Wood Cellulose Research Articles

Wood-Derived Carbon with Selectively Introduced C═O Groups toward Stable and High Capacity Anodes for Sodium Storage.

Biomass-derived carbon is a promising sustainable anode material for sodium-ion batteries (SIBs). Although the electrochemical performance can be improved by introducing functional groups, the selective introduction of single functional groups into biomass carbon remains difficult. Here, we overcome this challenge by developing a wood-derived carbon with selectively introduced C═O groups by combining tetramethoxysilane (TMOS) with wood cellulose pulps. The integration of TMOS introduces abundant C═O groups into the carbon during the polycondensation and pyrolysis process. The C═O groups play a dominant role in anode surface-controlled processes, and this leads to improvements in pseudo-capacity and fast electrode process kinetics. Besides, the introduction of C═O groups generates oxygen functional active sites that promote Na+ adsorption and creates a sufficiently largegraphene interlayer distance. The as-obtained carbon shows a high capacity of 330 mAh g-1 at 40 mA g-1 and excellent cycling stability. Moreover, our strategy is simple and uses wood cellulose pulps as precursors. It therefore enables low-cost and large-scale synthesis of carbon anode materials for SIBs.

Wood cellulose as a hydrogen storage material

Hydrogen has become a strong candidate to be a future energy storage medium but there are technological challenges both in its production and storage. For storage, a search for lightweight, abundant and non-toxic materials is on the way. An abundant natural material such as wood cellulose would make an ideal storage medium from a sustainability perspective. Here, using a combination of static DFT calculations and ab initio molecular dynamics simulations at different temperatures, it is shown that wood cellulose has the ability to uptake H2 via a physisorption mechanism based on dispersion interactions of the van der Waals type involving the O-atoms of the d-glucose rings. The absorption causes little to no disturbances on the cellulose structure and H2 is highly mobile in the material. At an external pressure of H2(g) of 0.09 atm and T = 25 °C, cellulose has a theoretical gravimetric density of hydrogen storage of ≈1%.

Cellulose acetate with CTA I polymorph can be defibrated into nanofibers to produce a highly transparent nanopaper

Acetylated cellulose nanofibers (Ac-CNFs) were prepared by heterogenous acetylation of wood pulp and cellulose powder in toluene with acetic anhydride and a small amount of sulfuric acid as a catalyst, followed by defibration with a high-pressure homogenizer, but the resultant Ac-CNFs were thermally unstable due to the release of sulfuric acid from the sulfate ester group at elevated temperature. The sulfate ester group was removed before defibration by acidic hydrolysis to yield cellulose acetate (CA) with high thermal stability. The thermal decomposition temperature at 5% weight loss increased from 170 to 284 °C, and the crystalline structure was cellulose triacetate I (CTA I) after annealing at 230 °C. However, only thick Ac-CNFs with a diameter of more than 20 nm and many bundles were obtained by defibration of the desulfated CA. Thin Ac-CNFs with a diameter of 10 nm were obtained by changing the preparation process to defibration of CA followed by desulfation, probably due to the electrostatic repulsion and/or osmotic effect of the anionic sulfate ester group. Transparent nanopapers could be fabricated by slow evaporation of water from the Ac-CNF aqueous suspension. The obtained nanopapers revealed more than 80% transmittance in the visible light region and showed higher tensile strength and modulus than commercial CA films.

Green production of fluorescent carbon quantum dots based on pine wood and its application in the detection of Fe3+

Carbon quantum dots (CQDs) have novel applications as fluorescent nanomaterials in various fields. In this study, a green hydrothermal carbonisation (HTC) method is proposed to produce CQDs from pine wood (P-CQDs). The P-CQDs exhibited excellent fluorescence characteristics, with the optimal excitation wavelength being 330 nm and a corresponding emission wavelength of 447 nm. A blue light emission under ultraviolet light was observed and a typical graphene structure was seen in the HR-TEM images with a fringe spacing of 0.21 nm. Moreover, the mechanism of P-CQD formation during the HTC process was proposed. It was observed that P-CQDs demonstrated an aromatic polymer structure rich in oxygen-containing groups. This is because of the condensation, chain breaking, and chain forming reactions occurring among the hydrolytic products of the cellulose, hemicellulose, and lignin in pine wood. The fluorescence quenching results indicated that the P-CQDs selectively detected Fe3+ in an aqueous phase. This implies that these CQDs have broad application prospects for Fe3+ detection. More importantly, this signifies that the large-scale and low-cost production of CQDs and Fe3+ sensors will now be possible.

Changes to the Contour Length, Molecular Chain Length, and Solid-State Structures of Nanocellulose Resulting from Sonication in Water.

Sonication in water reduced the average contour lengths of nanocellulose prepared from wood cellulose fiber and microcrystalline cellulose. Most of the kinks in the wood cellulose nanofibrils were formed during the initial 10 min of sonication. Fragmentation occurred at the kinks and rigid segments associated with depolymerization during subsequent sonication for 10-120 min, resulting in the formation of cellulose nanocrystals with low aspect ratios. Solid-state cross-polarization magic angle sample spinning 13C-nuclear magnetic resonance revealed that the original crystalline regions of the cellulose were partly transformed to fibril surfaces or disordered regions by both pretreatment and the subsequent fragmentation of molecular chains during sonication. The nanocellulose prepared from microcrystalline cellulose had different fragmentation behavior with regard to molecular chain length following sonication. The results indicated that on average the hexagonal 36 cellulose chain structure formed the cross-section of each wood cellulose microfibril.

Low cost membrane of wood nanocellulose obtained by mechanical defibrillation for potential applications as wound dressing

Large wounds are characterized by clinical and surgical challenges, requiring numerous searches on demand for inexpensive biocompatible materials that produce the best quality of cutaneous healing. Cellulose is a biopolymer of greatest abundance, good biocompatibility and wide application due to its chemical and physical properties. This study was aimed to develop and characterize low cost membranes of wood cellulose nanofibrils for potential application as a wound dressing in comparison to a commercial porous regenerating membrane. An inexpensive mechanical method was used to defibrillate cellulose, and later the membranes were obtained from the nanofibrils by filtering and drying under mild pressure. The techniques employed for characterization included scanning electron microscopy, physical testing, application in vivo and cost-effectiveness analysis. The membranes presented promising physical properties for application as cutaneous dressing, with characteristic translucency allowing the evaluation of the wound without the need of removal and exchange of the dressing. Wood nanocellulose dressing seems to be promising for wound care since it presented good adhesion to the moist wound surfaces thus promoting the most efficient repitialization in the first 4 days. No allergic reaction or inflammatory response to wood nanocellulose dressings was observed. The wood nanocellulose membranes stand out as a potential wound dressing, as it shows similar efficacy of bacterial cellulose dressing. Besides the efficacy, the membrane developed in this study presents a simpler, faster and cheaper manufacturing process, which may reduce the production cost by 99%.

Rheological Properties of Aqueous Dispersions of Bacterial Cellulose

Bacterial cellulose as polysaccharide possessing outstanding chemical purity and a unique structure compared with wood cellulose, attracts great attention as a hydrocolloid system. It was shown, that at intense mechanical action on a neat bacterial cellulose film in presence of water, the gel-like dispersions are obtained. They retain stability in time (at least, up to several months) and temperature (at least, up to 60 °C) without macro-phase separation on aqueous and cellulose phases. The main indicator of the stability is constant viscosity values in time, as well as fulfilling the Arrhenius dependence for temperature dependence of viscosity. Flow curves of diluted dispersions (BC content less than 1.23%) show strong non-Newtonian behavior over the entire range of shear rates. It is similar with dispersions of micro- and nanocrystalline cellulose, but the absolute viscosity value is much higher in the case of BC due to more long fibrils forming more dense entanglements network than in other cases. Measuring the viscosity in increase and decrease shear rate modes indicate an existence of hysteresis loop, i.e., thixotropic behavior with time lag for recovering the structural network. MCC and NCC dispersions even at cellulose content more than 5% do not demonstrate such behavior. According to oscillatory measurements, viscoelastic behavior of dispersions corresponds to gel-like systems with almost total independence of moduli on frequency and essentially higher values of the storage modulus compared with the loss modulus.

A reaction of [3-(2-aminoethylamino)propyl]trimethoxysilane with wood and cellulose – chemical analyses

A reaction of [3-(2-aminoethylamino)propyl]trimethoxysilane with wood and cellulose – chemical analyses. The paper presents tests results for [3-(2-aminoethylamino)propyl]trimethoxysilane (AATMOS) reactivity with cellulose and Scots pine wood. The tested material was treated with ethanolic solution of aminosilane and analyzed using instrumental methods, including elemental analysis, atomic absorption spectrometry and infrared spectroscopy. The results of the chemical analysis indicated that [3-(2-aminoethylamino)propyl]trimethoxysilane exhibited reactivity with both cellulose and pine wood. In addition, AATMOS-treated cellulose showed a higher content of silicon and nitrogen and more significant changes in FTIR spectra than the treated wood, suggesting that AATMOS showed a higher reactivity to cellulose than to wood.

Flameless burning of wood: parameters of macrokinetics of pyrolysis and thermo-oxidative decomposition

Introduction. Many materials are subject to flameless, smoldering combustion: coal, cotton, peat, carbonizing ­polymers, etc. The fire hazard of smoldering burning of organic materials is that low-calorie ignition sources are sufficient to initiate the combustion process, the process is hidden, making it difficult to detect, and can spontaneously turn into a fiery one. Purpose and objectives. The purpose of this work was to determine the macrokinetics of pyrolysis and thermo­oxidative decomposition of wood of different types of conifers and deciduous species by thermal analysis. Methods. Samples were investigated by thermal analysis in an inert and air environment. For this, we used the automated modular system Du Pont-9900, including the TGA-951 thermobalance, and the DSK-910 diffe­rential scanning calorimeter. Results. It was found that the pyrolysis of the main components of wood (hemicellulose and cellulose) proceeds according to the nucleation and growth mechanism of nuclei according to the case law R ( n = 1) with activa­tion energies close in order of magnitude for different species (98–136 kJ/mol for hemicelluloses and 203–233 kJ/mol for cellulose). At the stages of thermooxidative decomposition of wood components and heterogeneous oxidation of the carbonized product, diffusion of the D3 (D4) type in spherical geometry becomes the mechanism controlling the process. The effective activation energy of the decomposition of hemicelluloses is reduced to 90.9–95.8 kJ/mol, and of cellulose to 138.3–160.9 kJ/mol. The reaction of heterogeneous oxidation of carbonized products makes a significant contribution to the flameless, smoldering combustion of the material. It is diffusion-controlled and is characterized by high values of activation energy (up to 285 kJ/mol). Conclusion. The results of the work make it possible to evaluate the macrokinetic parameters of pyrolysis and thermooxidative decomposition of wood of different species during flameless combustion. The obtained data can be used as the main parameters for modeling the heterogeneous combustion of wood of different species in buildings.

Transcriptomics and Proteomics Reveal the Cellulose and Pectin Metabolic Processes in the Tension Wood (Non-G-Layer) of Catalpa bungei.

Catalpa bungei is an economically important tree with high-quality wood and highly valuable to the study of wood formation. In this work, the xylem microstructure of C. bungei tension wood (TW) was observed, and we performed transcriptomics, proteomics and Raman spectroscopy of TW, opposite wood (OW) and normal wood (NW). The results showed that there was no obvious gelatinous layer (G-layer) in the TW of C. bungei and that the secondary wall deposition in the TW was reduced compared with that in the OW and NW. We found that most of the differentially expressed mRNAs and proteins were involved in carbohydrate polysaccharide synthesis. Raman spectroscopy results indicated that the cellulose and pectin content and pectin methylation in the TW were lower than those in the OW and NW, and many genes and proteins involved in the metabolic pathways of cellulose and pectin, such as galacturonosyltransferase (GAUT), polygalacturonase (PG), endoglucanase (CLE) and β-glucosidase (BGLU) genes, were significantly upregulated in TW. In addition, we found that the MYB2 transcription factor may regulate the pectin degradation genes PG1 and PG3, and ARF, ERF, SBP and MYB1 may be the key transcription factors regulating the synthesis and decomposition of cellulose. In contrast to previous studies on TW with a G-layer, our results revealed a change in metabolism in TW without a G-layer, and we inferred that the change in the pectin type, esterification and cellulose characteristics in the TW of C. bungei may contribute to high tensile stress. These results will enrich the understanding of the mechanism of TW formation.

Thermal Analysis of Ozonized Pinewood

The transformation of pinewood under the action of ozone is investigated via synchronous thermal analysis in combination with the mass spectral (MS) analysis of incondensable products of pyrolysis. TG/DTG and MS data are analyzed from the viewpoint of the conversion of wood lignin (LG), hemicelluloses (HCs), and cellulose (CL) in the composition of products of LG oxidation using different amounts of absorbed ozone. Results from TG/DTG analysis indicate the destruction of hemicelluloses during pinewood ozonation. The lower temperature of the thermal destruction of cellulose material (CM) produced from ozonized wood correlates with the lower LG content, the depolimerization of CL, and the formation of products of oxidation in biomass ozonation. Data from TG/DTG and MS analyses suggest that when wood is treated with ozone, aromatic lignin structures are not only destroyed but polymerized as well.

Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents

AbstractStrategies to mitigate the expected “cellulose gap” include increased use of wood cellulose, fabric reuse, and recycling. Ionic liquids (ILs) are employed for cellulose physical dissolution and shaping in different forms. This review focuses on the regeneration of dissolved cellulose as nanoparticles, membranes, nonwoven materials, and fibers. The solvents employed in these applications include ILs and alkali solutions without and with additives. Cellulose fibers obtained via the carbonate and carbamate processes are included. Chemical recycling (CR) of polycotton (cellulose plus poly(ethylene terephthalate)) is addressed because depending on the recycling approach employed, this process is akin to regeneration. The strategies investigated in CR include preferential dissolution or depolymerization of one component of the blend, and separation of both components using ILs. It is hoped that this review focuses the attention on the potential applications of regenerated cellulose from its solutions and contributes to the important environmental issue of recycling of used materials.

Superhydrophobic paper fabricated via nanostructured titanium dioxide-functionalized wood cellulose fibers

Herein, an eco-friendly and straightforward method was provided for the fabrication of superhydrophobic paper from native wood cellulose fibers via in situ hydrolysis of tetraethyl titanate(IV) without any chemical pretreatment. By simply adjusting the amount of acetic acid (HAc), the surface micro/nanomorphology could be well controlled. After papermaking and hexadecyltrimethoxysilane modification, superhydrophobic paper can be easily achieved with static water contact angle of 152.3° (± 1.3°). The paper also possessed good self-cleaning property against contamination and durability toward mechanical damages of finger wiping over 50 cycles as well as excellent oil/water separation, which expands its utility in various paper-based technologies. The whole procedure possesses the advantages of friendly raw material, mild reaction conditions and with no toxic modifier, which hold potential application in cellulose-based superhydrophobic material in large scale.

Changes in the chemical composition of young Chinese fir wood exposed to different soil temperature and water content

The chemical composition of wood is closely related to its growing conditions, such as soil temperature and water. Four different types of soil warming and precipitation exclusion treatments were used to simulate the underground response and adaptability of Chinese fir to global warming. The compaction method was used to reclaim the Chinese fir soil from the nearby woodland to ensure that the soil bulk density was as consistent as possible. The chemical constituents of Chinese fir wood were studied by taking Chinese fir discs at breast height of 1.3 m. With changing the growth environment, the content of different extracts and the chemical composition of Chinese fir have changed. The cellulose content of Chinese fir increased significantly with precipitation exclusion − 50%. The organic extract content of Chinese fir increased in different degrees under soil warming and precipitation exclusion, which may be related to the accumulation of organic matter content and be beneficial to the improvement of the biomass of Chinese fir. Due to the change of temperature and water content in soil, the internal adaptability of Chinese fir wood cellulose like crystalline zone, overall orderliness also may decrease. Precipitation exclusion − 50% still has the greatest impact on it. The soil warming and precipitation exclusion can inhibit lignin synthesis of Chinese fir. The lignin condensation index decreased with the decrease of lignin content, possibly due to the change of syringyl lignin content. Experiments show that the underground parts of terrestrial ecosystems may provide positive effects from global warming, although the extent of such consequences is uncertain.

Predicting the chemical composition of juvenile and mature woods in Scots pine (Pinus sylvestris L.) using FTIR spectroscopy

The chemical composition of wood is one of the key features that determine wood quality. The focus of this study was on identifying differences between juvenile and mature woods in Scots pine (Pinus sylvestris L.) and developing models for predicting the chemical composition of these two wood types. Chemical traits, determined by traditional wet chemistry techniques, included the proportion of lignin, polysaccharides and extractives. Partial least squares regression of Fourier transform infrared (FTIR) spectra was used for model building. The model performance was primarily evaluated by root mean squared error of predictions (RMSEP). High predictive power was attained for the content of lignin (RMSEP of 0.476 and 0.495 for juvenile and mature woods, respectively) and extractives (0.302 and 0.471), good predictive power for cellulose (0.715 and 0.696) and hemicelluloses in juvenile wood (0.719) and low predictive power for hemicelluloses in mature wood (0.823). A distinct band was observed at 1693 cm−1, and its intensity was strongly associated with the content of extractives (r = 0.968 and 0.861 in juvenile and mature woods, respectively). FTIR has proved suitable for the rapid, non-destructive, cost-efficient assessment of the chemical composition of juvenile and mature woods in Scots pine. The band at 1693 cm−1 is to be further investigated to unravel its link with individual extractive components.

Films of Bacterial Cellulose Prepared from Solutions in N-Methylmorpholine-N-Oxide: Structure and Properties

In the present study, one of the possible methods of the bacterial cellulose processing is proposed via its dissolution in N-methylmorpholine-N-oxide using the stage of mechano-chemical activation of the solid polymer–solvent system. Preliminary solid-phase activation is apparently a decisive factor affecting the dissolution rate of bacterial cellulose in N-methylmorpholine-N-oxide. The effects of bacterial cellulose concentration, solvent nature, degree of polymerization and temperature on dissolution time were studied. The rheological behavior of the solutions does not change at 120 °C for at least half an hour that allowed us to process such solutions for films preparation. The films from these solutions by means of dry-wet jet spinning in aqueous coagulant were formed. The structure of the nascent cellulose and formed films was tested by the X-ray diffraction method and SEM. The thermal behavior of the films revealed an increase in the carbon yield for the formed films compared to the nascent bacterial cellulose. The process of film pyrolysis is accompanied by exothermic effects, which are not typical for wood cellulose. Some reasons of such thermal behavior are considered.

Structure and properties of helical fibers spun from cellulose solutions in [formula omitted

Man-made fibers were spun from solutions of cotton and wood cellulose in ionic liquid (1-butyl-3-methyl-imidazolium chloride, [Bmim]Cl). Depending on the concentration, cellulose dissolved in [Bmim]Cl down to macromolecules or nanofibrils. The artificial fibers had a diameter of about 100 nm, were uniform, transparent, helical, and optically active. The fibers were composed of the core and shell (∼20% of the radius). The core was composed of the dense helical pseudofibrils of about 30 nm in thick occupying of about 40% of the area of the fiber core cross-section. The tensile strength of the whole fiber was, on average, 250 MPa, while that of the individual pseudofibrils was ∼1.1 GPa. The tensile-strength dependencies were two-stage with drastically different Young's modules. We explain the shape of the loading curves as well as the strength of the fibers by the friction between the twisted pseudofibrils in the core.

Strategies for structuring diverse emulsion systems by using wood lignocellulose-derived stabilizers

Wood cellulose, lignin, and hemicelluloses are abundant bioresources that can be valorized as sustainable emulsion stabilizers. The lignocellulose-derived stabilizers may act as surface-active compounds, Pickering particles, or viscosity enhancers.

Cage Bedding affects Microbiota and Metabolism in Mice

AbstractThe growing problem with the irreproducibility of the results of metabolic research urged us to analyse potential critical factors contributing to the disparities. Microbiota composition constitutes crucial variable in animal research. Gut flora changes depending on multiple factors including fibre intake. Mice derive fibre from diet but, especially under fasted conditions, also from bedding ingestion. Our project aims at assessing the impact of cage bedding on several aspects of metabolic research. Mice were divided into an overnight (ON) fasted, caloric restricted (CR) and ad libitum groups. In order to evaluate the effects of different beddings, mice were housed in cages with the most commonly used beddings: wooden, corncob or cellulose. Additionally, ON-fasted mice were kept without bedding or on metal grid preventing coprophagy. Mice bedding consumption and faeces production were measured. Oral glucose tolerance test (OGTT) was performed. Metabolites composition and microbial diversity were analysed in caecum content. Mice organ weight and gene expression measurements were conducted. Mice show preference towards wooden bedding and consume it in highest amount followed by corncob and cellulose beddings. As a result of the bedding ingestion, caecum weight increases in the CR compared to ad libitum fed mice. CR leads to a reduced faeces production and it is the lowest in the CR wood and CR cellulose groups. Housing on metal grid results in greater body weight loss and decreases stomach and caecum size. ON-fasted mice housed without bedding or on grids show lower glucose levels when submitted to OGTT. CR influences the caecal bacterial diversity as well as the caecal metabolic profile. In the CR group, mice on the corncob bedding show a distinct caecal microbial composition and caecal metabolic profile compared to wooden and cellulose groups. CR is associated with increased abundance of Marinifilaceaefrom the phylum Bacteroidales, and Erysipelotrichaceaefrom the phylum Firmicutes and with a decreased abundance of Lachnospiraceaefrom the phylum Firmicutes. The main metabolites effected by CR are organic acids, fructose, sucrose and glutamine. The type of bedding exerts the strongest effect on valeric acid, lysine, threonine and organic acids. CR- and ON-fasting-associated weight loss, bedding consumption and fibre accumulation in the caecum depends on the bedding type. CR mice housed on wooden and cellulose beddings show similarities and are distinguishable from CR corncob group. Thus, depending on the composition and consumed amount, bedding intake affects numerous parameters and shapes the microbiome.

Wood Functional Modification Based on Deposition of Nanometer Copper Film by Magnetron Sputtering

Abstract It can be helpful for selected applications to improve the functionality of wood by compounding nano-metal materials with wood, endowing the wood surface with certain physical properties, for example, metallicity, electrical conductivity, and hydrophobicity. Therefore, in this study, a thin copper film was deposited on the surface of Pinus sylvestris L. var. mongholica Litv. veneer by magnetron sputtering. The film was applied at both room temperature and 200°C to obtain nano-copper–wood composites. The physical properties of wood-based nano-metal composites were characterized. The results indicated that the wood veneer metallization had no effect on the crystallization zone of wood; there were still wood cellulose characteristic peaks, but the intensity of the diffraction peak decreased. At the same time, there were characteristic diffraction peaks of copper. The mechanical properties of the wood veneer surface changed greatly; the surface of copper-plated wood veneer had good electrical conductivity and the wettability of the wood surface transformed from hydrophilic to hydrophobic. When the base temperature was 200°C, not only was the sheet resistance of the sample with coating time of 15 minutes about 4.6 times that of the sheet resistance of the sample at room temperature, but also the quality of the copper film on the wood surface was better than that at room temperature. The copper film was mainly composed of small particles with a compact arrangement.