The main objective of this research is to evaluate the influence of coating based on cellulose micro/nanofibrils (CMF) and carboxylated styrene butadiene rubber (XSBR) on sack kraft paper, for possible use in packaging. Filmogenic solutions were applied manually as a coating on sack kraft paper. These solutions were prepared by suspensions of CMF 1.5 % w/v with the addition of different content of XSBR (0, 2, 10, and 20 % about the total mass of CMF). Uncoated sack kraft paper was used as control. Films were obtained by casting and characterized physically, morphologically, and mechanically. The results demonstrated that XSBR and CMF composite suspension showed good performance as a coating on sack kraft paper. The formation of homogeneous structures well distributed on paper can be observed on scanning electron microscope images. Coatings containing XSBR presented a smoother surface, less porosity and hydrophilicity, and a greater coalescence, with good properties of air resistance and water vapor permeability. However, regarding mechanical properties, there were no improvements in coated papers. Therefore, the present study contributed information on the development of more flexible and hydrophobic cellulosic papers for possible applications in the industrial packaging sector.

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 %).

Many of the amphiphilic molecules, or surfactants, are produced from fossil-based raw materials. With the increasing awareness of the climate situation, focus has shifted toward more environmentally friendly solutions to replace fossil-based products. This has led to more interest towards the forest. The circular bioeconomy is focused on making use of residues and waste and on optimizing the value of biomass over time via cascading. Nowadays, bark is seen as a waste product by industries and mainly incinerated as solid fuel. The bark contains interesting compounds but some of these are only available in low amounts, less than 1 % in the bark, while other components are present in several percentages. However, some of these components are potential candidates for the manufacture of amphiphiles and there seems to be a strong match between bark availability and surfactant demand. The global amount of bark available is approximately 359 million m3 and more than 10 million m3 of industrial bark are generated annually in Sweden and Finland. The bark of Norway spruce, Scots pine and silver birch contains approximately 25–32 % of extractives and part of these extractives has a potential as a surfactant backbone. This matches the global surfactant demand of about 15.6 million tons. Therefore, industrial bark has a significant potential value as a raw material source for amphiphilic molecules and polymers. This review focuses on betulin, condensed tannin and suberin. These compounds have been studied on individually and methods to extract them out from the bark are well investigated, but to utilize them as amphiphilic compounds has not been explored. With this review, we want to emphasis the potential of using bark, what today is seen as a waste product, as a raw material for production of amphiphiles. Moreover, a techno-economic analysis has been performed on betulin, tannins and suberin.

In this paper, dissolving pulp is produced from jute stick and jute fiber mixture in pre-hydrolysis soda-anthraquinone process. The overall pulp yield was 30.7 % with kappa number 14.8 at the conditions of 18 % alkali charge for 2 h cooking at 170 °C. The purity of the produced pulp was 94.1 % with residual pentosan content of 4.64 %, which improved to 95.3 % with residual pentosan content of 3.7 % by cold alkali extraction process. The prehydrolysis liquor from the jute stick – jute fiber mixture contained 5.07 % xylose, which was converted to furfural by varying H2SO4 concentration, time and temperature. The maximum furfural yield (60.5 %) was obtained at the conditions of 0.1 N H2SO4 for 60 min at 170 °C. Further increase of reaction parameter decreased furfural yield.

In this work, we aimed to analyze suspensions of cationic starch by adding 5 wt%, 7 wt%, and 10 wt% of bentonite as a bilayer coating on kraftliner paper (85 g/m2). The controls were doubly-wet-and-dry and uncoated kraftliner paper. In a coating machine, the formulations were applied until reaching a grammage of 15 g/m2 and then dried at 103 ± 2 °C. The test was carried out about pH, solids content, and viscosity of the suspensions. The physical characteristics of the coated papers were evaluated, as well as their ability to block water, water vapor, and oil/grease. We also analyzed with scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. The packaging, having a water contact angle of up to 78° and 189 g/m² for Cobb, showed a low resistance to water, which is further responsible for decreased mechanical resistance. Nevertheless, the coating did not change the permeability to water vapor, however, bentonite promoted a decrease in wettability and Cobb value of the paper. The addition of 7 wt% bentonite to the cationic starch matrix promoted high oil resistance with 12 for kit-oil, while 10 wt% bentonite promoted greater pencil hardness, with a value of 8H. Bentonite strength and cationic starch showed good interaction, increasing oil resistance.

A novel paper multifunctional protective solution was prepared by mixing berberine modified trimethoprimed carboxymethyl cellulose (TMP-DCMC-BBR), KH-791 modified nano-SiO2 (KH791-SiO2) and hydroxypropyl starch phosphate (HPDSP), and the mechanical properties, optical properties, antibacterial properties, aging resistance, acid and alkali resistance of the paper coated with the protective solution were investigated. It is shown that the paper coated with the multifunctional protective liquid showed good mechanical properties, and has little influence on optical properties of the paper. At the same time, it had good antibacterial properties, aging resistance and acid and alkali corrosion resistance, and there is no obvious change in paper appearance, no decolorization and ink diffusion, which is in line with the principle of “repairing the old as the old and keeping the original appearance”. Moreover, the compound solution has certain reversibility and can absorb a certain degree of ultraviolet rays, so as to weaken the damage of ultraviolet rays to the paper. It is an ideal multifunctional protective liquid for paper and has broad application prospects in paper protection.

Non-wood pulping faces environmental and processing problems due to lack of suitable technology. To overcome the challenges, potassium hydroxide pulping was suggested, which can also be integrated with biorefinery. To make a viable biorefinery, all dissolved components need to be utilized. Therefore, in this paper, the dissolved lignin from the potassium hydroxide pulping of corn stalks and dhaincha was isolated and characterized by UV, FTIR, 1H-NMR, 31P-NMR and 2D-NMR spectroscopy and molecular weight and compared with the corresponding dioxane lignins. 1H-NMR and 2D-NMR indicated that potassium hydroxide pulping cleaved β-O-4 aryl ether linkages, and consequently increased phenolic hydroxyl group and reduced molecular weight. It was found that phenolation is an effective method to improve the reactivity and reduce molecular weight, and thus the lignin from the potassium hydroxide liquor was further phenolated. The penolated lignin showed strong NIR bands at 5970 and 6896 cm−1 for aromatic C-H and phenolic O-H group.

Development of three-dimensional continuum models for paperboard is an active field and the need for reliable measurements to calibrate and validate such models is evident. An experimental device and protocol for cyclic out-of-plane loading is developed. This loading sequence is present during converting operations of paperboard. The experimental tests reveals that the commonly observed soft initial non-linear response during out-of-plane compression is a structural effect that stems from the surface roughness rather than being an inherent material behavior. A gluing procedure, used to perform cyclic out-of-plane loading, is mitigating the effect of the surface roughness. Several novel cyclic loading experiments are performed, alternating between compression and tension which indicates that fiber bonds are not recovered in compression after they have been broken through delamination. Measurements also show that the transition in compression and tension is continuous, hence the use of a switch function present in a number of constitutive continuum models for paperboard is deemed questionable.

The uses of kraft lignin (KL), obtained from the black liquor (BL) in the pulping process, allow the production of activated carbon (AC), a product with high added value in the pulp mill. The AC can be used in three different sectors in a cellulose pulp mill: sectorial treatment of the cellulosic pulp bleaching filtrates; wastewater treatment; and in the treatment of water received by the mill. Thus, this article considers the steps in the production of AC, their types, and the advantages and challenges of its use in the kraft cellulose pulp mill as well as in other industries.

Paper simulations that resolve the entire microscopic fiber structure are typically time-consuming and require extensive resources. Several such modeling approaches have been proposed to analyze different properties in paper. However, most use non-linear and time-dependent models resulting in high computational complexity. Resolving these computational issues would increase its usefulness in industrial applications. The model proposed in this work was developed in collaboration with companies in the papermaking industry within the Innovative Simulation of Paper (ISOP) project. A linear network model is used for efficiency, where 1-D beams represent the fibers. Similar models have been proposed in the past. However, in this work, the paper models are three-dimensional, a new dynamic bonding technique is used, and more extensive simulations are evaluated. The model is used to simulate tensile stiffness, tensile strength, and bending resistance. These simulated results are compared to experimental and theoretical counterparts and produce representable results for realistic parameters. Moreover, an off-the-shelf computer accessible to a paper developer can evaluate these models structural properties efficiently.

Disintegration potential of toilet grade tissue paper is one of the most important parameter keeping in mind the worldwide water scarcity faced by human race in current decade. The aim of this experimental study is to improve the disintegration potential of toilet tissue. Softener is used as debonding material. The right amount dry strength required by Toilet tissue is maintained by controlled fiber refining. High fiber bonding would lower the disintegration potential of the tissue paper, thus hampering the aim of study. The initial freeness of the pulp slurry was found 16°SR. It was then further refined in controlled manner to various degrees of freeness (i. e. 22, 24, 26, 28 and 30°SR). Bulk, Strength properties along with disintegration time and softness of 15GSM hand sheets prepared from each set of pulp slurry was investigated. Turbidity test was done to check the cloudiness. Upon analysing, it was found that the paper developed at 24°SR freeness having bulk 4.85 cc/gm, breaking length 750 meter, softness 80 Hand feel units, and disintegration time 08 seconds was most suitable having the better softness, optimum strength and higher disintegration potential as compared to the benchmarked samples.

Currently, there are two procedures to determine the basis weight in papermaking processes: the measurements made by the quality control laboratory or the measurements made by the quality control system. This research presents an alternative to estimating basis weight-based artificial neural network (ANN) modeling. The NN architecture was constructed by trial and error, obtaining the best results using two hidden layers with 48 and 12 neurons, respectively, in addition to the input and output layers. Mean absolute error and mean absolute percentage error was used for the loss and metric functions, respectively. Python was used in the training, validation, and testing process. The results indicate that the model can reasonably determine the basis weight given the independent variables analyzed here. The R 2 {R^{2}} reached by the model was 94 %, and MAE was 12.40 grams/m2. Using the same dataset, the fine tree regression model showed an R 2 {R^{2}} of 99 % and an MAE of 3.35 grams/m2. Additionally, a dataset not included in the building process was used to validate the method’s performance. The results showed that ANN-based modeling has a higher predictive capability than the regression tree model. Therefore, this model was embedded in a graphic user interface that was developed in Python.

The aim of this work is to investigate the influence of fiber fibrillation and fines on the pore structure of well-defined regenerated fiber sheets as well as the water flow through the sheet. For this purpose, sheets were produced with refined, fibrillated fibers only, with unfibrillated fibers and fines, as well as with fibrillated fibers and fines. Next, the samples were analyzed by brightfield and fluorescence microscopy, mercury porosimetry, and an ascending test. Both the fibrils and the added fines reach into the pores between the fibers or are deposited there. As a result, pore size decreases and capillary flow slows down. The two effects overlap when the fiber surface is fibrillated and fines are present. Sheets with thicker fibers form a pore structure with larger pores in between the fibers. However, such a change in pore size has no significant influence on the flow of water through the sheet in the performed ascending tests. It is shown that a statistical model with the parameters fibrillation and fines content can be used to describe the ascending rate nearly as well as the Lucas–Washburn equation. Consequently, the equation could be improved by the addition of further fiber and sheet properties.

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.

The pulp industry is a high natural resources consumer and has a large polluting potential. The pulping sector with the most effluent generation is the bleaching plant. Based on the need of water consumption reduction, this research aimed to evaluate the treatment of the alkaline effluent from an EP-stage bleaching plant and the white water from drying machine using ultrafiltration membranes in order to enable the reuse of the permeate in the process. An ultrafiltration pilot plant was used. Laboratory analyses were performed for the feed, permeate and retentate. Flux and transmembrane pressure (TMP) data were obtained from the pilot plant database. There were an average color and COD removals of 38 % and 39 %, respectively, for the EP-effluent and 58 % and 67 %, respectively for the white water; and a high turbidity and TSS removal (above 98 %) for both effluents. Substantial metals removal such as sodium, potassium, calcium, iron, magnesium and manganese was achieved. Some possibilities to reuse were considered: return to the water treatment plant, cooling of the digester bottom, equipment cooling, reuse in evaporation surface condensers. The use of ultrafiltration for the treatment of the alkaline effluent from the bleaching EP-stage and white water can be an interesting option.

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.

Although organosolv processes using high-boiling solvents have been investigated in recent decades for developing novel industrial processes, there are potential benefits of using high-boiling point solvents for traditional sulphate-based cooking processes, both from an industrial perspective and from a laboratory perspective. Using high-boiling solvents, experiments can be done under atmospheric conditions, thus making it easier to continually monitor laboratory experiments and extracting aliquots at desired intervals. Using such a system, alkaline consumption was monitored during impregnation of spruce chips in glycerol media using chemical charges of 1 M NaOH and 0.1 M NaHS, i. e., kraft pulping conditions, and compared to a similar investigation of alkaline consumption in water media using steel autoclaves. The resulting data was fitted to a first order kinetic model, with an apparent activation energy of 22 kJ mol−1 in glycerol media. Finally, a “normal quality pulp” of kappa number 28 and a viscosity of 1113 ml g−1 was successful produced using a cooking process with an impregnation step at 140 °C for 3 h and a cooking step at 160 °C for 4 h. A nuclear magnetic resonance study on the dissolved lignin produced for said experiment showed characteristics typical of other kraft lignins.

We describe a wet creping approach, applicable not only for softwood kraft papers in the grammage range of 30–120 g/m2 but also for 300 g/m2 CTMP board. Creping of board requires a certain level of deformability in the material, which is controlled by its solids content. The concept was tested at laboratory scale using a device on which temperature, blade angle and line load could be adjusted. The sample density was decreased by creping due to small-scale delamination of the structure, leading to separate inner layers with a wavy appearance. The strain at break was remarkably increased and agreed well with the theoretical estimate based on the crepe ratio and the breaking strain of the uncreped sample. Simultaneously, tensile strength was reduced by creping. In terms of tensile strength and stretch, 60–70 % solids content during creping was optimal for the tested board.

The aim of this study was to investigate an effective approach for improving the dissolving pulp properties for making specialty fiber. The caustic and enzymatic treatment of the properties of dissolving pulp was conducted by analyzing the macromolecular structure and chemical composition. The results showed that the enzymatic treatment was more effective on influencing the macromolecular properties, while the caustic treatment had more influence on structural changing, mainly cellulose crystal structure and crystallinity. Meanwhile, to maintain a higher purity and higher brightness, caustic treatment would be beneficial in comparison with enzymatic treatment. The performance of caustic treated sample was evaluated in regarding to chemical composition and acetylation reaction performance, using commercial pulp as reference. The competitive feature of treated sample suggested its potential in future application.

Interaction between the microwave heating rate and dielectric properties of agricultural wastes is important in identifying suitable microwave operating conditions. This work focuses on the interaction between microwave heating rate (power intensity) and dielectric properties of selected agricultural wastes, namely castor shell, empty fruit bunch and palm kernel shell. Heating rate was recorded every 30 s for 10 min in a 2.45 GHz microwave at power intensities of 100, 300, 450, 600, 700 and 800 W. All materials tested display an increase in heating rate with increasing power intensity. Castor shell and empty fruit bunch at 800 W, and palm kernel shell at 600 W exhibit high heating rates of 0.134, 0.165, 0.247 °C/s, respectively. For dielectric properties, palm kernel shell series shows a high value of loss tangent compared to the other counterparts, indicating its effectiveness to be heated via microwave.