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This study collected sludge samples from the kraft pulp mills of a Brazilian industry and physicochemically characterized them to investigate their biovalorization. The objective was to identify opportunities to produce value-added products, promoting the circular economy and environmentally appropriate destinations. The types of processes and raw materials influence sludge characteristics. The primary sludge was composed mainly of fibers and water, has a slightly alkaline pH, Carbon:Nitrogen (C:N) ratio is high attributed to fibers, and contains calcium, magnesium, phosphorus, and organic carbon. The biological sludge was rich in proteins, bacterial cells, and minerals. The analyses revealed functional groups such as hydroxyls and aliphatic methylene, high concentrations of carbon and oxygen, a fibrous and crystalline structure of cellulose in the primary sludge, and dense microparticles in the biological sludge. Thermogravimetry found a mass loss of 11 % and final combustion at 742 °C for the biological sludge. The primary sludge showed a mass loss of 38 % with peaks at 329 and 784 °C, which suggests that the primary sludge could be used as fuel. Potential routes for the use of the primary and biological sludge included its use as agricultural fertilizer, thermal processing, biochar, and production of activated carbon, despite the low calorific values. [ABSTRACT FROM AUTHOR]

In today’s world, the use of paper and cardboard increasing but the availability of raw materials and the environmental impact on the paper industry is a big concern. To address these concerns, researchers are exploring the potential of agricultural waste products as raw materials for pulp production. This study uses morphological, chemical composition, FTIR, XRD, and thermogravimetric analysis to examine the potential of banana pseudo-stem as a raw material for paper pulp to address environmental concerns and raw material shortages in the paper industry. The study reveals favorable characteristics for papermaking, including long fiber length (1750 μm), thin cell wall thickness (9.7 μm), and large lumen diameter (22.15 μm). The chemical composition of banana pseudo-stem contains cellulose (44.93 %), hemicellulose (23.7 %), and Klason lignin (11.1) showing its suitability for pulp production. FTIR analysis highlights the functional groups present on the banana pseudo-stem. The XRD analysis shows that it has a similar cellulosic peak and crystallinity index with common raw materials used in pulp production. The thermogravimetric analysis shows that the banana pseudo-stem has high thermal stability. The findings demonstrate that banana pseudo-stem, both by itself and in combination with other raw materials, might be a potential raw material for the pulp production. [ABSTRACT FROM AUTHOR]

Cellulose-based actuators hold great promise for diverse applications, including soft robotics, biomedicine, and electronics. Achieving reversible motion is crucial to design high performance bio-based actuators. In this study, we explore the impact of carboxymethylation and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation on the reversible performance of cellulose-based pH-responsive actuators. Both methods introduce negatively charged groups onto the surface of cellulose fibers, enabling increased water uptake at high pH. However, comparative analyses revealed structural differences, guiding the design of reversible actuators. Carboxymethylated CNFs (CMCNFs) displayed enhanced water uptake and pH sensitivity, attributed to their less cohesive structure. Actuation and reversibility tests on bilayer films validated these findings. This research advances the understanding of cellulose functionalization for tailored actuation, contributing to the development of programmable materials for multiple applications. [ABSTRACT FROM AUTHOR]

Aerogels are essential and effective materials for oily pollution adsorption and recovery. This work described a hydrophobic modified cellulose aerogel using waste palm leaf and its oil adsorption mechanism. By chemical vapor deposition, Methyltrimethoxysilane (MTMS) was employed as a hydrophobic modifier for aerogel of waste palm leaf cellulose at 80 °C for 5 h, and the modified aerogel demonstrated exceptional and stable hydrophobicity with a water contact angle of 132.4° that can still be maintained above 120° after two months of air exposure. After 10 adsorption and extrusion cycles, kerosene adsorption capacity can still reach over 18 times its weight with good regeneration and reuse performance. The kinetic analysis found that the pseudo-second order model was more appropriate for the aerogel's oil absorption process, including mainly physical adsorption at the beginning and the following chemical adsorption. Owing to its low cost, hydrophobicity, high absorption capacity, and favorable reusability, this aerogel is expected to be used in oils, organic solvent spill cleanup, and oil/water separation fields. [ABSTRACT FROM AUTHOR]

In this study, hydroxypropyl cellulose (HPC) was utilized as the raw material, with the addition of β-cyclodextrin (β-CD), citric acid (CA) as the crosslinking agent, and sodium hypophosphite (SHP) as the catalyst to produce hydroxypropyl cellulose/β-CD composite films. The inclusion of β-CD resulted in an increase in the tensile strength of the film, with the maximum value of 13.5 MPa for the 1 % β-CD composite membrane. Additionally, after degradation in soil for 28 days, the degradation ability was significantly enhanced, with the 1.0 % β-CD composite film exhibiting the highest degradation rate of 27.21 %. Furthermore, the water permeability of the composite membrane was improved with the addition of β-CD. Specifically, when the β-CD content was 1.0 %, the water vapor transmission reached its lowest point at 2,445 g* (m 2 * 24 d) − 1 . The findings demonstrated that the 1 % β-cyclodextrin/hydroxypropyl cellulose composite film effectively preserved the freshness of strawberries, reducing the weight loss rate by 1.65 % compared to the control group. In conclusion, this research highlights the potential for preparing composite membranes using HPC and β-CD crosslinking, thereby expanding the application of hydroxypropyl cellulose and β-CD in food preservation. [ABSTRACT FROM AUTHOR]

Calcium hydroxide was used as a swelling agent and grinding aid to grind together with cellulose raw materials to prepare microfibrillated cellulose (MFC). Carbon dioxide was introduced to obtain MFC coated with calcium carbonate (CMFC). The effect of calcium hydroxide dosage on the fibrillation process of cellulose materials and the characteristics of MFCs and CMFCs were studied. Results show that when the dosage of calcium hydroxide was 5 % (based on cellulose materials), calcium hydroxide could be completely dissolved in water and had a swelling effect on cellulose materials. When the dosage reached 10 %, undissolved calcium hydroxide particles could serve as grinding media to assist in the fibrillation of cellulose materials. When the dosage exceeded 50 %, the auxiliary grinding effect of calcium hydroxide was more obvious. After accelerated carbonation, the generated calcium carbonate nanoparticles were coated on the surface of MFC, which increased its viscosity and decreased water retention value. The presence of calcium carbonate also facilitated the concentration, redispersion, and drying of MFC. The pretreatment, mechanical fibrillation, and accelerated carbonation were carried out in the same equipment without the need for heating or washing. Therefore, this study provides a in situ and one step method for the preparation of MFC. [ABSTRACT FROM AUTHOR]

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, fI, 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; fI is the slope of the direct plot at ΓI, and fI 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 the adsorbing 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. [ABSTRACT FROM AUTHOR]

Kraft pulping of wood is based on efficient depolymerization and solubilization of lignin, while cellulose is relatively undamaged. Non-cellulose cell wall polysaccharides are however in some cases heavily degraded, especially pectin and to a lesser degree also glucomannan while, xylan is relatively stable. In this mini-review, the most important reactions in lignin and polysaccharide degradation in kraft pulping are described, both the technically favorable and the problematic reactions, and the chemical background to discuss the advantages and drawbacks of the process. An attempt to put the different reactions in the perspective of the goals of the pulping process is made and a special focus is on the development of color in the pulp fiber during the kraft pulping. [ABSTRACT FROM AUTHOR]

Biobased coating material is required to replace synthetic polymer-based paper coating material for a safe and clean environment. The study aimed to investigate the use of biobased nanocomposites as a coating material for paper. The biobased nanocomposite was prepared using nanocellulose, sodium alginate (SA), and bio-synthesized silver nanoparticles (AgNPs). Nanocrystalline cellulose (NCC) was produced through acid hydrolysis, followed by fractionation. The average size of the crystals was 15 nm in width and 125 nm in length. AgNPs were prepared by the reduction of AgNO3 with lignin. The synthesis of silver nanoparticles was confirmed by UV–visible and FTIR spectroscopy. SA-NCC composite coating improved the barrier and strength properties of paper. The paper with composite coating demonstrated a 29.11 % increase in tensile index in the cross direction, 20.82 % increase in the machine direction, and 77.89 % improvement in burst index at a coating weight of 1.68 g/m2. The composite-coated paper showed better air barrier and lower water absorption characteristics than sodium alginate-coated paper. The incorporation of AgNPs in the coating mixture introduced the antimicrobial activity of the paper as well. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are potentially alternative solvents for cellulose dissolution. In this article, effect of hemicellulose in cellulose dissolution in ILs and the regeneration process were investigated. Hardwood pulps were produced by kraft (KP) and pre-hydrolysis kraft (PHKP) processes. The α-cellulose and residual pentosan contents were 95.6 % and 4.2 % in PHKP and 84.3 % and 9.9 % in KP, respectively. Both pulps were dissolved in 1-butyl-3-methylimidazolium chloride [C4mim]Cl, 1-butyl-3-methylimidazolium acetate [C4mim]CH3CO2 and their double salt (DSIL), [C4mim](CH3CO2)0.6Cl0.4 at 90 °C. It was observed that PHKP had slightly higher solubility in both ILs and DSIL. The dissolved pulps were regenerated by water and characterized by FTIR, TGA, X-ray diffraction, and viscosity. Regenerated pulp film formed smooth and homogenous surface. The viscosity of regenerated PHKP was higher than the original PHKP, which affected the strength of the produced cellulose film. As observed in FTIR, the regenerated cellulose showed a stronger absorption band at 1,647 cm−1 corresponding to the C–O stretching vibration of C–O–H. The crystalline structures of regenerated KP and PHKP from [C4mim](CH3CO2)0.6Cl0.4 changed to cellulose II form from the original cellulose I form. [ABSTRACT FROM AUTHOR]

Paper cultural relics, as the carriers of human civilization, inevitably deteriorate during the long-term storage. The restoration of those damaged or aged paper cultural relics is an important part of cultural relics protection. How to obtain the fiber with high permanence property is the key to the repair paper used to cultural relic restoration. Herein, in order to obtain high permanence lignocellulosic fiber, nano-CaCO3 was introduced inside the Wikstroemia bast fiber by in-situ mineralization. Under accelerated aging condition, the microstructure, chemical structure, crystallinity, degree of polymerization, variation of pH, alkali reserve and mechanical strength of the fiber before and after mineralization were studied. The results showed that nano-CaCO3 had no obvious effect on the properties of paper prepared from those mineralized fibers, but it can effectively neutralize the acid generated inside the fiber, slow down the degradation rate of cellulose and improve the permanence of the paper during the aging process. It provides a new insight for the manufacture of repair paper for cultural relics restoration. [ABSTRACT FROM AUTHOR]

Using cellulosic micro/nanofibrils (MFC/NFC) in developing films for coatings and packaging has aroused industrial interest to replace plastic. This study proposes functionalizing packaging films composed of hybrid suspensions of 80 % titica vine (Heteropsis flexuosa) and 20 % Pinus to improve their mechanical properties. The MFC/NFC were produced by mechanical fibrillation and adding proportions of 1, 2.5, and 5 % of nanolignin, vegetal tannin, and synthetic termite saliva. Both suspensions had concentrations of 1 % (w/w). The MFC/NFC were evaluated for energy consumption, microstructural, and stability, while the films were for physical, optical, barrier, and mechanical properties. Films with nanolignin 2.5 % obtained lower WVP and degradation in water, with greater hydrophobicity and puncture strength. The treatment with tannin 1 % obtained higher density and lower porosity, while termite saliva 1 % presented higher tensile strength at around 53.1 MPa. The additives improved the quality index of the MFC/NFC (>51.1 points). It is concluded that adding different binders can help expand the use of MFC/NFC. New studies are essential to seek pre-treatments or alternative fibrillation methods to increase their application and efficiency for fiber cell wall fibrillation, in addition to the need for a deeper analytical understanding of the interactions of additives with cellulose. [ABSTRACT FROM AUTHOR]

In this study, Kozo fibres were fibrillated using the stone wet milling method and the wet atomisation method both deriving from nanocellulose production processes. Kozo fibres with a high degree of external fibrillation were obtained by using the stone mill wet grinding method. Although fibres exhibited the same structure as untreated Kozo fibres, their bonding properties improved. Applying the wet atomisation method, fibrillated Kozo fibres with different degrees of fibrillation were obtained depending on the number of treatments. Fibrillated Kozo fibres can be used in conservation as an adhesive for lining and other stabilisation treatments and may in certain cases replace starch paste, which is susceptible to microbiological damage. Only Kozo fibres and water were used in both mechanical fibrillation methods; therefore, the resulting material can be considered a safe alternative to more traditional adhesives. [ABSTRACT FROM AUTHOR]

Recycled paper has become increasingly used as a raw material in the paper industry. However, hornification limits its application. Herein, the effect of recycling on the mechanical properties and microstructure of khasi pine pulp was systematically studied. The mechanical properties deteriorated and water retention value decreased after recycling. X-ray diffraction and Fourier-transform infrared spectroscopy revealed that cellulose crystallinity increased and partial cocrystallization occurred on cellulose microfibrils. Through the analysis of the morphology of secondary fibers by FQA, the loss of fine fibers caused by each reuse was found. Using the filtration method to prepare the recycled paper reduced the loss of fine fibers and improved the mechanical properties, with the tensile strength of a sample prepared using a sand core filter unit for five cycles (8.37 MPa) being like that of a sample prepared using a paper machine after one cycle. The investigation of the internal structure of the paper showed that the retained fine fibers were bonded between the long fibers, promoting the bonding between the fibers. Fine fibers improve the curling and twisting of fibers to some extent, especially in the first three recycling cycles. The hornification phenomenon of recycled paper was studied from the viewpoint of the fiber components, which is important to promote the development and application prospect of recycled paper. [ABSTRACT FROM AUTHOR]

Jabon (Anthocephalus cadamba) is a promising plant species with straight, visually pleasing trunks that can be harvested at a young age as a resource for pulp and paper production due to the rapid growth rate possessed. Therefore, this study aims to investigate the chemical composition and fiber biometry of 3, 6, and 9-year-old Jabon wood, determining their suitability as a pulp and paper raw material. Samples were collected from both stem and branch sections and analyzed according to the Tappi standard. Fiber cell maceration was conducted to enable the precise measurement of fiber dimensions and derivatives. The results showed high cellulose, holocellulose, and lignin content in Jabon wood, with low to moderate levels of extractives and ash. Additionally, the crystallinity index (CrI) increased with age, particularly from 3 to 9 years old. The branch of the plant, with Grade II fiber derivative quality, had lower CrI compared to the stem, while the inner stem showed a lesser value than the outer part. In conclusion, 3-year-old Jabon wood is a potential raw material for pulp and paper production. [ABSTRACT FROM AUTHOR]

Water plays an important role in the properties of cellulose. In materials design, the water uptake of cellulose has been traditionally seen as a drawback, since water reduces mechanical resistance of paper and cardboard, and at high hydration, cellulose-based products are disintegrated. However, recently, the hydration of cellulose has been considered as an advantage to design water-responsive soft actuators. In Nature, water is the fuel for several plant functions that involve motion, such as the seed release or the plant protection from high temperature and radiation. Inspired by these natural systems, cellulose-based actuators have been designed to display different movements (bending, twisting, curling) in response to water. Biopolymer structuration inducing anisotropy within the system allows the asymmetric expansion of layers, which results in macroscopic movement. This review gives an overview of the soft actuators triggered by the hydration/dehydration processes of cellulose. We present representative examples of water-triggered natural actuators, which have inspired researchers to design anisotropic cellulose-based materials that develop controlled movement in response to water. [ABSTRACT FROM AUTHOR]

Due to the increasing demands of consumers from the food packaging, it enabled the improve of active packaging practices. Antimicrobial and antifungal coatings or films are an active packaging application. In such packaging materials, natural or synthetic antimicrobial material is added to the film or coating to help the packaging protect food. The use of biofilms produced from biopolymers in food packaging is more suitable than polymers with many damages such as PET, PE. Film production of many biopolymers such as cellulose derivatives, chitosan, PVA, starch PLA can be realized. Pelargonium graveolens plant is a natural source with strong antifungal and antimicrobial properties. For the reasons explained above, the experimental study aims to manufacture printable film with antimicrobial properties which is used in active packaging, using cellulose butyrate acetate and Pelargonium graveolens essential oil. For this purpose, cellulose butyrate acetate bio films, having variative ratios (0.1, 2.5, 5, 10 %) of Pelargonium graveolens oil, were produced with spin coating method. The transparency of prepared five different films were defined by UV–vis. spectroscopy. The antimicrobial properties of the produced films were measured against gram positive and negative bacteria. All produced biofilms were printed. The printability parameters of biofilms, (color, gloss) were determined. Consequently, cellulose butyrate acetate films loaded with Pelargonium graveolens oil were successfully produced. It is concluded that obtained all biofilms are with no color, transparent and printable with oil based inks. It was determined that the quantity Pelargonium graveolens oil raised in the biofilms had a strong inhibitory effect against gram positive and negative bacteria. With these features; produced films are considered to be suitable for active packaging applications. [ABSTRACT FROM AUTHOR]

This study involved analysing the carbon-13 isotope ratio (δ13C) of cellulose, lignin, and whole wood powder of Balanites aegyptiaca to determine the optimal substrate for future ecophysiological studies. From seven different trees (i.e., three from the Sudanian zone and four from the Chadian Sahelian zone), 21 samples were taken for this study. Identical variation trends were observed with cellulose, lignin, and whole wood powder, with δ13C values for cellulose always higher than for the other substrates, although the trees were located under different climatic conditions. The means obtained were −26.0 ‰, −28.7 ‰, and −27.1 ‰, for cellulose, lignin, and whole wood powder, respectively. Spearman's correlation test, which was used to analyse relationships between the results, revealed a strong correlation (r2 = 0.93) between the δ13C cellulose values and those of whole wood powder from B. aegyptiaca, as well as between the δ13C cellulose values and those of lignin (r2 = 0.73). This strong correlation between cellulose and wood powder results, and between cellulose and lignin, suggests that the isolation of cellulose is not necessary for δ13C analysis of B. aegyptiaca wood. [ABSTRACT FROM AUTHOR]

In this research work, cellulose was isolated from Dodonaea viscosa plant by means of various chemical processes followed by the preparation of nanocellulose through sulfuric acid hydrolysis. These chemical processes begin with the removal of non-cellulosic material such as lignin, pectin, crude wax, and hemicellulose followed by alkaline treatment and chlorine-free bleaching methods. Fourier transform infrared (FTIR) spectroscopy showed the successful isolation of cellulosic material after removing hemicellulose, lignin, and other extractives. Thermogravimetric analysis (TGA) elucidated the thermal degradation profile of the cellulose-based materials obtained after various chemical procedures at each step. Additionally, nanocellulose was prepared from cellulosic material using acid hydrolysis, and its structural and thermal properties were discussed. Nanocellulose extraction from the lignocellulosic biomass sources and its further utilization has been the subject of intensive research as the global community needs the use of green chemistry principles in recent life. Nanocellulosic material due to its unique characteristics and properties is of great importance and has many applications in various industries, including materials science and engineering. [ABSTRACT FROM AUTHOR]

Thermally modified timber (TMT) reduces hygroscopicity, increases dimensional stability, and decay resistance. Although there is a substantial amount of research on heat-treated wood, investigations on the sensitivity of cell wall swelling behavior to water variation are limited. Therefore, this study focused on the swelling behavior of TMT from cellular and chemical perspectives. The effects of heat treatment on the hygroscopicity and swelling behavior of the wood cell walls were studied using dynamic vapor sorption and confocal laser scanning microscopy. Changes in the chemical composition and cellulose crystallinity were studied using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction. The results revealed that the hygroscopic swelling of latewood significantly decreased with increasing treatment temperature, reducing the anisotropy of the wood cell swelling. The hygroscopicity of wood was reduced by heat treatment, and a clear decrease in hysteresis was observed at elevated treatment temperatures. The FTIR spectra indicated that both hemicellulose and lignin were degraded. The crystallinity and lateral size of the cellulose increased after heat treatment. Similar changes in the chemical composition and crystallinity of cellulose were observed in the latewood and earlywood. [ABSTRACT FROM AUTHOR]

Adhesion of fibers within a spun tow, including carbon fibers and precursors, is undesirable as it may interrupt the manufacturing process and entail inferior fiber properties. In this work, softwood kraft lignin was used together with a dissolving pulp to spin carbon fiber precursors. Lignin–cellulose precursors have previously been found to be prone to fiber fusion, both post-spinning and during carbon fiber conversion. In this study, the efficiency of applying different kinds of spin finishes, with respect to rendering separable precursors and carbon fibers, has been investigated. It was found that applying a cationic surfactant, and to a similar extent a nonionic surfactant, resulted in well separated lignin–cellulose precursor tows. Furthermore, the fiber separability after carbon fiber conversion was evaluated, and notably, precursors treated with a silicone-based spin finish generated the most well-separated carbon fibers. The underlying mechanism of fiber fusion post-spinning and converted carbon fibers is discussed. [ABSTRACT FROM AUTHOR]

This research study reports on the extraction of nanocellulose followed by structural and thermal analysis and application of nanocellulose in hydroxypropyl methyl cellulose (HPMC) nanocomposite films. The cellulose nanocrystals were isolated from Artemisia scoparia straw through an alkaline treatment and bleaching process, followed by sulphuric acid hydrolysis. The HPMC nanocomposite films were prepared by a solution casting method and dried at room temperature. Fourier transform infrared-ray (FTIR) spectroscopy and thermogravimetric analysis (TGA) techniques were used to analyze the structural and thermal properties of the materials, including the cellulosic material, the nanomaterial, and the nanocomposites. The FTIR spectra indicated that the extraction procedure was adequate, demonstrating the removal of lignin and hemicellulose and the preparation of nanocellulose. The TGA results revealed the thermal degradation pattern of the cellulose and showed that the HPMC films had enhanced thermal stability. This research demonstrates that A. scoparia straw has potential for the extraction of cellulosic nanomaterial and a wide range of applications in nanocomposites. [ABSTRACT FROM AUTHOR]

In this study, the effect of different concentrations of calcium hydroxide (Ca(OH)2) was evaluated as a pre-treatment for accelerated carbonation and its influence on the fibrillation of cellulosic pulps to obtain nanofibrils, and its application as a coating agent for papers. Eucalyptus (EUC) and Pine (PIN) unbleached cellulosic fibers were submitted to pre-treatment with Ca(OH)2 at concentrations of 5 and 10% and subjected to accelerated carbonation, being subsequently mechanically fibrillated to produce cellulose nanofibrils (CNF). Pretreatment with calcium hydroxide followed by accelerated carbonation provided a 35% reduction in energy consumption. Cellulosic pulps EUC and PIN pretreated with calcium hydroxide showed higher fibrillation efficiency. There was a reduction in the cobb test values for papers coated with CNF in PIN. The WVP was lower for papers coated with CNF of EUC and control PIN. The CNF coating of EUC and PIN provided an oil barrier for the kit 11 solution. The CNF coating improved the dispersion of PVA and PVOH. The papers coated in this work have the potential to be used as packaging for fatty and oily foods or as a spreading agent for other industrial coatings. [ABSTRACT FROM AUTHOR]

A never-dried (ND) fines-free softwood bleached kraft pulp was converted to air-dried and thermally dried handsheets, which were then disintegrated or sonicated in water under various conditions. These disintegrated or sonicated pulps were converted to handsheets and used to obtain fundamental data on paper recycling. The water-vapor-adsorption isotherms of the pulp and sheet samples after super-critical-point drying showed clear differences between the water volumes adsorbed by the ND pulp, once-dried pulp, and dried sheets at the same relative humidities above 50%. These differences are caused by hornification of the pulp and sheet samples during drying and recycling. Air and thermal drying of wet webs decreased the adsorbed-water-vapor volume by 7%–9% and 14%–18%, respectively, relative to that adsorbed by the original ND pulp. We hypothesize that the decrease in water-vapor-adsorption volume from that of the original ND pulp at relative humidities >50% reflects the degree of irreversible formation of hydroxyl groups in the originally hydrophilic hemicelluloses and crystalline cellulose microfibril surfaces in the pulp and sheet samples during drying and paper recycling. The water-vapor-adsorption isotherms of pulp and sheet samples can be used to quantify the degree of hornification or the amount of irreversible hydrogen bonds formed during paper recycling. [ABSTRACT FROM AUTHOR]

Approaches to obtain nanocellulose have been extensively suggested, and among the most competitive methodologies includes mechanical defibrillation, which results in a nanocellulose gel suspension that can be used in a variety of applications. However, standard procedures results in inhomogeneous fibre sizes due to its physical approach. Pre-treatments have been suggested, such as enzymes, but their cost is a disadvantage. In this work, we suggest the use of cryoslash for bleach kraft pulp using a simple methodology of embedding the dry kraft pulp in distilled water following by freezing at −80 °C, which was slashed using a common blender and submitted to an ultra-fine friction grinder. Samples were studied at various grinding steps 5, 15, 30, 60 and 120. Overall, the energy difference required to defibrillate with cryoslash was ∼3.26 kWh/kg at 30 steps and ∼6 at 120 steps, which was similar to enzymatic pre-treatment with nanofibrils significantly smaller. Cryoslash presented a unique C–H in plane structure from nanocellulose, related to a decrease in average size of fibrils, while crystallinity and thermal properties of nanocellulose remained stable at 60 steps, but mechanical properties increased until 120 steps along with the transmittance values related to the energy consumption curve. [ABSTRACT FROM AUTHOR]

Reasonable use and disposal of agricultural and forestry wastes become an urgent focus of attention with the dangers of pollution and squandering. In this paper, palm leaves, a typical kind of cellulose-rich agricultural and forestry waste, were attempted to prepare high-valued porous aerogels with cellulose by a short and mild extraction followed by the process of cross-linking with polyvinyl alcohol (PVA). Scanning electron microscope (SEM), Fourier transform-infrared (FTIR), X-ray diffraction (XRD), Bruno-Emmett-Teller (BET), and thermogravimetric analysis (TGA) were applied to examine their structures, chemical composition, and performance compared with hardwood cellulose aerogels. The results showed that palm leaf cellulose could be extracted friendly under mild extraction of 5% NaOH solution for 7 h, following 10% H2O2 solution for 8 h at 80 °C, which inhibits effectively the alkaline hydrolysis of cellulose with the extraction rate of 35.25%, the cellulose purity of 87.12%, and crystallinity of 69.9%. Compared with hardwood cellulose aerogel, the prepared environmentally friendly and recyclable palm leaf cellulose aerogel is a promising application material with similar ultra-low density, high porosity, specific surface area, thermal stability, and better compression resilience, which provides a new technical direction for the high-value application of agricultural and forestry wastes. [ABSTRACT FROM AUTHOR]

Due to the complex storage environment, paper documents will suffer different degrees of damage during storage. Studying the aging behavior of paper after strengthening treatment is an important aspect of evaluate the effect of strengthening agent treatment. In this paper, the aging resistance properties of base paper, APTES, AEAPMDMS, and APTES/AEAPMDMS reinforced samples after dry heat aging and moist heat aging were studied. The results show that in the early stage of aging, the amorphous region of the fiber is mainly degraded gradually. With the passage of time, the crystalline region of cellulose is also degraded continuously, and the crystalline region of cellulose is degraded more significantly during moist heat aging. Compared with the base paper, the AAAS reinforced paper sample can significantly slow down the aging and degradation of the paper sample and has better aging resistance. [ABSTRACT FROM AUTHOR]

The process of retting bast fiber plants for the production of long fiber has presented major challenges. Water retting, dew retting, chemical extraction, and micro-organism (fungi, enzymes) techniques were applied to the extraction of natural fibers. The two nettle samples were extracted with water retting for 14 days and dew retting for 4 weeks. This research investigated the effects on the traditional retting process of nettle fiber by fungi and bacteria formation in lignocellulosic. The latter biological extraction methods successfully degraded the lignin and pectin materials of the fiber and increases the cellulose content. These extraction methods produced high quality fiber and tensile strength at a low cost. This study determined the chemical, physical, and mechanical characteristics such as fiber cellulose, non-cellulosic content, tensile strength, tenacity, and elongation break to see how treatments affected them. The treated fiber surface morphology was characterized using scanning electron microscopy. To evaluate functional group alterations, Fourier-transform infrared spectroscopy was used on the fiber specimen. [ABSTRACT FROM AUTHOR]

Improving the retention and drainage aid performance of high speed papermaking processes is an important and challenging issue. In this study, fiber modification was used to improve the papermaking retention and drainage aid performance. The graft copolymerization of glycidyl methacrylate (GMA) with cellulose fibers was initiated using Fe2+-thiourea dioxide(TDO)-H2O2 in a mild aqueous medium; the synthesized polyglycidyl methacrylate grafted cellulose (CPGMA) was used to replace softwood bleached kraft pulp(SBKP) and hardwood bleached kraft pulp(HBKP), to study their retention and drainage aid behavior in the cationic polyacrylamide (CPAM)/colloidal SiO2/ anionic polyacrylamide (APAM) system. Graft copolymerization significantly enhanced the fiber hydrophobicity. Additionally, the papermaking process drainage aid performance and retention rate of the filler increased significantly with an increase in the CPGMA substitution rate. A small amount of CPGMA (0.5 %) significantly improved the dewatering ability and some improved the retention performance of the wet end of papermaking. SBKP-polyglycidyl methacrylate grafted cellulose (S-CPGMA) exhibited better retention and drainage aid performance than HBKP-polyglycidyl methacrylate grafted cellulose (H-CPGMA). Thus, introducing Fe2+-thiourea dioxide(TDO)-H2O2 initiated graft copolymerized S-CPGMA (in mild aqueous media) into pulp could improve the retention and drainage aid performance of the wet part of paper production. [ABSTRACT FROM AUTHOR]

Pre-treatments reduce energy consumption for the production of cellulose micro/nanofibrils (MFC/CNF). The objective of this work was to study sodium silicate (Na2SiO3) solutions as pre-treatment for Eucalyptus sp. and Pinus sp. pulps. The treatments were identified as EUC SS 5 % and EUC SS 10 % when 5 and 10 % Na2SiO3 were used, respectively. The treatments for Pinus sp. pulp were identified as PIN SS 5 % and PIN SS 10 %, and the untreated pulps as EUC control and PIN control. The lowest hemicellulose content was obtained for PIN SS 10 %. EUC SS 10 % showed the highest WRV values. EUC SS 5 % (∼ 4100 kWh/t) and EUC SS 10 % (∼ 4200 kWh/t) showed the lowest energy consumption. The pre-treated MFC/CNF showed diameters below 45 nm. The lowest viscosity was obtained for EUC SS 5 % (5.5 cP) and the highest for PIN control (7.7 cP), respectively. The zeta potential indicated moderate stability of the suspensions (−24 ∼ −18 mV). Na2SiO3 showed efficiency for MFC/CNF production due to reduced energy consumption and better individualization. The suspensions have compatible characteristics for application as a stabilizer of colloidal systems and reinforcement of composites. [ABSTRACT FROM AUTHOR]

High alkali impregnation (HAI) increases the total yield of softwood pulps following kraft cooking. This yield improvement is also maintained after oxygen delignification. This study evaluates how bleaching with either chlorine dioxide or hydrogen peroxide affects the final yield of samples obtained with standard and HAI. The chemical composition, viscosity, brightness, mechanical and morphological properties were studied. Compared to cooking after standard impregnation the yield improvement achieved by HAI was preserved in both types of bleaching sequences (2 % units for chlorine dioxide and 4 % units for hydrogen peroxide). The introduction of charged groups into the cellulose fibers was higher with hydrogen peroxide bleaching than with chlorine dioxide however, no significant impact was seen on the swelling or mechanical properties. The brightness was higher for the pulps bleached with chlorine dioxide compared with hydrogen peroxide. Hydrogen peroxide bleaching resulted in similar brightness development for both standard and HAI. Fibers bleached with chlorine dioxide had the highest curl index (16–17 %) compared to the fibers bleached with hydrogen peroxide (15 %). [ABSTRACT FROM AUTHOR]

The production of bioethanol from materials of renewable origin is an important matter for a more sustainable economic development, and at the same time it challenges researchers to seek more efficient technologies that can make it viable. Wood is a profitable and advantageous option, with special emphasis on eucalyptus, whose cultivation has high turnover in Brazil, where land is available for this purpose. Therefore, the goal of this research was to optimize the hydrolysis stage using acid instead of enzymes for the conversion of chips of Eucalyptus urograndis into bioethanol, with additional co-production of furfural and commercial lignin, in order to make the process more advantageous. To obtain bioethanol, a pre-treatment adapted from autohydrolysis was performed to remove the hemicelluloses, followed by soda pulping to remove the lignin and, finally, the acid hydrolysis of the β-(1→4) glycosidic bonds between the C1–C4 cellulose carbons releasing β-D-glucose monomers to be fermented into bioethanol. In the acid hydrolysis step, sulfuric acid of concentration 1127 gL−1 was used. After the experimental analyses performed, it could be observed that in acid hydrolysis, treatments using 70 mL and 80 mL of sulfuric acid did not differ statistically in relation to glucose production. However, by increasing the volume of acid to 90 mL, there was an increase in the production of fermentable sugars into bioethanol, 63.7 %, which began decreasing when adding acid above 93 mL, because the excess of acid also caused the degradation of sugars into 5-hydroxymethylfurfural (HMF); and in the treatment of 100 mL there was a higher production of HMF. The production of bioethanol proved to be competitive after the fermentation of the sample from the 90 mL treatment with a production of 103.7 L of bioethanol/ton of wood, in addition to being beneficial to the process as a whole with the co-production of furfural, 28.8 kg of furfural ton−1 of wood, and commercial lignin, 428.3 kg of lignin per ton of wood, precursors to various chemicals such as resins, coatings and inks. [ABSTRACT FROM AUTHOR]

This study examined the influence of lignin dehydrogenation polymer (DHP) deposition on the morphology and properties (e.g., tensile property, thickness, and water content) of cellulose microfibril-based gels. Cellulose microfibrils were isolated from wood powder and a stable hydrogel with a layered structure after treatment with 8% (w/v) NaOH were produced. Gels were artificially lignified of by repeated immersion in an ethanol solution containing lignification agents (coniferyl alcohol, horseradish peroxidase, and H2O2) and evaporating the ethanol under vacuum. The use of ethanol allowed DHPs to penetrate the gel, and the deposition of DHPs was achieved by evaporating ethanol under reduced pressure. With increase in the number of lignification cycles to 10, the thickness and water content of the microfibril gels decreased and the ratio of DHP to cellulose, elastic modulus, and tensile strength increased. These results indicate that the elastic modulus of the gels improved not only because of the decrease in water content, but also because of the constrained motion of the microfibril network due to of DHP deposition. The reported artificially lignified cell wall model will help improve the understanding of how lignification contributes to the mechanical strength of plant cell walls. [ABSTRACT FROM AUTHOR]

This paper presents the concept of an alkali-O2 oxidation process for producing lignin dispersants in a feasible manner at a kraft pulp mill. The oxidation process uses O2 gas to increase the anionic charge of lignin and the final oxidised lignin can serve as a concrete plasticiser or versatile dispersant. The integrated process provides several benefits for lignin recovery, the following lignin oxidation, and recycling of chemicals. Firstly, CO2 precipitated kraft lignin can be used without a sulphuric acid washing step. This simplifies the lignin recovery and no excess sulphur is introduced into mill cycle. As the unwashed lignin is alkaline in nature, the need for fresh alkali in the lignin oxidation is reduced. Moreover, oxidised white liquor, readily available in the mill, can be applied as a partial source of alkali. Finally, membrane filtration of the oxidised lignin solution enables the recirculation of sodium and sulphur back to the chemical cycle and provides a concentrated lignin product. Based on a simulation study, this novel concept significantly decreased the need for purging fly ash at the mill when compared to conventional lignin recovery. It was also demonstrated that the novel lignin dispersants can compete with the tested commercial oil-based plasticisers. [ABSTRACT FROM AUTHOR]

The accumulation of petroleum products causes damage to ecosystems, which can be avoided with cellulose-based products. The influence of different ratios of cellulose micro/nanofibrils (MFC/NFC) on the properties of hydroxypropyl methylcellulose (HPMC) films was evaluated. Films were prepared using proportions of 0, 25, 50, 75 and 100 % (w/w) of MFC/NFC from Pinus sp. in relation to HPMC. Physical, barrier, surface, optical, morphological and mechanical properties were evaluated. Solids content, basis weight and density values increased with higher amount of MFC/NFC and thickness and porosity were reduced. SEM images showed that films with more than 50 % MFC/NFC had a more granular surface, which decreased transparency from 80 to 65 %. Water vapor penetration did not differ between films and degradation in water was reduced from 40 to 5 % with MFC/NFC addition. There were no differences in contact angle and wettability, but all films showed high resistance to fat penetration. Films with MFC/NFC content between 75 and 100 % showed higher values for tensile strength (50 to 65 MPa) and Young's modulus (6 to 10 MPa) and lower elongation at break (1 to 2 %). The experimental results indicated that films with MFC/NFC content above 50 % have potential to be used as packaging material. [ABSTRACT FROM AUTHOR]

Previously it was shown that wood chip compression or enzyme impregnation prior to refining reduces energy consumption and improves pulp quality. This work characterizes the effect of different magnitudes and rates of compression on the extent of enzymatic hydrolysis. A laboratory compressor and a controlled uniaxial load set-up were used to apply different compression ratios and compression times to mixed-softwood wood chips. The chips were subsequently subjected to enzymatic hydrolysis with a high-yield exoglucanase preparation to demonstrate changes in cellulose hydrolysis. Enzymatic hydrolysis yield increased with compression ratio but was unaffected by compression time. Increasing compression ratio increased removal of soluble molecules such as sugars and acid-soluble lignin. Microscopy imaging showed increased cell wall buckling and fracturing with increased compression. The morphological changes led to improved enzyme diffusion and resulted in higher available surface area. The improved cellulose hydrolysis is due to changes in wood morphology as well as the removal of extractives. [ABSTRACT FROM AUTHOR]

Conductive cellulose fibers may find application in producing antistatic materials and fibrous electronic elements for smart textiles (textronics). In this paper, we present a method of fabrication of cellulose fibers modified with the reduced graphene oxide (rGO) and graphene oxide (GO). The fibers were obtained by using N-methylmorpholine-N-oxide (NMMO) as a direct solvent, adding dispersion of GO during the cellulose dissolution process. In the next step, the GO enclosed in the fibers was reduced for ca. half an hour at 90°C with the excess of water solution of hydrazine to obtain fibers containing rGO. The viscosity of the spinning solution increased when GO was added; however, the difference is important at low shearing rates but decreases at high shearing rates, similar to that used in the process of fiber spinning. Cellulose fibers containing 3, 4, 6, and 10% w/w of rGO were obtained. Fiber morphology was studied using electron microscopy. The results of the electrical properties' measurements showed that the conductivity of modified fibers strongly depends on the concentration of rGO. At 10% rGO conductivity was 9 x 10−3 S/cm. The mechanical properties of the obtained fibers were slightly changed by the presence of GO and rGO. Tenacity and elongation at break decreased with the increase in the content of GO and rGO in the fibers but remain at an acceptable level from the textiles processing point of view. [ABSTRACT FROM AUTHOR]

The main challenges in the conversion of a paper-grade pulp and producing dissolving-grade pulp are the selective removal of hemicelluloses and the high pulp reactivity ([13]; [24]; Kopck 2010; [25]; [33]). Dissolving pulps are chemically refined bleached pulps that exhibit high cellulose content (over 90%) with advantageous properties such as high purity, high brightness, uniform molecular mass distribution and high cellulose reactivity, which represents a significant niche in the pulp industry ([24]; [25]; [26]; [35]; [43]). Keywords: bagasse soda pulp; cold caustic extraction; dissolving pulp; IONCELL-P(ulp); xylanase EN bagasse soda pulp cold caustic extraction dissolving pulp IONCELL-P(ulp) xylanase 473 483 11 05/09/22 20220501 NES 220501 1 Introduction Human dependence on petroleum-based products has raised concerns due to the negative impacts on the environment. [Extracted from the article]

In this study, the effect of bacterial cellulose nanofibers (BCNF) incorporation on the structural and rheological properties of casein gels was investigated, where the mixed BCNF and casein gels were prepared by adding gluconic acid δ-lactone (GDL) to acidify the mixed polymer solutions at 3.0% casein concentration (w/v) and varying BCNF concentrations (0–0.5%, w/v). By changing the addition amount of GDL, the mechanical and structural properties of the mixed gels were studied at above, near and below the electric point (pI) of the casein. At pH above the pI of the casein, the introduction of BCNF initially increased the gel strength, but further addition of BCNF weakened the mixed gels. At near and below the pI of the casein, the incorporation of BCNF continuously increased the gel strength. Besides, all gels showed good structural homogeneity, without macroscopic phase separation occurring, which indicated good compatibility of BCNF with the casein gels. [ABSTRACT FROM AUTHOR]

The paper aims to present the main tendencies on the global and European natural polymer markets in recent years from the point of view of the requirements and achievements of the European Commission that have been expressed in recent programs and Strategies, with special reference to the Circular Economy New Action Plan and the European Green Deal—the EU Strategies for Climate Neutrality. Natural polymers play an important role among biodegradable products whose role in the production and international trade has been systematically increasing, especially since the middle of the last decade of the new century (2015). Natural polymers are also recommended by the EU from the point of view of their specific importance in the group of biodegradable products. [ABSTRACT FROM AUTHOR]

The article presents a method of obtaining films based on carboxymethyl polysaccharide derivatives cross-linked with citric acid and reinforced with cellulose fibers (CFs). The addition of CFs to a film improves the mechanical properties of the composite. With the increase of filler content, the water solubility drops from 64 to 61%, respectively, for a system without a filler and that containing 7 wt% CFs, whereas Young’s modulus increases from 4.8 to 24.8 MPa for a film containing 5 wt% filler.