Wood Pulp Fibers Research Articles

Hierarchical porous MOF-199 mediated cellulosic paper for selective CO2 capture

MOF-199 is considered to be an excellent CO2 adsorbent owing to its substantial specific surface area, suitable pore structure and abundant sorption sites. However, powdered MOF-199 is prone to agglomeration and has poor recyclability. Herein, we proposed a MOF-199-based adsorbent by combining the MOF synthesis process with traditional papermaking process. Through such a design, MOF-199 particles are adhered on the surface of wood pulp fiber. The sufficient hydroxyl groups and electrostatic forces of cellulose facilitates the homogeneous and tight adhesion of MOF crystals. The optimal MP-4 sample demonstrated a high CO2 adsorption capacity (1.80 mmol·g‐−1 at 25 °C) and good CO2/N2 selectivity (30.06). Moreover, the composite sorbent can be easily regenerated. The adsorption mechanism was analyzed by the density functional theory approach. The simulation results showed that the carboxyl functional groups with a large number of oxygen atoms and active metal sites are the key to boost the CO2 adsorption performance.

Cellulose Nanofibrils/Alginates Double-Network Composites: Effects of Interfibrillar Interaction and G/M Ratio of Alginates on Mechanical Performance.

Interfibrillar phases and bonding in cellulose nanofibril (CNF)-based composites are crucial for materials performances. In this study, we investigated the influence of CNF surface characteristics, the guluronic acid/mannuronic acid ratio, and the molecular weight of alginates on the structure, mechanical, and barrier properties of CNF/alginate composite films. Three types of CNFs with varying surface charges and nanofibril dimensions were prepared from wood pulp fibers. The interfacial bonding through calcium ion cross-linking between alginate and carboxylated CNFs (TCNFs) led to significantly enhanced stiffness and strength due to the formation of an interpenetrating double network, compared to composites from alginates and CNFs with native negative or cationic surface charges. Various alginates extracted from Alaria esculenta (AE) and Laminaria hyperborea (LH) were also examined. The TCNF/AE composite, prepared from alginate with a high mannuronic acid proportion and high molecular weight, exhibited a Young's modulus of 20.3 GPa and a tensile strength of 331 MPa under dry conditions and a Young's modulus of 430 MPa and a tensile strength of 9.3 MPa at the wet state. Additionally, the TCNF/AE composite demonstrated protective properties as a barrier coating for fruit, significantly reducing browning of banana peels and weight loss of bananas stored under ambient conditions.

Thermoformed products from high-density polyethylene and Softwood kraft pulp.

Plastic recycling, waste minimization such as process outfall valorization promotes a circular economy. Herein, food trays have been produced in the moulded pulp thermoforming process. To this end, high-density polyethylene (HDPE) outfall has been dispersed in water via Poly vinyl alcohol (PVA) addition in a Northern Bleached Softwood KraftPulp (NBSKP) slurry. Samples physical and mechanical properties have been evaluated. With an increasing HDPE content, parts air permeability was drastically reduced to a minimum of 2.4±0.8 mL min-1. In addition, water and grease hold out properties have been increased with minimum waterCobb1800 value of 10.9±5.4 gm-2 and oil Cobb1800 value of13.18±6.5 gm-2. Samples with high HDPE content demonstrated hydrophobic surface with water contact angle value above 90°. HDPE melting and binding to wood pulp fibers was monitored by SEM images. Regarding the mechanical properties, HDPE induced plastic deformation with a reduced Young modulus by 17 %. Moreover, the addition of HDPE increased wet strength by 81 %. However, the produced foodtray composites with high HDPE content demonstrated low repulpability index.

Analysis of polydisperse polymer adsorption on porous cellulose fibers.

The adsorption of cationic water-soluble polymers onto negatively charged porous wood pulp fibers is an essential aspect of papermaking. Adsorption data can be displayed as a direct plot of the amount adsorbed, Γ, versus the amount of polymer added or as an isotherm plot showing the amount adsorbed versus the residual unadsorbed polymer. In either data presentation, the analysis is more transparent if the units of each axis are the same (e.g., mg/g or meq/g), giving dimensionless slopes. Values for Γmax, ΓI, f I , and Γme can be extracted from many isotherms where: Γmax is the maximum capacity of the fibers to adsorb polymer; ΓI is the y-axis isotherm intercept and gives the maximum dose that can be fully adsorbed; f I is the slope of the direct plot at ΓI, and f I is the mass fraction of the added polymer that can access interior (pore) surfaces; and, Γme is the saturated amount of polymer adsorbed on exterior surfaces. Additionally, the molecular weight distribution of theadsorbing polymer in conjunction with the adsorption isotherm can be used to estimate the molecular weight distributions of adsorbed polymer on interior and exterior fiber surfaces as functions of the polymer dose.

Preparation of interwoven structure composite paper via polylactic acid infiltrating fiber network

AbstractCellulose is commonly acknowledged as a sustainable material owing to its abundance and renewability. However, the abundance of hydroxyl groups makes the paper material highly hydrophilic, and the hydrogen bonds between the fibers are easily broken by water, leading to the degradation of mechanical properties. This work details the fabrication of a composite paper comprising interwoven cellulose and polylactic acid (PLA) structures through hot‐pressing and PLA impregnation onto handwritten paper derived from conventional wood pulp fibers as the substrate. The investigation assessed how varying PLA concentrations influenced the overall characteristics of the composite paper, including its morphology, structure, mechanical properties, water absorption behavior, and water contact angle. Experimental results revealed that the composite paper fabricated through our approach exhibited an intertwined structure comprising both PLA and cellulose. With a tensile index reaching 33.24 kN·m/kg and a mere 31.1% loss in tensile index post‐water treatment, the mechanical properties of the composite paper were significantly enhanced due to the robust interfacial compatibility between cellulose and PLA, as well as the adhesive effect of PLA. Furthermore, the composite paper (CP) is easily processable and amenable to thermoforming into paper trays as required, indicative of its potential applications in the packaging industry.

Evaluation of Recycled Paperboard Properties and Characteristics

Paperboard boxes represent a sought-after class of packaging products, where the use of recycled fibers offers a cost-effective and environmentally friendly alternative to virgin fibers. The presence of a significant proportion of recycled fibers in the paperboard leads to a number of limitations associated with the deterioration of its characteristics. In this study, the properties of coated and uncoated paperboards containing recycled fibers, wood pulp, and virgin cellulose fibers were investigated using a laboratory sample of paperboard produced from 100% recycled fibers without any chemical additives for comparison. Properties such as smoothness, bulk density, absorbency, and tensile strength, as well as colorimetric characteristics, were determined for the recycled paperboards; for the latter test, charts were printed using inkjet printing and UV-curable inks. Whiteness was calculated by three formulae (CIE, Berger, and Stensby), and all the paperboards had a relatively low whiteness (not exceeding 90 CIE), with a yellowish tint due to recycled fibers and mechanical pulp in the composition. The absence of optical brightening agents in the paperboards was experimentally confirmed. The color gamuts of the paperboards were in direct ratio to their whiteness, with the highest ones demonstrated by the coated paperboards. Color reproduction, according to the tone value increase curves, also depended on the whiteness. Uncoated paperboards demonstrated smaller color shifts than the coated ones, with the greatest increase in tone for yellow color. Coated recycled paperboards are suitable for packaging printing under the same conditions as virgin fiber boards, while uncoated boards are the recommended choice for digital printing with UV inks.

Development of a beverage carton closure cap based on 100% wood pulp fibres

Single-use plastic products have been identified as an environmental challenge. When such products are not recycled, they may end up in nature and thus cause, e.g., marine littering. Thermoformed wood pulp fibre products are gaining more interest to replace fossil plastic products. However, beverage caps made of wood pulp fibres are challenging due to the hygroscopic nature of wood fibres, i.e., they absorb water, deform and loose functionality. Hence, the purpose of this study was to develop a fibre-based beverage cap that could replace plastic tethered cap systems. Both unbleached and bleached Kraft pulp and chemo-thermo-mechanical pulp (CTMP) fibres were tested in thermoforming trials, using tailor-made metal moulds. The results showed that Kraft pulp fibres formed denser structures, with more limited water absorption, compared to CTMP. The mechanical properties of thermoformed specimens were suitable for the application, i.e., the strength, modulus and elongation were between 32 and 36 MPa, 4–4.9 GPa and 1.6–1.9%, respectively, depending on the type of pulp fibre. Additionally, in order to secure that the caps were functional in relevant conditions in contact with liquids (water or milk), the caps were surface modified by silylation and esterification to increase the liquid barrier. The results indicate that surface esterification increased the contact angle to 95°. On the other hand, the surface-modified caps could not entirely limit the liquid absorption over longer periods of time (>∼1 h) when the caps were directly exposed to liquid. However, the liquid barrier was satisfactory when the products were exposed to increased relative humidity in refrigerated conditions (relative humidity >76% and temperature <7 °C).

Click chemistry modifications for the selective crosslinking of wood pulp fibers - effect on the physical and mechanical properties of paper.

The Cu(i)-catalyzed Huisgen cycloaddition click chemistry reaction is of particular interest in the production of paper sheets or natural fiber composites since it leads to the formation of chemically stable bonds between two fibers. This study focuses on the click chemistry modification of kraft pulp fibers. We based our approach on prior research that treated kraft fibers using click chemistry, including propargylation and tosylation reactions. Our focus was on enhancing these treatments to achieve better final sheet properties. After the azidation of tosylated fibers, the crosslinking is carried out with and without a catalyst using water as a solvent to form enhanced kraft fiber sheets. The chemical characterization and the mechanical properties of fibers obtained at intermediate stages confirmed the presence of various functions on the surface of the modified fibers, with a very high degree of substitution and the inter-fiber cross-linking by click chemistry. The presence of inter-fibers covalent bonds led to significant improvements in the mechanical strength and tensile stiffness of the sheets.

Experimental studies of dynamic compression of cellulose pulp fibers

The ability to control the structure of the wood-pulp fiber cell wall is an attractive means to obtain increased accessibility to the fiber interior, providing routes for functionalization of the fibers that support further processing and novel material concepts, e.g. improved degree of polymerization, nanofiltration as demonstrated in previous studies. It has been proposed that dynamic compression and decompression of the cellulose pulp fibers in the wet state make it possible to modify the cell wall significantly.We hypothesize that hydrostatic pressure exerted on fibers fully submerged in water will increase the accessibility of the fiber wall by penetrating the fiber through weak spots in the cell wall. To pursue this, we have developed an experimental facility that can subject wet cellulose pulp samples to a pressure pulse ∼10 ms long and with a peak pressure of ∼300 MPa. The experiment is thus specifically designed to elucidate the effect of a rapid high-pressure pulse passing through the cellulose sample and enables studies of changes in structural properties over different size ranges. Different characterization techniques, including Scanning electron microscopy, X-ray diffraction, and wide- and small-angle X-ray scattering, have been used to evaluate the material exposed to pulsed pressure. The mechanism of pressure build-up is estimated computationally to complement the results. Key findings from the experiments consider a decrease in crystallinity and changes in the surface morphology of the cellulose sample.

Paper-Based Hydroelectric Generators for Water Evaporation-Induced Electricity Generation.

The research presented in this paper introduces a novel environmental energy-harvesting technology that harnesses electricity from the evaporation of water using porous structural materials. Specifically, a strategy employing paper-based hydroelectric generators (p-HEGs) is proposed to capture the energy produced during water evaporation and convert it into usable electricity. The p-HEGs offer several advantages, including simplicity in fabrication, low cost, and reusability. To evaluate their effectiveness, the water evaporation-induced electrical output performance of four different p-HEGs are compared. Among the variants tested, the p-HEG combining wood pulp and polyester fiber exhibits the best output performance. At room temperature, this particular p-HEG generates a short-circuit current and open-circuit voltage of ≈0.4µA and 0.3V, respectively, thereby demonstrating excellent electrical stability. Furthermore, the electrical current and voltage generated by the p-HEG through water evaporation are able to power an LED light, both individually and in series and parallel connections. This study delves into the potential of electricity harvesting from water evaporation and establishes it as a viable method for renewable energy applications.

The Effect of Cellulose Nanofibres on Dewatering during Wet-Forming and the Mechanical Properties of Thermoformed Specimens Made of Thermomechanical and Kraft Pulps.

Due to environmental concerns regarding single-use plastic materials, major efforts are being made to develop new material concepts based on biodegradable and renewable resources, e.g., wood pulp. In this study, we assessed two types of wood pulp fibres, i.e., thermomechanical pulp (TMP) and Kraft pulp fibres, and tested the performance of the fibres in wet-moulding and thermopressing trials. Kraft pulp fibres appeared to retain more water than TMP, increasing the dewatering time during wet-moulding and apparently increasing the compression resistance of the pulp during thermoforming. Additionally, cellulose nanofibres (CNF) were added to the pulps, which improved the mechanical properties of the final thermopressed specimens. However, the addition of CNF to the pulps (from 2 to 6%) had a further decrease in the dewatering efficiency in the wet-moulding process, and this effect was more pronounced in the Kraft pulp specimens. The mechanical performance of the thermoformed specimens was in the same range as the plastic materials that are conventionally used in food packaging, i.e., modulus 0.6-1.2 GPa, strength 49 MPa and elongation 6-9%. Finally, this study demonstrates the potential of wood pulps to form three-dimensional thermoformed products.

A Study on Optimum Use of Fly Ash and GGBS in Fiber Cement Sheet to Enhance Sustainable Manufacturing

The biproducts of different industries must be reused or recycled which will avoid disposal of waste materials in the environment in different forms to protect our environment. Also the hazardous material used for the manufacturing of the products to be eliminated or minimized. In this paper a study has been conducted for optimum use of fly ash generated from power plants and Ground Granulated Blast Furnace Slag (GGBS) generated from steel plants in the manufacturing of fiber cemented roofing sheets. Also different percentages of fly ash, GGBS and pulp were added during the manufacturing of fiber cement roofing sheets in a fiber cement roofing sheet manufacturing plant and the quality of the final product has been tested subsequently in the laboratory to minimize the use of cement and asbestos fiber. Different results have been achieved in different percentages of fly ash, cement, GGBS, wood pulp and asbestos fiber combination. It is found that up to 36% addition of fly ash is acceptable with respect to the quality acceptance criteria of the final product, above 36% degrades the quality of the product which doesn’t meet the BIS: 459 standard requirements. Similarly, 10.38% of GGBS can be added without hampering the quality of the product. Finally, the best combination of raw mix design as per environmental sustainability point of view as well as the economic point of view has been suggested for the sustainable manufacturing of fiber cement roofing sheets.

Functional fibers from regenerated wood pulp cellulose and a natural‐based phytate with enhanced flame retardancy properties

AbstractThe manufacture of sustainable functional fibers with low environmental footprint and superior properties is a pressing research issue under the auspices of more sustainable industrial textile processes. In the present study, regenerated cellulose fibers (CellReg) with flame retardancy properties are manufactured by functionalizing regenerated wood pulp fibers (obtained through the dissolution of paper‐grade pulp in an ionic liquid followed by regeneration in water) with a natural derived phosphorus compound, namely phytic acid ammonium (PAA). The pale‐yellow modified fibers present a phosphorus content up to 1.80% and a uniform and smooth surface morphology. Furthermore, the functional cellulose fibers exhibit moderate antioxidant activity (ca. 18.4% of maximum radical scavenging), water contact angles below 92°, as well as good thermal‐oxidative stability up to 200°C. The flame‐retardant performance of the CellReg/PAA fibers was investigated by the vertical burning test, and as anticipated, the results show a higher flame retardancy with the increasing content of phosphorus, meaning that the fibers ceased to burn before flaming or glowing, even after several flame applications. The accomplished properties validate the potential of these functional fibers of regenerated wood pulp cellulose and PAA for application as textile fibers with flame retardancy properties.

Influences of epoxidized natural rubber and fiber modification on injection molded-pulp/poly(lactic acid) biocomposites: Analysis of mechanical-thermal and weathering stability

Accelerated weathering tests were conducted to evaluate the weathering resistance of poly(lactic acid) (PLA) based biocomposites without and with epoxidized natural rubber (ENR), that were reinforced with unmodified wood pulp fiber (WP) and silanized wood pulp fiber (modified WP). Changes in mechanical and thermal properties and morphology were observed, and structural and chemical degradation were analyzed. The addition of ENR improved the impact strength of the biocomposites before weathering, acting as an impact modifier. After the weathering test, the flexural properties of PLA-based biocomposite with ENR and silanized wood pulp fiber (ENR-modified WP) was better than the flexural properties of a biocomposite without ENR. The biodegradability of the biocomposites largely depended on the PLA matrix. The modified fibers have lower UV absorbance and can protect composites from UV light better than unmodified fibers. ENR and modified WP helped prevented the degradation of PLA. While weathering reduced the molecular weight of the WP and modified WP biocomposites by 78% and 61%, respectively, the molecular weight of the same biocomposites with ENR decreased by 51% and 50%, respectively. The accelerated weathering test produced cracks and increased surface roughness in the biocomposites and the glass transition temperature was reduced as a result of crystallization and chain shortening. These indicated that the biocomposite based containing ENR and silanized wood pulp fiber had better weathering resistance due to lowest absorption of UV radiation which was more suitable for applications in construction, furniture, and exterior and interior decoration.

木材パルプ／バイオプラスチック積層複合材料の表面処理による力学特性の改善

In this study, wood-pulp／bio-based poly (butylene succinate) (Bio-PBS) laminated composites were made by using papermaking techniques. Wood-pulp fibers were treated with 3-aminopropyltrimethoxysilane (APTMS) and poly (vinyl alcohol) (PVA) to improve the interfacial adhesion between the wood-pulp fibers and Bio-PBS. Wood-pulp fibers without being processed (PF), wood-pulp fibers treated by APTMS (PF-Si), and wood-pulp fibers treated by both APTMS and PVA (PF-Si/PVA) were converted to sheets by the papermaking technique. Those sheets and Bio-PBS films were used to make wood-pulp/Bio-PBS laminated composites by hotpressing and cut into test pieces. Tensile testing and the heat distortion temperature measurements were conducted with those samples. As a result, the tensile strength of composites was close in value to that expected by the Reuss model when the volume fraction of wood-pulp was 12％ and 24％. Furthermore, the tensile strength of composites containing PF-Si/PVA was higher than that of composites containing PF and PF-Si. The heat distortion temperature of the composites was higher than that of Bio-PBS, although the effects of surface treatment on the heat distortion temperature were not confirmed. Microscopy observations of composite fractures indicated that the surface treatment of wood-pulp fibers enhanced interfacial adhesion between the woodpulp fibers and Bio-PBS.

Visualization of Fibrillated Cellulose in Polymer Composites Using a Fluorescent-Labeled Polymer Dispersant

The fibrillated cellulose embedded in the polymer matrix was visualized using confocal laser scanning microscopy (CLSM). A rhodamine-appended diblock copolymer (RhBCP) was used as a novel polymer dispersant to adsorb fibrillated celluloses and achieve fluorescent labeling and good dispersion in high-density polyethylene. The composite was produced through in situ fibrillation of wood pulp fibers during the process of melt compounding using urea as the fibrillation-accelerating agent. The length and width of the fiber, aspect ratio, and polydispersity values were determined using RhBCP and CLSM. The optimal RhBCP content to achieve good CLSM images and a high Young’s modulus was 2 wt %. The effects of urea concentration and kneading time on the fibrillation were investigated, indicating that the fiber length and aspect ratio were approximately 40 μm and 40, respectively, under optimal conditions. The maximum Young’s modulus was recorded under these conditions, and the recorded value agreed well with the value predicted by the Halpin–Tsai equation. Cellulose fibers fragmented under conditions of low urea concentration and prolonged kneading times. The method developed has the potential to analyze various cellulosic composite systems and improve their application prospects.

A feruloyl esterase/cellulase integrated biological system for high-efficiency and toxic-chemical free isolation of tobacco based cellulose nanofibers

Tobacco based cellulose nanofiber (TCNF) is a novel nanocellulose that has recently been used to replace undesirable wood pulp fibers in the preparation of reconstructed tobacco sheets (RTS). However, given the strict requirements for controlling toxic chemical content in tobacco products, there is a global interest in developing a green, efficient, and toxic-chemical free approach to isolate TCNF from tobacco stem as a bioresource. In this study, we propose a creative and environmentally friendly method to efficiently and safely isolate TCNF from tobacco stem pulp, which involves integrated biological pretreatment followed by a facile mechanical defibrillation process. Feruloyl esterase is used to pretreat the stem pulp by disrupting the ether and ester bonds between lignin and polysaccharide carbohydrates within the fiber wall, which effectively facilitates cellulase hydrolysis and swelling of the stem pulp fiber, as well as the following mechanical shearing treatment for TCNF isolation. The results demonstrate that TCNF obtained by the comprehensive feruloyl esterase/cellulase/mechanical process exhibit uniform and well-dispersed nanofiber morphology, higher crystallinity, and stronger mechanical properties than those of the control. The addition of 0.5 % TCNF can replace wood pulp by 18 wt% ~ 25 wt% in the production of RTS samples while maintaining their reasonable strength properties.

Sonic disruption of wood pulp fibres aided by hydrophobic cavitation nuclei

For paper manufacturing and biofuel production, the controlled deformation of wood pulp is of interest, provided that the integrity of the fibre structure remains intact. Conventional ultrasonic pretreatment in the near-audible range has been observed to cause uncontrolled inertial cavitation damage in wood pulp fibres. To prevent internal damage, we proposed to subject wood pulp mixed with hydrophobic particles to 1-MHz short pulses above the nucleation threshold of the particles but below the Blake threshold, and to observe the interaction of pulsating cavities and wood pulp fibres assisted by high-speed photography. Our 1-MHz results showed the interaction of a collapsing bubble with a wood pulp fibre wall to form a liquid jet hitting the fibre, without apparent destruction of the structure, whilst our 20-kHz controls confirmed previously observed structural destruction. This study shows the feasibility of controlled wood fibre deformation at a high ultrasound frequency.

From Regenerated Wood Pulp Fibers to Cationic Cellulose: Preparation, Characterization and Dyeing Properties

The global demand for sustainable textile fibers is growing and has led to an increasing research interest from both academia and industry to find effective solutions. In this research, regenerated wood pulp fibers were functionalized with glycidyltrimethylammonium chloride (GTAC) to produce modified regenerated cellulose with cationic pending groups for improved dye uptake. The resultant cationic cellulose with a degree of substitution (DS) between 0.13 and 0.33 exhibited distinct morphologies and contact angles with water ranging from 65.7° to 82.5° for the fibers with DS values of 0.13 and 0.33, respectively. Furthermore, the thermal stability of the modified regenerated cellulose fibers, albeit lower than the pristine ones, reached temperatures up to 220 °C. Additionally, the modified fibers showed higher dye exhaustion and dye fixation values than the non-modified ones, attaining maxima values of 89.3% ± 0.9% and 80.6% ± 1.3%, respectively, for the cationic fibers with a DS of 0.13. These values of dye exhaustion and dye fixation are ca. 34% and 77% higher than those obtained for the non-modified fibers. Overall, regenerated wood pulp cellulose fibers can be used, after cationization, as textiles fiber with enhanced dye uptake performance that might offer new options for dyeing treatments.

A method for chemical and physical modification of oriented pulp fibre sheets

Wood pulp fibres are promising reinforcements for biocomposites due to their renewable resource origin and mechanical properties. An oriented and dense fibre reinforcement structure is beneficial for biocomposite properties. We present a method of modifying fibres (e.g. to increase strain to failure) in pre-formed oriented high-density paper structures intended for biocomposites or as hot-pressed fibre materials. Mildly delignified, well-preserved holocellulose fibres from softwood are used. Cold alkali treatment (hemicellulose removal) and mercerisation (conversion to cellulose II) were carried out successfully on oriented fibre sheets. Controlled anisotropy and sheet density are achieved from untreated and straight fibres in the sheet formation step. High mechanical properties and increased ductility of mercerised sheets were observed, which may be valuable for hot-pressed fibre materials (E ≈ 7.1 GPa, strength of 108 MPa and strain to failure of 5.3%) and biocomposites. In contrast, modified wood pulp fibres were difficult to orient, resulting in higher sheet porosity and weak interfibre bonding.Graphical abstract