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Wet-strength additives are vital in maintaining the structural integrity of paper and paper-based products in wet conditions. Most wet-strength additives are synthetically produced and pose environmental and human health risks. Therefore, there is a growing interest in developing natural and environment-friendly wet-strength additives for paper. However, the unavoidable replacement of these harmful wet-strength additives with greener materials to achieve similar wet-strength without compromising product performance, with the added option of sustainability, is challenging. This review discusses up-to-date conventional synthetic, natural, and other wet-strength additives used in developing wet-strength in paper-based products. A detailed description of the additive's reaction mechanisms and working principles for achieving the required wet-strength is also analyzed. Moreover, a detailed comparative literature review of the physio-chemical properties of these wet-strength additives is also discussed. Finally, the paper also discusses the challenges associated with bio-based additives in improving the wet-strength of paper-based products, comparing the well-established synthetic wet-strength additives. [ABSTRACT FROM AUTHOR]

Background and objectives: Paper industry in addition to reducing the consumption of various resources such as water, energy, and wood, continues to recycle used paper in different countries due to less pollution. One of the major drawbacks of the old corrugated container (OCC) recycling is its relatively weak strength, which has limited its use in various sections of the packaging industry. In this study, the effect of using some additives to improve the strengths of OCC to make the top liner of cartons in both wet and dry conditions was studied. Methodology: OCC was selected from domestically produced cartons. To determine the performance and optimal amount of additives, corn cationic starch (at 1, 1.4 and, 2%), wet strength resin (at 1, 2 and, 3%), AKD (at 1, 2 and, 3%), and long fiber of imported bulk tea wrapping paper (at 10, 15 and, 20%) based on the dry weight of OCC pulp were separately used as additives. The handsheets were made using laboratory sheet former with the basis weight of 120 g/m² and then tensile, burst, and tear indices were measured both at wet and dry conditions to compare the effect of additives. Also, water absorption was measured by the Cobb test on the test samples. The optimal level of each additive was determined based on the results, and then handsheets data from optimal combination treatment including appropriate levels of all additives, and different properties of handsheets were statistically compared. Results: The water absorption of handsheet was statistically decreased to 90% level compared to the control by adding AKD. This additive was able to reduce the water absorption of handsheet made from OCC to about 20 g/m² as the appropriate range. The greatest increase of wet tensile strength of the handsheet was achieved using 3% wet strength resin compared to the control. The resin maintained the wet tensile, burst, and tear indices of the residual strength of handsheet by 25, 46, and 58%, respectively, compared to dry strengths which indicates its good performance. The results showed that by adding cationic corn starch and recycled long fiber paper, all the dry strengths of handsheet independently increased compared to the control. The optimal combination treatment was determined according to the results independent use of additives in OCC pulp, including 1% cationic starch, 1% AKD, and 3% wet strength resin based on technical-economic considerations. There is no significant difference between dry tensile and burst strength of handsheet using this treatment and 20% recycled long fiber of wrapping paper, which both means ranked statistically in the same group. Conclusion: The use of 20% recycled long fiber of wrapping paper significantly improved the dry strength of OCC pulp, but adding 1% cationic corn starch to OCC pulp caused limit increase in dry strength. The wet strength of handsheet was significantly improved by adding 3% wet strength resin whereas 1% AKD significantly decreased the water absorption of the OCC pulp to 14 g/m². The optimal combination treatment of chemical additives including 1% cationic corn starch, 1% AKD, and 3% wet strength resin improved the wet and dry strength of handsheet made from OCC pulp that could be used for packaging products which need to be kept in refrigerator and freezer. [ABSTRACT FROM AUTHOR]

To investigate the effects of different organic acid additives and their concentrations on the fermentation quality and bacterial community of paper mulberry silage, paper mulberry was left untreated (control) or was treated with ethylenediaminetetraacetic acid (EDTA), propionic acid (PA) or citric acid (CA), the amount of each additive was 2 g.kg−1 FM, 5 g.kg−1 FM and g.kg−1 FM. All groups were ensiled for 3, 7, 15, 30 and 60 days. Compared to the control, adding EDTA reduced protein breakdown, preserved more water-soluble carbohydrates of the silages (WSCs, 24.74 g.kg−1 DM), and high concentrations of EDTA inhibited the activity of undesirable microorganisms. Adding PA increased the abundance of Lactiplantibacillus and decreased the abundance of Enterococcus, and it caused a rapid decrease in the pH of the silage at an early stage (from 6.50 to 5.31) while altering the microbiota, and low concentrations of PA resulted in high LA (66.22 g.kg−1 DM) concentration and low PA (9.92 g.kg−1 DM) concentration at 60 days of ensiling. Different concentrations of additives altered the microbial community of paper mulberry to different degrees. High concentrations of PA and CA can increase the abundance of Lactiplantibacillus. High concentrations of CA resulted in a rapid decrease in silage pH at an early stage and higher WSC concentration. These results suggest that EDTA, PA and CA can be used as additives to improve the quality of paper mulberry silage.

Paper mulberry (Broussonetia papyrifera L., PM) is being used as a new type of animal protein feed to address the feed crisis. To investigate the effect of additives on the chemical composition, fermentation quality, and bacterial community of PM silage (at room temperature, 25°), paper mulberry was fermented with formic acid (FA), Amomum villosum essential oil (AVEO) and lactic acid bacteria (LAB) inoculant treatments. The results showed that fresh PM had a low water-soluble carbohydrate (WSC) content and large amounts of unclassified bacteria. Compared with the CK and LAB treatments, the FA and AVEO treatments significantly (P < 0.05) decreased the pH and increased the lactic acid content of PM silage after 60 days of ensiling. In the AVEO-treated silages the abundance of Lactococcus in the early stage of ensiling increased by 14.09%, the abundances of Levilactobacillus and Lentilactobacillus in the late stage of ensiling increased by 58.34 and 91.12%, respectively, and the abundance of Stenotrophomonas decreased by 94.71%, resulting in improved PM silage quality. These results confirmed that AVEO could potentially be developed as a new additive for improving the fermentation quality of silage.

Background and Objectives: Paper recycling is currently considered as one of the most important solutions for environmentally friendly and sustainable paper production. This process not only reduces the consumption of resources like water, energy, and virgin fibers but also contributes leads to a decrease in pollution. As a result, the paper recycling rate is continuously increasing in various countries, further emphasizing its importance in achieving a greener and more sustainable paper industry. Recycled paper is predominantly utilized in the production of packaging paper and board. However, it is crucial for these paper products to possess not only dry strength but also the ability to maintain the necessary strength when exposed to wet conditions, especially for packaging goods that require cold or freezing storage. To achieve this, various techniques such as refining and additives consumptions can be employed. The objective of this study is to explore the individual impact of each factor, as well as their interaction effects, in order to enhance the properties of office deinked pulp (DIP) for the production of packaging paperboard in order to improve the overall characteristics and performance of the packaging paperboard. Materials and Methods: DIP, sourced from Latif Paper Company, was subjected to refining until it reached an SR value of 30. The additives including cationic corn starch (at four levels of 1%, 1.4%, 2%, and 3% based on the dry weight of pulp), wet strength resin (at three levels of 1%, 2%, and 3% based on the dry weight of pulp), and AKD (at three levels of 1%, 2%, and 3% based on the dry weight of pulp), were individually incorporated into the pulp suspension. Handsheets were made with the basis weight of 120 g/m2 . To evaluate and compare the impact of the optimal additive treatment on the treated pulp, various tests were conducted on the handsheets. These tests included measuring water absorption, tensile strength, burst strength, tear strength, wet strength retention, and absolute wet strength retention. The relative retention strength was determined by assessing the independent effects of each treatment on the tensile strength, burst strength, and tear strength of handsheets under both wet and dry conditions. Results: The impact of refining on the strength of handsheets made from DIP was found to be statistically significant in dry conditions. The results demonstrated that incorporating 2wt% cationic corn starch into the refined pulp led to the improved performance, particularly in terms of tear strength, compared to the independent factor of refining alone. Additionally, the utilization of wet strength resin and AKD showed a remarkable increase in the strength of handsheets under wet conditions, as well as a significant reduction in water absorption when compared to the control sample. Furthermore, employing both refining and the optimal combination treatment of additives - including 2wt% cationic corn starch, 3wt% wet strength resin, and 1wt% AKD - simultaneously resulted in a significant enhancement in both the wet and dry strength of the handsheets, as well as a decrease in water absorption. This indicates that the combined treatment presented a positive effect on the overall performance of the handsheets. Conclusions: The application of the optimal combination treatment, which involved refining DIP and adding additives simultaneously, resulted in the improvement of all handsheet properties when compared to the control sample. This enhanced handsheet could be suitable for packaging products that require refrigeration or freezing conditions. In dry state, the strength of the handsheets exceeded the standard strength of bleached kraft paper as per Iran national standard no. 2875, with the exception of tear strength. The evaluation of absolute relative retention wet strength indicated that the performance of the combination treatment was highly favorable compared to previous research reports. The combination treatment remarkably reduced water absorption of the handsheet by 22 g/m², making it suitable for paper storage in freezing conditions. [ABSTRACT FROM AUTHOR]

The demand for eco-friendly packaging materials has urged researchers to look for alternatives to petroleum-based polymers. In this regard, paper-based products have turned out to be a promising choice; however, their weak resistance to water has limited their application. The use of various additives to enhance paper's moisture resistance is a common practice. However, considering the growing global agenda for sustainable development, the search for new bio-based paper additives has become increasingly important. This study investigated the potential synergistic impact of the addition of nanofibrillated cellulose (NFC) and chitosan additives (CHIT) to different fiber combinations to improve paper's properties, in particular, their wet strength. The efficacy of the additive application order was examined and was found to be crucial in achieving the desired outcomes. The results showed that incorporating CHIT after NFC enhanced the paper's tensile and burst indicators, as well as the paper stretch in the dry state, by 35–70%, 35–55%, and 20–35%, respectively. In addition, the tensile index and stretch in the wet state improved 9–13 times and 2.5–5.5 times over, respectively. The air permeability decreased 2.5–12 times over. These findings demonstrate that the sequential addition of the NFC and CHIT additives yield a greater enhancement of paper's properties than using each additive separately. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria occupy an important position in silage microorganisms, and the effects of exogenous lactic acid bacteria on silage quality have been widely studied. Microbial metabolism has been proved as an indicator of substrate utilization by microorganisms. Paper mulberry is rich in free carbohydrate, amino acids, and other components, with the potential to be decomposed and utilized. In this study, changes in the microbial metabolism characteristics of paper mulberry silage with Lactiplantibacillus plantarum (LP) and Lentilactobacillus buchneri (LB) were studied along with a control (CK) using BIOLOG ECO microplates. The results showed that average well-color development (AWCD), Shannon diversity, Shannon evenness, and Simpson diversity exhibited significant temporal trends. LB and LP responded differently in the early ensiling phase, and the AWCD of LB was higher than LP at 7 days. Principal component analysis revealed that CK, LB, and LP samples initially clustered at 3 days and then moved into another similar cluster after 15 days. Overall, the microplates methodology applied in this study offers important advantages, not least in terms of accuracy.

[Display omitted] • PCB was co-pyrolyzed in fixed and fluidized bed (FB) pyrolyzers with Ca-based additives. • Catalytic and dehalogenation capacities of CaO, Ca(OH)2, and CaO + Ca(OH)2 were compared. • CaO reduced the halogen content of bio-oil up to 80 and 92% in fixed bed and FB. • Halide fixation in the solid phase by additives was more effective in FB than fixed bed. • Up to 40.6% liquid recovery was achieved in a FB containing CaO + Ca(OH) 2. This study compares the impact of the calcium-based additives and the pyrolyzer on the recovery and the halide content of the oil produced from the pyrolysis of paper-laminated phenolic resin printed circuit boards (FR2-PCB). The preliminary experiments showed that the maximum liquid recovery (40.6%) was achieved in a fluidized bed pyrolyzer containing a 50:50 mixture of CaO and Ca(OH) 2 operating at T = 620 °C and PCB-to-additive ratio (FR2/A) = 5.4 g/g for 22 min. Extra tests were then carried out under these conditions in fixed and fluidized bed pyrolyzers to separately explore the impact of CaO, Ca(OH) 2 , and CaO + Ca(OH) 2 on the liquid recovery (L R) and the halogen content of the non-solid products. In the fluidized bed, L R in the presence of CaO, Ca(OH) 2 , and CaO + Ca(OH) 2 was 34.5%, 41.2%, and 38.9 wt%, respectively. The fraction of phenolic compounds in the pyrolysis oil ranged from 86% to 93%, about 1–3% higher than the corresponding values in the fixed bed. Using additives led to lower halide content in the pyrolysis oil of the fluidized bed than that of the fixed bed. However, the opposite trend was observed in the absence of additives. Regardless of the type of pyrolyzer, Ca(OH) 2 was more successful than CaO in increasing L R , whereas CaO was more effective than Ca(OH) 2 in pyrolysis oil dechlorination. Co-pyrolysis of FR2-PCB and CaO + Ca(OH) 2 in a fluidized bed reactor was identified as a practical approach to enhance the recovery of pyrolysis oil comprising only 5% of the original halogen content of the feedstock. [ABSTRACT FROM AUTHOR]

The use of paper dry strength additives is one of the methods for producing packaging boards with a lower grammage while maintaining mechanical properties. In the present work, papers were formed using dissolving grade kraft fibres, kraft fibres and carboxymethylated cellulose (CMC) modified kraft fibres (C-kraft fibres), with either cationic starch (CS), anionic polyacrylamide (APAM) or anionic polyelectrolyte complexes (PECs). Fibres and sheets were characterized to evaluate how the saturation adsorption of the different strength additives influences the properties of the treated fibres and the final handsheets. The tensile index of papers made from C-kraft fibres was the highest due to the highest adsorption capacity of strength additives. Moreover, the strength additives increased the tensile index by 33–84 %, while z-directional tensile strength was increased dramatically by 46–139 %. Bending stiffness was improved by 2.6–25 %, and the combination of CS and APAM or PECs resulted in a significant improvement in bending stiffness compared to the addition of CS alone. Importantly, the strength improvement did not sacrifice the density significantly. In summary, the knowledge gained from the current study expands the understanding of strength additives and their relationship with fibres of different surface charge and the overall paper properties. [ABSTRACT FROM AUTHOR]

This contribution focuses on understanding of paper wet-strength properties, by taking a closer look at the spatial distribution of wet-strengthening polymers inside the cellulosic fiber network deposited under different treatment conditions using confocal laser scanning microscopy as in situ imaging tool. We compare the behavior of paper samples treated with a photochemically cross-linkable copolymer using an impregnation process employing three different solvents, namely water, 2-propanol (IPA) and 1-butanol (BuOH), respectively. As these solvents swell paper fibers to quite different extents, the deposition of the polymer, on, in or in-between the cellulosic fibers varies quite strongly, as is shown by in-depth analysis using confocal laser scanning microscopy. The difference in accessibility of distinct surface sites exclusively on or also in and between the fibers controls the macroscopic tensile strength under both dry and wet conditions. [ABSTRACT FROM AUTHOR]

In this study, extractives from Pinus rigida heartwood (PRW), Eucalyptus camaldulensis var. obtusa aerial parts (ECL), and Eucalyptus flower buds (ECF) were used as additives in paper sheets produced from the pulp of linen fibers, and their effects on the mechanical and antifungal properties of the paper sheets were studied. The highest tensile and tear indices were 31.5 Nm/g, and 17.3 mNm2/g as pulp treated with PRW (4%), and ECL (1%), respectively. All the pulp additives yielded lower burst index values compared to the control (2.24 KPa.m2/g); the nearest value was 2.23 KPa.m2/g (ECL 4% pulp additive). The brightness percentages (ISO%) ranged from 65.7% to 70.2%, which were lower than the control treatment (70.3%). The paper sheets produced from pulp treated with 2% or 4% PRW, and with 4% ECL suppressed Aspergillus niger growth on the paper disc; pulp treated with 2% or 4% PRW, 4% ECL, and with 2% or 4% ECF completely suppressed A. terreus growth. However, all pulp extract additives did not inhibit the growth of Fusarium culmorum. [ABSTRACT FROM AUTHOR]

Assembly of biofibers into paper-based products fits well into green chemistry principles. Biobased additives such as cationic starch and carboxymethyl cellulose are widely used in the paper industry. Edible additives, which often can be regarded as “safer” than regular biobased additives, may also play a role in tailorable design of paper-based products. [ABSTRACT FROM AUTHOR]

A paper strength agent is an important type of chemical additive used in the papermaking industry. In this work some new paper strengthening agent samples were obtained by treating konjac glucomannan with hydrogen peroxide under acidic conditions, and their effects on paper properties were studied. Results showed that oxidized konjac glucomannan (OKG) can improve the paper properties effectively. When 1% oxidized glucomannan (oxidation 60 min, 35 ?C) was added, the burst index, tensile index, and folding endurance were increased by 7.0%, 16.9%, and 102.3%, respectively, compared to the control. With increasing of oxidation time, the paper strength increased first and then decreased, reaching the maximum in 60 min. In addition, OKG can improve the properties of recycled paper more significantly. When the pH of paper making system was 7, the tensile index, burst index, and folding endurance of the recycled paper were increased by 22.2%, 19.9%, 59.9%, respectively, compared to the control. SEM analysis showed that paper strengthening agent resulted in a more contiguous junction between the fibers in paper. [ABSTRACT FROM AUTHOR]

There is current interest in using agro-based biopolymers in industrial applications. Because cottonseed protein is abundantly available, it would be useful to explore its feasibility as a polymeric additive and possible substitute for petroleum-based materials. In this work, we studied cottonseed protein isolate as a paper additive and observed its effects on the paper’s dry and wet strength. The tensile strength of paper was found to vary with the amount of the protein applied. By application of an 11% protein solution to the paper, the dry and wet strength increased by 33 and 16% compared with the paper by itself, respectively. The combined use of cottonseed protein and an acid (acetic, adipic, aspartic, and citric acids) to promote adhesion resulted in even greater dry paper strength but not in greater wet paper strength. Thermogravimetric analysis, infrared spectroscopy, and scanning electron microscopic studies suggested that the protein interacted with acid and that both components interacted with paper fibers to produce increased strength. [ABSTRACT FROM AUTHOR]

During the Taimurid (1370-1507 A.D.) and Safawid 1501-1736 A.D.) to Qajar periods (1785-1925 A.D.), Iranian masters introduced a number of paper dyes in order to prepare a suitable support for their calligraphies and paintings. This paper will discuss the different types of dyes and application techniques as described in Persian historical sources. Eighteen manuscripts from the thirteenth to the nineteenth century were selected and studied in detail; recipes were translated and categorized according to colour, materials and techniques in order to be able to draw comparisons. Studying these historical references not only adds a new dimension to the identification of materials used in manuscripts and miniature paintings of the period under study, but also can help to preserve the colours by providing a better understanding of their composition, manufacture and use. [ABSTRACT FROM AUTHOR]

A short overview of the most prospective applications of industrial lignosulfonates in various industries, such as newsprint paper production, is presented. Lignosulfonates can be utilized in technological processes in various forms, including (1) forms immobilized by paper components and (2) chemically modified forms used as functional additives to the composition of paper-making stock. [ABSTRACT FROM AUTHOR]

The exploitation of renewable and cheaper paper coating formulations especially for graphic paper products is gaining increasing importance due to concerns regarding the use of fossil based raw materials. For this reason, a novel process for enzymatic modification of lignosulfonates to substitute fossil based styrene-butadiene (SB) latex as binders in conventional paper coating formulations was developed. Laccase polymerization of ultrafiltrated lignosulfonates (LS) resulted in an increase of the molecular weight from an average of 26 kDa to 170 kDa as compared to non-ultrafiltrated LS which increased from 5.7 kDa to 76 kDa. When used in coating formulations, laccase polymerized LS resulted in coated paper with improved printing properties (reduced picking compared to non polymerized LS) provided that the LS was ultrafiltrated before polymerization. Abo Akademi gravimetric water retention properties of the paper coatings were comparable (395 g m − 2 ) to those obtained with reference latex (350 g m − 2 ). Similarly, cross sectional fluorescence microscopy images showed that ultrafiltration prior to laccase polymerization reduced penetration of the polymerized lignosulfonates into the base paper to 33% and additionally reduced polymerization time from 6 h to 2 h. These results demonstrate the possibility of substituting fossil based styrene-butadiene (SB) latex binders with on-site produced lignosulfonates which have traditionally been considered so far mainly as a by-product used for energy production in the pulp and paper industry. [ABSTRACT FROM AUTHOR]

White ledger is white-grade recycled pulp that replaces the bleached kraft pulp (BKP) that typically forms the top ply of duplex boards. However, sheets made from white ledger are inferior in strength compared with those made from virgin pulp. Therefore, it is necessary to select a proper additive in order to overcome the disadvantages of using white ledger. In this study, the physical properties of white ledger used at a mill that produced duplex boards were analyzed. The effect of cationic polyacrylamides (C-PAMs) with different charge densities and molecular weights on first-pass retention and paper strengths was simultaneously measured. White ledger contains fiber fines and filler fines, which reduced the strength of paper made from white ledger compared with paper made with BKP. This indicates that the improvement of first-pass retention and paper strength is important when the amount of white ledger increases in the top ply of a duplex board. The charge density of CPAM, which acts as a retention aid, is more important than its molecular weight in terms of improving the first-pass retention and paper strength of white ledger. The charge density of C-PAM must be high enough to catch anionic fine particles. [ABSTRACT FROM AUTHOR]

The article discusses the experimental study on the use of fly ash, major by-products of thermal power plants as wet end filler in papermaking. According to the author, the effects of fly ash addition as compared to those of kaolin clay is more superior. Fly ash obtained from burning of pulverized coal are dumped close to power plants creating environmental pollution. It has a wide variation in particle size and acts as an inert material. The author added that this is the first evaluation of the possible use of fly ash in paper industry.

The synthesis of poly[vinylamine-co-(sodium acrylate)] [P(VAm-co-NaAA)] and its application as a paper strength additive have been investigated. P(VAm-co-NaAA) was synthesized by the alkaline hydrolysis of poly[Nvinylformamide- co-(acrylic acid)] (PNVFAA). The influence of polymer concentration, hydrolysis temperature, and NaOH concentrations on the extent of hydrolysis were examined experimentally. The hydrolysis was 100% completed under the following conditions: hydrolysis temperature 80 °C, hydrolysis time 8 h, polymer concentration 2%, and NaOH concentration 0.045 mol/g of PNVFAA. P(VAm-co-NaAA) obtained in this manner increased the tensile strength and folding endurance of paper by 44% and 48%, respectively, and the strength increase was greater than that obtained with the commercially available polyvinylamine. [ABSTRACT FROM AUTHOR]

Abstract: For many centuries paper was the main material for recording cultural achievements all over the world. Paper is mostly made from cellulose with small amounts of organic and inorganic additives, which allow its identification and characterization and may also contribute to its degradation. Prior to 1850, paper was made entirely from rags, using hemp, flax and cotton fibres. After this period, due to the enormous increase in demand, wood pulp began to be commonly used as raw material, resulting in rapid degradation of paper. Spectroscopic techniques represent one of the most powerful tools to investigate the constituents of paper documents in order to establish its identification and its state of degradation. This review describes the application of selected spectroscopic techniques used for paper characterization and conservation. The spectroscopic techniques that have been used and will be reviewed include: Fourier-Transform Infrared spectroscopy, Raman spectroscopy, Nuclear Magnetic Resonance spectroscopy, X-Ray spectroscopy, Laser-based Spectroscopy, Inductively Coupled Mass Spectroscopy, Laser ablation, Atomic Absorption Spectroscopy and X-Ray Photoelectron Spectroscopy. [Copyright &y& Elsevier]

The hypothesis has been tested that a carboxymethyl hemicellulose improves more effectively the dry strength of papers than a native hemicellulose. To that end, β- d-glucan from oat was treated with an alkaline ethanolic solution of sodium chloroacetate for different times to obtain a range of carboxymethylated β- d-glucan (CM-glucan) samples. The derivatization was confirmed by Fourier transform infrared spectroscopy and elemental analysis. The physical properties of paper concerning burst and tensile strength as well as folding endurance were essentially improved if CM-glucan was added to unbleached kraft fiber suspension from pine before papermaking. The effects could be maximized by a proper selection of carboxymethylation time and the amount of CM-glucan added to the suspension. The effect was also beneficial in the case of recycled fibers. [ABSTRACT FROM AUTHOR]

Chemically modified cellulose micro- and nanofibrils were successfully used as paper strength additives. Three different kinds of cellulose nanofibrils (CNFs) were studied: carboxymethylated CNFs, periodate-oxidised carboxymethylated CNFs and dopamine-grafted carboxymethylated CNFs, all prepared from bleached chemical fibres of dissolving grade, and one microfibrillated cellulose from unbleached kraft fibres. In addition to mechanical characterization of the final paper sheets the fibril retention, sheet density and sheet morphology were also studied as a function of addition of the four different cellulose fibrils. In general, the cellulose fibrils, when used as additives, significantly increased the tensile strength, Young's modulus and strain-at-break of the paper sheets. The effects of the different fibrils on these properties were compared and evaluated and used to analyse the underlying mechanisms behind the strengthening effect. The strength-enhancing effect was most pronounced for the periodate-oxidised CNFs when they were added together with polyvinyl amine (PVAm) or poly(dimethyldiallylammonium chloride) (pDADMAC). The addition of periodate-oxidised CNFs, with pDADMAC as retention aid, resulted in a 37% increase in tensile strength at a 2 wt% addition and an 89% increase at a 15 wt% addition (from 67 to 92 and 125 kNm/kg, respectively) compared to a reference with only pDADMAC. Wet-strong sheets with a wet tensile index of 30 kNm/kg were also obtained when periodate-oxidised CNFs and PVAm were combined. This significant increase in wet strength is suggested to be the result of a formation of cross-links between the aldehyde groups, introduced by the periodate oxidation, and hydroxyl groups on the lignocellulosic fibres and the primary amines of PVAm. Even though less significant, there was also an increase in wet tensile strength when pDADMAC was used together with periodate-oxidised fibrils which shows that the aldehyde groups are able to increase the wet strength without the presence of the primary amines of the PVAm. As an alternative method to strengthen the fibre network, carboxymethylated CNFs grafted with dopamine, by an ethyl dimethylaminopropyl carbodiimide coupling, were used as a strength additive. When used as an additive, these CNFs showed a strong propensity to form films on and around the fibres and significantly increased the mechanical properties of the sheets. Their addition resulted in an increase in the Young´s modulus by 41%, from 5.1 to 7.2 GPa, and an increase in the tensile strength index of 98% (from 53 to 105 kNm/kg) with 5 wt% retained dopamine-grafted CNFs. [ABSTRACT FROM AUTHOR]

Cellulosic paper has combined characteristics of renewability, biodegradability, flexibility, and recyclability. Based on disassembly-initiated fiber processing, the conversion of regular paper into a multifunctional wet-strength product was explored. In this concept, disassembly generates cellulosic additives for surface engineering. Encouragingly, the use of the aqueous solvent system containing mixed metal salts allows controllable fiber disassembly and formation of room-temperature-stable cellulosic solutions, leading to wet and dry strengthening of paper following cellulose regeneration. In-situ generation of cellulosic film-forming additives led to the increase of dry and wet strengths by more than 8 and 35 times respectively, in the case of a typical grade of quantitative filter paper. The engineered paper shows flame-retardant, antibacterial, and liquid-barrier features. The combination of functional properties of cellulosic paper can shed light on diversified applications, e.g., replacement of difficult-to-degrade synthetic plastics. [Display omitted] [ABSTRACT FROM AUTHOR]

The risk associated with wood extractives, biocides, and other additives in pulp and paper mill effluents was evaluated by performing a characterization of process waters and effluents in terms of toxicity and chemical analysis. The individual toxicity of 10 resin acids, two unsaturated fatty acids, and three biocides was estimated by measuring the bioluminescence inhibition with a ToxAlert® 100 system. Median effective concentration values (EC50) of 4.3 to 17.9, 1.2 to 1.5, and 0.022 to 0.50 mg/L were obtained, respectively. Mixtures of these three families of compounds showed antagonistic effects. Chemical analysis of process waters was performed by liquid chromatography--and gas chromatography--mass spectrometry. Biocides such as 2-(thiocyanome-thylthio)-benzotiazole (TCMTB) (EC50 = 0.022 mg/L) and 2,2-dibromo-3-nitrilpropionamide (DBNPA) (EC50 = 0.50 mg/L) were the most toxic compounds tested and were detected at concentrations of 16 and 59 mg/L, respectively, in a closed-circuit recycling paper mill. Process waters from kraft pulp mills, printing paper mills, and packing board paper mills showed the highest concentration of resin acids (up to 400 µg/L) and accounted for inhibition percentages up to 100%. Detergent degradation products such as nonylphenol (NP) and octylphenol (OP) and the plasticizer bisphenol A (BPA) were also detected in the waters at levels of 0.6 to 10.6, 0.3 to 1.4, and 0.7 to 187 µg/L, respectively. However, once these waters were biologically treated, the concentration of detected organic compounds diminished and the toxicity decreased in most cases to values of inhibition lower than 20%. [ABSTRACT FROM AUTHOR]

Lithium metal anodes, which deliver high specific capacity, low electrochemical potential, and low density have been considered as the most ideal anode material for Li secondary batteries. However, the development of Li anodes is limited by Li dendrite formation, infinite volume effects, and unstable solid electrolyte interphase (SEI) layers. Herein, aluminum nitride (AlN) nanoflakes as an additive to stabilized Li plating, and carbon paper (CP) as three‐dimensional (3D) current collector to alleviate volume effect, are reported. The stabilization is attributed to the higher binding energy between Li and the AlN nanoflakes and a preferential adsorption on the AlN nanoflake surface compared to copper (Cu) and CP surface during Li plating. With the combination of the AlN nanoflake additive and 3D CP current collector, both dendritic Li and volume effects are remarkably inhibited. [ABSTRACT FROM AUTHOR]

Microbial-induced calcite precipitation (MICP) is an innovative technology in civil engineering. However, the high cost of components and the fragility of the treated soil limit its wide use. One of the possible solutions is organic waste incorporation at different stages of the technology. In the present study, we consider the use of spent brewer's yeast (BSY) to produce bacterial inoculates and wastepaper, flax shives and sawdust as reinforcing additives into the soil. We showed that the replacement of expensive components of LB medium by BSY extract increased biomass growth characteristics of Bacillus subtilis K51, B. cereus 4b and Micrococcus luteus 6 strains by 1.4, 1.5 and 1.8 times, respectively, while for B. subtilis 168, they were comparable to LB medium. The urease activities of all strains were not reduced compared to the control. Among the three kinds of cellulose-containing waste, wastepaper incorporation into MICP-treated soil samples led to an increase in compressive strength by 2.1 times and precipitated calcite percentage by almost 1.5 times compared to a sample without additives. Thus, we showed the potential for soil stabilization through MICP using organic waste. [ABSTRACT FROM AUTHOR]

A natural polymeric material, cellulose nanofibrils (CNFs), that can replace structural additives made of synthetic polymers was studied and characterized. The use of CNFs as a structural additive and the effect of adding them on the basic mechanical parameters of laboratory samples of packaging materials (corrugated sheet, i.e., the intermediate layer of corrugated cardboard) were studied. Addition of a structural additive made of natural renewable raw material to the recycled paper composite for corrugation was shown to increase the key paper quality indicators. [ABSTRACT FROM AUTHOR]

The influence of rosin (0.1-0.3%), alum (0.4-0.6%), polyaluminum chloride (0.3-0.7%), and starch (0.5-1.5%) in the making of paper from old corrugated container (OCC) pulp on the freeness, breaking length, tear index, and burst index of pulp and paper sheets was studied. Using a full factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the chemical additives were derived that reproduced the former with errors lower than 5%. Using a high starch (1.5%), high PAC (0.7%), low alum (0.4%), and low rosin (0.1%) combination led to pulp that was sufficient to obtain paper with good strength properties (breaking length 5720m; burst index: 3.1 kPam2g-1; tear index: 6.2mNm2/g; Cobb test: 94; fold endurance: 1.52) SEM analysis show increasing in bonding between fibers together at this level of additives. The influence of starch on Cobb test values was not significant.

The aim of this work is to evaluate of the effect of incorporating nanofibrillated cellulose (NFC) and chitosan (CH) in a dual system as dry additives during papermaking for unbleached bamboo alkaline sulfite anthraquinone methanol (ASAM) under different beating revolutions. Pulp beating at 4000 and 6000 revolutions has comparable properties with varying dosages of NFC (5% and 10%) and different chitosan concentrations (0.5%, 1, 1.5%, and 2%). Hand sheets of a basis weight (60 g/cm2) were produced and measured for thickness, tear, tensile, burst index, and resistance to folding under TAPPI standard methods. Results revealed that with an increase in the number of beating revolutions, there was a decrease in the value of freeness. All analyzed pulp had freeness values within the permissible amount of 300–500 mL in papermaking, except 10% NFC, which was 244–190 mL at 6000 revolutions. Furthermore, the addition of chitosan to 1.5% with 5% NFC at 6000 beating revolutions enhanced the tensile index (85.16 Nm/g) and burst index (7.69 kPa. m2/g) in comparison to the sample control. The incorporation of nanofibrillated cellulose and chitosan significantly altered the physical and mechanical strength. Optimal alkaline sulfite anthraquinone methanol ASAM-enhanced paper properties are displayed with 5% NFC and 1.5% chitosan at 6000 beating revolutions. [Display omitted] • Nanofibrillated cellulose/chitosan potential as a dry strength additive in pulp. • Nanofibrillated cellulose acted as an adhesion promoter by bridging adjacent fibers • Larger fibers contribute to boost the load-bearing capacity of the paper. • Chitosan is structurally like cellulose and contain active hydroxyl and amino group. • The incorporation of Nanofibrillated cellulose/Chitosan enhanced paper properties [ABSTRACT FROM AUTHOR]

A xylan-based antimicrobial additive agent was prepared and studied for use in paper products against Escherichia coli bacteria. The derived cationic-xylan-grafted-guanidine polymer (CX-g-PHGH) was successfully synthesized by graft copolymerization of cationic-xylan with polyhexamethylene guanidine hydrochloride (PHGH) using ceric ammonium nitrate as an initiator. The obtained CX-g-PHGH had a maximum PHGH grafting ratio of 18.4% and efficiency of 58.4% and showed good viscosity and thermal stability. Furthermore, the paper samples prepared in this work were reinforced noticeably with the addition of CX-g-PHGH, after which exhibited improved mechanical properties. Compared to the reference paper without any of the xylan derivatives, the index of tensile, tear, burst, and folding endurance of the paper were increased by up to 20.1%, 25.3%, 30.2%, and 77.8%, respectively. Moreover, the prepared CX-g-PHGH paper exhibited efficient antimicrobial barrier properties against E. coli bacteria, by which many applications based on the new xylan derived additive agent obtained in this work could be found, especially in field of antimicrobial paper products against E. coli bacteria from contaminated food. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers (CNF) have increasing relevance in different applications, for instance, in the paper industry as a sustainable strength additive. This application is especially beneficial for recycled paper, which reaches higher product quality despite its limitations. CNF change paper properties and also can affect the production process, especially the drainage stage, in which retention additives (RA) are commonly used to promote interaction of cellulose fibers. CNF probably interact with fibers and RA, affecting the drainage stage. However, these interactions vary depending on the type and flocculation mechanism of RA. This research is aimed at establishing possible synergies between CNF and RA to improve paper strength, avoiding negative effects on the drainage process. No further RA were used to retain CNF, taking advantage of the RA already used in the process. Polyvinylamine, chitosan, cationic starch, C-PAM, and C-PAM-B were selected as RA. CNF from eucalyptus kraft pulp and corn stalk organosolv pulp were tested. Strength properties of laboratory sheets were studied, and interactions were assessed by measuring Z-potential. Synergies between PVA, chitosan, C-PAM, and C-PAM-B with CNF were found. Drainage time decreased ranging between 30 and more than 40% using CNF. Strength depended on RA and formation quality. Among the studied options, CNF with C-PAM-B or chitosan resulted in the best formation and higher strengths with a significant drainage time reduction. [ABSTRACT FROM AUTHOR]

The article discusses the dual-layer technique for the application of a fixative on water-sensitive media on paper. It enumerates the methods used in testing and refining the dual-layer technique with the use of cyclododecane. It mentions the proper way of applying the dual-layer technique to obtain best results. It also offers information on how to remove the dual-layer without affecting the quality of the paper being preserved. Furthermore, it highlights the advantages of using dual-layer waterproofing technique in preserving archival materials.

• Adding AL and SLS increased the HS content and degree of humification. • The faster evolution of quinone-like substances was the key to improve HS content. • This work provided a case for comprehensive utilization of papermaking wastes. Alkali lignin (AL) and sodium lignosulfonate (SLS) are by-products of the papermaking industry and could influence composting processes due to their rich aromatic structures. In this study, the roles of AL and SLS additives in the formation of humic substances (HS) during paper mill sludge composting were investigated. Results showed that HS content and degree of polymerization of the final products in AL (44.42 mg·g−1 and 0.70, respectively) and SLS (45.87 mg·g−1 and 1.14, respectively) treatments were appreciably higher than those of the control sample (34.36 mg·g−1 and 0.67). Excitation-emission matrix-parallel factor coupled with two-dimensional FT-IR correlation spectroscopy analysis suggested that AL and SLS additives could speed the transformation of quinone-like substances by increasing the amounts of low molecular weight lignin depolymerized products, which led to higher HS concentrations. This work provided a way of promoting HS formation and the comprehensive utilization of papermaking wastes. [ABSTRACT FROM AUTHOR]

Nanocelluloses are being explored and produced at an impressively increasing pace. Due to their good characteristics as reinforcement agent, their application in the most diverse fields has proven to be very beneficial. Their use in papermaking has been investigated in several studies, but the industrial implementation is still in a preliminary stage. In the present study, the influence of nanocelluloses, produced by four different treatments (mechanical, enzymatic hydrolysis, TEMPO-mediated oxidation and carboxymethylation) in the properties of filler-containing laboratory handsheets was assessed. Furthermore, five series produced with different additives, among internal strength and sizing agents as well as a retention agent, allowed to investigate the interactions between the common additives used in paper production and nanocelluloses. It was found that the different properties of the studied nanocelluloses led to very different interactions with the paper components. In this sense, by properly selecting the furnish to use (in terms of nanocellulose typology and presence or absence of each additive), high improvements of filler retention and dry and wet--web strength, as well as reduced surface roughness and water penetration, could be achieved. [ABSTRACT FROM AUTHOR]

The paper studies the chemical and phase composition of the product from heat-resistant nickel-based superalloy formed by wire-feed electron beam additive manufacturing (EBAM). Microsegregation on macro-(dendrites/interdendritic space) and microscale (γ/γˈ) was evaluated. It is shown that in additively formed material, there is a significant (by an order of magnitude) refinement of structural and phase elements. The degree of microsegregation remains unchanged after the additive process, despite the increase in the volume fraction of dendrites, and the complex thermal history does not lead to the formation of undesirable phases. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria occupy an important position in silage microorganisms, and the effects of exogenous lactic acid bacteria on silage quality have been widely studied. Microbial metabolism has been proved as an indicator of substrate utilization by microorganisms. Paper mulberry is rich in free carbohydrate, amino acids, and other components, with the potential to be decomposed and utilized. In this study, changes in the microbial metabolism characteristics of paper mulberry silage with Lactiplantibacillus plantarum (LP) and Lentilactobacillus buchneri (LB) were studied along with a control (CK) using BIOLOG ECO microplates. The results showed that average well-color development (AWCD), Shannon diversity, Shannon evenness, and Simpson diversity exhibited significant temporal trends. LB and LP responded differently in the early ensiling phase, and the AWCD of LB was higher than LP at 7 days. Principal component analysis revealed that CK, LB, and LP samples initially clustered at 3 days and then moved into another similar cluster after 15 days. Overall, the microplates methodology applied in this study offers important advantages, not least in terms of accuracy. [ABSTRACT FROM AUTHOR]