Volume 37, Issue 4

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, 1 H-NMR, 31 P-NMR and 2D-NMR spectroscopy and molecular weight and compared with the corresponding dioxane lignins. 1 H-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.

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 m 3 and more than 10 million m 3 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.

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.

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 H 2 SO 4 concentration, time and temperature. The maximum furfural yield (60.5 %) was obtained at the conditions of 0.1 N H 2 SO 4 for 60 min at 170 °C. Further increase of reaction parameter decreased furfural yield.

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 %).

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.

ZD-tester is a measurement technique for rapid compression in Z-direction. The strain rate of compression of this device is far beyond the ordinary mechanical testing methods applied in papermaking industries. Thus, it provides insights to the material responses which are relevant to industrial applications, e. g. calendaring, printing, etc where the strain rate ranges from hundreds to thousands per second. A physics model that describes the dynamic process of the probe has been developed, where a linear Maxwell model is used to account for the viscoelasticity of paperboard. The simulation has successfully reproduced both the general features and quantitative details of the experiment. The model reveals that the ratio of the elastic modulus to the viscosity modulus of the material governs the amplitude attenuation while the angular frequency of the striking-rebounding cycle depends mainly on the elastic modulus. The dropping height determines the initial striking velocity but has no direct impact on either attenuation or angular frequency. The model and simulation provided interpretations of both experimental observations and dynamic behaviours of the material. With help of simulation, the impacts of the individual parameters, e. g. the Young’s modulus, E , the viscosity modulus, η , and the drop height, H , were also explored.

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.

PAAs can be further functionalized (hydroxylation and alkoxylation) by side chain substitution. In this study, we synthesized a SiPAAOH containing hydroxyl and siloxane groups based on the Aza-Michael addition reaction and applied it for reinforcement of aged paper. The results showed that the optimum conditions of SiPAAOH synthesis were as follows: the monomer molar ratio of APTES to EtA was 0.7:0.3, the solvent system for SiPAAOH reinforced aged paper was ethanol/water = 1:5 (v/v). The alkaline SiPAAOH could increase the pH of paper to 7.68, and to improve the amount of alkaline reserve to 200 mmol/kg. The whiteness and color difference of the treated paper were not significantly different from those of the untreated paper, and the mechanical properties of the paper were obviously improved. The results of contact angle and thermogravimetry showed that the SiPAAOH-treated paper was hydrophobicity and high temperature resistance.

Gas grafting treatment with fatty acid chloride is a hydrophobization method based on the principle of forming ester bonds by reacting hydroxyl groups on the surface of hydrophilic substances with a gaseous fatty acid chloride. In order to increase the hydrophobization efficiency through gas grafting treatment, it is necessary to form an ester bond concentrated on the surface of the polyvinyl alcohol (PVOH) coating layer. When palmitoyl chloride, a fatty acid chloride, reacts with the hydroxyl groups of PVOH to form polyvinyl palmitate, the by-product hydrochloric acid promotes the dehydration of PVOH, causing discoloration while producing polyacetylene. Using this discoloration principle of polyene, it was estimated whether evaporated fatty acid chloride penetrated into the PVOH coating layer. The top layer was coated with PVOH having a saponification degree of 89 %, and the bottom layer was coated with PVOH having a saponification degree of 99 %. There was a difference in the discoloration according to the degree of saponification of PVOH, even the amount of palmitoyl chloride was small as much as 300 mg/m 2 . It was confirmed that the vaporized fatty acid chloride during gas grafting treatment permeates the PVOH layer of 7 g/m 2 even in a very small amount.

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 Fe 2+ -thiourea dioxide(TDO)-H 2 O 2 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 SiO 2 / 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 Fe 2+ -thiourea dioxide(TDO)-H 2 O 2 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.

Although smart packaging systems protect food, they also provide information about the shelf life of the content. This information is provided by the formation of severe shifts in color as a result of the reaction of the gases released by the decomposition of the food, the colorant used in smart packaging. The inks or films used in smart packaging systems may exhibit this feature. Because both ink and film materials come into direct contact with the food product in smart packaging, it is more suitable for the intended use of the packaging to be produced from edible and natural resources. In this study, we aimed to investigate the production of films and their use in active packaging systems using the natural source starch and another bio source black chokeberry (Aronia melanocarpa) fruit in order to produce smart packaging. In this study, the coloring matter was extracted from Aronia melanocarpa fruit using ethyl alcohol. The monomeric anthocyanin and total phenol contents of the extracted Aronia melanocarpa were determined by the pH differential method. Colorimetric edible films sensitive to pH changes were produced using starch biopolymer by adding different amounts of the obtained aronia extract. The chemical structures of the produced films were determined by ATR-FTIR, the color properties were determined using spectrophotometer, and the contact angles were determined using goniometer. In addition, the swelling ability was calculated based on the pH. The disk diffusion method was applied to the obtained films against gram-positive and gram-negative bacteria, and the antibacterial properties of the films were determined. The swelling ability of the films prepared with aronia and starch was approximately half as low as the blank film. The prepared films maintained their stability at all pH levels, including high acids and bases. While the edible films produced had a pink-red color at acidic pH, they turned dark blue at basic pH values. This shows that the color of the films changes depending on the nitrogen output from the spoiled meat and can be used as smart packaging. When the antibacterial properties were examined, the blank film (F0) did not have any antibacterial properties, however as the amount of aronia increased, an increase of 17–22 mm (F1 to F4) against gram-positive bacteria and 4–9.9 mm (F1 to F4), respectively, was observed against gram-negative bacteria. In addition, the fact that the films produced have inhibitory properties against gram-positive bacteria adds an extra feature to the packaging material, as it protects the food against degradation.

In order to solve the environmental problems caused by landfilling and incineration of Fenton sludge, realize the recycling of papermaking solid waste. In this paper, we explored the formation of a layer of calcium carbonate coating on the surface of Fenton sludge by crystallization coating in the Fenton sludge-[Ca(OH) 2 /H 2 O]-CO 2 three-phase reaction system to improve the brightness of Fenton sludge and apply it to the filling of paper. The effects of particle size, temperature, stirring rate and calcium hydroxide addition on crystallization coating effect were studied. The advantages and disadvantages of the coating effect are mainly judged by the brightness and dustiness of the powder material. The research results show that when the particle size is 38–48 μm, the temperature is 25 °C, the stirring speed is 600 r/min, and the ratio of calcium hydroxide to Fenton sludge is 2:1, the brightness of the composite can be increased from 3.56 % ISO to 64.24 % ISO.

Pre-treatments reduce energy consumption for the production of cellulose micro/nanofibrils (MFC/CNF). The objective of this work was to study sodium silicate (Na 2 SiO 3 ) 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 % Na 2 SiO 3 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). Na 2 SiO 3 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.

A single Norway spruce tree ( Picea abies ) was manually fractionated into heartwood, sapwood, juvenile wood and branches. These fractions were chemically pulped, individually, in laboratory scale. The pulps were characterized and investigated in relation to dewatering behavior and sheet strength properties. An unbleached and unbeaten commercial kraft pulp from softwood fibers was used as a reference, and the fractionated pulps were within the same range in all tested properties. The fractionated pulps were then compared with each other, and fiber characteristics were used to explain differences in dewatering and strength. Heartwood pulp results in stronger and stiffer papers that are harder to dewater. Sapwood pulp gives more open network structures resulting in easy dewatering and high air permeance, although with lower strength properties compared to heartwood. Pulp from Juvenile wood gives s quite strong but brittle sheets, with efficient dewatering. Pulp from branches gives paper sheets with efficient dewatering, air permeance and relatively high elongation of break but lower strength. The results show that there is definitely potential for utilizing more parts of the trees for pulp and paper making, especially when tailoring the raw material origins after preferred paper properties.

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.