Orientadores: Sérgio Roberto Peres Line, Alexandre Augusto Zaia / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-19T14:41:36Z (GMT). No. of bitstreams: 1 Frozoni_MarcosRobertodosSantos_D.pdf: 22284992 bytes, checksum: f3df32a5434f64642e63697df5e27202 (MD5) Previous issue date: 2011 / Resumo: Na polpa saudável, os odontoblastos pós-mitóticos responsáveis pela secreção de dentina primária e secundária sobrevivem durante a toda a vida do dente e são responsáveis pelas respostas às injúrias externas através da produção de dentina terciária focalmente abaixo do local da agressão. Os odontoblastos sobreviventes à injúria secretam uma matriz de dentina reacional, entretanto, os irreversivelmente danificados, são substituídos por uma segunda geração de células com as mesmas características morfofisiológicas. Estas células são derivadas do recrutamento, proliferação e diferenciação de células pulpares que possuam propriedades de células tronco, para formar uma nova matriz de dentina reparativa como parte do processo de reparo do complexo dentino pulpar. O mecanismo de reparo que segue após uma injúria dental é fundamental para a sobrevivência da polpa e envolve uma série de processos que precisam ser completamente esclarecidos mais precisamente a origem das células precursoras da nova geração de odontoblastos que irão secretar dentina reparativa. Embora evidências sugiram que esta nova geração de odontoblastos tenha origem de células do tecido conjuntivo pulpar, a exata origem destas células ainda não está completamente esclarecida. O objetivo deste estudo foi utilizar camundongos transgênicos que expressam green fluorecent protein (GFP) em todas as células do corpo, com exceção dos eritrócitos, e a técnica cirúrgica de parabiose para unir dois camundongos isogênicos, um GFP e outro não-GFP de maneira a formar um par parabiótico, que possa compartilhar a mesma circulação sanguínea cruzada (células marcadas do camundongo GFP passam para a corrente circulatória do camundongo não-GFP). Após a parabiose foi realizada uma exposição pulpar, devidamente capeada, nos molares dos camundongos não-GFP para estimular a produção de dentina terciária reparativa e conseqüentemente a diferenciação de novos odontoblastos. Os animais foram sacrificados e os molares dos camundongos não-GFP, processados para análise em microscopia de fluorescência. Foi observada a presença de células GFP (células verdes ao microscópio de fluorescência), originárias do sangue periférico (SP) de camundongos GFP, participando do processo de dentinogênese reparativa nos molares de camundongos não-GFP. Este estudo sugere a primeira evidência da participação de células troco mesenquimais do sangue periférico (CTM-SP) no processo de diferenciação de novos odontoblastos durante a dentinogênese reparativa / Abstract: In the healthy pulp, the post-mitotic odontoblasts responsible for secretion of primary and secondary dentin survives during the tooth life and are able to respond to injuries with the production of tertiary dentin focally beneath the site of the injury. If the odontoblast survives the injury it secrets a reactionary dentin matrix but if it is irreversibly damaged, it is replaced by a second generation of odontoblast-like cells, with the same morphophysiological profile. Those cells are derived from recruitment, proliferation, and differentiation of pulp cells, which can have stem cell properties to form a new reparative dentin matrix as part of repair process in the dentin-pulp organ. The repair mechanism that follows a tooth injury is critical to the pulp survival and involves a series of processes that need to be completely understood more precisely the origin of the odontoblast-like cells that will secrete reparative dentin. Although evidences suggesting that odontoblast-like cells originate from cells within dental pulp connective tissue the exact origin of these odontoblast-like cells is not clearly defined. The aim of this study was to use transgenic mice expressing green fluorescent protein (GFP) in all body cells except erythrocytes and parabiosis surgical technique for joining two inbred mice, a GFP and other non-GFP to form one parabiotic pair, who can share the same cross-circulation (labeled cells from GFP mice move into the bloodstream of non-GFP mice After parabiosis a pulp exposure, properly capped, was performed on the molar of the recipient non-GFP mice to stimulate the production of tertiary reparative dentin and hence differentiation of odontoblastlike cells. The animals were sacrificed and the molars of the non-GFP mice processed for fluorescence microscopy. It was observed the presence of GFP cells (green cells to the fluorescence microscope), originating from peripheral blood (PB) from GFP mice, participating in the reparative dentinogenesis process in the molars of non-GFP mice. This study suggests the first evidence of the participation of mesenchymal stem cells from PB (MSC-PB) in the differentiation process of odontoblast-like cells during reparative dentinogenesis / Doutorado / Endodontia / Doutor em Clínica Odontológica

A thesis submitted in fulfillment of the requirement for the Degree Master of Technology: Biotechnology, M.L. Sultan technikon, 2000. / The ever-increasing demand for a wide variety of paper products has led to the pulp and paper industry becoming one of the largest industries in the world. In 1988 the United States alone produced almost 71 million metric tonnes of paper and pulp board (Jeffries, 1992). South Africa has also become one of the major international producers of pulp and paper products. Since 1970, the production of paper and board by the South African industry achieved an average growth rate of 5.2% per annum, and in 1997 South Africa was the twelfth largest producer of pulp and 24th biggest supplier of paper and board in the world (Molony, 1999 / M

The ability of eucalypt trees to grow in different soil aspects, under variable climatic and environmental conditions and to grow fast consistently producing straight stems has made them preferred plantation trees in many parts of the world. The world‘s increased demand for pulp wood has been the major contributor to the aggressive extensive development of eucalyptus plantations around the world. The productivity of these trees is however hindered in both native and introduced plantations by pests and pathogens. Chapter 1 of this thesis is a literature review on Teratosphaeria suttonii as the causative agent of Teratosphaeria Leaf Disease on Eucalyptus. The chapter highlights the taxonomic placement of T. suttonii in the genus Teratosphaeria and the name changes of the species as a consequence of molecular taxonomy. The effects of the pathogen on Eucalyptus plantations in different parts of the world as well as the incidence and range of Eucalyptus species that host the pathogen are presented. In addition the review summarizes much of the information published on the distribution, hosts range and evolutionary relationships of T. suttonii with closely related species in the genus Teratosphaeria. In conclusion, it highlights the lack of understanding of the degree of diversity of the pathogen from different parts of the world. In order to characterize and establish the phylogenetic relationships between T. suttonii isolates from different countries, chapter 2 of this thesis considered microscopic examination and DNA sequence comparisons of isolates from its native and introduced localities. The isolates were classified into a single genetically and morphologically diverse group within which representatives of different countries were intermixed in smaller groups. A high level of genetic variation was evident among Australia isolates but despite the diversity there was no overwhelming evidence for sibling species. In Chapter 3 of this thesis eleven microsatellite markers were developed from three T. suttonii isolates obtained from 2 geographic areas. The markers were used in Chapters 4 and 5 to investigate the genetic diversity of T. suttonii in both its native and introduced environments and to establish factors underlying such diversity. The application of the markers in Chapters 4 and 5 provide the first consideration of the diversity of T. suttonii in both its native and introduced localities respectively. Both native and introduced pathogen populations exhibit substantially high genotypic diversities. It is evident from these studies that Australia is the point of origin of T. suttonii and that anthropogenic activities have resulted in repeated introductions of the pathogen from Australia into many countries. Teratosphaeria suttonii is of great significance to the eucalyptus plantation industry across the world. Movement of diseased germplasm and introduction of new genotypes favors pathogen adaptability. In order to reduce the distribution of the pathogen into new areas or any other places where it might have negative effects, strict quarantine procedures should be followed. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Microbiology and Plant Pathology / Unrestricted

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

For all kinds of paperboard packages, the bending stiffness of the paperboard is a crucial property. In multi-ply folding boxboard (FBB) grades, this is obtained by placing different stocks in the outer and centre plies of the board. In the outer plies, a stock with a high tensile stiffness is used, typically made from refined kraft pulp fibres. In the middle ply/plies a stock with more bulky properties is placed, typically comprising of a high proportion of CTMP (chemi-thermomechanical pulp). CTMP fibres are stiffer and more inflexible with poor bonding abilities resulting in low strength properties. To increase the bonding strength in the middle ply, broke, containing chemical pulp is added, and sometimes refined chemical kraft pulp as well. Both fibres and fines, i.e. smaller fibre fragments, in a pulp have a significant contribution to the properties of the product. Fines produced during refining of chemical pulp are especially beneficial for increasing the strength. To achieve pulp fraction with higher fines content the pulp can be fractionated with a micro-perforated screen basket; a fine fraction produced from a screen with very small holes will contain a large proportion of fines. By adding such a fine fraction to a middle ply stock, the bulk properties of the main pulp, for example a CTMP, can be conserved as less refining of this pulp is required to achieve the targeted strength properties. However, a drawback is that the fine fraction usually has a very low mass concentration after the screening process as a lot of water pass through the screen together with the fines and fibre fragments. The excess water must be removed to maintain the water balance of the papermaking process. Further, the larger volumes require extra pumping capacity. A resource-efficient production of a fine fraction must target a high fine fraction mass concentration and a high content of fines and short fibre fragments in order to be implemented industrially. The focus of the present work was on separation efficiency (i.e. the difference in fibre length distribution caused by screening) and process efficiency (i.e. the concentration of the fine fraction) for production of a fine fraction of chemical pulp by screening, and the utilisation of the fine fraction as strength agent. Pilot-scale fractionation trials with a pressure screen with different microperforated screen baskets were performed in order to evaluate how the separation efficiency and process efficiency were affected by parameters such as feed concentration, pulp type (hardwood or softwood kraft pulp), hole size of the screen, and refining treatment prior to screening. The trials were evaluated using fibre length distributions, flow rates and concentrations of viii the feed flow and the fractions. Here, two complementary quantitative measures, Proportion in fine fraction (for process efficiency) and Fine fraction enrichment (for separation efficiency), were developed. To evaluate the strength enhancing effect of the obtained fine fraction, a lab scale study was performed where the fine fraction of a highly refined pulp was compared with the highly refined pulp as strength agent for a CTMP. The results of this study were verified in a pilot paper machine trial. In a second pilot paper machine trial, sheets with different CTMP proportions in the middle ply were studied in order to find out if the bulk could be increased while maintaining strength, by using a fine fraction made from refined chemical pulp. Regarding process efficiency, it was found that the most important parameter to obtain a high fine fraction concentration was a high feed concentration. Further, a higher fine fraction concentration for a given screening process was also obtained when using hardwood pulp and refining the pulp prior to the screening process. A higher feed concentration also had a positive effect on the separation efficiency. Small holes and a smooth surface of the screen basket were also important to improve the separation efficiency. It was shown that, when used as a strength agent in a CTMP pulp, the fine fraction of highly refined kraft pulp was twice as efficient as the highly refined kraft pulp, when added at equal mass proportion. However, both in the lab and pilot trial the strength increase was accompanied by a decreased bulk. This was expected, and to avoid this the proportion of the bulky CTMP had to be increased. The pilot paper machine trial with an increased CTMP proportion in the middle ply and a fine fraction of refined kraft pulp as strength agent demonstrated that it was possible to produce sheets with an increased bulk and maintained z-strength. / Böjstyvheten är en viktig egenskap för alla sorters hårda förpackningar. I flerskiktskartong får man böjstyvhet genom att ha ytterskikt med hög dragstyvhet tillverkade av fibrer från kemisk massa och ett mittskikt med hög bulk från styva fibrer, ofta med en stor andel CTMP (kemitermomekanisk massa). CTMP-fibrer är styva men ger lägre styrka i arket. För att öka styrkan i mittskiktet tillsätter man utskott (kasserad kartong) som delvis innehåller kemisk massa, och ibland även ren högmald kemisk massa. Både fibrer och finmaterial (fines) har stor betydelse för slutproduktens egenskaper. Fines som skapas vid malning av kemisk massa är särskilt effektiva för att öka styrkan. Genom att fraktionera massa med en mikroperforerad sil kan man få en finfraktion med högt finesinnehåll. Mikroperforerade silar är effektiva för längdfraktionering av massa; fines anrikas i den fraktionen som passerar silen medan långa fibrer stannar i den andra fraktionen. Genom att använda en sådan finfraktion i mittskiktet kan man få tillräcklig styrka och samtidigt behålla mer av bulken från CTMP:n genom att man inte behöver mala den för att få styrka. En nackdel är att finfraktionen vanligtvis har väldigt låg masskoncentration eftersom mycket vatten passerar silen tillsammans med fines och fiberfragment. Detta extra vatten måste tas bort för att vattenbalansen i papperstillverkningsprocessen ska bibehållas. Dessutom kräver den större volymen ökad pumpkapacitet. För att kunna använda en finfraktion industriellt behövs en effektiv produktion med hög koncentration och högt finesinnehåll. Fokus i det här arbetet lades på separationseffektivitet (skillnaden i fiberlängdsfördelning som resultat av silningen) och processeffektivitet (koncentrationen i finfraktionen) för tillverkning av en finfraktion av kemisk massa genom silning samt dess utnyttjande som styrkehöjande tillsats i ett mittskikt av kartong. För att utvärdera hur separationseffektiviteten och processeffektiviteten påverkas av parametrar som koncentrationen i flödet in till silen, typ av kemisk massa (gjord av lövved eller barrved), hålstorlek i silen samt malningen av massan, gjordes fraktioneringsförsök i pilotskala med en trycksil med olika mikroperforerade silkorgar. Resultatet av fraktioneringen utvärderades med hjälp av fiberlängdsfördelningar, flöden och koncentrationer i flödet till silen och de två fraktionerna efter silen. För utvärderingen togs två olika utvärderingsmetoder fram: Proportion i finfraktionen (för processeffektivitet) och Finfraktionsanrikning (för x separationseffektivitet). För att utvärdera hur effektiv en finfraktion av kemisk massa var som styrkeadditiv i ett CTMP-ark gjordes labbförsök där tillsats av högmald kemisk massa jämfördes med tillsats av enbart en finfraktion av den högmalda kemiska massan. Resultaten verifierades med ett försök på en pilotpappersmaskin. I ett följande försök på pilotpappersmaskinen tillverkades ark med ökat CTMP-innehåll för att öka bulken, och med en tillsats av en finfraktion av kemisk massa som styrkeadditiv. När det gäller processeffektivitet var hög koncentration i flödet till silen den viktigaste parametern för att få hög koncentration på finfraktionen. Detta var också positivt för separationseffektiviteten, färre av de längre partiklarna hamnade i finfraktionen. Vidare blev finfraktionens koncentration högre för lövvedsmassa. En finfraktion som ska användas som styrkeadditiv ska vara tillverkad av mald massa, malning av massan var också fördelaktigt för finfraktionens koncentration. Små hål och en slät yta på silkorgen var också positivt för separationseffektiviteten. Som styrkeadditiv i CTMP var finfraktionen av högmald kemisk massa dubbelt så effektiv som den högmalda kemiska massan vid lika stor tillsats. Men i både labbförsök och pilotförsök minskade bulken när styrkan ökade. Det var väntat eftersom att ersätta en del av originalmassan som har hög bulk, med en finfraktion eller högmald massa, som båda har mycket lägre bulk, alltid minskar bulken på arket. För att undvika en bulkförlust måste massasammansättningen i arket ändras. Försöket på pilotpappersmaskinen med ökat CTMP innehåll och en finfraktion av mald kemisk massa som styrkeadditiv visade att det är möjligt att tillverka ett ark med högre bulk och bibehållen styrka.

This study evaluated the potential toxicity, genotoxicity, and cellular uptake of various sizes and concentrations of chitosan (CS) nanoparticles cultured with normal human dental pulp cells. Normal human dental pulp cells (hDPCs) were derived from human dental pulp tissues and cultured with (50–67) nm and (318–350) nm CS-nanoparticles in concentrations of 0.1 mg/mL, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, and 4 mg/mL as study groups and 0 mg/mL as a control group for time intervals of 16 hours, 24 hours, 3 days, 7 days and 14 days. Attachment efficiency and proliferation rate were assessed by measuring the optical density of crystal violet-stained cells. Cell viability was determined by the activity of mitochondrial dehydrogenase enzymes. Genotoxicity was assessed using the cytokinesis-block micronucleus method and by measuring the fluorescent intensity of phosphorylated H2AX nuclear foci. Cellular uptake was determined by tagging chitosan nanoparticles with FITC stain and then measuring the fluorescence intensity of FITC-tagged chitosan nanoparticles using a spectrophotometer. Statistical analysis was performed using chi-square, one-way ANOVA, and post-hoc Tukey tests. All concentrations of the (50–67) nm group significantly reduced attachment efficiency in comparison with control (P< 0.01) and with (318–350) nm group (p<0.01). Proliferation rate and cell viability were significantly reduced in cells exposed to various concentrations of (50-67) nm chitosan when compared to (318-350) nm group (P<0.05) and control group (P<0.05). For both size groups, higher concentrations significantly showed lower proliferation rate and cell viability when compared to lower concentration (P< 0.01). CS-nanoparticles were able to internalize hDPCs and significantly induced micronuclei, nuclear buds, and pH2AX at concentrations of 0.5 mg/mL and 2 mg/mL as compared to 0.1 mg/mL (P<0.01) and control groups (P< 0.01). At both the 0.5 mg/mL and 2 mg/mL concentrations, (50–67) nm chitosan significantly induced higher proportions of micronuclei (P= 0.001), nuclear buds (P= 0.009), and pH2AX nuclear foci (P= 0.00004) compared to (318–350) nm chitosan. In conclusion, CS-nanoparticles at sizes (50–67) nm and (318–350) nm at a concentration of (0.5–4) mg/mL internalized hDPCs and exhibited cytotoxic and genotoxic effects in dose-dependent and size-associated manners.

The characteristics of products made from pulp can be modified through different methods. If the pulp is refined either laboratory or industrially, the fibres in the pulp become more flexible and therefore creates stronger bonds to each other, which results in a final product with a higher strength. The refining process also causes the formation of small fibre pieces that are called fines, which also contribute to the increased strength. The major component in pulp is cellulose, which can be chemically modified to materials with changed properties. Periodate oxidation of cellulose results in dialdehyde cellulose that can be further reduced with sodium borohydride to obtain dialcohol cellulose, which is a material with a higher ductility compared to regular cellulose. In this thesis, different pulp compositions and their influence on the production of dialcohol cellulose (DALC) were investigated. The aim of the study was to find out how the ductility of paper sheets made from DALC were affected by the presence of fines in the pulp. Nine different pulp compositions were prepared for the modification: unrefined pulp, unrefined pulp with added fines, industrially refined pulp, dewatered industrially refined pulp, and pulp refined 1000, 3000, 5000, 10 000 and 15 000 revolutions with a PFI Mill. Paper sheets were made with a Rapid Köthen sheet former and the mechanical properties of the sheets were tested with a Zwick Roell tensile tester. The surface of the sheets were analyzed using a scanning electron microscope (SEM). The results obtained from the tensile tests showed that DALC made from unrefined pulp and DALC made from pulp highly refined with a PFI Mill, resulted in sheets with a high strain-at-break. For each increased degree of refining with the PFI Mill, the resulting DALC sheets showed an improved elongation and tensile strength. When DALC was produced from industrially refined pulp and from unrefined pulp with added fines, the resulting sheets had a lower strain-at-break. These findings indicate that the presence of fines in the pulp do have a negative effect on the ductility of the resulting DALC sheets.

Xylan is the main hemicellulose in birch, eucalyptus, and most other hardwood species. During kraft pulping a series of chemical reactions and physical processes involving xylan take place. The processes studied in this thesis are the following: dissolution, degradation, redeposition onto the fibres, side group conversion, and cleavage of side groups off the xylan back bone. The side group in native xylan consists of methylglucuronic acid, which is mainly converted into hexenuronic acid during kraft cooking. Hexenuronic acid affect the pulp in terms of increased brightness reversion and deteriorated bleachability. The kinetics of the side group cleavage and conversion reactions were analysed using various analytical tools. The study revealed that the most commonly used methods for methylglucuronic acid measurements are not as accurate as has been claimed in the literature. A modification of two of the methods was suggested and evaluated. A common practice used to minimise the hexenuronic acid content involves use of a high cooking temperature. The kinetic study showed that the degree of substitution of pulp xylan is only slightly affected by temperature, and that the observed effects are likely to be more associated with the xylan content of the pulp than with the hexenuronic acid content of the xylan. For the dissolved xylan, however, the degree of substitution showed a high temperature dependency and moreover it was always higher than in the pulp. Xylan itself is known to have the capacity to increase the strength of the manufactured pulp. This knowledge was applied by exchanging cooking liquors between birch kraft cooks, in which a high amount of xylan is dissolved, and spruce cooks, which contain very small amounts of native xylan. This seems like an attractive alternative for softwood kraft cooking, since both the tensile strength and stiffness increased significantly. The magnitude of the strength increase was correlated with the molecular weight of the added xylan and with the increased surface charge of the fibres. / QC 20101111

Graphic paper is experiencing severe competition from other materials and, most of all, from other media. This means there is a great need to improve paper quality while reducing raw material and production costs. Polyelectrolyte multilayer (PEM) treatment (i.e., consecutively adding cationic and anionic polyelectrolytes to the charged surface of wood fibres and fines, to form layers of these polyelectrolytes on the fibres/fines) has in recent years been found to offer great potential both to introduce new properties and to improve the mechanical properties of papers made of the treated fibres. The main objective of this thesis was to develop a strategy for the PEM treatment of cationic and anionic starch to improve the mechanical properties of paper made of thermomechanical pulp (TMP), since PEM treatment of fibres has displayed great potential to improve the mechanical properties of sheets made of chemical pulp. Mechanical pulp, however, has a large fine material content. Since the fine material is highly charged, polyelectrolyte consumption would be unacceptably high if the entire pulp were PEM treated, so we applied PEM treatment only to a fibre fraction of the pulps in most trials in the present work. The polyelectrolytes used for PEMs have so far mostly been well-defined, expensive ones unsuitable for use in standard paper grades; to develop a more economically realistic alternative, we used cationic and anionic starches. PEM formation on SiO2 surfaces from three differently charged cationic and anionic starches was first evaluated at three different salt levels using quartz crystal microbalance with dissipation (QCM-D) and stagnation point adsorption reflectometry (SPAR). The starch combinations displaying the highest potential for stable PEM formation at higher salt concentrations were then evaluated on an entire TMP pulp, as well as on a fraction of the pulp to reduce the amount of starch needed for PEM formation. The results indicate that it is possible to form PEMs from cationic and anionic starch on a SiO2 surface. The charge density, salt concentration, and combination of starches all influenced PEM formation. PEM formation on mechanical fibres produced large improvements in the mechanical properties of the sheets made of the treated fibres, and the tensile index, stretch-at-break, Z-strength, and Scott bond values all increased. Fractionating the pulp and PEM treating only a fraction of the pulp, the long fibre and middle fraction, produced large decreases in the amount of starch needed and large improvements in the mechanical properties of the sheets when no fine material was subsequently added. As untreated fine material was subsequently added, the improvement in mechanical properties decreased. PEM formation produced almost no reduction in formation and only a slight increase in sheet density. / Grafiskt papper är under hård konkurrens från andra material och, framför allt, andra media.  På grund av detta finns det ett stort behov av att förbättra papperskvalitén samtidigt som råmaterial- och produktionskostnader sänks. Polyelektrolyt-multiskikt (multiskikt) på massa (dvs. växelvis adsorption av katjoniska och anjoniska polyelektrolyter till träfibrer och finmaterial) har på senare år visat sig ha bra potential både för att ge nya egenskaper och för att förbättra de mekaniska egenskaperna hos papper gjorda av behandlad fiber. Huvudsyftet med denna avhandling var att utveckla en strategi för multiskiktsbehandling med katjonisk och anjonisk stärkelse för att förbättra de mekaniska egenskaperna hos papper gjort av behandlad termomekanisk massa (TMP). Multiskiktsbehandling av fiber har visat stor potential för att ge förbättrade mekaniska egenskaper till ark gjorda av behandlad kemisk massa. Mekanisk massa innehåller dock en stor andel högladdat finmaterial som kan öka mängden polyelektrolyt som krävs för multiskiktsbehandling, därför multiskiktsbehandlas bara en fraktion av massan i de flesta experiment i detta arbete. De polyelektrolyter som använts för multiskikt har hittills mest varit väldefinierade och dyra, och därmed opassande för användning i vanliga papperskvalitéer. För att utveckla ett mer realistiskt alternativ så användes katjonisk och anjonisk stärkelse i detta arbete. Multiskiktsuppbyggnad på SiO2-ytor av tre katjoniska och tre anjoniska stärkelser med olika laddningsdensitet utvärderades först vid tre olika saltnivåer genom att använda kvartskristal‑mikrogravimetri (QCM-D) och reflektometri (SPAR). Stärkelsekombinationerna som uppvisade störst potential för en stabil multiskiktsuppbyggnad på högre saltkoncentrationer blev sedan utvärderade på en hel TMP-massa, men även på en fraktion av massan för att minska mängden stärkelse som krävdes för multiskiktsuppbyggnad. Resultaten visar på att det är möjligt att bygga upp multiskikt av katjonisk och anjonisk stärkelse på en SiO2-yta. Laddningsdensiteten, saltkoncentrationen och kombinationen av stärkelser var faktorer som påverkade multiskiktsuppbyggnaden. Multiskiktsuppbyggnad på mekaniska fibrer gav stora förbättringar av de mekaniska egenskaperna hos ark gjorda av behandlad fiber, och dragindex, töjning, Z-styrka och Scott bond-värde ökade. Fraktionering av massan och multiskiktsbehandling av endast en del av massan, långfiber- och mellanfraktion, innebar att mycket mindre stärkelse behövdes och gav stora förbättringar av de mekaniska egenskaperna hos arken om inget obehandlat finmaterial tillsattes efteråt. Då obehandlat finmaterial tillsattes så blev förbättringarna hos de mekaniska egenskaperna mindre. Multiskitsuppbyggnad gav nästan ingen reduktion av formationen och endast en liten ökning i arkdensitet.

In the wish to replace oil-based chemicals and materials with such based on biodegradable and renewable resources, this work has been performed. In a biorefinary concept, waste birch bark from paper pulp mills and timber production has been evaluated as a potential source for polyesters.  In the present thesis investigations are made on synthesis of epoxy-functionalized polyesters from the birch outer bark aliphatic suberin ω-hydroxy fatty acid, cis-9,10-epoxy-18-hydroxyoctadecanoic acid. Studies of accessibility and reactivity of cellulose have been performed as a first step to enable covalent attachment or grafting of the epoxy-functionalized polyesters to cellulose.  Candida antarctica lipase B (Novozym 435) is reported to be an efficient catalyst for condensation polymerization of cis-9,10-epoxy-18-hydroxyoctadecanoic acid to form poly(9,10-epoxy-18-hydroxyoctadecanoic acid) with high molecular weight (Mw). Performed in toluene in the presence of molecular sieves a Mw of 20000 (reaction time 68 h, Mw/Mn 2.2) was obtained. Performed in bulk without any drying agent a Mw of 15000  was obtained at a much shorter reaction time (reaction time 3h, Mw/Mn 2.2). Further the same lipase has been used for succesful co-polymerizations of cis-9,10-epoxy-18-hydroxyoctadecanoic acid with lactones. By combining condensation and ring-opening polymerization, epoxy-functionalized linear polyesters and cyclic oligomers have been synthesized. For example, co-polymerization of cis-9,10-epoxy-18-hydroxy-octadecanoic acid and ε-caprolactone performed in toluene in the presence of molecular sieves gave mainly cyclic oligomers, especially at shorter reaction times. Co-polymerization performed in bulk gave linear polyesters with a Mw of 35000 (reaction time 24 h, Mw/Mn 6), irrespective molecular sieves were added or not.  The epoxy-functionalized polyesters could be used for surface modification of pulp fibres and cellulose fibrils, which further can be used for production of new valuable composite materials with improved features. Knowledge of how different processing conditions affect the structure of cellulose is an important tool in the work to achieve successful grafting of produced polyesters to cellulose fibres/fibrils. CP/MAS 13C-NMR spectroscopy has been used to study structural changes caused by the dissolving pulp process. An irreversible increase in average fibril aggregate width from raw pulp to final pulp during the process is shown. This increase in aggregate width could negatively influence the reactivity of the cellulose.