Published by De Gruyter

Volume 63 Issue 3

Issue of Holzforschung

Submit manuscript

Contents
Journal Overview

Original Papers

February 10, 2009

Laboratory and mill scale evaluation of biopulping of Eucalyptus grandis Hill ex Maiden with Phanerochaete chrysosporium RP-78 under non-aseptic conditions

Fernando Masarin, Paulo C. Pavan, Marcos P. Vicentim, Priscila B. Souza-Cruz, Clarice Loguercio-Leite, André Ferraz

Page range: 259-263

Abstract

Biopulping of Eucalyptus grandis wood chips with Phanerochaete chrysosporium RP-78 was evaluated under non-aseptic conditions in laboratory and mill wood-yard. The ability of P. chrysosporium to compete with indigenous fungi present in fresh wood chips was notorious under controlled laboratory experiments. A subsequent step involved an industrial test performed with 10-ton of fresh wood chips inoculated and maintained at 37±3°C for 39 days in a biopulping pilot plant. Biotreated wood chips were pulped in a chemithermomechanical pulping mill. Net energy consumption during refining was 745 kWh ton -1 and 610 kWh ton -1 of processed pulp for control and biotreated wood chips, respectively. Accordingly, 18.5% net energy saving could be achieved. Biopulps contained lower shive content and had improved strength properties compared to control pulps. Tensile index improved from 25±1 N m g -1 to 33.6±0.5 N m g -1 and delamination strength from 217±19 kPa to 295±30 kPa.

January 13, 2009

New kinetics and mechanisms of oxygen delignification observed in a continuous stirred tank reactor

Yun Ji, Emilia Vanska, Adriaan van Heiningen

Page range: 264-271

Abstract

Special oxygen delignification experiments were performed in a differentially operated continuous stirred tank reactor (CSTR). Because the dissolved oxygen and alkali concentrations in the reactor are constant, the rate of lignin removal may be determined from the dissolved lignin content in the outflow stream measured by UV absorption. The delignification kinetics were determined at different temperatures, oxygen pressures and caustic concentrations on softwood kraft pulps of different kappa numbers. The kinetics are first order in residual lignin content [hexenuronic acid (HexA) corrected], and follow a Langmuir-type behavior for adsorption of oxygen on the active aromatic lignin sites. The first order in residual lignin content implies that the active lignin sites are uniformly distributed and have the same reactivity. It is proposed that the active site is the 3 carbon of the aromatic ring, where oxygen reacts to form a hydroperoxide, with a p K a of almost 2 units higher than that of phenolic lignin. The kinetics of phenolic delignification can be described by assuming that the reaction between adsorbed oxygen and carbon 3 of the aromatic ring is the rate determining step. Alternatively, the decomposition of the hydroperoxide anion is rate determining. Peeling delignification has been proposed as an additional delignification route by peeling of hemicelluloses which have lignin fragments covalently bound to them. It is shown that the impact of peeling delignification is relatively small and limited to the initial delignification phase. Finally, data are presented showing that radicals may provide an essential contribution to delignification by their removal of non-lignin and non-HexA oxidizable structures contributing to the kappa number.

February 10, 2009

A study of anthraquinone-fortified green liquor pretreatment of loblolly pine chips

Weiping Ban, Qiujuan Liu, Jiqiang Guo, Haibo Mao, Lucian A. Lucia

Page range: 272-277

Abstract

Green liquor (GL) pretreatment for kraft pulping technologies was modified by applying anthraquinone (AQ) during the pretreatment stage. Analysis of the pulp lignin contents and final pulp yields demonstrated that the addition of AQ improved delignification selectivity. A proposed mechanism for the behavior of AQ during the GL pretreatment is that it amplifies delignification rather than preserves hemicelluloses. An analysis of the pulp carboxylic acid groups indicated that AQ did not affect the total carboxylic acid content in the pulp, but provided a lower hexenuronic acid content at a specific level of lignin content. In general, green liquor pretreatment reduces the energy requirement for pulping and improves chemical reactivity during delignification. As a result, net pulping efficiency for a kraft pulping operation can be improved.

December 3, 2008

Reactions of aromatic structures in brightness reversion of fully-bleached eucalyptus kraft pulps

Anna-Stiina Jääskeläinen, Katri Toikka, Anni Lähdetie, Tiina Liitiä, Tapani Vuorinen

Page range: 278-281

Abstract

The role of aromatic structures in brightness reversion of fully bleached pulps was studied by UV resonance Raman (UVRR) and reflectance UV-Vis spectroscopy. The results clearly showed that ageing increased the aromatic band at approximately 1600 cm -1 in the UVRR spectra and the lignin band at approximately 280 nm in the UV-Vis spectra. This increase was probably due to increased conjugation of lignin and it was observed for all pulps regardless of the bleaching sequence. In addition to these lignin reactions, other unsaturated structures, such as hexenuronic acid groups, reacted during ageing.

December 16, 2008

Effect of surface sizing on the surface chemistry of paper containing eucalyptus pulp

Isabel Maria Teixeira Moutinho, Anne Marjatta Kleen, Maria Margarida Lopes Figueiredo, Paulo Jorge Tavares Ferreira

Page range: 282-289

Abstract

The effect of different surface sizing formulations on the chemical features of surfaces of the papers produced from Eucalyptus kraft pulp was studied. The surface analysis techniques, electron spectroscopy for chemical analysis and time-of-flight secondary ion mass spectrometry were applied. An uncoated base paper, the reference material, was sized with blends of cationic starch with either co-acrylonitrile-acrylate or co-styrene-acrylate. The results of both techniques are in good agreement and complete each other. It was possible not only to detect the presence of the surface sizing agents on the paper surface but also to distinguish them and evaluate their distribution and relative concentration. In addition, it was found that application of higher amounts of the sizing formulations, at a constant ratio of 20% copolymer to starch, did not significantly change the chemical properties of the paper surfaces.

December 16, 2008

Kraft lignin as feedstock for chemical products: The effects of membrane filtration

Ida Brodin, Elisabeth Sjöholm, Göran Gellerstedt

Page range: 290-297

Abstract

The use of technical lignins as feedstock for chemical products will require improvements in purity, molecular mass distribution, and thermal behavior. Therefore, industrial black liquors from kraft pulping of softwood (spruce/pine) and hardwood (birch and Eucalyptus globulus ) have been subjected to fractionation according to molecular mass by ceramic membranes. After acidification and isolation of the lignin fractions, a variety of analytical methods have been applied to help understand their structure – property relationships. From all types of lignin, the chemical and polymeric properties of fractions isolated from the membrane permeates were more homogeneous. This demonstrates that technical kraft lignins, irrespective of origin, may constitute an interesting feedstock for products, such as carbon fibers, adhesives, and phenol-based polymers.

January 13, 2009

Modification of lignin with laccases for the adsorption of anionic ferulic acid studied by quartz cristall microbalance with dissipation and AFM

Terhi Saarinen, Anna Suurnäkki, Monika Österberg, Janne Laine

Page range: 298-306

Abstract

The adsorption of laccases and ferulic acid on a lignin substrate has been studied using a quartz crystal microbalance with dissipation (QCM-D) and an atomic force microscope (AFM). Two different additional strategies were applied: ferulic acid was added after laccase pretreatment, or coadsorbed together with laccase. The effect of two laccases isolated from Trametes hirsuta and Melanocarpus albomyces was compared on lignin activation. The QCM-D results were also compared against bulk experiments on chemithermomechanical pulp. The two laccases affected the adsorption of ferulic acid differently. Adsorption of T. hirsuta laccase was not observed, while the adsorption of M. albomyces laccase was obvious. However, both laccases still activated lignin and the amount of ferulic acid adsorbed was significantly higher on laccase-activated lignin than on the non-activated one. Rinsing after activation removed some slightly bound laccase from the substrate and decreased the adsorbed amount of subsequently added ferulic acid. Interestingly, only T. hirsuta laccase could catalyse the lasting attachment of polymerised ferulic acid onto lignin. The QCM-D and AFM results correlated with the findings of studies concerning bonding of ferulic acid on chemithermomechanical pulp. Thus, this approach is useful in studying the behaviour of enzymes on lignin substrates.

February 11, 2009

Modeling xylan solubilization during autohydrolysis of sugar maple wood meal: Reaction kinetics

Ashutosh Mittal, Siddharth G. Chatterjee, Gary M. Scott, Thomas E. Amidon

Page range: 307-314

Abstract

The objective of this work was to study the kinetics of hemicelluloses extraction during hydrothermal pretreatment of sugar maple wood meal. Pretreatment was conducted in a batch reactor at 145–185°C with reaction times up to 8 h and with liquor to solid ratio of 20:1. Under these conditions, hemicelluloses were selectively solubilized and little degradation (approximately 6–9% of the initial amount) of cellulose and lignin was observed. A kinetic model was developed. It was supposed that there are no diffusion limitations and that the reaction rate constants have first-order kinetics with Arrhenius-type temperature dependence. The model proposes the formation of xylose directly from wood xylan as well as from xylooligomers formed in the liquid phase by the hydrolysis of xylan. The model is able to correlate satisfactorily experimentally measured yields of residual xylan, xylooligomers, xylose, and furfural obtained during the pretreatment.

January 13, 2009

Grandidentatin isomer from bark of suwon poplar (Populus alba L.×Populus glandulosa Uyeki)

Jin-Kyu Kim, Young-Soo Bae

Page range: 315-318

Abstract

The phenolic glucoside cis -2-hydroxycyclohexyl 6- O - p -coumaroyl-β- d -glucopyranoside was isolated from the bark of the hybrid poplar Populus alba × glandulosa by column chromatography over Sephadex LH-20 and Silica gel preparative TLC. The structure elucidation was performed by NMR spectroscopy (2D NMR COSY, DEPT, HMQC, and HMBC) and MS spectrometry.

December 3, 2008

Amination of pyrogallol nucleus of condensed tannins and related polyphenols by ammonia water treatment

Koh Hashida, Rei Makino, Seiji Ohara

Page range: 319-326

Abstract

The reaction behavior of condensed tannins and related polyphenols with ammonia (NH 3 ) water was examined. NH 3 water treatment of pyrogallol, gallic acid, and epigallocatechin, which have a pyrogallol nucleus, caused regioselective amination in the presence of molecular oxygen (O 2 ) to form 2-aminoresorcinol, 4-amino-3,5-dihydroxybenzoic acid and 4′- C -amino-epigallocatechin, respectively. In contrast, other polyphenols, such as catechol, protocatechuic acid, and epicatechin, which have a catechol nucleus, did not undergo amination even in the presence of O 2 . Under nitrogen atmosphere (in the absence of O 2 ), epimerization at the C-2 position took place during NH 3 treatment of epigallocatechin, in addition to amination. The same epimerization took place during NH 3 treatment of epicatechin regardless of the presence or absence of O 2 . By NH 3 treatment, pyrogallol-type B-rings of condensed tannin from Acacia mearnsii underwent regioselective amination to yield 4′-amino-3′,5′-dihydroxybenzene-type B-rings in the presence of O 2 , whereas catechol-type B-rings of condensed tannin from quebracho showed little amination regardless of the presence or absence of O 2 . From these results, it was concluded that amination of pyrogallol nucleus by NH 3 treatment should proceed via oxidation and reduction, and therefore this reaction would be attributed to the oxidation property of condensed tannins and related polyphenols.

February 18, 2009

On the time-temperature equivalency in green wood: Characterisation of viscoelastic properties in longitudinal direction

Jana Dlouhá, Bruno Clair, Olivier Arnould, Petr Horáček, Joseph Gril

Page range: 327-333

Abstract

Aiming at modelling tree mechanics, viscoelastic properties of green wood along fibres was investigated through a sequence of creep tests in the temperature range of 30°C–70°C. The apparent validity of time-temperature equivalency was questioned by discrepancies evidenced in the approximated complex plane (ACP). This paradox was solved by assuming that the temperature not only accelerates the viscoelastic processes but also slightly increases their intensity. This softening effect of the temperature on the compliance was described by a 2nd degree polynomial. Time-temperature dependency fitted very well to the Arrhenius law up to 60°C. Based on the ACP, the power law was proposed for modelling creep behaviour in green wood. The method was successfully used for all specimens investigated.

February 13, 2009

Temperature drop sensor for monitoring kiln drying of lumber

Diego Miguel Elustondo, Luiz Oliveira, Peter Lister

Page range: 334-339

Abstract

The main objective of this study was to test a new sensor based on the temperature drop across the load (TDAL). The TDAL sensor was designed to determine the transition point between wet and dry wood without any specific information about the drying process. When additional information is available, the TDAL sensor can also be used to monitor drying rate and estimate the drying end-point. In this study, three potential applications of TDAL sensor for lumber drying were explored, namely, to monitor drying rate, to detect the transition point between wet and dry wood, and for determination of drying end-point after calibration. For the first application, it was demonstrated that the transition point between wet and dry wood coincides with the time at which the TDAL decreases with time at a constant logarithmic slope. For the second application, the TDAL sensor was calibrated with nine experimental drying runs, and the end-points determined with the calibrated TDAL sensor did not show a significant difference with the end-points determined by the in-kiln MC meter. Finally, the TDAL sensor was used to monitor drying rate during drying.

February 18, 2009

Experimental and numerical determination of the hygroscopic warping of cross-laminated solid wood panels

Thomas Gereke, Per Johan Gustafsson, Kent Persson, Peter Niemz

Page range: 340-347

Abstract

The moisture-induced warping of three-layered cross-laminated solid wood panels made of Norway spruce was studied. The panels were exposed to different climate conditions at 65% and 100% relative humidity at the two panel faces. The results showed increasing cup deformation with an increasing relative thickness of the outer layers. The annual growth ring orientation was found to have a significant influence on the magnitude of the cup deformation. Measurements and numerical simulations of the moisture distribution within the panel were made in order to provide data for numerical simulations of the warping. A distinctive moisture profile with a conspicuous influence of the adhesive bond lines was found. The coefficient of diffusion of the adhesive bond lines was determined from the measurements and simulations. The mechanical material model used for the warping simulations takes into account elastic strain, moisture-induced swelling, and mechano-sorptive strain. The simulations showed good agreement with the warping test results. The most important material parameters for the cup deformation, which were identified in a parametric study of a panel with vertically oriented annual rings, are the moduli of elasticity and the swelling coefficients in the longitudinal and radial direction. Furthermore, the mechano-sorptive coefficient in radial direction was found to have a significant influence on warp.

December 3, 2008

A single point NMR method for an instantaneous determination of the moisture content of wood

Maks Merela, Primož Oven, Igor Serša, Urša Mikac

Page range: 348-351

Abstract

Nuclear magnetic resonance (NMR) enables an instantaneous determination of the proton density in liquids and is thus convenient for determining the moisture content (MC) of wood. We demonstrated that the MC of a wood sample can be determined instantaneously on the basis of its mass ( m ) and the amplitude of its NMR free-induction-decay (FID) signal. The measurement is based on the assumption that the only liquid in the wood is water and that the relationship between the amplitude of the FID signal ( S ) and the mass of the water ( m w ) in the sample is linear, i.e., S = k m w + k′ ( m - m w ), and can be precisely calibrated for a given NMR probe and NMR spectrometer setup (in our case k =10 5 AU g -1 and k / k′ = 34). With the FID signal converted into the mass of water, the MC is calculated as: MC =( S - m k′ )/( m k - S ). After the initial calibration of the FID signal with respect to the content of water, the correctness of the method was verified on samples of different wood species with various MCs. The results confirmed that the proposed method is comparable in terms of accuracy and reliability to the gravimetric method, regardless of the species of wood. As the method is instantaneous, it might become the method of choice in applications where a short measurement time combined with a high accuracy is demanded.

December 15, 2008

Air permeability in longitudinal and radial directions of compression wood of Picea abies L. and tension wood of Fagus sylvatica L.

Asghar Tarmian, Patrick Perré

Page range: 352-356

Abstract

The air permeability in longitudinal and radial directions of compression wood in spruce ( Picea abies ) and tension wood in beech ( Fagus sylvatica ) was compared with that of the corresponding normal wood. The primary aim of the present study was to explain why the reaction woods dry more slowly than the normal woods in the domain of free water. A number of boards conventionally dried to an average final moisture content of 12% were chosen to perform the measurements. Bordered pits on the radial walls of longitudinal tracheids in the compression and normal wood and intervessel or intervascular pits in the tension and normal wood were also examined. The reaction wood of both species is less permeable than the normal wood, both in longitudinal and radial directions. The difference in permeability was more pronounced between compression and normal wood of spruce, especially in longitudinal direction. From an anatomical point of view, this is likely related to some differences in anatomical characteristics affecting the airflow paths, such as the pit features. Such results can explain the difference in drying kinetics of the reaction and normal woods in the capillary regime of drying.

December 15, 2008

A simulation of void variation in wood-strand composites during consolidation

Peng Li, Chunping Dai, Sunguo Wang

Page range: 357-361

Abstract

The void variation in a wood-strand composite mat during consolidation was simulated using computer-aided design, finite element analysis, and computer image processing. Compared with prior models, this simulation provided a different and more visual approach to analyzing the mat structure, particularly the void variation during consolidation. The simulated results showed similar trends to the experimental data. The size of voids in the final panel decreased with the panel density and increased with the strand thickness, whereas the relationship between the void size and the strand length was non-linear. The wood-strand density and strand thickness had a much greater effect on the non-linear void variation than the wood strand width and length. The simulated results are beneficial to improve the fundamental understanding of composite processing and performance characteristics.

December 4, 2008

Sterols and lignin in Eucalyptus globulus Labill. wood: Spatial distribution and fungal removal as revealed by microscopy and chemical analyses

Mariela Speranza, Ana Gutiérrez, José Carlos del Río, Lina Bettucci, Ángel T. Martínez, María Jesús Martínez

Page range: 362-370

Abstract

Wood decay experiments were carried out aiming at the selective removal of lipophilic compounds with selected basidiomycetes isolated from Eucalyptus globulus plantations in Uruguay: Dendrophora albobadia , Lentinus tigrinus , Peniophora cinerea , Peniophora lycii , and Phanerochaete crassa . Localization and composition of lipophilic compounds and lignin of E. globulus were determined by gas chromatography-mass spectrometry, fluorescence microscopy using filipin staining, confocal laser scanning microscopy (CLSM), and low temperature scanning electron microscopy. Free and esterified sterols, mainly sitosterol, were the predominant lipophilic compounds in the control wood. Sterols were present in ray parenchyma cells, together with polyphenols, and in vessels. This confirms earlier observations indicating that these cell types are the principal source of lipophilic extractives involved in pitch problems during pulping and bleaching. Sterols are also present in the vestures of fiber and vessel pits. Different fungal degradation patterns of E. globulus wood were determined. P. lycii showed the highest specificity for lignin degradation during short incubation time together with considerable sterol removal capacity. Ray parenchyma cells and their lumen deposits were strongly degraded by P. lycii . Eucalypt lignin located in vessel walls and fiber cell corners was more resistant to fungal attack, as revealed by CLSM. The initial decay stage of L. tigrinus was restricted to vessels and tyloses where the sterol compounds were removed.

January 8, 2009

Protection mechanisms of DMDHEU treated wood against white and brown rot fungi

Pradeep Verma, Ulrich Junga, Holger Militz, Carsten Mai

Page range: 371-378

Abstract

The resistance of beech and pine wood blocks treated with 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) against Trametes versicolor and Coniophora puteana increased with increasing weight percent gain (WPG) of DMDHEU. Full protection [mass loss (ML) below 3%] was reached at WPGs of approximately 15% (beech) and 10% (pine). Untreated and DMDHEU treated blocks were infiltrated with nutrients and thiamine prior to fungal incubation and it was observed whether the destruction or removal of nutrients and vitamins during the modification process has an influence on the ML caused by the fungi. This study revealed that no considerable differences were found. Then, the cell wall integrity was partly destroyed by milling and the decay of the fine wood powder filled into steel mesh bags was compared to that of wood mini-blocks. The purpose of this study was to examine whether the effects of surface area, cell wall bulking, and reduction in micro-void diameters play a role in decay resistance. The ML caused by the fungi, however, also decreased with increasing WPG and showed comparable patterns similar to the case of mini-blocks. ML of powder bearing the highest WPG appeared to be caused by losses in DMDHEU during fungal incubation. For brown rotted wood, the infrared absorption ratios at 1030 cm -1 and 1505 cm -1 revealed decreasing decay of polysaccharides with increasing WPG of treated wood.

Meeting

Publicly Available February 3, 2009

Meetings

Page range: back cover-back cover

More Download PDF

Abstract

No Abstract available

About this journal

Objective
Holzforschung (HF) is an international scholarly journal that publishes cutting-edge research on the biology, chemistry, physics and technology of wood and wood components. High quality papers about biotechnology and tree genetics are also welcome. Rated year after year as one of the top scientific journals in the category of Pulp and Paper (ISI Journal Citation Index), Holzforschung represents innovative, high quality basic and applied research. The German title reflects the journal's origins in a long scientific tradition, but all articles are published in English to stimulate and promote cooperation between experts all over the world. Ahead-of-print publishing ensures fastest possible knowledge transfer.

Topics

Biology, chemistry, physics and technology of wood and wood components
Biotechnology and tree genetics

Article formats
Original articles, Reviews, Short notes

> Information on submission process