<p>Polysaccharides constitute an important source of raw materials for the packaging industry today. Polysaccharides have good natural barrier properties which are necessary for packaging films. Cellulose is the forerunner among renewable polymers for such applications. Hemicelluloses represent a new interesting breed of barrier materials. We have chosen to work with the hemicellulose O-acetyl-galactoglucomannan (AcGGM). The high water solubility of this particular hemicellulose extracted from process waters is both an advantage and a limiting factor. However, through the right modification, the water sensitivity of AcGGM can be regulated.</p><p>This thesis presents four ways to modify AcGGM: (i) benzylation, (ii) plasma surface treatment followed by styrene addition, (iii) vapor-phase (VP) surface grafting with styrene, and (iv) lamination of an unmodified film with a benzylated material. The most important methods of analysis of the films produced include contact angle measurement, dynamic mechanical analysis under moisture scan, and oxygen gas permeability measurement.</p><p>It was found that unmodified AcGGM films have low oxygen permeability at intermediate relative humidity (50 % RH) and good dynamic mechanical properties over a wider humidity range. Films of benzylated material (BnGGM) exhibited a decrease in oxygen permeability at lower humidity but showed better tolerance to higher humidities and indicated better dynamic mechanical behavior than AcGGM films. Lamination proved to be the most promising technique of modification, combining the good gas barrier properties of AcGGM films with the moisture-insensitivity of the BnGGM films.</p>

O presente trabalho, na área das Ciências Ambientais, estudou a compostagem de resíduos sólidos provenientes da indústria de celulose e papel. Partindo-se da hipótese que a compostagem é resultado da ação de microorganismos e a aeração é um dos fatores principais para o desenvolvimento de suas atividades, o objetivo deste trabalho foi verificar qual a melhor composição de resíduos (lodo primário, lodo secundário, rejeitos de depuração, casca de eucalipto, dregs, grits e cinza) e a eficiência da biodegradação das leiras de compostagem submetidas à duas metodologias de aeração: revolvimento mecânico e aeração passiva. O revolvimento mecânico foi realizado semanalmente com o auxílio de uma pá carregadeira e a aeração passiva foi proporcionada pela presença de tubos flexíveis perfurados no interior da leira, onde por conseqüência da diferença de temperatura entre a parte interna e externa, possibilitou a inserção de oxigênio no material. Para alcançar os objetivos foram montadas nove leiras com misturas diferentes de resíduos, sendo que seis eram periodicamente revolvidas e três eram estáticas e montadas com tubos em seu interior. Ao longo de 120 dias foram monitoradas temperatura, umidade, microorganismos patogênicos, relação C/N e metais pesados. Os resultados indicaram que: a) No final do processo todos os compostos atenderam os limites estipulados pelo CONAMA 375/2006; b) Houve redução de Salmonellas e Coliformes Termotolerantes; c) A metodologia de aeração passiva foi eficiente na aeração das leiras; d) O composto atingiu o grau de maturação. A leitura dos resultados obtidos permitiu concluir que para os resíduos da industria de celulose e papel a compostagem pelo método de aeração passiva foi eficiente e não é necessário a incorporação do lodo primário no material a ser compostado. / Through this work, in the area of Environmental Science, it was studied the composting of solid waste from pulp and paper industry. Based on the hypothesis that composting is a result of the action of microorganisms and the aeration is one of the major factors for the development of its activities, the objective of this study was to determine which is the best waste composition ( primary sludge, secondary sludge, tailing sludge, bark from eucalyptus, dregs, grits and ash) and efficiency of biodegradation of the compost piles subjected to two methods of aeration: mechanical tillage and passive aeration. Mechanical tillage was done weekly using a front loader and the passivity was proposed in this work provided by the presence of drilled flexible pipes inside the windrow, where consequently the temperature difference between the internal and external areas enabled the insertion of oxygen in the material. Achieving the objectives it has been set up nine piles with different mixtures of waste, providing that six were periodically tilled and three were static and had drilled flexible pipes inside then. During 120 days it was monitored temperature, humidity, pathogenic microorganisms, C / N ratio and heavy metals. The results showed that: a) all piles met the criteria set by CONAMA 375/2006, b) there was a reduction of Salmonellas and fecal coliforms c) the methodology for passive aeration was effective in the plowing of windrows process, d) the compound reached the degree of maturation. The reading of the results enables us to draw the conclusion that for the waste from pulp and paper industry the composting of treatment was effective in piles that used the method for passive aeration and those ones which did not have in their composition any primary sludge.

The composition of lignin in the outer cell-wall layers of spruce and poplar has been studied and the data obtained have been compared with those of the mature reference wood in which the secondary cell wall predominates. Materials with exclusively or predominantly outer cell-wall layers were examined. Accurate data relating to the lignin monomer composition and the number of β-O-4´ bonds were obtained from pure middle lamella/primary cell wall lignin. Firstly, a 10 000 year old white spruce material, with most of the secondary cell wall missing, was studied. The aged lignin was composed of guaiacyl units only, and was slightly more condensed but otherwise similar to the reference lignin. Secondly, the developing xylem of a Norway spruce clone was analyzed during a growth season. In spring and early summer, growth is very rapid and the intention was to sample tissues in which the secondary cell-wall layers had not yet lignified, but where the outer layers at least had started to lignify. Microscopy, Klason lignin and carbohydrate analyses showed that the lignin in the developing xylem of samples from mid-June was located exclusively in the middle lamella. The lignin was more condensed, was composed of guaiacyl units only and contained more end-groups than the reference Norway spruce wood. Thirdly, the cambial tissues of a Balsam poplar clone were surveyed during a growth season. Both the phloem side and the xylem side of the cambial region were examined. The Klason lignin content and carbohydrate monomer distribution showed that in June and August the tissues on the phloem side contained material with mainly middle lamella/primary walls. In June, the xylem side in the cambial region contained mainly middle lamella/primary walls, and in August the secondary cell wall carbohydrates were being deposited. Both tissues contained lignin that was more condensed and had more end-groups than the reference lignin. In mid-June, the developing xylem had a ratio of syringyl to guaiacyl units of 0.6, whereas the ratio for the reference wood was 1.3. In the final study, lignin from the primary cell walls from a hybrid aspen cell suspension culture was investigated. The lignin contained only guaiacyl units which were more condensed than those observed in the reference poplar wood. / <p>QC 20100920</p>

In the early 1990’s, a lot of work was focused on extending the kraft cook to a low lignin content (low kappa number). The driving force was the need to further reduce the environmental impact of the bleaching, as less delignification work would be needed there. However, the delignification during the residual phase of a kraft cook is very slow and, due to its poor selectivity, it is a limiting factor for the lignin removal. If the amount of lignin reacting according to the residual phase could be reduced, it would be possible to improve the selectivity of the kraft cook. In the work described in this thesis, special attention has been given to the activation energy of the slowly reacting residual phase of a kraft cook on softwood raw material and to the influence of different cooking parameters on the amount of the residual phase lignin. The activation energy of the residual phase delignification of the kraft cook was shown to be higher than that of the bulk phase delignification. In order to decrease the amount of residual phase lignin, it was essential to have a high concentration of hydrogen sulphide ions when cooking with a low hydroxide concentration. It was also important to avoid a high sodium ion concentration when cooking with low hydroxide and low hydrogen sulphide ion concentrations. Furthermore, it was demonstrated that dissolved wood components had a positive effect on the delignification rate in the bulk phase of a kraft cook. The influence of different cooking parameters in the extended softwood kraft process on the bleachability (i.e. the ease with which the pulps can be bleached to a target brightness) of the manufactured pulp was also investigated. If variations in bleachability were seen, an attempt would also be made to find chemical reasons to explain the differences. It was difficult to establish clear relationships between the chemical structures of the residual lignin and the bleachability of the pulp. However, it was seen that the higher the content of β-aryl ether structures in the residual lignin after cooking, the better was the QPQP*-bleachability. In the middle/end of the 1990’s, the focus moved from extended cooking to efficient utilisation of the wood raw material, e.g. by interrupting the kraft cook at higher kappa number levels and choosing appropriate cooking conditions to maximise the cooking yield. A high cooking yield often leads to a somewhat higher hexenuronic acid (HexA) content of the pulp at a given kappa number. Therefore additional attention was devoted to how the HexA content and carbohydrate composition were affected, e.g. by a set of cooking parameters. Performing these studies it was also important to investigate the effects of a low HexA (after cooking) strategy on such vital factors as the cooking yield, the bleachability and the yellowing characteristics of the pulp obtained. It proved to be difficult to significantly reduce the HexA content in a kraft pulp by altering the cooking conditions for both softwood and the hardwood Eucalyptus Globulus. A reduction in HexA content can be achieved by extending the cook to lower kappa numbers, or by using a high hydroxide concentration, a low hydrogen sulphide concentration or a high sodium ion concentration. However, neither of these strategies is attractive for industrial implementation since they would result in an extensive loss of yield, viscosity and strength. / <p>QC 20100825</p>

A utilização de fontes renováveis para a produção de biocombustíveis tem sido incentivada no mundo todo. Assim, na proposta de um novo cenário energético mundial, aliado as condições ambientais, surge a necessidade de se procurar outras fontes alternativas de matéria primas renováveis. Neste contexto, o Brasil possui condições especiais, se considerarmos os resíduos lignocelulósicos do setor florestal. Atualmente, o Brasil é o maior produtor mundial de celulose à partir de fibra curta de Eucalyptus spp, com um setor bem desenvolvido e em plena expansão. Toda esta atividade industrial produz anualmente cerca de 2,8 a 5,7 milhões de toneladas resíduos sólidos na forma de casca (principalmente de eucaliptos). Em muitos casos o destino aplicado para essas biomassas é pouco eficiente e representa uma perda significativa do potencial energético, pois estes resíduos lignocelulósicos são passíveis de biotransformação a compostos com elevado valor agregado, tais como os biocombustíveis (etanol). Portanto, o objetivo deste trabalho foi avaliar o potencial das cascas de eucalipto frente a produção de etanol combustível. Desta maneira, as cascas de 5 clones comerciais (E.urophylla x E. grandis e E. grandis) foram caracterizadas quanto a composição química. As cascas de eucalipto foram submetidas a uma série de pré-tratamentos ácidos e alcalinos, avaliados em planejamento fatorial com o objetivo de recuperar os açúcares potencialmente fermentecíveis. As cascas de eucalipto apresentaram aproximadamente 20% de carboidratos solúveis totais CST (glicose, frutose e sacarose). Os CST foram extraídos com água quente à temperatura de 80oC e em seguida fermentados com leveduras convencionais (Saccharomyces cerevisiae). A produção de etanol por tonelada de casca seca foi de 106 litros (etanol de primeira geração). Após a extração dos CST, as biomassas residuais das cascas de eucalipto foram submetidas a uma série de pré-tratamentos. O pré-tratamento alcalino (NaOH) apresentou uma eficiência enzimática de conversão da glicose de aproximadamente 30% após 24 horas de incubação. Com os resultados obtidos da hidrólise enzimática, estima-se que possam ser produzidos mais 94 litros de etanol por tonelada de casca livre de extrativos (etanol celulósico). / The use of no fossil source for biofuels production has been stimuled in the all world. Proposing a new global scenario related to the energy matrix, together with the environmental conditions, there is the need to search alternative renewable raw materials. In this context, Brazil presents special conditions, considering the lignocellulosic residues from the forestry industry. Nowadays, Brazil is the largest cellulose short fiber producer from Eucalyptus spp, having a strong sector in expansion. This industrial activity produces in average 2,8 to 5,7 million tons of solid waste in the form of bark (mostly from eucalyptus). Usually, the destiny of this biomass is inefficient and represents a significant loss of the energetic potential, since these lignocellulosic residues can suffer biotransformation and produce high value components, like the biofuels (ethanol). Therewith, the aim of this work was to evaluate the potential of the eucalyptus bark related to ethanol fuel production. In this way, barks from 5 commercial clones (E. urophylla x E. grandis e E. grandis) were characterized due to the chemical composition. Eucalyptus barks were subjected to a series of acid and alkaline pretreatments, evaluated in factorial design aiming to recover potentially fermentable sugars. Eucalyptus bark presented on average 20% of total soluble carbohydrates TSC (glucose, fructose and sucrose). TSC were extracted with hot water (80 °C) and fermented by Saccharomyces cerevisiae. Ethanol production per ton of dry bark was 106 liters (first generation ethanol). After TSC extraction, the residual biomass from eucalyptus bark were subjected to several pretreatments. The alkaline pretreatment (NaOH) presented a high enzymatic efficiency of glucose conversion of approximately 30% after 24 hours of incubation. With the results obtained in enzymatic analysis, is estimated that it can be produced more than 94 liters of ethanol per ton of bark (cellulosic ethanol).

Atualmente, o reaproveitamento de resíduos resultantes de atividades industriais vem se tornando um dos pontos mais importantes na melhoria dos aspectos produtivos, como também na minimização de problemas ambientais decorrentes da forma de produção e do descarte final do resíduo gerado no decorrer do processo de produção. Desta maneira, as indústrias estão buscando implantar um sistema de gestão ambiental (SGA), no qual o resíduo, anteriormente descartado, passa a ser considerado matéria prima para a fabricação de novos materiais. Dentro deste enfoque, e considerando os impactos gerados pelas indústrias de papel e celulose, estudos que visam demonstrar o potencial de utilização do lodo residual gerado durante a produção de papel na indústria Votorantim Celulose e Papel (VCP), município de Jacareí, SP-Brasil, têm sido desenvolvidos, por meio de uma parceria de indústria e universidades (UNESP - Bauru e USP - São Carlos). Após análises químicas e toxicológicas do lodo residual, obteve-se uma composição de aproximadamente 58,9% de fibras, sendo classificado como Classe II, segundo a NBR 10.004/87. Para avaliar o seu potencial de utilização em materiais de construção, foram confeccionados tijolos de adobe com o solo arenoso proveniente do município de Bauru, SP, nos traços 0%, 10%, 15%, 20%, 25%, 30% e 40% em volume de resíduo. Foram realizados diversos ensaios para caracterização dos tijolos (retração, absorção de água e resistência à compressão simples), bem como ensaios de intemperismo, gotejamento, verificação da ação do fogo (perda de massa, propagação das chamas e ensaio de incombustibilidade dos materiais de construção), como também a obtenção de suas características térmicas e acústicas. Com os resultados dos ensaios, foi realizada uma análise geral, por meio da interação dos melhores valores encontrados e, assim, escolhido o traço numa faixa de 20% a 25% de resíduo. Os resultados demonstraram a viabilidade do uso do resíduo em tijolos de adobe, conferindo aos mesmo bons níveis de resistência, manuseio, leveza e durabilidade. / Nowadays, reuse of residues from industrial activities is one of the most important aspects in productivity improvement, as well as, minimization of environmental problems originated from production way and residue disposal during the productive process. Industries are requesting and Environmental Management System (SGA), in which residues, formerly discarded, began to be considered raw materials for production of new materials. In this context and considering impacts generated by paper and cellulose manufacturing, studies have been developed, aiming to demonstrate potential use of residual mud generated during paper production in Votorantin Cellulose and Paper Industry (VCP), located in Jacareí, São Paulo State, Brazil, through a partnership between this industry and universities (UNESP - Bauru and USP - São Carlos). After chemical and toxicological analyses of the residual mud, a composition of aproximately 58,9% of fibres was obtained and classified as Class II acording to NBR 10.004/87. For evaluating its potential use in buildings, adobe bricks were made with sandy soil from Bauru (São Paulo State), considering 0% (witness), 10%, 15%, 20%, 25%, 30% and 40% of residuary volume. Several rehearsals were carried out for brick characterization (retraction, water absorption and resistance to simple compression), and to verify intemperism, leak and fire action (mass loss, flame propagation and fireproof rehearsals), as well as thermal and acoustic characteristics (qualities). A general analysis interacting all values obtained indicated the percentage of residuary volume, in the range of 20% to 25% as the best condition. The results demonstrated viability of use of paper and cellulose residual mud in adobe bricks manufacturing, since they presented good levels of resistance, handling, lightness and durability.

<p>Detta examensarbete genomfördes från begäran av två företag, Pöyry Sweden AB, Karlstad och Kiram AB. Arbetet var uppdelat i två delar, en litteraturstudie samt en experimentell del. I litteraturstudien kartlades olika processer för framställning av dissolvingmassa och olika processer för beredning av viskosfiber. Utöver det sammanställdes även några av de ledande aktörerna av joniska vätskor samt applikationer för cellulosabaserade produkter. Fokus genom hela arbetet har legat på svavelfria processer som t.ex. användandet av joniska vätskor för upplösning av cellulosa. I den experimentella delen undersöktes det om man via en förhydrolys följt av ett soda-AQ kok, en svavelfri process, kunde producera dissolvingmassa. Utöver produktion av dissolvingmassa undersöktes också filtratet som drogs av efter förhydrolysen.</p><p>Under den experimentella delen varierades olika parametrar för att se hur det påverkade kvaliteten av massan. De parametrar som varierades vid förhydrolysförsöken var tid och antrakinon (AQ), för soda-AQ koket varierades tid, AQ och effektiv alkali (EA) halt. För ett förhydrolysförsök varierades även vätske/vedförhållandet. Vilka betingelser som skulle användas samt de mål som skulle uppnås fick man fram under litteraturstudien.</p><p>För att nå målet med ett utbyte på ca 85 % efter förhydrolysen krävdes en temperatur på 160°C och tid på 1 timme för en förhydrolys med enbart vatten. Hypotesen om att en AQ tillsats redan vid förhydrolysen skulle sänka utbytet visades inte stämma, man fick då istället ett ökat utbyte. Målet för massorna efter soda-AQ koket var ett utbyte på ca 40 %, ett kappatal runt 30 och en viskositet > 1000 ml/g. Utförde man en förhydrolys som beskrivits ovan följt av ett soda-AQ kok med dessa betingelser: temperatur 160°C, tid ≥ 2 h, EA sats > 21 % och en AQ halt ≥ 1 kg/ton, fick man en dissolvingmassa som uppfyllde kraven.</p><p>Kolhydratanalysen på filtratet visade att mestadels glukomannan brutits ner och lösts ut under förhydrolysen. Däremot skedde det ingen nedbrytning av cellulosa. Utförde man förhydrolysen på ett sådant sätt som beskrivits ovan bröt man ner en hemicellulosa mängd på ca 72 kg/ton flis. Det får ses som en ganska rejäl mängd eftersom man enbart använder vatten under förhydrolysen.</p> / <p>This project was carried out on a request from two companies, Pöyry Sweden AB, Karlstad and Kiram AB. The work was divided in two parts, one literature study and one experimental part. In the literature study different processes for production of dissolving pulp and different processes for viscose preparation were identified. Besides that, some of the lending companies of ionic liquids and some applications of cellulose based products were compiled. The main focus throughout this work has been on processes without sulfur, for an example the use of ionic liquids for dissolving cellulose. In the experimental part, dissolving pulp production by a prehydrolysis followed by a soda-AQ cooking was investigated. The filtrate gained from the prehydrolysis was also examined.</p><p>In the dissolving pulp production different parameters for the prehydrolysis and cooking stage were alternated. For the prehydrolysis the following parameters were varied: time and concentration of anthraquinone and for the cooking stage the parameters time, EA and concentration of anthraquinone. In one experiment the liquid to wood ratio was varied. The conditions that would be used and the target of the experimental work were received from the literature study.</p><p>To reach the target yield of approximately 85 % after an prehydrolysis, with water, the following conditions were required, a temperature of 160°C and a time of 1 hour. The hypothesis that an AQ additive, already in the prehydrolysis, should lowered the yield proved to be wrong. The target for the dissolving pulps after a soda-AQ cooking were a yield of ~ 40 %, a kappa number around 30 and finally a viscosity > 1000 ml/g. A soda-AQ cooking with these conditions: temperature 160°C, time ≥ 2 h, EA > 21 % and an AQ conc. ≥ 1 kg/ton, after a prehydrolysis, mentioned above, resulted in a pulp which achieved the targets.</p><p>The carbohydrate analysis on the filtrate showed that mostly glucomannan was settled out during the prehydrolysis. It also showed that no cellulose was settled out. A result after a prehydrolysis like the one mentioned above was that the amount of hemicellulose was reduced with ~ 72 kg/ton wood.</p>

This thesis is focused on the novel wood chip refining process called AdvancedThermomechanical Pulp (ATMP) refining. ATMP consists of mechanical pretreatmentof chips in Impressafiner and Fiberizer prior to first stage refining atincreased intensity. Process chemicals (this study was concentrated on hydrogenperoxide and magnesium hydroxide) are introduced into the first stage refiner.It is known that the use of chemicals in TMP process and first stage refining atelevated intensity can reduce the energy demands of refining. The downside is thatthey also alter the character of the produced pulp. Reductions in fibre length andtear index are usually the consequences of refining at elevated intensity. Additionof chemicals usually leads to reduction of the light scattering coefficient. Usingstatistical methods it was shown that it is possible to maintain the TMP character ofthe pulp using the ATMP process. This is explained by a separation of thedefibration and the fibre development phases in refining. This separation allowsdefibration of chips to fibres and fibre bundles without addition of chemicals orincrease in refining intensity. Chemicals are applied in the fibre developmentphase only (first stage refiner). The energy demand in refining to reach tensileindex of 25 Nm/g was reduced by up to 1.1 MWh/odt (42 %) using the ATMPprocess on Loblolly pine. The energy demand in refining of White spruce, requiredto reach tensile index of 30 Nm/g, was reduced by 0.65 MWh/odt (37%).Characterizations of individual fibre properties, properties of sheets made fromlong fibre fractions and model fibre sheets with different fines fractions werecarried out. It was established that both the process equipment configuration (i.e.the mechanical pre‐treatment and the elevated refining intensity) and the additionof process chemicals in the ATMP process influence fibre properties such as external and internal fibrillation as well as the amount of split fibres. Improvementof these properties translated into improved properties of sheets, made from thelong fibre fractions of the studied pulps. The quality of the fines fraction alsoimproved. However, the mechanisms of improvement in the fines quality seem tobe different for fines, generated using improved process configuration andaddition of process chemicals. The first type of fines contributed to better bondingof model long fibre sheets through the densification of the structure. Fines whichhave been influenced by the addition of the process chemicals seemed in additionto improve bonding between long fibres by enhancing the specific bond strength.The improved fibre and fines properties also translated into better airpermeability and surface roughness of paper sheets, properties which areespecially important for supercalendered (SC) printing paper. The magnitude offibre roughening after moistening was mainly influenced by the processequipment configuration while the addition of process chemicals yielded lowestfinal surface roughness due to the lowest initial surface roughness. There was nodifference in how fines fractions from the studied processes influenced the fibreroughening. However, fines with better bonding yielded model fibre sheets withhigher PPS, probably due to their consolidation around fibre joints. Hence, thedecrease in PPS can probably be attributed to the improvements in the long fibrefraction properties while the improvement of fines quality contributed to thereduction of air permeability.The process chemicals, utilized in the ATMP process (Mg(OH)2 and H2O2) alsoproved to be an effective bleaching system. Comparable increases in brightnesscould be reached using the ATMP process and conventional tower bleaching.Maximum brightness of the pulp was reached after approximately 10 minutes ofhigh‐consistency storage after refining or 40 minutes of conventional bleaching.This study was conducted using a pilot scale refiner system operated as a batchprocess. Most of the experiments were performed using White spruce (Piceaglauca). In Paper I, Loblolly pine (Pinus taeda) was used. It is believed that theresults presented in this thesis are valid for other softwood raw materials as well,but this limitation should be considered.

A large part of the world paper manufacturing consists of production of corrugated board components, kraftliner and fluting, that are used in many different types of corrugated boxes. Because these boxes are stored and transported, they are often subjected to changes in relative humidity. These changes together with mechanical loads will increase the deformation of the boxes compared to the case where the same loads are applied in a static environment. This enlarged creep due to the changes in relative humidity is called mechano-sorptive or accelerated creep. Mechano-sorptive creep forces producers to use high safety factors when designing boxes, and therefore, this is one of the key properties of kraftliner boards.   Different strategies to decrease mechano-sorptive creep, and to simultaneously gain more knowledge about the causes for this phenomenon in paper, are the aim of this work. Derivatised and underivatised black liquor lignins, a by-product produced in pulp mills in large quantities, have been used together with biomimetic methods, to modify the properties of kraftliner pulp. Furthermore, the properties of kraftliner pulp have been compared to other pulps in order to evaluate the influence of fibre morphological factors, such as fibre width and shape factor, on the mechano-sorptive creep. In addition the influence of the chemical composition of the kraftliner pulp has been evaluated both by means of treating a kraftliner pulp with chlorite and xylanase and by producing pulps with different chemical composition.   By using lignin and biomimetic methods, to create radical coupling reactions, it has been shown that it is possible to increase the wet strength of kraftliner pulp sheets. This method of treating the pulp showed, however, no significant effects on the mechano-sorptive creep. The addition of an apolar suberin-like lignin derivative, which has been shown to be possible to produce from natural resources, did show a positive effect on mechano-sorptive creep properties, but at the expense of stiffness properties in constant climate. Different pulps were compared with a kraftliner pulp and it was observed that the ratio between tensile stiffness and hygroexpansion can be used to estimate the mechano-sorptive creep properties. The hardwood kraft pulps investigated had lower hygroexpansion, probably due to more slender and straighter fibres, and higher tensile stiffness, probably due to lower lignin content. As the lignin content was varied by different methods in kraft pulps, it was observed that increased lignin content gives an increased hygroexpansion and decreased tensile stiffness as well as an increased mechano-sorptive creep. There were also indications of increased mechano-sorptive creep due to higher xylan content. / En stor del av världens papperstillverkning utgörs av produktion av wellpappkomponenter, kraftliner och fluting, som används i en uppsjö av olika wellpapplådor. När dessa lådor lagras och transporteras utsätts de ofta för förändringar i relativa luftfuktigheten. Dessa förändringar tillsammans med mekanisk belastning ökar lådornas deformation jämfört med om samma belastning skulle ha applicerats vid ett statiskt klimat. Denna förhöjda krypning på grund av förändringarna i relativ luftfuktighet kallas mekanosorptiv- eller accelererad krypning. Mekanosorptiv krypning tvingar producenterna att ha höga säkerhetsmarginaler vid dimensioneringar av lådor och är därför en av nyckelegenskaperna för kraftliner.   Olika strategier för att minska denna effekt, och på samma gång erövra mer kunskap om orsakerna till detta fenomen, har varit syftet med arbetet. Derivatiserade och oderivatiserade svartlutslignin, en biprodukt möjlig att få ut i stora kvantiteter från massabruk, har används tillsammans med biomimetriska metoder, för att modifiera kraftlinermassas egenskaper. Dessutom har kraftlinermassans egenskaper jämförts med andra massors egenskaper för att utvärdera inverkan av fibermorfologiska faktorer, såsom fiberbredd och fibreform på det mekanosorptiva krypet. Också inverkan av den kemiska sammansättningen av kraftliner massan har undersökts både genom behandling med klorit och xylanas och genom att producera massor med olika kemiska sammansättningar.   Genom att använda lignin och biomimetriska metoder för att skapa radikal-kopplingsreaktioner har det visats på möjligheten att öka våtstyrkan i massa-ark. Det här sättet att behandla massa visade dessvärre inga signifikanta effekter på det mekanosorptiva krypet. Tillsatts av ett apolärt suberin-liknande ligninderivat, som visats möjligt att producera ur naturliga råmaterial, visade en positiv effekt på det mekanosorptiva krypegenskaperna även om det var på bekostnad av styvheten vid konstant klimat. Olika massor jämfördes med en kraftlinermassa och det observerades att relationen mellan dragstyvhet och hygroexpansion kan användas för att uppskatta de mekanosorptiva krypegenskaperna. Lövvedssulfatmassorna som undersöktes hade lägre hygroexpansion, antagligen beroende på smalare och rakare fibrer, och högre dragstyvhet, troligen beroende på en lägre ligninhalt. När ligninhalten varierades i sulfatmassor med olika metoder observerades att ökad ligninhalt ger en ökad hygroexpansion och minskad dragstyvhet liksom en ökad mekanosorptiv krypning. Dessutom fanns indikationer på en ökad mekanosorptiv krypning till följd av högre xylaninnehåll. / QC 20100629

The surface charges of cellulosic fibers contribute to several papermaking operations that influence the manufacture and final properties of paper. This thesis investigates the effect of the surface charges on wet-end chemistry, e.g. through the interaction of cationic polyelectrolytes with the fiber surface charges, and on the network strength of pulp suspensions. The polyelectrolyte titration method was used to investigate the interaction of the fiber charges with cationic polyelectrolytes. Techniques were developed to fluorescent label the adsorbing cationic polyelectrolyte in order to visualize the adsorption behavior. Fluorescent confocal laser scanning microscopy (CLSM) was used to determine the extent to which the cationic polyelectrolyte adsorbs into the porous fiber wall. It was shown that the polyelectrolyte charge density limits the adsorption to the surface under electrolyte-free conditions. Adsorption into the fiber wall only occurs for two conditions: 1) if the molecular mass is sufficiently low or 2) the electrolyte concentration is high enough to screen the charges along the polyelectrolyte backbone but not the interactions between the polyelectrolyte and the fiber charges. Aside from the polyelectrolyte properties, the fiber charge density contributes to the adsorption behavior of cationic polyelectrolytes. The fiber charge profile was altered by bulk and surface carboxymethylation. The electrolyte concentration at which a deviation from 1:1 stoichiometry occurs was shown to be dependent on the amount of surface charges, such that the deviation in stoichiometry occurs at a higher electrolyte concentration for pulps having a higher surface charge. A hypothesis was developed to test the conditions at which the deviation in adsorption stoichiometry occurs, which was defined as the critical electrolyte concentration (CEC). It was found that the CEC corresponded to the electrolyte concentration at which the distance between the fiber charges was on the order of the Debye length. Electron spectroscopy for chemical analysis (ESCA) was used as an independent calibration procedure to validate for which a 1:1 stoichiometry occurs. The analysis with ESCA agreed well with the polyelectrolyte titration method for measurement of fiber surface charges. When measured under appropriate conditions, i.e. electrolyte concentration and molecular properties, the fiber surface charge can accurately be measured by the polyelectrolyte titration method. The charge profiles of various pulp types and treatments were also examined. Having been established as a valid technique, the polyelectrolyte titration method was again used to measure the surface charge while conductometric titration was used to measure the total charge content. The amount of bulk and surface charges vary depending on the pulping method and type of wood, although the ratio between the bulk and surface charge (i.e. the charge ratio) is similar for chemical pulps. The mechanical pulp has a higher charge ratio because it contains more fines material than chemical pulp. Bleaching of the chemical pulp decreases the amount of bulk and surface charges, although the charge ratio remains essentially constant. However, methods such as beating or carboxymethyl cellulose (CMC) grafting are available to increase the charge ratio. The effect of the charge profile on fiber-fiber interactions was studied on both a microscopic and macroscopic level. Colloidal probe microscopy (CPM) was used to investigate the microscopic interactions between two cellulose surfaces. Cellulose surfaces, prepared by spin-coating a dissolving pulp onto silica, were used to model the fiber surface, which is too rough for surface force measurements. The charge density of the model surface was increased by CMC grafting. Results showed that increasing the surface charge density created large electrosteric repulsions, due to CMC the chains protruding out from the surface. These interactions on the microscopic scale affect the fiber network strength, which was measured with a parallel plate rheometer. When the repulsion is increased between the fibers, caused by the increase in the surface charge, fiber flocs break apart more easily due to a reduced friction between the fiber surfaces. The forces acting on the fiber network can also be mechanical in origin. The fiber length and flexibility were altered in order to study the influence of mechanical surface linking and elastic fiber bending on the fiber network strength. Using the storage modulus (G’0) as a measure of fiber network strength, longer fibers were found to create a stronger network due to an increased amount of fiber contacts. Flexible fibers have a lower network strength than stiff fibers because the fibers come to rest in a less strained position such that the the influence of elastic fiber bending on the fiber network strength is predominant. / QC 20100831