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The kapok (Ceibapentandra (L.) Gaertn) seed fibre is unicellular with length up to 35 mm, however, it is covered by a hydrophobic waxy layer that limits its application in paper production. In this study, the effect of various pulping methods namely mechanical, chemi-mechanical, semichemical and chemical pulping on kapok fibre properties was investigated. Each kapok pulp was then blended with the secondary fibre recovered from kraftliner board for handsheet making to examine their reinforcing ability on strength properties. The results showed that kapok mechanical pulps (with and without dewaxing (5% (v/v) diluted detergent) and chemimechanical pulp were unable to improve the strength properties of the handsheet. Kapok pulps chemically treated with 18–25% of sodium hydroxide gave a better effect on handsheet strength properties whilst fibre treated with 20% sodium hydroxide showing the highest increment. Although the reinforcing effect of the 4% native cooked starch was slightly higher than that of the 10% kapok pulp blended in recycled paper, the recycling potential of the latter was better as all strength properties retained unchanged after recycling. The findings indicated that kapok chemical pulp is a promising reinforcing fibre source with superior recycling potential.

Tall oil is a valuable byproduct in chemical pulping of wood, and its fractions have a large spectrum of applications as chemical precursors, detergents, and fuel. High recovery of tall oil is important for the economic and environmental profile of chemical pulp mills. The purpose of this study was to investigate critical parameters of tall oil separation from black liquor. To investigate this in a controlled way, we developed a model test system using a “synthetic” black liquor (active cooking chemicals OH- and HS- ions), a complete process for soap skimming, and determination of recovered tall oil based on solvent extraction and colorimetric analysis, with good reproducibility. We used the developed system to study the effect of the ratio of fatty acids to rosin acids on tall oil separation. When high amounts of rosin acids were present, tall oil recovery was low, while high content of fatty acids above 60% significantly promoted tall oil separation. Therefore, manipulating the content of fatty acids in black liquor before the soap skimming step can significantly affect the tall oil solubility, and hence its separation. The findings open up chemical ways to improve the tall oil yield.

Lignin content and its molecular structure influence various wood characteristics. In this study, the anatomical and physicochemical properties of wood derived from a naturally occurring mulberry mutant deficient in cinnamyl alcohol dehydrogenase (CAD), a key enzyme in lignin biosynthesis, were analyzed using conventional staining assays on stem sections, length and width measurements of xylem fiber cells, wood pulping and saccharification assays, and sugar compositional analysis of extractive-free wood powder. The present data indicate that the mutation in the CAD gene leads to improved wood delignification efficiency, increased pulp yield under alkaline pulping conditions, and enhanced saccharification efficiency following alkaline pretreatment. This study opens up new avenues for the multipurpose use of the mulberry CAD-deficient mutant as a raw material for biorefinery processes, in addition to its traditional use as a favored feed for silkworms.

Integrated forest biorefineries have been proposed as a viable option for the transformation of lignocellulosic biomass into a wide spectrum of profitable products for the pulp and paper industry. Hemicelluloses, a class of wood components can be extracted from a Kraft pulping process prior to chemical pulping and transformed by means of chemical and biochemical processes into biofuels, biochemical and biomaterials. The objective of this study is to identify the opportunities and challenges for implementing hemicelluloses based biorefineries in the context of the Canadian forest industry. The modifications required at the receptor mill, the selection of the target products based on geographical location and the potential collaboration with other industrial stakeholders to form a cluster were analyzed. Practical guidelines for developing an integrated forest biorefinery have been proposed; the results can be applied to biorefinery development proposals.

This study introduces a new combined method of wood impregnation and chemical pulping processes leading to the production of superparamagnetic cellulose fibers with a magnetic nanoparticle-free outer surface. First, magnetic wood chips (MWCs) were prepared by in situ synthesizing of magnetite (Fe3O4) nanoparticles during the wood impregnation process. The MWCs were then converted into magnetic fibers by kraft pulping. The results showed that the resulting magnetic fibers had an outer surface comparable to that of non-magnetic fibers while showing superparamagnetic behavior. The XRD results confirmed that the in situ synthesized magnetic nanoparticles were magnetite. Papers made from the new type of magnetic cellulose fibers had much more desirable tensile properties, appearance, and printability than papers made from conventional magnetic cellulose fibers, comparable to those made from non-magnetic fibers.

Paper production through chemical pulping has been identified as one of the ideal avenues of exploring the uses of groundnut shells as they are rich in cellulose. Ideally, the cellulose can be used to synthesize fibres that can be converted into useful paper products. In this study, chemical pulping was the chosen process for liberating the fibres as it is effective in dissolving lignin embedded within the cellulose. In addition, the fibres produced have superior physical properties compared to mechanical pulping. It is imperative that optimal conditions are identified for the chemical treatment process, in order to ensure that energy and chemical consumption are minimized. All these measures are aimed at reducing production costs and make chemical pulping economically viable, as compared to the mechanical pulping process which is less costly. Response surface methodology (RSM) was used in this study to evaluate the effect of three independent variables (cooking time, temperature, and sulphidity) on pulp yield and kappa number. These parameters are critical in the chemical pulping process and the optimal conditions obtained were 180 min, 100 °C and 23.6 wt.%, respectively. At the optimal cinditions, the pulp yield was 64.39wt% with a kappa number of 19.5. The results showed that all parameters investigated, had a statistically significant effect on the production of pulp. The increased cooking time was efficient in ensuring complete impregnation of the groundnut shells with chemicals for pulping and ensuring that the dissolution of lignin is not selective and does not result in dead spots inherently compromising the quality of the pulp. On the other hand, lower temperatures limited the peeling effect due to hydrolysis of carbohydrates which increased pulp yield due to a higher cellulose retention. Consequently, this contributed towards obtaining pulp that is well cooked, has a low bleach consumption and a higher quality., Chemical engineering; Chemical Synthesis; Materials Characterization; Natural product chemistry; Groundnut shells; chemical pulping; response surface modelling; low temperature; Lignin

Lignin, an underutilized by-product from chemical pulping of wood, can be modified enzymatically through oxidation by laccase. However, little is known about the molecular details surrounding the cross-linking which is a result of the oxidation. To reduce this lack of knowledge, we used oxygen consumption rate data, phenolic content data and molecular weight data together with data from NMR and FTIR spectroscopy to characterize laccase-catalyzed cross-linking of the industrial lignin preparations organosolv lignin and lignosulfonate. The organosolv lignin preparation had a M

Hybrid poplar genetically engineered to possess chemically labile ester linkages in its lignin backbone (zip‐lignin hybrid poplar) was examined to determine if the strategic lignin modifications would enhance chemical pulping efficiencies. Kraft pulping of zip‐lignin and wild‐type hybrid poplar was performed in lab‐scale reactors under conditions of varying severity by altering time, temperature and chemical charge. The resulting pulps were analyzed for yield, residual lignin content, and cellulose DP (degree of polymerization), as well as changes in carbohydrates and lignin structure. Statistical models of pulping were created, and the pulp bleaching and physical properties evaluated. Under identical cooking conditions, compared to wild‐type, the zip‐lignin hybrid poplar showed extended delignification, confirming the zip‐lignin effect. Additionally, yield and carbohydrate content of the ensuing pulps were slightly elevated, as was the cellulose DP for zip‐lignin poplar pulp, although differences in residual lignin between zip‐lignin and wild‐type poplar were not detected. Statistical prediction models facilitated comparisons between pulping conditions that resulted in identical delignification, with the zip‐lignin poplar needing milder cooking conditions and resulting in higher pulp yield (up to 1.41 % gain). Bleaching and physical properties were subsequently equivalent between the samples with slight chemical savings realized in the zip‐lignin samples due to the enhanced delignification.

Malaysia has a high rate of depleting forest activities than any other tropical countries in the world. This lead to an increasing of pollution and loss of forest trees include animal to our nature. Lemon grasses as a substitute material from non-wood material had been choose for pulp and papermaking industry. This study was going through the chemical composition analysis and fibre properties for lemon grass pulp. These conclude that lemon grass had a high percentage of cellulose; with a low lignin content; good fibre length by TAPPI method. Thus, lemon grass has a potential to be alternative material for becoming waste-wealth product especially for Malaysia’s pulp and papermaking industry.

A number of industrial and technical lignins from forestry and agriculture were extracted by different chemical pulping processes and characterized by evaluating their physical and chemical properties. Several qualitative and quantitative methods were performed to elucidate lignin profiles and their potentials as substitutes for use in biobased products. The morphology, molecular weight distributions, elemental compositions, glass transition temperature, and several important functional groups containing hydroxyl units such as phenolic, aliphatic, and carboxylic acid were classified and their contents were determined quantitatively by employing 31P NMR spectroscopy. The emerging information is relevant to pressing scientific development issues for value-added applications from lignins during industrial production of biomaterials.

The use of cellulose nanofibres (CNF) for the enhancement of paper’s mechanical properties has beenreported by many authors. Concretely, the available literature is mainly focused on TEMPO-oxidizedcellulose nanofibres. However, recent industrial research projects, in which LEPAMAP group has beeninvolved, have demonstrated that this type of nanocellulose has unaffordable production costs for thepapermaking industry. In this sense, the present work aims to produce low-cost lignocellulosic nanofi-bres (LCNF), finding some strong alternatives to TEMPO-mediated oxidation. For that, lignocellulosicnanofibres (LCNF) were produced from stone groundwood pulp (SGW) from pine after a chemical pulp-ing process (sodium hydroxide and antraquinone). The effect of lignin content was studied and controlledthrough bleaching steps and quantified. It was found that high lignin content makes nanofibrillation dif-ficult. The reinforcing effect of CNF was mechanically characterized by the addition of 3 wt% of CNF intodifferent papermaking pulps. The results showed that it is possible to obtain low-cost LCNF that providethe same increase in mechanical properties than TEMPO-oxidized CNF when they are used for paperreinforcement. It was also found that lignin plays an important role in the obtaining of LCNF by fullymechanical treatments, where lower lignin contents expedite the nanofibrillation AcknowledgementWe wish to acknowledge the financial support of the SpanishEconomy and Competitiveness Ministry to the referenced projects:CTQ2012-3686-C02-01 and CTQ2013-48090-C2-2-R

The agriculture waste material can give benefit to many production industries. The studied crop is corn (Zea Mays)stalk. The objective of this work was to analysis the chemical composition; to study chemical pulping and papermaking properties of corn stalk and; to investigate the fiber morphology of properties of those crops. Firstly, the chemical composition of corn stalk were determined and compared with other non-woods. After that, chemical corn stalk was conducted in this analysis followed the physical and mechanical properties. The result showed that, corn stalk have cellulose (39.0%) and lignin content is the lowest (7.3%) content rather than other composition. In chemical pulping, reached high pulp yields had been produced and the strength properties: tear index, tensile index, burst and fold verified that they were of an acceptable quality for papermaking. This crop morphology was observed by Scanning Electron Microscopic (SEM), which showed a condensed composition of fiber structure. This study can developed a friendly product and promote the green technology, suitable to be used as an alternative pulp in paper making industry.Keywords:Fiber, Corn stalk, Composition, Green technology, Pulp and paper making.

The spent liquor, SL, of neutral sulphite semi chemical pulping process contains lignosulfonate and hemicelluloses, but it is currently treated in the wastewater treatment of the process. This treatment decomposes the lignosulfonate. However, lignosulfonate can be extracted for a better use, but the extraction process is not an easy task. The main objective of this work was to extract lignosulfonate from SL via treating the SL with surfactant. The results showed that the acidification of SL to pH 1.8 caused 6% lignosulfonate, 53% hemicelluloses, and 7% COD removals from SL. Acidification followed by dodecyltrimethylammonium chloride, DTAC, treatment of SL at the optimal conditions of 22 °C, 1.8 pH and 10 mg/g of DTAC/SL yielded 40% lignosulfonate, 78% hemicelluloses, and 25% COD removals. Model solutions were prepared via dissolving commercial lignosulfonate and xylan in solutions or purifying SL via membrane dialysis in order to investigate the impact of SL components, i.e. hemicelluloses and residual cooking chemicals, on the isolation of lignosulfonate from SL. The model analyses confirmed that the presence of impurities, i.e. residual cooking salts, significantly affected the isolation of lignosulfonate from the SL, but the presence of hemicellulose had a minor effect in extracting lignosulfonate from SL via DTAC treatment. In addition, the elemental analysis confirmed that DTAC and lignosulfonate had a ratio of 0.584 mol/mol in precipitates.

Malaysia has an abundance of agro waste material that have not been fully utilized to a maximum production. Thus, the finding of a new alternative fiber in non wood material will be favorable in paper production. Pineapple (Ananas Comosus) is the common tropical plant, which consists of coalesced berries. This pineapple is leading member of the family of Bromeliaceae and it came from genusAnanas. Fiber bundle from pineapple leaf can be separated from the cortex where it reveals the pineapple leaf fiber in multi-cellular and lignocelluloses pattern. This leaf has a ribbon-like structure and cemented together by lignin, pentosan-like materials, where it contributes to the strength of fiber [7]. All parts in pineapple from fruits to leaves could be consumed to give a health benefit for human life. Pineapple had been used as textile fiber, anti-inflammatory and also anti-helminthic agent. According to the FAO online database, the Malaysian country had consumed 255,000 tones per year and in third position in the world of consuming pineapple production. Pineapple is mainly produced as canned fruits and also coarse textiles in some Southeast Asian countries. Leaves of pineapple had been used as coarse textiles because of the fiber composition and structure inside the leaves [3]. All fibrous in non wood materials especially pineapple leaf consists of cellulose, holocellulose, hemicelluloses and lignin along with some extraneous material called extractives such as gum and resin. Previous research indicates pineapple leaf fiber contained higher cellulose content than wood fiber. Pineapple leaf fibers also consist of lignin [23], an adhesive component that binds the cellulose and hemicellulose. Pineapple leaf fiber had the lowest lignin content than other alternative fiber, which is favorable during chemical processing [12]. The chemical composition aspects have been considered in the previous literature, such as banana stem, coconut and oil palm and had been reported extensively. Pineapple leaf reported has a lowest lignin (10.5%) rather than banana stem (18.6%), oil palm (20.5%) and coconut (32.8%) that suggest can undergo bleaching more easily and have high fiber strength [12]. Besides that, pineapple leaf contains high holocelulose content (87.6%) than banana stem (65.2%), oil palm (83.5%) and coconut (56.3%) [11]. Those properties depend on the content of chemical composition in the pineapple leaf fiber, which is cellulose, hemicelluloses and lignin content [15].

International audience; The aim of the research was to evaluate the influence of certain components of paper such as lignin and papermaking additives (fillers and sizing) on the efficiency of a recently proposed treatment for simultaneous deacidification and mechanical strengthening with polyaminosiloxane copolymer networks. Mixed mechanical and chemical pulp papers containing various additives were treated with aminoalkylalkoxysilanes (AAAS) by immersion or by spray. Upon treatment, the deposited alkaline reserve varied from 0.34 to 1.14 mol kg −1 . For all the papers, copolymers formed from binary mixtures of a di- and a tri-functional AAAS provided the best improvement in the mechanical properties, i.e. in the tensile strength and the folding endurance, indicating an increase in the interfiber bonding energy and in the paper flexibility and plasticity, respectively. It was found that fillers had no influence while sizing hampered the efficiency of the treatment. The presence of mechanical pulp was shown to have a significant impact on the effect of the treatments as well by increasing the tensile resistance more than the folding endurance, indicating an increase in the paper rigidity. This observation was attributed to the response of lignin to the treatment.

Rice husk and empty fruit bunches are agricultural and plantation wastes which have fiber cellulose and hemicellulose, it can be converted to pulp and paper. This research aims to study the effect of NaOH concentration (2, 4, 6 and 8% w/v) and raw material composition to pulp yield and to study characteristics of the paper combination of rice husk and empty fruit bunches using soda process based on SEM and XRD analysis. This research using soda process because it is suitable for non-wood raw materials, low cost operations and not use sulfur compounds. Dry raw materials are mixed with NaOH and digesting using autoclave (100°C, 1 atm) for 60 minutes. NaOH concentration optimum used in the pulping process a combination rice husk and empty fruit bunches (1:3, 1:2, 1:1, 2:1 and 3:1) and then cooled for 30 minutes. Pulp is bleached with NaClO 5.25% (v / v), then formed and dried as paper. The lowest pulp yield obtained in a ratio of 2: 1 is 27.6%. Based on the observation of SEM known the fiber of rice husk and empty fruit bunches is 5.88 to 9.8 μm and 8.82 to 14.71 μm, while based on XRD observations, chemical treatment can improve the characteristic of peak intensity on paper combination. The highest advances of peak intensity in the 1:3 ratio is 71.28% (cellulose I) dan 83.33% (cellulose II). Keywords: rice husk, empty fruit bunches, chemical pulping, soda process

Autohydrolysis pre-treatments were performed for the production of hemicellulose-rich autohydrolysates from silver birch (Betula pendula) chips prior to chemical pulping. Pre-treatment conditions were varied with respect to time (from 30 to 120 min) and temperature (130 and 150 °C), covering a P-factor range from 10 to 238. Hydrolysates were analyzed in terms of carbohydrates, lignin, volatile organic acids, and furanoic compounds. The analytical data were subjected to various chemometric techniques to establish the relationships between dissolved organic components, hardwood and softwood used in the experiments, and applied pre-treatment conditions. Using this method, differences between the wood species could be clearly seen, and a relatively accurate model for the autohydrolysis of birch chips was developed.

Alkaline pre-treatments were performed for the production of organics-containing effluents from silver/white birch (Betula pendula/pubescens) and Scots pine (Pinus sylvestris) chips prior to chemical pulping. Pre-treatment conditions were varied with respect to time (from 30 min to 120 min), temperature (130 °C and 150 °C), and alkali charge (1, 2, 3, 4, 6, and 8% of NaOH on oven-dried wood). The analytical data (total content, weight average molar mass, and molar mass distribution) on dissolved lignin were subjected to principal component analysis to examine the relationship between molar mass and molar mass distributions in lignin removed from different wood species under varying alkaline pre-treatment conditions. Using this method, differences between the wood species and effects of the various pre-treatment process variables (i.e., time, temperature, and alkali charge) were determined. peerReviewed

Softwood-based kraft mill bleaching effluents from the initial bleaching stages D0 and E1 (the bleaching sequence being D0E 1D 1 E2D2) were treated by the oxidative Fenton method (H20rFeS04) to decompose organic pollutants contammg adsorbable organic halogens (AOX). Experiments designed using the Taguchi method were applied to predict the process conditions that would result in a cost-effective and adequate removal of AOX. In addition to the composition and concentration of the reagents (H202 and Fe2+), the main process parameters selected were temperature and reaction time, while pH was adj usted to an approximate value of 4 (the volumetric ratio of the mixed effluents D0:E 1 was 3 :2). The results indicated that an AOX removal of about 70% for this mixture ( corresponding to about 50% for the mill) was achieved when the eftluent samples were treated for 60 min at 70°C with H202 and Fe2+ at a concentration of 1 600 mg/1 and 28 mg/1, respectively.

Extraction of hemicelluloses prior to pulping and conversion of the extracted hemicelluloses to other bioproducts could provide additional revenue to traditional pulp and paper industries. The effect of hemicelluloses pre-extraction with a hydrothermal (HT) process on Pinus radiata chemimechanical pulp (CMP) properties was investigated in this study. The HT extraction resulted in a release of 7% to 58% of the initial amount of hemicelluloses from the wood. The extraction yield increased with temperature and extraction time. This hemicellulosic fraction was in the form of low molar mass oligomers with molecular weights varying from 1.5 to 100 kDa. Compared with the control (unextracted) CMP pulp, the HT pre-extraction significantly reduced the refining energy to obtain a given fibrillation degree (freeness). The pulp yield with the HT/CMP process was in the range of 56% to 75%. Fiber properties of the pulps from pre-extracted wood, such as fiber length, were reduced, while increases in fiber width, fines content, fiber coarseness, and kink index were observed in comparison with the control pulps. The strength properties of CMP pulps decreased with increasing amounts of hemicellulose removal during the stage prior to pulping.

Lignosulfonate is a type of macromolecular surfactant widely used as interfacial additive in various industrial fields and it is produced during chemical pulping process. In this paper, we present a new effective method for measurement of the critical aggregation concentration (CAC) of sodium lignosulfonate (SL) in water solution, with which a value of 0.38 g L(-1) was obtained. Through the determination of CAC and observation by DLS, the state and dynamics of the formation of the SL micelles were disclosed. The results showed that SL was the state of individual molecules when its mass concentration was less than CAC; the individual SL molecules started to aggregate above CAC and thus micelles formed and grew with increasing SL concentration. The SL solution was quickly frozen and the structures of SL molecules or micelles were observed by ESEM, revealing that the spherical micelles were the main form of SL in the solution. Based on the results, the spherical hollow vesicular structure is proposed as a model of the aggregated micelles of SL in the solution.

A general mathematical model for the chemical pulping of wood including coupled chemical reactions and diffusion limitations in anisotropic wood chips was developed. The model, which consists of co ...

Crofton weed (Eupatorium adenophorum Spreng) is an invasive species in China, which has dam- aged native ecosystems and caused great economic losses. To use the weed instead of simple control and manage- ment of it, the weed stem of was delignified by Acetosolv and Milox processes to obtain lignin. The lignins (Aceto- solv lignin, AL; and Milox lignin, ML) were characterized and compared through several analysis methods. It was found that both of AL and ML were syringyl-guaiacyl type (GS) lignin, but that the chemical composition and structure of the two lignins were somewhat different. The obtained C9 expanded formulas for AL and ML were C9H9.16O3.50N0.13(OCH3)0.97(PhAOH)0.34Ac0.22 and C9H7.96O3.13N0.13(OCH3)1.23(PhAOH)0.51Ac0.14, respectively. According to an elementary analysis, the two lignins had similar higher heat value of 20.0-21.0 MJ kg � 1 , which were similar to that of raw coal. Gel permeation chromatogra- phy analysis indicated the two lignins had similar molecu- lar weights. Notwithstanding that the Ultraviolet, Fourier transform infrared, and 1 H-NMR spectra illustrated that the two lignins had similar chemical functional groups, the AL showed more acetyl groups signals. V C 2009 Wiley

We determined the pulping yields for steam‐exploded and untreated mixed hardwood chips for kraft pulping processes with and without anthraquinone and/or polysulphide. The pulp yield from steam‐exploded chips was 1–3% lower than from untreated chips under similar conditions. The benefit of kraft pulping with anthraquinone and/or polysulphide was found to be more pronounced for the exploded chips than for the untreated chips.

The variation in wood chemistry among aspen clones of similar age, harvested from a common site in northern British Columbia, Canada, was evaluated. The aspen clones were evaluated for ease of chemical pulping and differed by as much as 4.5% in pulp yield at a common H-factor. The results demonstrate both the need for understanding the resource and the substantial opportunities that exists in natural population of trees for selecting superior clones for reforestation and afforestation. The syringyl/guaiacyl ratio, as determined by nitrobenzene oxidation, was directly correlated with the ease of pulping, whereas thioacidolysis results were not as predictive. These results were supported by quantitative NMR analysis, which demonstrated differences in the amount of β-O-4/Ar groups and the degree of condensation. Furthermore, it was shown that, in addition to total lignin content, which differed by as much as 5%, structural differences in the lignin may influence pulping efficacy. Among the other parameters evaluated, the distribution of molecular mass and methoxyl content is relevant for pulping. More specifically, among the fractions isolated in this study [milled wood lignin (MWL), MWELsol, and MWELinsol], the insoluble fraction was the most indicative of the pulping efficiency.

A non-conventional pulping process based on the delignification of cardoon (Cynara cardunculus L) in ethanol–water mixtures has been studied to evaluate its pulping potential and to establish the optimum pulping conditions for this lignocellulosic material. The variables analyzed were the concentration of ethanol in the cooking liquor, the pulping time and temperature. Variable optimization was performed by a central composite design. High viscosity, low kappa number and acceptable screened yield were used as pulp quality criteria to optimize cooking conditions. Pulps having low kappa numbers and viscosities greater than 900 cm3/g−1 were obtained. The total pulp yield was low compared with wood pulping due to the high contents of extractives and ash in cardoon. The amount of rejects in the pulp is of importance, especially for pulps with a high kappa number. The most suitable pulping conditions were 188 °C, 135 min and 50% (w/w) ethanol concentration. In these conditions the kappa number of the pulp was around 26, the pulp viscosity greater than 1100 cm3 g−1 and a screened pulp yield of about 31% was obtained. Copyright © 2005 Society of Chemical Industry

This study was carried out in order to investigate the suitability of ash (Fraxinus angustifolia Vahl.), a native tree (species) in Turkey, for pulp and paper making. Four pulping methods, which included NSSC, cold soda, kraft and kraft + anthraquinone pulping processes, were used for this study. The test materials were supplied from two different stands found in Istanbul Bahcekoy region. When ash wood samples as ash 1 and ash 2 chemical contents were analyzed, the chemical components of ash 1 were higher than that of ash 2. Pulps and handsheets were obtained from ash 1 and were suitable for use in papermaking. These pulps were obtained by NSSC (neutral sulfite semi chemical pulping), cold soda, kraft and kraft + anthraquinone processes. Handsheets made from different pulping methods were compared with each other for strength and optical properties. Strength properties were found to be higher for kraft and kraft + anthraquinone processes, while optical properties were found to be higher for cold soda and NSSC processes.Key words: Ash, Fraxinus angustifolia Vahl., NSSC, cold soda, kraft, kraft + anthraquinone.

Populus tremula* tremuloides wood samples were processed in acetic acid–water–HCl media (Acetosolv pulping) and then subjected to totally chlorine free (TCF) bleaching sequences in order to obtain dissolving grade pulps. Several bleaching sequences (ZEQP1P2, EOQP1P2, EOPaaQP1P2, and EOZQP1P2) were assayed for this purpose. The best results corresponded to an EOZQP1P2 sequence, which led to pulps suitable for the manufacture of viscose and cellulose nitrate.

The chemical composition of three pitch samples coming from an Eucalyptus globulus ECF bleached kraft pulp mill was studied by GC-MS. All samples are rich in fatty acids, including several ω- and α-hydroxyfatty acids and several oxidation products of β-sitosterol, such as 5,6-epoxy-24-ethylcholestane-3-ol and 24-ethylcholestane-3,5,6-triol. One oxidation product of oleic acid, namely 9,10-dihydroxyoctadecanoic acid was also identified. The α-hydroxyfatty acids, the sterols oxidation products and 9,10-dihydroxyoctadecanoic acid are reported here for the first time as components of pitch issued from ECF bleached kraft pulp mills.

Strategies to diversify the Canadian fibre supply have provided an impetus for investigating a wide variety of alternative fibres including industrial hemp (Cannabis sativa L.) in Canada. The alkaline delignification kinetics of Canadian hemp (bast, core and whole stem fractions), using micro pulping units was investigated. The nature of hemp (macromolecule proportions) was a major contributor to the chemical pulping behaviour shown in the results. The initial lignin and holocellulose content of the bast were 10% and 85%, respectively, and the core lignin and holocellulose contents were 21% and 72%, respectively. The bast fibre had a comparative pulping advantage over the core fibre region due to its chemical constitution. The activation energies for lignin removal from hemp are 41 kJ/mol, 76 kJ/mol and 76 kJ/mol for the bast, core and whole stem respectively. These are considerably lower than the reported values for traditional wood pulp species.

Summary A direct and rapid method for determining the average molecular weight (MW) and content of lignin and hemicelluloses in spent cooking liquor by high performance size-exclusion chromatography (HPSEC) using a cartridge glass column and 2.5 mM NaOH as an eluent was developed. A Uv290 detector in line with a RI detector was applied to characterise lignin and hemicelluloses, respectively, from liquor during the kraft cooking of grey and black alder wood. During the main delignification stage, the concentration of high-MW wood components in liquor changed through the maximum. The MW values of hemicelluloses in the liquor decreased to DPn = 30 ± 5 and DPw = 55 ± 5. The M̄ n and M̄ w of lignin in spent kraft cooking liquor during the main and final delignification stages did not exceed 3000 and 5000, respectively.

Paper sheets from olive tree wood pulp obtained by soda, sulphite or kraft pulping were studied to examine the influence of pulp beating on properties of the paper sheets. Paper sheets from kraft and sulphite pulps exhibited the highest resistance, and sulphite pulp the highest brightness. Soda pulp required more intensive beating than did kraft or sulphite pulps; in fact, the PFI beater had be operated at a 40–50% higher number of beating revolutions to obtain soda pulp with 70–80° SR. The breaking length, stretch, burst index and tear index of paper sheets obtained from kraft pulp, beaten to a Shopper–Riegler index of 70–80° SR were 20–30%, 30–50%, 50–60% and 15–35% higher, respectively, than those of sheets obtained from soda pulp.

The autocatalyzed pulping of Eucalyptus globulus wood with methanol-water mixtures was studied. A surface response design was employed to develop mathematical models describing the pulp properties as a function of cooking time, cooking temperature and methanol concentration. The ranges studied for these variables were 40–120 min, 170-200°C and 30-70% (w/w), respectively. The pulp properties modeled were kappa number, total yield, screenings content, screened yield and viscosity. Under the optimum cooking conditions pulps with low kappa number and acceptable viscosity can be obtained with a high yield. On a etudie la mise en pâte autocatalyse de bois de Eucalyptus globulus avec des melanges methanol-eau. On a eu recours a un plan experimental de reponse en surface afin de mettre au point des modeles mathematiques pouvant decrire les proprietes de la pâte en fonction du temps de cuisson, de la temperature de cuisson et de la concentration de methanol. Les gammes etudiees pour ces variables sont de 40-120 min, 170-200°C et 30-70% (w/w), respectivement. Les proprietes de pâte modelisees sont le nombre de kappa, le rendement total, la teneur des dechets de criblage, le rendement crible et la viscosite. Dans les conditions de cuisson optimales, des pâtes ayant un faible nombre de kappa et une viscosite acceptable peuvent etre obtenues avec un rendement eleve.

This research was conducted to study the organic and inorganic constituents and pulping behaviour of compression wood (CW), in comparison to normal wood (NW) and opposite wood (OW). It was found that differences in the chemical properties of OW and NW were not significant, except in alpha-cellulose and hemicellulose content; whereas both differed significantly from CW which contained more lignin and calcium and less alpha-cellulose. These chemical characteristics of CW resulted in high residual lignin and poor pulp yields, in comparison with normal and opposite woods, when different cooking times and temperatures were applied. Bleachable grade pulp could be obtained from normal wood with H-factor 2300. Using CW, however, this was not practical even under severe cooking conditions.

This study deals with pretreatment of wheat straw with lignin-degrading fungi and its effect on chemical pulping. Ceriporiopsis subvermispora strains, which preferentially attack the lignin, were used for biochemical pulping of bagasse. Treatment of depithed bagasse with different strains of C. subvermispora reduced the kappa number by 10-15% and increased unbleached pulp brightness by 1.1-2.0 ISO points on chemical pulping at the same alkali charge. Bleaching of biopulps at the same chemical charge increased final brightness by 4.7-5.6 ISO points and whiteness by 10.2-11.4 ISO points. Fungal treatment did not result in any adverse effect on the strength properties of pulp.

China's booming paper industry has results in a strong growth in the Alkaline peroxide Mechanicla Pulping (APMP) sector, largely due to the fact that China has limited forest resource, and the APMP process can deliver a high pulp yield and good pulp properties for various paper grades. The loads of COD and BOD of the effluent from the APMP process are higher than those from the conventional mechanical pulping, but lower than those from the chemical pulping processes. The MTBE extractives were 147.2mg/L which consist mainly of resin and fatty acids that are generally regarded as the main toxicity contributors in pulping effluents. GC analysis indicates that there were about 30 kinds of compounds in the extractives. The antibacterial effects were tested by inhibition zone experiment, S13 fermentation experiment and activated sludge system. At 147.2 mg/L wood extractives, the COD removal efficiency of S13 fermentation was about 50%, When the concentration of wood extractives was increased by three times to 441.6mg/L, the COD removal efficiency decreased only about 20% (from 50% down to 40%). At the activated sludge system, the concentration of wood extractives was tripled to 441.6mg/L, resulting in 60% decrease in COD removal efficiency (from 50% down to 20%). All those studies indicated that the extractives of APMP effluent contain some toxic organic compounds.

The amount of lignin removed from spruce wood meal at 50°C to 110°C with mono-, di-, and trichloroacetic acid, as well as its molecular weight (MW) distribution was studied. Trichloroacetic acid gives rise to the lowest Mn (2,000–4,000), the lowest Mw (4,500–8,000), the lowest upper MW limit (∼40,000), and the lowest polydispersity (1.5–3.0) of lignin. The removed lignin is split by the tested acids to different extents.

This paper presents a mathematical model for pulping that considers the effect of alkali diffusion and chemical reaction. An approximation for 3-dimensional diffusion in wood chips is tested against pulping data. A method for predicting pulp viscosity is also presented. The model simulates the effect of key pulping variables on pulp kappa number, viscosity, yield, residual alkalinity and pulping uniformity. Experimental data from a number of sources are successfully predicted by the model. On presente dans cet article un modele mathematique pour la mise en pite qui prend en consideration l'effet de la diffusiondes alcalins et de la reaction chimique. Une approximation de la diffusion tridimensionnelle dans des copeaux debois est testee par rapport e des donnees de mise en pite. Une methode de prediction de la viscosite de la pâte est egalementpresentee. le modele simule l'effet de variables cles de mise en pâte sur le Kapa de la pâte, la viscositt, le rendement, l'alcalinite residuelle et l'uniformite du traitement. Des donnees experimentales de differentes sources sont predites avec succes par le modele.