrobead fabrication and PEI surface modification process improved the underwater stability of the P/CMCNF, and it showed excellent reuse efficiency.

In this study, poly(butylene sebacate-co-terephthalate) (PBSeT) was successfully synthesized using various ratios of sebacic acid (Se) and dimethyl terephthalate (DMT). The synthesized PBSeT showed a high molecular weight (Mw, 88,700&ndash, 154,900 g/mol) and good elastomeric properties. In particular, the PBSeT64 (6:4 sebacic acid/dimethyl terephthalate mole ratio) sample showed an elongation at break value of over 1600%. However, further increasing the DMT content decreased the elongation properties but increased the tensile strength due to the inherent strength of the aromatic unit. The melting point and crystallization temperature were difficult to observe in PBSeT64, indicating that an amorphous copolyester was formed at this mole ratio. Interestingly, wide angle X-ray diffraction (WAXD) curves was shown in the cases of PBSeT46 and PBSeT64, neither the crystal peaks of PBSe nor those of poly(butylene terephthalate) (PBT) are observed, that is, PBSeT64 showed an amorphous form with low crystallinity. The Fourier-transform infrared (FT-IR) spectrum showed C&ndash, H peaks at around 2900 cm&minus, 1 that reduced as the DMT ratio was increased. Nuclear magnetic resonance (NMR) showed well-resolved peaks split by coupling with the sebacate and DMT moieties. These results highlight that elastomeric PBSeT with high molecular weight could be synthesized by applying DMT monomer and showed promising mechanical properties.